Blogs / 80beats

Spikes in blood sugar levels seem to be linked to memory problems, and may be a major factor in the normal memory and cognitive problems that crop up as people age, according to a new study. People’s ability to regulate blood sugar begins to deteriorate by their third or fourth decade and continues to decline, so older people are more prone to these sugar spikes. “This would suggest that anything to improve regulation of blood glucose would potentially be a way to ameliorate age-related memory decline,” said senior study author Dr. Scott Small…. The findings may also help explain why people who exercise don’t have as many cognitive problems as they age: Exercise helps stabilize blood glucose levels [HealthDay News].

The findings have important implications for the increasing number of overweight children who are at risk of diabetes, commented neuroscientist Bruce McEwen. “When we think about diabetes, we think about heart disease and all the consequences for the rest of the body, but we usually don’t think about the brain,” he said. “This is something we’ve got to be really worried about. We need to think about their ultimate risks not only for cardiovascular disease and metabolic disorders, but also about their cognitive skills, and whether they will be able to keep up with the demands of education and a fast-paced complex society. That’s the part that scares the heck out of me” [The New York Times].

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The health benefits of eating more fish outweigh the risks of mercury poisoning, according to a new Food and Drug Administration (FDA) proposal that would revise current federal seafood advisories. The proposal is drawing fire from the Environmental Protection Agency (EPA) and environmental groups that accuse the FDA of pandering to the seafood industry. Richard Wiles, director of an environmental advocacy group, said, “This is an astonishing, irresponsible document…It’s a commentary on how low FDA has sunk as an agency. It was once a fