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Citrus fruits could help prevent obesity-related heart disease, liver disease, diabetes

Oranges and other citrus fruits are good for you — they contain plenty of vitamins and substances, such as antioxidants, that can help keep you healthy. Now a group of researchers reports that these fruits also help prevent harmful effects of obesity in mice fed a Western-style, high-fat diet.

The researchers are presenting their work today at the 252nd National Meeting & Exposition of the American Chemical Society (ACS).

“Our results indicate that in the future we can use citrus flavanones, a class of antioxidants, to prevent or delay chronic diseases caused by obesity in humans,” says Paula S. Ferreira, a graduate student with the research team.

More than one-third of all adults in the U.S. are obese, according to the U.S. Centers for Disease Control and Prevention. Being obese increases the risk of developing heart disease, liver disease and diabetes, most likely because of oxidative stress and inflammation, Ferreira says. When humans consume a high-fat diet, they accumulate fat in their bodies. Fat cells produce excessive reactive oxygen species, which can damage cells in a process called oxidative stress. The body can usually fight off the molecules with antioxidants. But obese patients have very enlarged fat cells, which can lead to even higher levels of reactive oxygen species that overwhelm the body’s ability to counteract them.

Citrus fruits contain large amounts of antioxidants, a class of which are called flavanones. Previous studies linked citrus flavanones to lowering oxidative stress in vitro and in animal models. These researchers wanted to observe the effects of citrus flavanones for the first time on mice with no genetic modifications and that were fed a high-fat diet.

The team, at Universidade Estadual Paulista (UNESP) in Brazil, conducted an experiment with 50 mice, treating them with flavanones found in oranges, limes and lemons. The flavanones they focused on were hesperidin, eriocitrin and eriodictyol. For one month, researchers gave groups either a standard diet, a high-fat diet, a high-fat diet plus hesperidin, a high-fat diet plus eriocitrin or a high-fat diet plus eriodictyol.

The high-fat diet without the flavanones increased the levels of cell-damage markers called thiobarbituric acid reactive substances (TBARS) by 80 percent in the blood and 57 percent in the liver compared to mice on a standard diet. But hesperidin, eriocitrin and eriodictyol decreased the TBARS levels in the liver by 50 percent, 57 percent and 64 percent, respectively, compared with mice fed a high-fat diet but not given flavanones. Eriocitrin and eriodictyol also reduced TBARS levels in the blood by 48 percent and 47 percent, respectively, in these mice. In addition, mice treated with hesperidin and eriodictyol had reduced fat accumulation and damage in the liver.

“Our studies did not show any weight loss due to the citrus flavanones,” says Thais B. Cesar, Ph.D., who leads the team. “However, even without helping the mice lose weight, they made them healthier with lower oxidative stress, less liver damage, lower blood lipids and lower blood glucose.”

Ferreira adds, “This study also suggests that consuming citrus fruits probably could have beneficial effects for people who are not obese, but have diets rich in fats, putting them at risk of developing cardiovascular disease, insulin resistance and abdominal obesity.”

Next, the team will explore how best to administer these flavanones, whether in citrus juice, by consuming the fruit or developing a pill with these antioxidants. In addition, the team plans to conduct studies involving humans, Cesar says.

Cesar acknowledges funding from the Support Program for Scientific Development of the School of Pharmaceutical Sciences at UNESP and by Citrosuco, an orange juice production company in Matão, Sao Paulo, Brazil.

https://www.sciencedaily.com/ Science Daily

https://www.sciencedaily.com/releases/2016/08/160821093054.htm  Original web page at Science Daily

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Scavenger crows provide public service, research shows

Crows are performing a useful function and keeping our environment free from rotting carcasses, research carried out at the University of Exeter in Cornwall has discovered.

Using motion activated cameras in and around Falmouth and the University’s Penryn Campus, Cornwall, ecologists observed what happened to experimental rat carcasses which they placed under view.

The researchers found that most of the carcass removal ecosystem service — which has been well studied in more natural and exotic habitats, such as vultures in Africa — is being carried out by crows, with a little help from foxes, magpies, badgers and herring gulls.

Dr Richard Inger, a researcher attached to the Environmental and Sustainability Institute at Penryn Campus, said: “If you consider all the wildlife that lives in the habitats in our towns and countryside, it might seem odd that we rarely see dead animals, apart from roadkill. This is because other animals act as scavengers and eat them.

“It’s a bit grizzly but crows and other scavengers, which are often perceived as pests and generally fairly unloved species, are performing a very valuable service. Without these scavengers dead animals would be scattered around our environment rotting and causing a hygiene hazard.”

The researchers observed and filmed 17 vertebrate species eating rat carcasses which they placed at 12 study sites between May and September 2015. Seven species including the Carrion Crow, the Common Buzzard, European Magpie, Herring Gull, Fox and Badger were recorded eating the carcasses, with 98 per cent of the activity carried out by the Crows.

Dr Inger highlighted the importance of the scavenger role and added: “We know what can happen when natural scavengers are removed as this was the case with the vulture populations of India, which plummeted massively in the 1990s. Vultures were fatally poisoned by a veterinary drug given to cattle, meaning that carcasses were not eaten by vultures but instead by feral dogs, which grew in numbers and caused a huge increase in cases of rabies.”

Professor Kevin J.Gaston, Director of the Environment and Sustainability Institute, and co-author on the paper, said: “It is vital that we understand the different ecological functions and services that organisms provide, if we are to value and manage them most appropriately. Sometimes, as in this case, it will be individual species that are especially important. In others it will be the diversity of species. In both cases, the level of function and service depends on having sufficient individuals thriving in the landscape.”

https://www.sciencedaily.com/ Science Daily

https://www.sciencedaily.com/releases/2016/07/160712110430.htm Original web page at Science Daily

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Red meat consumption linked with increased risk of developing kidney failure

A new study indicates that red meat intake may increase the risk of kidney failure in the general population, and substituting red meat with alternative sources of protein from time to time may significantly reduce this risk. The findings appear in an upcoming issue of the Journal of the American Society of Nephrology (JASN).

Increasing numbers of individuals are developing chronic kidney disease (CKD), and many progress to end-stage renal disease (ESRD), which requires dialysis or a kidney transplant. Current guidelines recommend restricting dietary protein intake to help manage CKD and slow progression to ESRD; however, there is limited evidence that overall dietary protein restriction or limiting specific food sources of protein intake may slow kidney function decline in the general population.

To examine the relationship between dietary intake of major sources of protein and kidney function, a team led by Woon-Puay Koh, MBBS (Hons), PhD (Duke-NUS Medical School and Saw Swee Hock School of Public Health in National University of Singapore) analyzed data from the Singapore Chinese Health Study, a prospective study of 63,257 Chinese adults in Singapore. This is a population where 97% of red meat intake consisted of pork. Other food sources of protein included poultry, fish/shellfish, eggs, dairy products, soy, and legumes.

After an average follow-up of 15.5 years, the researchers found that red meat intake was strongly associated with an increased risk of ESRD in a dose-dependent manner. People consuming the highest amounts (top 25%) of red meat had a 40% increased risk of developing ESRD compared with people consuming the lowest amounts (lowest 25%) No association was found with intakes of poultry, fish, eggs, or dairy products, while soy and legumes appeared to be slightly protective. Substituting one serving of red meat with other sources of protein reduced the risk of ESRD by up to 62%.

“We embarked on our study to see what advice should be given to CKD patients or to the general population worried about their kidney health regarding types or sources of protein intake,” said Dr. Koh. “Our findings suggest that these individuals can still maintain protein intake but consider switching to plant-based sources; however, if they still choose to eat meat, fish/shellfish and poultry are better alternatives to red meat.”

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/07/160714193627.htm  Original web page at Science Daily

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Beware of antioxidant supplements, warns scientific review

The lay press and thousands of nutritional products warn of oxygen radicals or oxidative stress and suggest taking so-called antioxidants to prevent or cure disease. Professor Pietro Ghezzi at the Brighton and Sussex Medical School and Professor Harald Schmidt at the University of Maastricht have analyzed the evidence behind this. The result is a clear warning: do not take these supplements unless a clear deficiency is diagnosed by a healthcare professional.

Humans depend on oxygen to produce energy, but oxygen also has the potential to generate so-called oxygen radicals, which may cause oxidative stress and disease. Markers of oxidative stress have been correlated with cardiovascular disease, cancer, diabetes, and other conditions. Because of these associations, antioxidant supplements are taken by millions of people; however, none of the antioxidants tested in randomized clinical trials have demonstrated any benefit. On the contrary, some of them may cause harm.

This is because oxygen radicals not only trigger disease but also perform many important functions in the body, such as for immune defense and hormone synthesis. Thus anti-oxidants will interfere with both healthy and disease-triggering oxygen molecules.

“Oxidative stress could be important in some conditions and only in a small proportion of patients,” said Prof. Ghezzi. “It can be targeted in a totally different manner, with drugs targeted only at those sources of oxygen molecules that are triggers of disease and leave the healthy ones alone,” added Prof. Schmidt. The review is published the British Journal of Pharmacology.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/07/160719094130.htm  Original web page at Science Daily

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Diet lacking in zinc is detrimental to human, animal health

The trace element zinc has an impact on the essential metabolic functions of most living organisms. New research carried out by the Chair of Animal Nutrition at the Technical University of Munich (TUM) has found that even minimal zinc deficiency impairs digestion, albeit without any typical symptoms such as skin problems or fatigue. Hence, short-term zinc deficiency in the diet should be avoided.

The test series established that even slight zinc deficiency in an animal’s diet impedes pancreatic digestive activity and results in significant digestive impairment, even at an early stage. The study undertaken by Daniel Brugger of the Chair of Animal Nutrition at TUM was recently published in the British Journal of Nutrition.

Scientist Brugger charted a new path since all previous studies had compared the functions of animals with clinical zinc deficiency to those of animals that had adequate amounts of this trace element in their bodies. “It is important to note that, in nature, clinical zinc deficiency does not really occur, neither in animals nor in humans,” explains lead author Brugger. Hence, Brugger carried out his study on animals with short-term or subclinical zinc deficiency. As the trace element only exists in small amounts in an organism, it has to be consumed by way of nutrition. In piglets, for instance, a clinical or manifest zinc deficiency can — under feeding conditions applied in practice — only be achieved after about ten days, explains the TUM scientist. This is why he ended his test series early, after just eight days.

The unnoticed start of zinc depletion occurs without any visible symptoms, but minute changes can be identified in the liver and in the blood. For the purpose of this study, piglets which had just been weaned were fed a diet containing different amounts of zinc to develop early-stage zinc deficiency. This was the only way for the scientists to trace and analyze what effects dwindling zinc deposits would have on the animals’ metabolisms. On one hand, it was observed that the body tried to absorb zinc more efficiently, while on the other, it reduced pancreatic zinc excretion. Since clinical zinc deficiency reduces the test animals’ appetite, “various hypotheses were derived, for example, that zinc deficiency had a direct impact on the vagus nerve. The real reason, however, may be much simpler: the accumulation of undigested food inside the gastrointestinal tract due to zinc deficiency results in feeling less hungry,” says Brugger.

The pancreas is the control center for food digestion and energy homeostasis in the body. It pumps zinc into the gastrointestinal tract in order to maintain a consistent zinc level. Conversely, if an organism is depleted of zinc, it reduces its pancreatic zinc excretion to a minimum. The starting point for Daniel Brugger’s study was the hypothesis that this mechanism may be related to digestion.

Feed digestion is of enormous importance for growing livestock and especially the first few weeks after young animals are weaned from their mothers are of crucial importance. This is a factor that must not be underestimated by farmers.

“We proved that there is a direct correlation between the amount of digestive enzymes inside the pancreas and zinc levels in the organism as a whole,” explains Brugger. “Even short intervals of zinc deficiency in the diet should therefore be avoided. Given the similarities between a pig’s organism and the human organism, we may draw the following conclusion when applying our results to the human body: an egg or two more once in a while can do no harm.” Brugger advises vegans, vegetarians and older people to monitor their zinc intake. Among other things, a subclinical zinc deficiency in humans has been attributed to increased levels of inflammation markers and reduced immunocompetence.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/06/160609115127.htm Original web page at Science Daily

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How do some birds get such bright red feathers?

In the bird world, the color red has special significance. Many species use red signals to attract mates or deter rivals, adding the color to their beaks, feathers, or bare skin. Generally speaking, as far as many birds are concerned, redder is better. Now, two teams of researchers have independently identified an enzyme-encoding gene that allows some bird species to convert yellow pigments from their diets into that remarkable red. Their findings are reported on May 19 in Current Biology.

“To produce red feathers, birds convert yellow dietary pigments known as carotenoids into red pigments and then deposit them in the feathers,” says Miguel Carneiro of Universidade do Porto in Portugal. “Birds also accumulate these same red pigments in one of the cone photoreceptor types in their retina to enhance color vision. We discovered a gene that codes for an enzyme that enables this yellow-to-red conversion in birds.”

“It was known that some birds have the ability to synthesize red ketocarotenoids from the yellow carotenoids that they obtain in their diet, but the gene or enzyme involved, and its anatomical location, have been obscure,” adds Nick Mundy of the University of Cambridge. “Our findings fill this gap and open up many future avenues for research on the evolution and ecology of red coloration in birds.”

Carneiro’s team, including Joseph Corbo of Washington University School of Medicine in St. Louis and Geoffrey Hill of Auburn University, made their discovery thanks to canary fanciers who crossed a yellow canary with a red siskin almost 100 years ago, producing the world’s first red canary. In the new study, the researchers compared the genome sequences of yellow and red canaries to red siskins in search of the gene responsible for the birds’ color differences.

Their search led them to a cytochrome P450 enzyme, dubbed CYP2J19. Further analysis of the gene’s expression showed that the enzyme is expressed at high levels in the skin and liver of red factor canaries, strongly implicating it as the enzyme responsible for red coloration.

In the other report, Mundy and colleagues, including Staffan Andersson of the University of Gothenburg, and Jessica Stapley of the University of Sheffield, found their way to the cytochrome P450 gene cluster through comparisons of standard zebra finches, which have a distinctive red beak, and mutant zebra finches with yellow beaks. Zebra finches have three related cytochrome P450 genes, and the researchers found multiple mutations in this genetic region in the yellowbeak birds. They further found that the enzyme was expressed in almost undetectable levels in the birds’ yellow beaks.

The genetic findings pave the way for new kinds of studies on the red coloration of birds, according to the researchers. They also raise many new and intriguing questions. For example, the gene now identified belongs to a family of genes known to play an important role in detoxification.

“In sexual selection, red color is thought to signal individual quality and one way it can do this is if the type or amount of pigmentation is related to other physiological processes, like detoxification,” Andersson says. “Our results, which link a detoxification gene to carotenoid metabolism, may shed new light on the debated honesty of carotenoid-based signals.”

Corbo says one thing that came as a particular surprise to them was the discovery that the “redness gene” is present in the genomes of many, if not most, bird species, not just those with red feathers.

“Diurnal birds appear to use this gene to produce red pigments in the retina to enhance color vision,” Corbo says. “However, only birds with red feathers additionally express the gene in their skin. These findings suggest that nearly all birds have the latent capacity to make red feathers, but in order to actually do so, they must evolve the means of expressing this gene in the skin in addition to the retina.”

Mundy and Andersson are now returning to the birds where their search for the “red-maker” once began, the African widowbirds and bishops, which show “spectacular differences among different species.” Most intriguingly, Andersson adds, “dazzling red colors have evolved repeatedly in this group, mostly by the mechanism described here, but there are some very interesting exceptions.”

Corbo and colleagues also plan to explore red feathers in many more bird species, to see whether they rely on the same or different mechanisms. They say they also will continue using the canary as a model for uncovering the genetic basis of other interesting traits in birds.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/05/160519130102.htm  Original web page at Science Daily

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Don’t feed the monkeys: Why your generosity is harming their health

Tourists who feed wild monkeys in Morocco are risking the health of an endangered species by making them larger, more susceptible to disease, and more stressed, according to new research.

Behavioral ecologists compared the health of two groups of wild Barbary macaques in Ifrane National Park in the Atlas Mountains, Morocco; one which spent nearly 50 per cent of their feeding activity eating food provided by humans, and another which rarely encounter tourists and instead relied on natural food resources.

The macaques which ate food from tourists were found to have poorer quality fur, with some patches of alopecia, and also suffered from higher levels of stress hormones compared with the other group.

All the females in the non-fed group gave birth, but only a third of females in the groups of Barbary macaques frequently fed by tourists had babies. The monkeys which relied on natural food were observed to only suffer one incident of a stomach upset, while the group which received large amounts of food from tourists had 32 bouts of illness.

The study also found that the effects of feeding by tourists were different depending on sex; while males did not differ between groups in body size and fur quality, the females fed by tourists had larger body sizes, but better coat quality. However, the males suffered more from alopecia and higher stress levels. The findings are published in the journal, PLOS ONE.

The study was led by Dr Laëtitia Maréchal as part of her PhD at the University of Roehampton. Dr Maréchal, now a post-doctoral fellow in the School of Psychology, University of Lincoln, UK, said: “Barbary macaques are an endangered species and recently tourism was proposed as a potential tool for the conservation of this species in Morocco. But such tourism is currently unregulated, and feeding is a common practice; therefore regulating tourist provisioning may improve animal welfare.

“We assessed the primates’ health using a range of non-invasive measures, such as birth and survival rates, the quality of their fur, body size, occurrence of injury and disease, and stress hormone levels in fecal samples. Our findings support previous research which indicates that wildlife tourism, and particularly so-called ‘tourist provisioning’, has negative impacts on the health of wild animals.

“The study suggests that measures need to be taken to avoid causing more harm to an already endangered species. We are confident that changes will soon be made to regulate wildlife tourism in Morocco, as the Moroccan authorities and the local community have supported our study. Now tourists who encounter wildlife need to be informed that feeding wild animals is harmful, and so they should not do it.”

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/05/160520142955.htm Original web page at Science Daily

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How Arctic spring kills birds in Africa

Red knot birds are becoming smaller as temperatures warm in their Arctic breeding grounds. But the migrating birds don’t pay the price for this climate-caused shrinkage until they arrive at the more stable climate of their tropical winter homes. Having analyzed the data collected for more than three decades, scientists managed to show that the effects of climate changes in the Arctic may come out on a completely different continent, a few thousand kilometers away from the Arctic ice.

One of the authors, Eldar Rahimberdiev, researcher at the Biological faculty of MSU, says that the work is unique, as earlier scholars did not consider these problems so complex.

This article considers a small bird of the suborder waders — red knot (Calidris canutus). This bright red in summer and almost white in winter bird is one of a record-breakers for distance flight, being able to cover about 5000 kilometers non-stop. Every year in the autumn it flies to winter at the coast of Mauritania (or, depending on the subspecies, Australia or South America), and in the spring returns to breed on Taimyr peninsula — the northernmost mainland of Eurasia (or, again, depending on the subspecies, Greenland, Alaska and the Canadian Arctic archipelago). And then the bird has another record, choosing the most northern and cold nesting latitudes. The arrival of the red knots to these severe lands was “calculated” by evolution so that the birth of the chicks happens just at the peak of abundance of insects, their main food.

But that was before the global warming has seriously changed the lives of the birds within a few decades. These changes are described in the new article. At the disposal of the researchers was a data archive for 33 years, which included complete measurement by Polish scientists on the morphology changes in 1990 juvenile birds who committed intermediate stops in Poland within this period, and satellite images of the Taimyr Peninsula and the results of the Dutch zoologists’ observations on the birds at the coasts of Mauritania.

During these 30 years the arrival of spring on the Taimyr Peninsula, and the peak of the insect population moved for almost two weeks earlier in time. If the snow on the peninsula disappeared by the middle of July in the past, it is gone now at the end of June. Arrival dates of birds stayed stable, but phenologically birds begin to nest later than 30 years ago, and miss the peak of insect abundance essential for juvenile growth. The lack of food has caused a decrease in the size of the young birds, which is impossible be compensated later in life. However, at first glance, the problems for birds did not increase: with the arrival of cold weather, young red knots still go to their long journey and still successfully get to Africa, preparing to spend the whole winter there, and fly back only in spring. But the real difficulties come further. During the winter in the Banc d’Arguin National Park in Mauritania, red knots eat bivalve mollusks hiding in the sediment, and they need quite a long bill for reaching this food. Birds with long beaks often diversify their diet with Loripes lucinalis, burrowing deep enough into the sand. Even though that shellfish produces a toxin in their body, in a birds’ diet its proportion may be up to 40%. Red knots with a shorter bill reach another food source — Dosinia isocardia, and those not lucky with the length of the beak are to be fed with plant food — small rhizomes of Zostera (Zostera noltii). Survival rate of the birds that are not able to get to mollusks Loripes was significantly lower than those which were not restricted in their diet.

Dietary restrictions imposed on too short-beak birds particularly impact the young birds, most of them are unable to survive their first winter. Thus, the consequences of the problem that occurred in the Arctic act in a few months, and moreover — on another continent. If the knot still manages to fly back on the Taimyr Peninsula, a short break even helps — to hunt insects is much easier than with a long one. But, as practice shows, the birds hardly survive in Africa.

According to Eldar Rahimberdiev, researcher of the biological faculty of the Lomonosov MSU, the threat of extinction is more than real for red knots. Now populations of all northern waders greatly decreases, some subspecies are already on the edge of extinction. If the bird’s bill is reduced to such an extent that they will not manage at all to get shellfish, the species will simply disappear. Moreover, many birds of the population are already close to the critical point, when any random fluctuations of numbers can destroy the population.

The work of scientists is unique, as the authors have shown that the transfer of the appeared problem is possible only in time but also in space. Earlier the articles of such level did not appear in Science magazines, and scientists, according to Eldar Rahimberdiev, rarely paid attention to the whole annual cycle.

‘When I was a student and worked with the same species, we were always arguing with foreign colleagues, who said that the birds die because the problems occur during migration. We thought that the problem was at the breeding grounds. And those who worked on the wintering grounds in Africa, argued that there is no problem in Africa. Now it becomes clear that all these parts are interconnected and a sharp change in any part leads to unexpected consequences,’ the scientist says.

https://www.sciencedaily.com/  Science Daily

https://www.sciencedaily.com/releases/2016/05/160512145457.htm Original web page at Science Daily

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Food limitation linked to record California sea lion pup strandings

Large numbers of California sea lion pups have flooded animal rescue centers in Southern California in the past few years. Now, as part of an ongoing investigation into the Unusual Mortality Event of California sea lions by a team of NOAA scientists and private partners, researchers may have an explanation.

Booming sea lion numbers combined with declines in the highest-calorie prey around the Channel Islands breeding rookeries have left nursing females struggling to support the nutritional needs of their pups, according to a new study published today in Royal Society Open Science.

The study by NOAA Fisheries scientists is the first to analyze changes in fish populations sea lions prey on for clues as to what is causing the record strandings. Scientists examined changes in the abundance of four of the main prey species: sardine, anchovy, rockfish and market squid over the 2004-2014 time period. They found that that high-calorie sardines and anchovies, both rich in fat that is vital to the growth of young sea lions, have declined since the mid-2000s in the areas around the Channel Islands where the females forage. That has forced the female sea lions to prey instead on market squid and rockfish, which contain far less fat and fewer calories.

“When you have hundreds of thousands of animals to feed and you have a fluctuating prey base that has trended downward, you are going to have starving animals,” said Sam McClatchie of NOAA Fisheries’ Southwest Fisheries Science Center in La Jolla, Calif., and lead author of the new research. “Sardines and anchovies have both trended downward, and that compounds the problem for the sea lions.”

The scientists did not study how changes in fish species affect the composition and quality of milk that mother sea lions feed their pups, which affects the growth of the pups. However, the close correlation between the fish available and the weight of sea lion pups provides “compelling evidence of a food limitation effect on the weight of dependent pups,” the scientists wrote. The trends in the relative abundance of forage taxa highlight a decade-long decline in the availability and quality of forage for sea lions.

Nature, in effect, has put the sea lions on a low-calorie diet. Market squid, for instance, contain less than half the calories and about one-tenth the fat content by weight compared to sardines. While adult males and females without pups can survive on a low calorie diet, lactating females and their dependent pups seem to be sensitive to reductions in high calorie prey. The results build on earlier studies at San Miguel Island that showed pup weights decrease during El Niño events and when female diet, as determined from scat analysis, was predominantly squid and rockfish.

The long-term and widespread nature of the changes in prey suggest that environmental shifts are driving them, the researchers concluded. Although sardines have been subject to limited fishing pressure, anchovies were much more lightly fished prior to 2013; yet both populations have declined.

“The overall driver appears to be the natural fluctuations in fish populations,” McClatchie said. “They do fluctuate up and down over time, and since 2004, they’re doing it in phase.”

The changes in prey were documented by Southwest Fisheries Science Center surveys off the California Coast, which sample the composition of fish species. Changes in pup condition were collected by the Alaska Fisheries Science Center, Marine Mammal Laboratory.

Sea lions are not endangered but are protected by the 1972 Marine Mammal Protection Act. Their population has grown from about 50,000 to over 300,000 in the last 40 years, and is expected to ultimately fluctuate around a still-unknown carrying capacity, the researchers said. The carrying capacity would be expected to vary with climate and ocean conditions.”Given the likelihood that the California sea lion population is approaching carrying capacity, density-dependent effects such as food limitation (and stranding) of pups may be a long-term consequence of a rebuilt sea lion population during periods of low abundance of high-quality forage,” the scientists wrote.

Sea lions have faced similar declines in sardines and anchovies during previous El Niño conditions, but the shifts are not limited only to El Niño periods, the researchers found. The latest spike in sea lion strandings began before the current El Niño pattern took hold, and before the large expanse of warm water known as “the blob” began dominating West Coast Waters in 2014.

The results refocus the debate on the causes of sea lion pup weight loss from episodic stresses associated with El Niño years to a decadal-long trend of declining forage quality in the waters around the California Channel Island rookeries, the researchers wrote. The large areas where surveys documented declines in sardine and anchovy and increases in market squid and rockfish suggests that the drivers for this decadal trend is environmental. Both the warm blob and El Niño events may continue to disrupt historical spawning times and locations of sardine and anchovy populations. It is unknown how long low-quality forage abundance will persist. Recently completed NOAA Fisheries surveys suggest that while both sardine and anchovy populations have trended downward in recent years, the 2015 numbers of anchovy larvae appear to be stronger than in the past 10 years along portions of the U.S. West Coast. Sardines, which normally spawn off central California in spring, last year spawned off Oregon. However, there is uncertainty, whether the young anchovies and sardines that were observed will successfully mature into the adult populations.

NOAA Fisheries surveys and stock assessments continue to track the status of sardine, anchovy and other coastal pelagic species, while monitoring the health and abundance of sea lion populations, to provide data for the public and effective management of these species in changing ocean conditions.

https://www.sciencedaily.com/ Science Daily

https://www.sciencedaily.com/releases/2016/03/160303094054.htm  Original web page at Science Daily

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Food limitation linked to record California sea lion pup strandings

Large numbers of California sea lion pups have flooded animal rescue centers in Southern California in the past few years. Now, as part of an ongoing investigation into the Unusual Mortality Event of California sea lions by a team of NOAA scientists and private partners, researchers may have an explanation.

Booming sea lion numbers combined with declines in the highest-calorie prey around the Channel Islands breeding rookeries have left nursing females struggling to support the nutritional needs of their pups, according to a new study published today in Royal Society Open Science.

The study by NOAA Fisheries scientists is the first to analyze changes in fish populations sea lions prey on for clues as to what is causing the record strandings. Scientists examined changes in the abundance of four of the main prey species: sardine, anchovy, rockfish and market squid over the 2004-2014 time period. They found that that high-calorie sardines and anchovies, both rich in fat that is vital to the growth of young sea lions, have declined since the mid-2000s in the areas around the Channel Islands where the females forage. That has forced the female sea lions to prey instead on market squid and rockfish, which contain far less fat and fewer calories.

“When you have hundreds of thousands of animals to feed and you have a fluctuating prey base that has trended downward, you are going to have starving animals,” said Sam McClatchie of NOAA Fisheries’ Southwest Fisheries Science Center in La Jolla, Calif., and lead author of the new research. “Sardines and anchovies have both trended downward, and that compounds the problem for the sea lions.”

The scientists did not study how changes in fish species affect the composition and quality of milk that mother sea lions feed their pups, which affects the growth of the pups. However, the close correlation between the fish available and the weight of sea lion pups provides “compelling evidence of a food limitation effect on the weight of dependent pups,” the scientists wrote. The trends in the relative abundance of forage taxa highlight a decade-long decline in the availability and quality of forage for sea lions.

Nature, in effect, has put the sea lions on a low-calorie diet. Market squid, for instance, contain less than half the calories and about one-tenth the fat content by weight compared to sardines. While adult males and females without pups can survive on a low calorie diet, lactating females and their dependent pups seem to be sensitive to reductions in high calorie prey. The results build on earlier studies at San Miguel Island that showed pup weights decrease during El Niño events and when female diet, as determined from scat analysis, was predominantly squid and rockfish.

The long-term and widespread nature of the changes in prey suggest that environmental shifts are driving them, the researchers concluded. Although sardines have been subject to limited fishing pressure, anchovies were much more lightly fished prior to 2013; yet both populations have declined.

“The overall driver appears to be the natural fluctuations in fish populations,” McClatchie said. “They do fluctuate up and down over time, and since 2004, they’re doing it in phase.

The changes in prey were documented by Southwest Fisheries Science Center surveys off the California Coast, which sample the composition of fish species. Changes in pup condition were collected by the Alaska Fisheries Science Center, Marine Mammal Laboratory.

Sea lions are not endangered but are protected by the 1972 Marine Mammal Protection Act. Their population has grown from about 50,000 to over 300,000 in the last 40 years, and is expected to ultimately fluctuate around a still-unknown carrying capacity, the researchers said. The carrying capacity would be expected to vary with climate and ocean conditions.”Given the likelihood that the California sea lion population is approaching carrying capacity, density-dependent effects such as food limitation (and stranding) of pups may be a long-term consequence of a rebuilt sea lion population during periods of low abundance of high-quality forage,” the scientists wrote.

Sea lions have faced similar declines in sardines and anchovies during previous El Niño conditions, but the shifts are not limited only to El Niño periods, the researchers found. The latest spike in sea lion strandings began before the current El Niño pattern took hold, and before the large expanse of warm water known as “the blob” began dominating West Coast Waters in 2014.

The results refocus the debate on the causes of sea lion pup weight loss from episodic stresses associated with El Niño years to a decadal-long trend of declining forage quality in the waters around the California Channel Island rookeries, the researchers wrote. The large areas where surveys documented declines in sardine and anchovy and increases in market squid and rockfish suggests that the drivers for this decadal trend is environmental. Both the warm blob and El Niño events may continue to disrupt historical spawning times and locations of sardine and anchovy populations. It is unknown how long low-quality forage abundance will persist. Recently completed NOAA Fisheries surveys suggest that while both sardine and anchovy populations have trended downward in recent years, the 2015 numbers of anchovy larvae appear to be stronger than in the past 10 years along portions of the U.S. West Coast. Sardines, which normally spawn off central California in spring, last year spawned off Oregon. However, there is uncertainty, whether the young anchovies and sardines that were observed will successfully mature into the adult populations.

NOAA Fisheries surveys and stock assessments continue to track the status of sardine, anchovy and other coastal pelagic species, while monitoring the health and abundance of sea lion populations, to provide data for the public and effective management of these species in changing ocean conditions.

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https://www.sciencedaily.com/releases/2016/03/160303094054.htm  Original web page at Science Daily

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To find energy-rich food, like tropical ripe fruit, is a challenge for chimpanzees

In our supermarkets we buy raspberries in winter and chestnuts in summer. But how challenging would life become, if we needed to consume large amounts of fruit for our daily meal and had to collect them ourselves? With a largely plant-based diet, simple stomachs, and the additional cost of maintaining relatively large brains, chimpanzees face a serious challenge in their daily search for energy and nutrients. Using data on the monthly availability of young leaves, unripe and ripe fruits in three tropical rain forests in East, Central and West Africa, a consortium of researchers of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, Harvard University, McGill University, the University of St. Andrews and the Université Félix Houphouët Boigny, estimated how difficult it is for chimpanzees to find food and to predict its availability in individual trees. This study reports which cognitive strategies chimpanzees can use to gain privileged access to the most energy-rich but ephemeral food.

Tropical forest habitats and their distribution have a major impact on primate evolution, since the majority of primate species and all great apes forage on food produced by tropical forest trees. Given their lack of specialized morphological and physiological dietary adaptations, great apes are, in contrast to many old world monkeys, unable to digest chemically defended forest foods such as many mature leaves and certain seeds. This increases their reliance on the consumption of energy-rich food, such as young leaves or ripe fruit, when they are available. A low percentage of ripe fruit in the diet has negative effects on female reproductive physiology, including conception, and other life history traits.

Karline Janmaat of the Max Planck Institute for Evolutionary Anthropology and her colleagues merged three sets of long-term data collected from three tropical rain forests located in East, Central, and West Africa spanning from five to 20 years and investigated the temporal fruiting patterns of rain forest trees. The researchers quantified how difficult it is for chimpanzees to find energy-rich young leaves, unripe and ripe fruit and, in particular, large ripe fruit crops in individual trees. Their study revealed a chimpanzee’s challenge is not so much to find food plants, since they are surprisingly abundant, but to find those that actually produce food. Calculations revealed that chimpanzees were 17 times more challenged to find ripe fruit, the most energy-rich food source, than unripe fruit. Moreover, trees with large crops of ripe fruit were at least nine times scarcer than other trees: in pristine forests only one large ripe fruit crop was encountered every 10 kilometers of straight-line travel, on average. In fruit scarce months no such trees were encountered.

“When I saw chimpanzees outrun others to reach feeding trees and leave their nests before sunrise to reach high-energy fruit, I realized that the persistent idea of abundance created by giant fruit trees and lush foliage was an illusion,” says Janmaat. “This unique collaboration has finally enabled us to provide evidence that explains the chimpanzees’ intriguing monitoring behaviors and to develop well-grounded hypotheses that test how clever chimpanzees are compared to other primates with less complex or smaller brains.”

Furthermore, Janmaat and colleagues found that individual trees varied tremendously in their productive output; in some extreme cases individuals bore ripe fruit more than seven times as often as other trees of the same species. Moreover, the duration during which individual trees carried more than 50 percent of ripe fruit varied widely: In the case of Sarcocephalus pobeguinii in the Taï forest, one tree produced more than half of its maximal crop during four in 53 months, while another produced only small amounts of fruit (all scores less than 50 percent) during the same 53 months. Considering that some species showed much more variation than others, the researchers think it to be likely that chimpanzees have a species-specific knowledge of fruit production histories of some individual trees. This knowledge might help them to avoid travelling towards trees that are likely empty and to optimize monitoring times.

“The sounds of the field team calling out the data leaves an impression: ‘Young leaves: zero. Immature fruit: zero. Ripe fruit: zero.’ While a preponderance of zeros poses challenges to statistical ecologists, the challenges to those who must rely on obtaining large amounts of fruit for survival are much more consequential,” says co-author Leo Polansky.

To buffer periods of food scarcity some chimpanzees use tools to crack energy rich nuts or to extract honey from underground bee nests. The results of this study indicate that there may be another way to maximize their energy intake, namely by employing a suite of cognitive mechanisms that enable them to outcompete other animals in exploiting easily accessible energy-rich and ephemeral foods, such as ripe fruit. This suite can include abilities to generalize or classify food trees, remember the relative metrics of quantity and frequency of fruit production across years, and flexibly plan return times to feeding trees to optimize high-energy food consumption in individual trees, and efficient travel between them.

“Traditionally we have been thinking that the life in the savannah is hard and that therefore our ancestors needed to become intelligent when they left the forest. Now, this view did not concur with the intelligence we see in our closest living cousin, the chimpanzees. This new study shows convincingly that the challenge of finding ripe fruit can be more demanding in the forest then we have thought before,” says Christophe Boesch, director of the Department of Primatology at the Max Planck Institute for Evolutionary Anthropology.

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http://www.sciencedaily.com/releases/2016/01/160128133350.htm  Original web page at Science Daily

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To feed or not to feed: Researchers engage citizen scientists in reducing bird-window collisions

Getting in touch with nature in an urbanized world can be as simple as putting a bird feeder in your backyard. However, what are the potential consequences of this act? Bird-window collisions are one of the largest threats facing urban bird populations in Canada. A new study out of the University of Alberta engages citizen scientists to determine the effects of feeders on bird-window collisions.

Despite the popularity of feeding wild birds, the effects of bird feeders and year-round feeding on birds have not been well documented, particularly in relationship to bird-window collisions. “Backyard bird feeders create an important link between humans and nature,” says Justine Kummer, a graduate student at the University of Alberta and lead author of the study, the first ever to manipulate bird feeders at actual residential houses. “Improving the relationship between the general public and nature can promote biodiversity and conservation. We are working to find successful ways to reduce bird-window collisions, beneficial not only for birds but also for the millions of people who feed them.”

In Canada, it is estimated that up to 42 million birds die each year from collisions with windows, with residential homes accounting for 90% of building-related mortality. Trials were conducted on 55 windows at 43 residences in Edmonton and the surrounding area. Homeowners were asked to search their study window daily for evidence of bird-window collisions. Though there were 94 reported collisions with the presence of a bird feeder, there were also 51 collisions in cases when no feeder was present, meaning there is no black and white answer. Twenty-six of the windows never experienced a collision during the study, showing that some houses are more at risk than others, regardless of the presence of the feeder.

“We’ve determined that the presence of a bird feeder does indicate collision risk, but there are other factors involved,” says Kummer. She notes that vegetation and house characteristics can also influence whether a residence is likely to have a large number of collisions. “The general public enjoys feeding birds in their yard, but they want to know how to do so safely. Homeowners can certainly reduce some window collision risk by altering feeder placement.”

The study builds on previous work at the University of Alberta, well known for its conservation and biodiversity efforts. The paper was co-authored by Kummer’s graduate supervisor Erin Bayne, associate professor in biological sciences at the University of Alberta. Bayne’s research team focuses on understanding the cumulative ecological impacts of human activities on biodiversity.

The findings, “Bird feeders and their effects on bird-window collisions at residential houses,” were published this fall in the journal Avian Conservation and Ecology.

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http://www.sciencedaily.com/releases/2015/11/151119211432.htm  Original web page at Science Daily

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Blood sugar levels in response to foods are highly individual

Which is more likely to raise blood sugar levels: sushi or ice cream? According to a Weizmann Institute of Science study reported in the November 19 issue of the journal Cell, the answer varies from one person to another. The study, which continuously monitored blood sugar levels in 800 people for a week, revealed that the bodily response to all foods was highly individual.

The study, called the Personalized Nutrition Project, was conducted by the groups of Prof. Eran Segal of the Department of Computer Science and Applied Mathematics and Dr. Eran Elinav of the Department of Immunology. Prof. Segal said: “We chose to focus on blood sugar because elevated levels are a major risk factor for diabetes, obesity, and metabolic syndrome. The huge differences that we found in the rise of blood sugar levels among different people who consumed identical meals highlights why personalized eating choices are more likely to help people stay healthy than universal dietary advice.”

Indeed, the scientists found that different people responded very differently to both simple and complex meals. For example, a large number of the participants’ blood sugar levels rose sharply after they consumed a standardized glucose meal, but in many others, blood glucose levels rose sharply after they ate white bread, but not after glucose. “Our aim in this study was to find factors that underlie personalized blood glucose responses to food,” said Dr. Elinav. “We used that information to develop personal dietary recommendations that can help prevent and treat obesity and diabetes, which are among the most severe epidemics in human history.”

David Zeevi and Tal Korem, PhD students in Prof. Segal’s lab, led the study. They collaborated with Dr. Niv Zmora, a physician conducting PhD studies in Dr. Elinav’s lab, and with PhD student Daphna Rothschild and research associate Dr. Adina Weinberger from Prof. Segal’s lab. The study was unique in its scale and in the inclusion of the analysis of gut microbes, collectively known as the microbiome, which had recently been shown to play an important role in human health and disease. Study participants were outfitted with small monitors that continuously measured their blood sugar levels and were asked to record everything they ate, as well as such lifestyle factors as sleep and physical activity. Overall, the researchers assessed the responses of different people to more than 46,000 meals.

Taking these multiple factors into account, the scientists generated an algorithm for predicting individualized response to food based on the person’s lifestyle, medical background, and the composition and function of his or her microbiome. In a follow-up study of another 100 volunteers, the algorithm successfully predicted the rise in blood sugar in response to different foods, demonstrating that it could be applied to new participants. The scientists were able to show that lifestyle also mattered: The same food affected blood sugar levels differently in the same person, depending, for example, on whether its consumption had been preceded by exercise or sleep.

In the final stage of the study, the scientists designed a dietary intervention based on their algorithm; this was a test of their ability to prescribe personal dietary recommendations for lowering blood-glucose-level responses to food. Volunteers were assigned a personalized “good” diet for one week, and a “bad” diet — also personalized — for another. Both good and bad diets were designed to have the same number of calories, but the diets differed between participants. Thus, certain foods in one person’s “good” diet were part of another’s “bad” diet. The “good” diets indeed helped to keep blood sugar at steadily healthy levels, whereas the “bad” diets often induced spikes in glucose levels — all within just one week of intervention. Moreover, as a result of the “good” diets, the volunteers experienced consistent changes in the composition of their gut microbes, suggesting that the microbiome may be influenced by the personalized diets while also playing a role in participants’ blood sugar responses.

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http://www.sciencedaily.com/releases/2015/11/151119143445.htm  Original web page at Science Daily

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* High-fat diet prompts immune cells to start eating connections between neurons

When a high-fat diet causes us to become obese, it also appears to prompt normally bustling immune cells in our brain to become sedentary and start consuming the connections between our neurons, scientists say.

The good news is going back on a low-fat diet for just two months, at least in mice, reverses this trend of shrinking cognitive ability as weight begins to normalize, said Dr. Alexis M. Stranahan, neuroscientist in the Department of Neuroscience and Regenerative Medicine at the Medical College of Georgia.

“Microglia eating synapses is contributing to synapse loss and cognitive impairment in obesity,” Stranahan said. “On the one hand, that is very scary, but it’s also reversible, meaning that if you go back on a low-fat diet that does not even completely wipe out the adiposity, you can completely reverse these cellular processes in the brain and maintain cognition.”

Stranahan is corresponding author of the study in the journal Brain, Behavior, and Immunity, which provides some of the first evidence of why fat is bad for the brain.

The trouble appears to start with too much fat in the body producing chronic inflammation, which stimulates microglia to have an autoimmune response. Microglia, like macrophages in the body, are known for their ability to ingest trash and infectious agents in the brain, and their highly acidic interior gets rids of it, which helps support the function and health of neurons. But as mice get obese, their microglia seem focused on overeating.

“Normally in the brain, microglia are constantly moving around. They are always moving around their little fingers and processes. What happens in obesity is they stop moving,” Stranahan said. “They draw in all their processes; they basically just sit there and start eating synapses. When microglia start eating synapses, the mice don’t learn as effectively,” Stranahan said.

The study looked at normal male mice: One group ate a diet in which about 10 percent of the calories came from saturated fat, and another consumed chow that was 60 percent fat. To ensure other factors were equal, the researchers chose chows that had similar levels of other key ingredients such as macronutrients and protein. The chows were on par with a healthy diet versus a fast-food diet in humans. “If you look at the lipid breakdown for the two diets, these guys are getting crazy, crazy amounts,” Stranahan said of the high-fat-fare mice.

At four, eight and 12 weeks, the MCG scientists took a series of metabolic measures, such as weight, food intake, insulin and serum glucose levels. They also measured in the hippocampus, the center of learning and memory, levels of synaptic markers, proteins found at synapses that correlate with the number of synapses.

“This gives us a window into what is occurring at the level of the synapse and also microglial activation,” Stranahan said. And, they measured levels of inflammatory cytokines, which microglia produce when “they start getting activated and angry.”

All levels in both groups were essentially the same at four weeks. The mice on a high-fat diet were fatter, but other measures were normal at eight weeks. By 12 weeks the fat-eating mice were obese, had elevated cytokine levels and a reduction in the markers for synapse number and function.

“When you get out to 12 weeks, you start seeing great increases in peripheral obesity. While you don’t see insulin resistance, you also start seeing loss of synapses and increases in inflammatory cytokines in the brain,” Stranahan said.

At that point, the research team switched half the mice on the high-fat diet to the low-fat regimen. It took about two months for their weight to return to normal, although their overall fat pad remained larger than their peers who had never gained weight. That fat layer makes it easier to gain weight in the future, Stranahan notes. As with most people, the mice that remained on the low-fat diet slowly accumulated a little weight as they aged.

Meanwhile, the group that stayed on the high-fat diet kept getting fatter, more inflamed and losing synapses, she said. Their microglia’s little processes, or protrusions, which normally help monitor synaptic function and help these cells move, continued to wither. Dendritic spines on neurons, which get input from synapses, similarly withered on the high-fat diet, but like the microglia processes, were restored with the lower-fat fare.

“That is very promising,” said Stranahan. The findings also point to some potential new purposes for existing drugs now used for conditions such as rheumatoid arthritis and Crohn’s disease, which block specific inflammatory cytokines and tumor necrosis factor alpha, both of which are elevated in the brains of the fat mice.

Obesity yields extreme overkill in microglia, which are typically extremely discriminating and helpful to neurons. During development, for example, they will prune a synapse that isn’t functioning. “That is one way the developing brain refines itself. It allows you to keep only those synapses that you need or the synapses you have been using. Fat dramatically alters their dynamic.

“Instead of doing garbage disposal, they are taking your mailbox, your front door, your kitchen sink and all the stuff that you need, and not doing their job of getting rid of trash,” Stranahan said.

She notes that the high-fat-eating mice actually ate less chow and consumed the same amount of calories as mice eating low fat. “The entire metabolic phenotype is driven by diet composition rather than the amount of calories,” Stranahan said. If high-fat-eating mice had greater variety in their diet, such as a sugar-water option, they might also consume more total calories, similar to the sensory-specific satiety phenomenon in humans, she said.

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http://www.sciencedaily.com/releases/2015/11/151123203118.htm  Original web page at Science Daily

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Processed meat can cause cancer

The International Agency for Research on Cancer (IARC), the cancer agency of the World Health Organization, has evaluated the carcinogenicity of the consumption of red meat and processed meat.

After thoroughly reviewing the accumulated scientific literature, a Working Group of 22 experts from 10 countries convened by the IARC Monographs Programme classified the consumption of red meat as probably carcinogenic to humans (Group 2A), based on limited evidence that the consumption of red meat causes cancer in humans and strong mechanistic evidence supporting a carcinogenic effect. This association was observed mainly for colorectal cancer, but associations were also seen for pancreatic cancer and prostate cancer.

Processed meat was classified as carcinogenic to humans (Group 1), based on sufficient evidence in humans that the consumption of processed meat causes colorectal cancer. The consumption of meat varies greatly between countries, with from a few percent up to 100% of people eating red meat, depending on the country, and somewhat lower proportions eating processed meat. The experts concluded that each 50 gram portion of processed meat eaten daily increases the risk of colorectal cancer by 18%.

“For an individual, the risk of developing colorectal cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed,” says Dr Kurt Straif, head of the IARC monographs programme. “In view of the large number of people who consume processed meat, the global impact on cancer incidence is of public health importance.”

The IARC working group considered more than 800 studies that investigated associations of more than a dozen types of cancer with the consumption of red meat or processed meat in many countries and populations with diverse diets. The most influential evidence came from large prospective cohort studies conducted over the past 20 years.

“These findings further support current public health recommendations to limit intake of meat,” says Dr. Christopher Wild, director of IARC. “At the same time, red meat has nutritional value. Therefore, these results are important in enabling governments and international regulatory agencies to conduct risk assessments, in order to balance the risks and benefits of eating red meat and processed meat and to provide the best possible dietary recommendations.”

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http://www.sciencedaily.com/releases/2015/10/151027135116.htm  Original web page at Science Daily

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* Feed supplement greatly reduces dairy cow methane emissions

A supplement added to the feed of high-producing dairy cows reduced methane emissions by 30 percent and could have ramifications for global climate change, according to an international team of researchers.

In addition, over the course of the 12-week study conducted at Penn State’s dairy barns, cows that consumed a feed regimen supplemented by the novel methane inhibitor 3-nitrooxypropanol — or 3NOP — gained 80 percent more body weight than cows in a control group. Significantly, feed intake, fiber digestibility and milk production by cows that consumed the supplement did not decrease.

The findings are noteworthy because methane is a potent greenhouse gas. The U.S. Environmental Protection Agency estimates that methane from livestock makes up 25 percent of the total methane emissions in the

United States. Globally, according to the United Nations’ Food and Agriculture Organization, animal agriculture emits 44 percent of the methane produced by human activity. Fermentation in the rumen — one of the four stomach chambers of livestock such as cattle, sheep and goats — generates the methane, as a result of microorganisms that aid in the process of digestion. The animals must expel the gas to survive. The 3NOP supplement blocks an enzyme necessary to catalyze the last step of methane creation by the microbes in the rumen.

It was important to conduct the study under industry-relevant conditions, said lead researcher Alexander Hristov, professor of dairy nutrition. The researchers published their results in a recent issue of the Proceedings of the National Academy of Sciences

“We tested methane-mitigation compounds using animals with similar productivity to those on commercial farms because the nutrient requirements of high-producing dairy cows are much greater than those of nonlactating or low-producing cows,” he explained.

“Any reduction in feed intake caused by a methane-mitigation compound or practice would likely result in decreased productivity — which may not be evident in low- producing cows.”

Methane expulsion through burping represents a net loss of feed energy for livestock, Hristov noted, adding that a high-producing dairy cow typically emits 450 to 550 grams per day of ruminal gas produced by fermentation. The spared methane energy was used partially for tissue synthesis, which led to a greater body weight gain by the inhibitor-treated cows.

The 48 Holsteins in the study received varying amounts of the inhibitor in their feed and were observed at regular daily intervals over three months. Their methane emissions were measured when the cows put their heads into feeding chambers that had atmospheric measurement sensors, and also through nostril tubes attached to canisters on their backs.

In recent years animal scientists have tested a number of chemical compounds to inhibit methane production in ruminants, and one even achieved a 60 percent reduction, Hristov said. However, the viability of that and other compounds as mitigation agents has been discounted due to concerns about animal health, food safety or environmental impact

The 3NOP compound, developed by DSM Nutritional Products, a Dutch company that is one of the world’s leading suppliers of feed additives, seems to be safe and effective, Hristov said.

If approved by the U.S. Food and Drug Administration and adopted by the agricultural industry, this methane inhibitor could have a significant impact on greenhouse gas emissions from the livestock sector, Hristov suggested. But producers will have to have an incentive to use the feed additive.

“It is going to cost money for dairy producers to put this into practice, and if they don’t see a benefit from it, they are not going to do it,” he said.

“The thing that is critical is body gain — dairy cows go through phases, and they lose a lot of weight when they calf. They don’t eat enough, and they produce a lot of milk and lose weight, so if we can cut down the energy loss with the inhibitor, the animals will gain more body weight and recover more quickly. Further, they may produce more milk in early lactation and have improved reproduction. It’s something that will convince producers to use it.

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http://www.sciencedaily.com/releases/2015/08/150804160930.htm  Original web page at Science Daily

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Diet that mimics fasting appears to slow aging

Study shows broad health benefits from periodic use of diet that mimics fasting in mice and yeast — which appear to translate to humans, also. A diagram of the fasting mimicking diet (FMD) protocol developed by the scientists, which retains the health benefits of prolonged fasting. In mice, FMD improved metabolism and cognitive function, decreased bone loss and cancer incidence, and extended longevity. In humans, three monthly cycles of a 5-day FMD reduced multiple risk factors of aging.

Want to lose abdominal fat, get smarter and live longer? New research led by USC’s Valter Longo shows that periodically adopting a diet that mimics the effects of fasting may yield a wide range of health benefits. In a new study, Longo and his colleagues show that cycles of a four-day low-calorie diet that mimics fasting (FMD) cut visceral belly fat and elevated the number of progenitor and stem cells in several organs of old mice — including the brain, where it boosted neural regeneration and improved learning and memory.

The mouse tests were part of a three-tiered study on periodic fasting’s effects — testing yeast, mice and humans — set to be published by Cell Metabolism on June 18. Mice, which have relatively short life spans, provided details about fasting’s lifelong effects. Yeast, which are simpler organisms, allowed Longo to uncover the biological mechanisms that fasting triggers at a cellular level. And a pilot study in humans found evidence that the mouse and yeast studies were applicable to humans.

Bimonthly cycles that lasted four days of an FMD which started at middle age extended life span, reduced the incidence of cancer, boosted the immune system, reduced inflammatory diseases, slowed bone mineral density loss and improved the cognitive abilities of older mice tracked in the study. The total monthly calorie intake was the same for the FMD and control diet groups, indicating that the effects were not the result of an overall dietary restriction.

In a pilot human trial, three cycles of a similar diet given to 19 subjects once a month for five days decreased risk factors and biomarkers for aging, diabetes, cardiovascular disease and cancer with no major adverse side effects, according to Longo. ‘Strict fasting is hard for people to stick to, and it can also be dangerous, so we developed a complex diet that triggers the same effects in the body,’ said Longo, Edna M. Jones professor of biogerontology at the USC Davis School of Gerontology and director of the USC Longevity Institute. Longo has a joint appointment at the USC Dornsife College of Letters, Arts and Sciences. ‘I’ve personally tried both, and the fasting mimicking diet is a lot easier and also a lot safer.’

The diet slashed the individual’s caloric intake down to 34 to 54 percent of normal, with a specific composition of proteins, carbohydrates, fats and micronutrients. It decreased amounts of the hormone IGF-I, which is required during development to grow, but it is a promoter of aging and has been linked to cancer susceptibility. It also increased the amount of the hormone IGFBP-, and reduced biomarkers/risk factors linked to diabetes and cardiovascular disease, including glucose, trunk fat and C-reactive protein without negatively affecting muscle and bone mass.

Longo has previously shown how fasting can help starve out cancer cells while protecting immune and other cells from chemotherapy toxicity. ‘It’s about reprogramming the body so it enters a slower aging mode, but also rejuvenating it through stem cell-based regeneration,’ Longo said. ‘It’s not a typical diet because it isn’t something you need to stay on.’ For 25 days a month, study participants went back to their regular eating habits — good or bad — once they finished the treatment. They were not asked to change their diet and still saw positive changes.

Longo believes that for most normal people, the FMD can be done every three to six months, depending on the abdominal circumference and health status. For obese subjects or those with elevated disease risk factors, the FMD could be recommended by the physician as often as once every two weeks. His group is testing its effect in a randomized clinical trial, which will be completed soon, with more than 70 subjects. ‘If the results remain as positive as the current ones, I believe this FMD will represent the first safe and effective intervention to promote positive changes associated with longevity and health span, which can be recommended by a physician,’ Longo said. ‘We will soon meet with FDA officers to pursue several FDA claims for disease prevention and treatment.

Despite its positive effects, Longo cautioned against water-only fasting and warned even about attempting the fasting mimicking diet without first consulting a doctor and seeking their supervision throughout the process.’Not everyone is healthy enough to fast for five days, and the health consequences can be severe for a few who do it improperly,’ he said. ‘Water-only fasting should only be done in a specialized clinic. Also, certain types of very low calorie diets, and particularly those with high protein content, can increase the incidence of gallstones in women at risk’.

‘In contrast,’ he added, ‘the fasting mimicking diet tested in the trial can be done anywhere under the supervision of a physician and carefully following the guidelines established in the clinical trials.’ Longo also cautioned that diabetic subjects should not undergo either fasting or fasting mimicking diets while receiving insulin, metformin or similar drugs. He also said that subjects with body mass index less than 18 should not undergo the FMD diet. For the study, Longo collaborated with researchers and clinicians from USC as well as from Texas, Italy and England. The study was funded by the National Institute on Aging

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http://www.sciencedaily.com/releases/2015/06/150618134408.htm  Original web page at Science Daily

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MRSA contamination found in supermarket sausages and minced pork in UK

A survey carried out earlier this year has found the first evidence of the ‘superbug’ bacteria Methicillin-Resistant Staphylococcus aureus (MRSA) in sausages and minced pork obtained from supermarkets in the UK. However, researchers stress that this does not pose a significant immediate risk to the public. In February, a team of researchers funded primarily by the Medical Research Council (MRC) bought and analysed a total of 103 (52 pork and 51 chicken) pre-packaged fresh meat products, labelled as being of UK farm origin, from supermarkets in five different locations across in England.

All of the meat products were frozen at -20?°C and sent to the Department of Veterinary Medicine at the University of Cambridge for testing. After thawing, researchers disinfected the exterior packaging before removing the meat. They then tested a 10g sample of meat from each packet and screened for MRSA. Two of the pork samples — one from sausages, one from minced pork — tested positive for MRSA; the sausage sample contained two strains of the bacteria.

In collaboration with the Wellcome Trust Sanger Institute an analysis of the genetic make-up of the bacteria and confirmed the presence of antibiotic resistant genes. The analysis showed that the bacteria belonged to a type of MRSA known as LA-MRSA CC398, which has emerged over the last few years in continental Europe, particularly in pigs and poultry, but was not previously believed to be widely distributed in the UK.

In many countries, LA-MRSA CC398 represents an occupational risk for those in close contact with livestock, particularly pigs and veal calves. Humans in contact with pigs (farm workers, abattoir workers and veterinarians, etc.) have significantly higher rates of the bacteria in their nasal carriage, according to epidemiological studies, for example. Other studies have revealed an association between clinical disease resulting from LA-MRSA CC398 infection and recent contact with pigs or pig farms. As with other MRSA, this type may be responsible for serious illness following wound or surgery site infections, although many people will carry MRSA on their skin or in their noses without showing signs of disease.

The researchers stress that adequate cooking (heating above 71°C) and hygienic precautions during food preparation should minimise the likelihood of transmission to humans via contaminated pork. However, they argue that the discovery of MRSA in pork identifies a potential way that the bacteria can spread from farms to the wider population.

While human contamination of carcasses or meat products in the abattoir or at the meat packing plant may occur, there is good evidence that these isolates are of animal origin — possibly through the use of antibiotics to treat or control infection in livestock. As the tests use a highly sensitive method of detection of bacterial contamination, the numbers of MRSA bacteria present may be low. The researchers say that as the two infected samples contained processed pork (sausages and minced pork), they cannot rule out that the meat packing plants from which the MRSA from this study originated also handle imported meat. If this were the case, it is conceivable that cross-contamination might have occurred between non-UK to UK sourced meat.

Dr Mark Holmes from the Department of Veterinary Medicine at the University of Cambridge says: “This is the first time that MRSA has been detected in retail meat products in the UK. The public should not be overly worried by this as sensible food precautions and good hygiene should prevent its spread. It’s also usually pretty harmless and only causes health problems if it infects someone in poor health or gets into a wound. “However, this does suggest that MRSA is established in our pig farms and provides a possible route of transmission from livestock, through those in direct contact with pigs, into the wider population.”

Dr Des Walsh, Head of Infections and Immunity at the MRC, added: “Studies like this are crucial not just to reveal concerns to human health through contaminated livestock, but to show resistance to antibiotics is a problem growing far beyond just humans. To win the fight against antimicrobial resistance, we need an all hands on deck approach, and that’s why we’ve teamed up with leading experts in biological, social and others sciences in a joint initiative designed to find new solutions, fast.”

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/06/150618122102.htm  Original web page at Science Daily

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Endangered tortoises thrive on invasive plants

Introduced plants make up roughly half the diet of two subspecies of endangered tortoise, field research in the Galapagos reveals. Tortoises seem to prefer non-native to native plants and the plants may help them to stay well-nourished during the dry season. Most research on the role of introduced species of plants and animals stresses their negative ecological impacts. But are all introduced species bad actors? In one fascinating case the answer might be no. The iconic giant tortoises of the Galapagos Islands are thriving on a diet heavy on non-native plants. In fact, the tortoises seem to prefer these plants to native ones.

Introduced plants began to increase in abundance on the Galapagos Islands in the 1930s as native highland vegetation was cleared for agriculture, and the rate of introductions has been increasing ever since. The giant tortoises, for their part, seem headed in the opposite direction. Until the late Pleistocene epoch, they were found on all the continents except Antarctica. Today they survive in only two locations: the Aldabra Atoll in the Indian Ocean, and the Galapagos Archipelago in the eastern Pacific Ocean. In the Galapagos, all of the remaining subspecies are considered vulnerable or endangered. But now in a surprising turn of events, field research in the Galapagos shows that introduced plants make up roughly half the diet of two subspecies of endangered tortoise. What’s more, these plants seem to benefit the tortoises nutritionally, helping them stay fit and feisty.

The research, published in the March issue of Biotropica, was conducted by Stephen Blake, PhD, an honorary research scientist at Washington University in St. Louis and Fredy Cabrera of the Charles Darwin Foundation in the Galapagos. “Biodiversity conservation is a huge problem confronting managers on the Galapagos Islands, “Blake said. “Eradicating the more than 750 species of invasive plants is all but impossible, and even control is difficult. Fortunately, tortoise conservation seems to be compatible with the presence of some introduced species.” The study was done on the island of Santa Cruz, an extinct volcano that is home to two species of giant tortoise, but also to the largest human population in the Galapagos. Farmers have converted most of the highland moist zones to agriculture and at least 86 percent of the highlands and other moist zones are now degraded by either agriculture or invasive species.

In earlier work, Blake had fitted adult tortoises on Santa Cruz with GPS tags and discovered that they migrate seasonally between the arid lowlands, which “green up” with vegetation only in the wet season, to the meadows of the highlands, which remain lush year-round. “This struck us as pretty odd, ” he said, “since a large Galapagos tortoise can survive for a year without eating and drinking. This is why sailors would collect the tortoises to serve as a source of fresh meat aboard ship.” “Why would a 500-pound animal that can fast for a year and that carries a heavy shell haul itself up and down a volcano in search of food?,” Blake said. ” Couldn’t it just wait out the dry season until better times came with the rains?” The answer, of course, depends on the tortoise’s energy balance. But the only detailed study of tortoise foraging the scientists were aware of had been completed in 1980, “largely before the explosion of introduced and invasive species hit the Galapagos,” Blake said. Over a period of four years, the scientists followed tortoises in the field and, during 10-minute “focal observations” recorded every bite the tortoises took, the plant species and which part they ate. As an additional measure of the fruits the tortoises were eating, the scientists also counted and identified seeds (sometimes more than 1,000) in tortoise dung piles.

Counts of bites and bouts (defined as all feeding on a given species during the focal observations) showed that tortoises actually spent more time browsing on introduced species than on native ones. “We weren’t really that surprised,” Blake said. “Consider it from a tortoise’s point of view. The native guava, for example, produces small fruits containing large seeds and a small amount of relatively bitter pulp in a thick skin. The introduced guava is large and contains abundant sweet pulp in a thin, pliable skin.” The team, which included Sharon Deem, a wildlife veterinarian and epidemiologist at the St. Louis Zoo, also assessed the tortoises’ health and nutritional status, weighing them by suspending them from a spring balance and taking blood samples. All of the indicators the scientists studied suggest that introduced species in the diet have either a neutral or positive effect on the physical condition of the tortoises. Introduced species may even help tortoises to improve their condition during the dry season. Since a return to “pristine” conditions is unlikely on the Galapagos, it is heartening to learn that this may not be all bad news for the islands’ charismatic megaherbivores.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/04/150406120857.htm  Original web page at Science Daily

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Food preservatives linked to obesity and gut disease

Mouse study suggests that emulsifiers alter gut bacteria, leading to the inflammatory bowel condition colitis. Chemicals known as emulsifiers are often added to processed foods such as ice cream. Artificial preservatives used in many processed foods could increase the risk of inflammatory bowel diseases and metabolic disorders, according to research published on 25 February in Nature.

In a study done in mice, chemicals known as emulsifiers were found to alter the make-up of bacteria in the colon — the first time that these additives have been shown to affect health directly. About 15 different emulsifiers are commonly used in processed Western foods for purposes such as smoothing the texture of ice cream and preventing mayonnaise from separating. Regulatory agencies such as the US Food and Drug Administration (FDA) rule that emulsifiers are “generally regarded as safe”, because there is no evidence that they increase the risk of cancer or have toxic effects in mammals. But when immunologist Andrew Gewirtz at Georgia State University in Atlanta and his colleagues fed common emulsifiers carboxymethylcellulose and polysorbate-80 to mice, they found evidence that the chemicals affected the animals’ health. Although their diet was not otherwise changed, healthy mice whose water contained the chemicals became obese and developed metabolic problems such as glucose intolerance. In mice genetically engineered to be prone to inflammatory gut diseases, emulsifiers also seemed to increase the severity and frequency with which the animals developed inflammatory bowel disease.

The most severe health effects were seen in mice that consumed the chemicals at a level similar to a person whose diet consists of only ice cream, says Gewirtz. But the researchers saw effects even at one-tenth of the concentration of emulsifiers that the FDA allows in a food product. To understand why emulsifiers affected the health of mice, researchers analysed bacteria from the animals’ colons. They found less diversity in the microbial species than in healthy mice, and found evidence that the microbes had migrated closer the cells lining the gut. Gewirtz and his colleagues suspect that the emulsifiers can break down the heavy mucus that lines the mammalian gut and prevents bacteria from coming into contact with gut cells. If this happens, the bacteria cause inflammation in the gut, which can also lead to changes in metabolism. Gewirtz says that previous studies may have missed these links because newly developed food additives are tested in large swathes of the population, masking any subtle effects in people whose genetics or gut-microbe composition predispose them to these diseases. For regulators, he says, “the idea that a subset of the population may be sensitive isn’t on the radar.”

This lack of specificity could explain why nutritionists and public-health agencies are constantly revising their dietary guidelines — just this month, for example, an advisory council to the US government recommended eliminating guidelines on cholesterol consumption. “If you look over a 50-year perspective, you would see that the recommendations go back and forth, back and forth,” says immunologist Eran Elinav of the Weizmann Institute of Science in Rehovot, Israel. “No one is lying or cheating, many of these studies are well-designed studies, but they all look at large populations.” Last year, Elinav and computational biologist Eran Segal, a colleague at the Weizmann Institute, found that artificial sweeteners such as saccharin can cause metabolic diseases such as obesity and diabetes by changing the make-up of bacteria in the gut in both mice and humans. They are now compiling a database of genetic and microbiome data from about 1,000 volunteers, measuring their metabolic response to different test foods. They hope that this will eventually allow nutritionists to make specific dietary recommendations for individuals based on these parameters. Elinav and Segal hope to incorporate consumption of emulsifiers, sweeteners and other artificial additives into their study, but caution that there are many components to inflammatory and metabolic diseases. “This is for sure not the only driving factor” for inflammatory bowel disease, Elinav says.

Gewirtz says that many more human and animal studies need to be completed before regulatory agencies would consider changing how additives are approved — after all, removing preservatives from foods would cause them to rot sooner, posing a different health risk. He hopes to do a study in humans soon and is already collecting biopsies from surgery patients to study where different bacteria live in the colon. But the findings have been enough to convince Gewirtz and co-author Benoit Chassaing, a microbiologist at Georgia State, to start checking the labels of the foods they buy, although both say they are not trying to eliminate emulsifiers entirely. It is not easy to find emulsifier-free food, Gewirtz says, and products marketed as ‘organic’ are just as likely to contain these agents. “When it comes to people making their own decisions, between our studies and others out there, it’s better to eat less processed food,” he says.

Nature doi:10.1038/nature.2015.16984

http://www.nature.com/news/index.html Nature

http://www.nature.com/news/food-preservatives-linked-to-obesity-and-gut-disease-1.16984 Original web page at Nature

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Test for horse meat developed

Scientists at the Institute of Food Research on the Norwich Research Park have teamed up with Oxford Instruments to develop a fast, cheap alternative to DNA testing as a means of distinguishing horse meat from beef. Because horses and cattle have different digestive systems, the fat components of the two meats have different fatty acid compositions, as the team report in the journal ‘Food Chemistry’. The new method looks at differences in the chemical composition of the fat in the meats, using similar technology to a hospital MRI scanner. In just ten minutes, a technician can determine whether a piece of raw meat is horse or beef. The method, developed with funding from Innovate UK and the Biotechnology and Biological Sciences Research Council (BBSRC) has recently been trialled in an industrial setting by a leading meat processor. It is currently being extended by the team of scientists to test for other meat species, including pork and lamb. The horse meat scandal of 2013 was sparked by the discovery of horse meat in a number of beef burgers. Soon, horse meat was detected in other meat products, leading to millions of pounds worth of food being taken off supermarket shelves. The crisis exposed the potential vulnerability of the meat supply chain to fraud and even to threats to public health, and highlighted gaps in testing. The currently favoured method of meat species testing relies on DNA, which can tell one meat from another based on the genetic makeup of the source animals, but is relatively slow and expensive and prone to contamination if not used carefully. In response to this, a new method using a totally different approach was developed by Oxford Instruments and IFR. The key technology is the ‘Pulsar’, a high resolution bench-top NMR spectrometer developed by Oxford Instruments. NMR spectroscopy is a well-respected analytical technique used in chemistry labs worldwide. However, conventional instruments are large and expensive, and rely on super-cooled magnets and highly trained personnel to run them. Pulsar in contrast is based on permanent magnets and ease of operation. For a test to be useful as a screening tool it needs to be quick and cheap. With this goal in mind, the team discovered that a couple of minutes shaking about a gram of meat in a solvent followed by a few minutes of data acquisition on Pulsar was enough to tell horse meat from beef. Software to carry out mathematical analysis of the spectral data has also been developed at IFR. “It’s a stroke of luck really that some of the most important meats turn out to have fat signatures that we can tell apart so easily with this method,” says Dr Kate Kemsley. “It’s been very satisfying to see results from a real industrial setting sit right on top of those we generated in our two labs. We think this testing method should work well at key points in the supply chain, say at meat wholesalers and processors.”

http://www.sciencedaily.com/ Science Daily

http://www.sciencedaily.com/releases/2014/12/141201125329.htm Original web page at Science Daily

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Calorie-restricting diets slow aging, study finds

Neuroscientists at NYU Langone Medical Center have shown that calorie-reduced diets stop the normal rise and fall in activity levels of close to 900 different genes linked to aging and memory formation in the brain. In a presentation prepared for the Society for Neuroscience annual meeting in Washington, D.C., on Nov. 17, researchers say their experimental results, conducted in female mice, suggest how diets with fewer calories derived from carbohydrates likely deter some aspects of aging and chronic diseases in mammals, including humans. “Our study shows how calorie restriction practically arrests gene expression levels involved in the aging phenotype — how some genes determine the behavior of mice, people, and other mammals as they get old,” says senior study investigator and NYU Langone neuroscientist, Stephen D. Ginsberg, PhD. Ginsberg cautions that the study does not mean calorie restriction is the “fountain of youth,” but that it does “add evidence for the role of diet in delaying the effects of aging and age-related disease.” While restrictive dietary regimens have been well-known for decades to prolong the lives of rodents and other mammals, their effects in humans have not been well understood. Benefits of these diets have been touted to include reduced risk of human heart disease, hypertension, and stroke, Ginsberg notes, but the widespread genetic impact on the memory and learning regions of aging brains has not before been shown. Previous studies, he notes, have only assessed the dietary impact on one or two genes at a time, but his analysis encompassed more than 10,000 genes. Ginsberg, an associate professor at NYU Langone and its affiliated Nathan S. Kline Institute for Psychiatric Research, says the research “widens the door to further study into calorie restriction and anti-aging genetics.” For the study, female mice, which like people are more prone to dementia than males, were fed food pellets that had 30 percent fewer calories than those fed to other mice. Tissue analyses of the hippocampal region, an area of the brain affected earliest in Alzheimer’s disease, were performed on mice in middle and late adulthood to assess any difference in gene expression over time.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2014/11/141117110650.htm  Original web page at Science Daily

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Junk food makes rats lose appetite for balanced diet

A diet of junk food not only makes rats fat, but also reduces their appetite for novel foods, a preference that normally drives them to seek a balanced diet, reports a study published in the open-access journal Frontiers in Psychology. The study helps to explain how excessive consumption of junk food can change behavior, weaken self-control and lead to overeating and obesity. The team of researchers, led by Professor Margaret Morris, Head of Pharmacology from the School of Medical Sciences, UNSW Australia, taught young male rats to associate each of two different sound cues with a particular flavor of sugar water — cherry and grape. Healthy rats, raised on a healthy diet, stopped responding to cues linked to a flavor in which they have recently overindulged. This inborn mechanism, widespread in animals, protects against overeating and promotes a healthy, balanced diet. But after 2 weeks on a diet that included daily access to cafeteria foods, including pie, dumplings, cookies, and cake — with 150% more calories — the rats’ weight increased by 10% and their behavior changed dramatically. They became indifferent in their food choices and no longer avoided the sound advertising the overfamiliar taste. This indicated that they had lost their natural preference for novelty. The change even lasted for some time after the rats returned to a healthy diet. The researchers think that a junk diet causes lasting changes in the reward circuit parts of the rats’ brain, for example, the orbitofrontal cortex, an area of the brain responsible for decision-making. They say these results may have implications for people’s ability to limit their intake of certain kinds of foods, because the brain’s reward circuitry is similar in all mammals. “The interesting thing about this finding is that if the same thing happens in humans, eating junk food may change our responses to signals associated with food rewards,” says UNSW Professor Morris. “It’s like you’ve just had ice cream for lunch, yet you still go and eat more when you hear the ice cream van come by.”

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2014/08/140827151744.htm  Original web page at Science Daily

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* Cheetah menu: Wildlife instead of cattle

Scientists from the German Leibniz Institute for Zoo and Wildlife Research (IZW) can give the all-clear: in a recent study they showed that cheetahs primarily prefer wildlife on their menu. The cheetah is a vulnerable species that only exists on Namibia’s commercial farmland in large populations. Here, local farmers see cheetahs as a potential threat for their cattle.

The conflict is an old one: wherever there are carnivorous wild animals, farmers are concerned about their livestock. In Namibia, the concern refers to the possible threat from cheetahs on cattle. When farmers in Namibia are missing a bovine calf, cheetahs are regularly under suspicion — nowhere else in the world are there as many animals of this vulnerable species as on commercial farmland in Namibia. But the suspicion can rarely be confirmed without demur. In their recent study, scientists of the IZW investigated whether cattle is on top of the cheetahs’ menu. For this purpose they used an indirect method with which they were able to assess the diet over longer periods. “Traditionally, carnivore diet is determined by examining samples of fresh faeces. Faecal samples only provide a snapshot of the diet, based on the detected hair and bone samples of prey animals. One cannot therefore conclude which food items cheetahs devour in the long run,” explains Christian Voigt from the IZW.

Instead the scientists used samples of cheetah hair to determine the stable isotope ratios of carbon and nitrogen. Herbivores have different food webs. One is based on shrubs, trees and herbs whose photosynthesis contains intermediate products with three carbon atoms (C3). In contrast, grasses exhibit a C4 photosynthesis. These food webs can be differentiated with the help of the involved carbon isotopes. Herbivores typically only belong to one food web and the isotope ratio hence deposits in their body tissue. Small antelopes such as springbok or steenbok specialise on shrubs and herbs whereas the oryx antelope feeds on grass — just like the cattle. One step up in the food chain the isotope ratio of the prey transfers to its predator. The study shows that herbivores of the C4 food chain, to which cattle belong, are nearly irrelevant to the cheetah’s diet. Grazers are only occasionally considered as prey by males when they occur in groups of two or three animals. In this project the IZW scientists collaborated closely with the farmers. “We live with the farmers on their farmland and share our scientific results with them. In this way, we attain a very high acceptance,” emphasises Bettina Wachter. “The farmers passed on their experience in dealing with these big cats, as cheetahs cannot be simply lured with bait like many other carnivores,” she adds. This is owed to the fact that cheetahs only eat prey they brought down themselves. Thus, aided by the farmers, the scientists installed box traps at marking trees, which were hidden by thorn bushes except for a narrow passage. The only way to reach their tree is passing the trap. Once a cheetah is captured it is sedated and thoroughly examined: body length and weight are determined, samples of blood and hair are taken and then the scientists release the cheetah equipped with a tracking collar. “We conclude that the farmer’s problems are smaller than they had assumed before this study,” Voigt sums up. This study, published in the scientific online journal PLOS ONE, will contribute to the protection of cheetahs — but not in adversity to the interest of the farmers. “We understand their position. The concepts of species conversation always need to be balanced against the livelihood of humans,” says Wachter. The study is therefore an important mile stone to resolve the conflict between farmers and cheetahs.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2014/08/140827151707.htm  Original web page at Science Daily

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Stem cells as future source for eco-friendly meat

The scientific progress that has made it possible to dream of a future in which faulty organs could be regrown from stem cells also holds potential as an ethical and greener source for meat. So say scientists who suggest in the Cell Press journal Trends in Biotechnology that every town or village could one day have its very own small-scale, cultured meat factory. “We believe that cultured meat is part of the future,” said Cor van der Weele of WageningenUniversity in The Netherlands. “Other parts of the future are partly substituting meat with vegetarian products, keeping fewer animals in better circumstances, perhaps eating insects, etc. This discussion is certainly part of the future in that it is part of the search for a ‘protein transition.’ It is highly effective in stimulating a growing awareness and discussion of the problems of meat production and consumption.” van der Weele and coauthor Johannes Tramper point out that the rising demand for meat around the world is unsustainable in terms of environmental pollution and energy consumption, not to mention the animal suffering associated with factory farming. van der Weele said she first heard about cultured meat in 2004, when frog steaks were served at a French museum while the donor frog watched on (http://tcaproject.org/projects/victimless/cuisine). Tramper has studied the cultivation of animal cells—insect cells mostly—in the lab for almost 30 years. In 2007, he published a paper suggesting that insect cells might be useful as a food source. It is already possible to make meat from stem cells. To prove it, Mark Post, a professor of tissue engineering at MaastrichtUniversity, The Netherlands, presented the first lab-grown hamburger in 2013. In the new Science & Society paper, van der Weele and Tramper outline a potential meat manufacturing process, starting with a vial of cells taken from a cell bank and ending with a pressed cake of minced meat. But there will be challenges when it comes to maintaining a continuous stem cell line and producing cultured meat that’s cheaper than meat obtained in the usual way. Most likely, the price of “normal” meat would first have to rise considerably. Still, the promise is too great to ignore. “Cultured meat has great moral promise,” write van der Weele and Tramper. “Worries about its unnaturalness might be met through small-scale production methods that allow close contact with cell-donor animals, thereby reversing feelings of alienation. From a technological perspective, ‘village-scale’ production is also a promising option.”

http://www.sciencedaily.com/ Science Daily

June 24, 2014

http://www.sciencedaily.com/releases/2014/05/140520123430.htm  Original web page at Science Daily

 

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Does a junk food diet make you lazy? Psychology study offers answer

A new UCLA psychology study provides evidence that being overweight makes people tired and sedentary — not the other way around. Life scientists led by UCLA’s Aaron Blaisdell placed 32 female rats on one of two diets for six months. The first, a standard rat’s diet, consisted of relatively unprocessed foods like ground corn and fish meal. The ingredients in the second were highly processed, of lower quality and included substantially more sugar — a proxy for a junk food diet. After just three months, the researchers observed a significant difference in the amount of weight the rats had gained, with the 16 on the junk food diet having become noticeably fatter. “One diet led to obesity, the other didn’t,” said Blaisdell, a professor of psychology in the UCLA College of Letters and Science and a member of UCLA’s Brain Research Institute. The experiments the researchers performed, Blaisdell said, also suggest that fatigue may result from a junk food diet. As part of the study, the rats were given a task in which they were required to press a lever to receive a food or water reward. The rats on the junk food diet demonstrated impaired performance, taking substantially longer breaks than the lean rats before returning to the task. In a 30-minute session, the overweight rats took breaks that were nearly twice as long as the lean ones. The research is currently online and is scheduled for publication in the April 10 print edition of the journal Physiology and Behavior. After six months, the rats’ diets were switched, and the overweight rats were given the more nutritious diet for nine days. This change, however, didn’t help reduce their weight or improve their lever responses.

The reverse was also true: Placing the lean rats on the junk food diet for nine days didn’t increase their weight noticeably or result in any reduction in their motivation on the lever task. These findings suggest that a pattern of consuming junk food, not just the occasional binge, is responsible for obesity and cognitive impairments, Blaisdell said. “There’s no quick fix,” he noted. What are the implications for humans? Do people who are overweight become less healthy or do less healthy people become overweight? “Overweight people often get stigmatized as lazy and lacking discipline,” Blaisdell said. “We interpret our results as suggesting that the idea commonly portrayed in the media that people become fat because they are lazy is wrong. Our data suggest that diet-induced obesity is a cause, rather than an effect, of laziness. Either the highly processed diet causes fatigue or the diet causes obesity, which causes fatigue.” Blaisdell believes the findings are very likely to apply to humans, whose physiological systems are similar to rats’. Junk food diets make humans — and rats — hungrier, he said. In addition, the researchers found that the rats on the junk food diet grew large numbers of tumors throughout their bodies by the end of the study. Those on the more nutritious diet had fewer and small tumors that were not as widespread. Blaisdell, 45, changed his diet more than five years ago to eat “what our human ancestors ate.” He avoids processed food, bread, pasta, grains and food with added sugar. He eats meats, seafood, eggs, vegetables and fruits, and he has seen dramatic improvements in his health, both physically and mentally. “I’ve noticed a big improvement in my cognition,” he said. “I’m full of energy throughout the day, and my thoughts are clear and focused.” An expert in animal cognition, Blaisdell conducts research that addresses the relationship between health and lifestyle (diet and exercise) and the relationship between a junk food diet and cognitive impairments it may induce. “We are living in an environment with sedentary lifestyles, poor-quality diet and highly processed foods that is very different from the one we are adapted to through human evolution,” he said. “It is that difference that leads to many of the chronic diseases that we see today, such as obesity and diabetes.”

http://www.sciencedaily.com/  Science Daily

April 29, 2014

http://www.sciencedaily.com/releases/2014/04/140404221904.htm  Original web page at Science Daily

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Low-protein diet may extend lifespan

A new theory about the foods that can extend life is taking shape, and it’s sure to be a controversial one. Two studies out this week, one in mice and another primarily in people, suggest that eating relatively little protein and lots of carbohydrates—the opposite of what’s urged by many human diet plans, including the popular Atkins Diet—extends life and fortifies health. The research challenges other common wisdom, too. The authors of both studies believe that calorie restriction, a drastic diet that helps mice and other species live much longer than normal, may work not because it slashes calorie intake, but mostly because it cuts down on protein. They also speculate that the low-protein/high-carbohydrate balance that appears to extend life in the two studies, published in Cell Metabolism, could clarify why slightly plump people live longer on average than skinny ones—something epidemiologists have been hard-pressed to explain. “If these two studies are really correct, what people in general are trying to do” to get and stay thin “might be completely wrong in terms of maintaining health and even longevity,” says Shin-ichiro Imai, a molecular biologist at Washington University in St. Louis who studies aging. The “if” is a big one, however. The interplay between diet and health is extraordinarily complicated, and protein diets in particular have sparked confusion. On the one hand, some researchers have found a correlation between consuming lots of protein and heart disease. On the other, high-protein diets have been linked to improved metabolic profiles, such as lower blood glucose levels. Teasing out the role of protein versus total calories or carbohydrates is no easy task. “There are a whole lot of variables here,” says Cynthia Kenyon, who studies the biology of aging at the University of California, San Francisco.

An Australian group led by nutritional physiologist Stephen Simpson and biogerontologist David Le Couteur at the University of Sydney tried to clear up some of the confusion by assigning 858 mice to one of 25 diets with different mixes of protein, carbs, fats, and fiber. All were allowed to eat as much as they wanted. The mice whose diets included 5% to 15% protein and 40% to 60% carbohydrates lived the longest, up to 150 weeks compared with 100 weeks for those on a diet of about 50% protein. By comparison, Americans on average take in about 16% of their calories from protein. The animals on the low-protein/high-carb plan also had lower blood pressure, better glucose tolerance, and healthier cholesterol. (Levels of fat in their diet didn’t seem to make much difference.) Mice that ate lots of protein were skinnier—just as people on high-protein diets tend to be. But for these mice, slender translated to ill health and earlier death. This finding, Le Couteur says, supports the “concept of healthy obesity,” which has been raised by epidemiology studies of slightly overweight people. He suggests that if their diet is higher in carbohydrates and lower in protein than usual, that might be responsible. The second study, led by gerontology researcher Valter Longo and graduate student Morgan Levine at the University of Southern California in Los Angeles, focused on data from 6381 adults over 50 years old who were interviewed once about their diet as part of NHANES, a national survey of health and nutrition. Longo’s team used death records to conclude that those under 65 whose self-reported diets they classified as high-protein—the participants said at least 20% of their calories came from protein—were at much higher risk of illness and death than a group who took in 10% or fewer of their calories from protein. The high-protein eaters were more than four times as likely to die from cancer over the 18 years after they were surveyed, and 75% more likely to die of any cause.

Those leaping to grab a breadstick instead of sausage should note, however, that as the NHANES cohort aged, protein became more important. In the over-65 crowd, those who ate lots of protein survived longer, on average, than those who ate less. Geriatricians, Longo says, have long extolled the value of protein in older people, and “they’re right.” Longo and Imai speculate that elderly individuals may be less likely to absorb the protein they take in, so need more of it. The findings do fit with some molecular clues. Cutting protein intake is known to reduce levels of a growth factor called IGF-1, and lower IGF-1 levels are linked to longer lifespan and reductions in the risk of cancer and diabetes. Limiting protein intake also reduces levels of a protein called mTOR, and lower mTOR extends life in mice. The Australians saw the mTOR effect in their animals. Longo’s team, testing stored samples from the survey participants, saw that higher IGF-1 levels correlated with more dietary protein. “There’s certainly some truth to this relationship” between protein consumption and lifespan, says Matt Kaeberlein, a molecular biologist at the University of Washington, Seattle, who studies longevity. “But it’s probably overly simplistic to say that everyone should go on a low-protein diet at this point.” Among the many caveats, for example, is that the mouse study used a single strain, though different strains can have different reactions to diets such as calorie restriction. Kaeberlein also thinks it’s unlikely that reduced protein alone explains the dramatic impact of calorie restriction on lifespan. Le Couteur wants to find out for sure: He and his colleagues are planning a study that pits a low-protein/high-carb diet head-to-head with restricted calories, to see which mice live the longest.

http://news.sciencemag.org/sciencenow  ScienceNow

March 18, 2014

http://news.sciencemag.org/biology/2014/03/low-protein-diet-may-extend lifespan  Original web page at ScienceNow

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Dietary treatment shows potential in mouse model of Alzheimer’s disease

New research findings indicate that an early onset of dietary treatment may slow down the progression of Alzheimer’s disease. The study was conducted on mice, and the results will be published in the February issue of Journal of Nutritional Biochemistry. Researchers from the University of Eastern Finland played a key role in the study, which was carried out as part of the LiPiDiDiet project funded by the European Union. According to current understanding, Alzheimer’s disease develops slowly and it may take up to 20 years before the first obvious symptoms occur. With the development of early diagnostics of the disease, the question of which treatments to offer to completely healthy people with an increased risk of developing Alzheimer’s becomes of key importance in the field of medicine. Various dietary treatments seem a promising alternative. Several epidemiological studies suggest that docosahexaenoic acid (DHA), an omega-3 fatty acid found in fatty fish, might reduce the risk of Alzheimer’s disease. Experimental studies have also observed a positive — although modest — association between DHA and several processes behind Alzheimer’s disease. This recently published study investigated whether the efficacy of DHA treatment can be enhanced by additional nutrients.

The study used transgenic female mice carrying APP and PS1 mutations linked with familial Alzheimer’s disease, and wild-type mice. All the mice began the dietary intervention at 5 months and continued on the diet until 13 months old. The fat content of the control chow was increased to better correspond to human diets. In addition to the control chow, some of the APP/PS1 mice were fed three experimental chows enriched with fish oil and having a similar fat content as the control chow: fish oil supplement only, plant sterol supplement or Fortasyn supplement, which contains uridine-monophosphate, phospholipids, B- vitamins, and antioxidants. As expected, APP/PS1 mice performed significantly poorer than wild-type mice in the Morris swim navigation task, which measures long-term spatial memory. Among transgenic mice on the experimental diets, the mice on the Fortasyn diet performed equally well as the wild-type mice, whereas other dietary treatments showed no improvement. However, all test diets reversed the memory deficit of the APP/PS1 mice in the odour recognition task. The levels of accumulated amyloid-β protein in the brain were examined at the end of the study. A significant reduction in the amyloid-β levels was observed in the plant sterol group while other experimental diets showed no effect. However, why was a substantial reduction in brain amyloid-β levels not accompanied by a positive memory effect in the spatial task in the plant sterol group? One explanation is that the plant sterol diet increased formation of reactive oxygen species in the hippocampus, whereas the Fortasyn diet, which yielded the best results in the spatial memory task, tended to have an opposite effect.

The results indicate that even slight changes in the composition of the diet may, under a sufficiently long period of time and at an early stage of the disease process, lead to significant changes in brain metabolism and improved memory performance. On the other hand, the mere brain amyloidosis in Alzheimer’s disease involves several mechanisms and it is unlikely that a single cocktail of nutrients will provide an optimal outcome. According to the researchers, the results definitely encourage further development of dietary treatments for Alzheimer’s disease. The now studied Fortasyn supplement is found in the medical nutrition formulation Souvenaid that just was introduced in Finland. In the light of the present results, the product can be warmly recommended for the treatment of mice suffering from mild cognitive impairment (pre-Alzheimer’s), but will it work as efficiently in humans, too? We will probably get the answer in a year, as results from a parallel clinical study of the LiPiDiDiet project become available. The study is coordinated by the Brain Research Unit at the Clinical Research Centre of the University of Eastern Finland.

http://www.sciencedaily.com/ Science Daily
February 18, 2014

http://www.sciencedaily.com/releases/2014/01/140124082558.htm Original web page at Science Daily

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Primate growing up with half of the calories: New understanding about humans health and longevity

New research shows that humans and other primates burn 50% fewer calories each day than other mammals. The study, published January 13 in the Proceedings of the National Academy of Sciences, suggests that these remarkably slow metabolisms explain why humans and other primates grow up so slowly and live such long lives. The study also reports that primates in zoos expend as much energy as those in the wild, suggesting that physical activity may have less of an impact on daily energy expenditure than is often thought. Most mammals, like the family dog or pet hamster, live a fast-paced life, reaching adulthood in a matter of months, reproducing prodigiously (if we let them), and dying in their teens if not well before. By comparison, humans and our primate relatives (apes, monkeys, tarsiers, lorises, and lemurs) have long childhoods, reproduce infrequently, and live exceptionally long lives. Primates’ slow pace of life has long puzzled biologists because the mechanisms underlying it were unknown. An international team of scientists working with primates in zoos, sanctuaries, and in the wild examined daily energy expenditure in 17 primate species, from gorillas to mouse lemurs, to test whether primates’ slow pace of life results from a slow metabolism. Using a safe and non-invasive technique known as “doubly labeled water,” which tracks the body’s production of carbon dioxide, the researchers measured the number of calories that primates burned over a 10 day period. Combining these measurements with similar data from other studies, the team compared daily energy expenditure among primates to that of other mammals.

“The results were a real surprise,” said Herman Pontzer, an anthropologist at Hunter College in New York and the lead author of the study. “Humans, chimpanzees, baboons, and other primates expend only half the calories we’d expect for a mammal. To put that in perspective, a human — even someone with a very physically active lifestyle — would need to run a marathon each day just to approach the average daily energy expenditure of a mammal their size.” This dramatic reduction in metabolic rate, previously unknown for primates, accounts for their slow pace of life. All organisms need energy to grow and reproduce, and energy expenditure can also contribute to aging. The slow rates of growth, reproduction, and aging among primates match their slow rate of energy expenditure, indicating that evolution has acted on metabolic rate to shape primates’ distinctly slow lives. “The environmental conditions favoring reduced energy expenditures may hold a key to understanding why primates, including humans, evolved this slower pace of life,” said David Raichlen, an anthropologist at the University of Arizona and a coauthor of the study. Perhaps just as surprising, the team’s measurements show that primates in captivity expend as many calories each day as their wild counterparts. These results speak to the health and well-being of primates in world-class zoos and sanctuaries, and they also suggest that physical activity may contribute less to total energy expenditure than is often thought.

“The completion of this non-invasive study of primate metabolism in zoos and sanctuaries demonstrates the depth of research potential for these settings. It also sheds light on the fact that zoo-housed primates are relatively active, with the same daily energy expenditures as wild primates,” said coauthor Steve Ross, Director of the Lester E. Fisher Center for the Study and Conservation of Apes at Chicago’s Lincoln Park Zoo. “Dynamic accredited zoo and sanctuary environments represent an alternative to traditional laboratory-based investigations and emphasize the importance of studying animals in more naturalistic conditions.” Results from this study hold intriguing implications for understanding health and longevity in humans. Linking the rate of growth, reproduction, and aging to daily energy expenditure may shed light on the processes by which our bodies develop and age. And unraveling the surprisingly complex relationship between physical activity and daily energy expenditure may improve our understanding of obesity and other metabolic diseases. More detailed study of energy expenditure, activity, and aging among humans and apes is already underway. “Humans live longer than other apes, and tend to carry more body fat,” said Pontzer. “Understanding how human metabolism compares to our closest relatives will help us understand how our bodies evolved, and how to keep them healthy.”

http://www.sciencedaily.com/  Science Daily February 4, 2014

http://www.sciencedaily.com/releases/2014/01/140113163809.htm  Original web page at Science Daily

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New DNA test identifies ingredients in foods

Almost all foodstuffs contain the genetic material of those animal and plant species that were used in their preparation. Scientists at the Institute of Molecular Genetics, Genetic Security Research and Consulting at Johannes Gutenberg University Mainz (JGU) have developed a novel screening procedure that provides for highly sensitive, quantifiable analysis of animal, plant, and microbial substances present in foodstuffs. For this, the researchers have adapted the latest techniques of DNA sequencing, which are otherwise currently employed in human genetics to unravel the genetic information of thousands of patients. “The innovative aspect in comparison with conventional DNA detection methods such as polymerase chain reaction, or PCR for short, is that by means of bioinformatic analysis of all biological DNA data available worldwide we can identify the presence of material from species that we would not otherwise expect. And, using a simple digital method of counting short snippets of DNA, we will also probably be able to determine the relative incidence of individual species-related material more precisely than was previously the case,” explained molecular geneticist Professor Dr. Thomas Hankeln, who developed the method in collaboration with bioinformaticist Professor Bertil Schmidt, Ph.D. and colleagues at the German and Swiss food control authorities.

In pilot studies, the researchers were able to use the new DNA method to detect the presence of a 1% content of horse meat in products and to determine the actual amount with a high level of precision. The Mainz researchers even found slight traces of the DNA of added mustard, lupin, and soy in a test sausage prepared for calibration purposes, something that could also be of interest with regard to allergy testing of foods. Because of its potential, the method — dubbed ‘All-Food-Seq’ by its developers — has already attracted the attention of food inspection experts. “This method is very interesting in connection with efforts to promote the molecular traceability of food,” said Hermann Broll of the German Federal Institute for Risk Assessment in Berlin and Dr. René Köppel of the Zurich Cantonal Laboratory in Switzerland. The method developed by the Mainz scientists is thus to be validated in comparison with conventional detection techniques in the near future.

Science Daily
April 16, 2013

Original web page at Science Daily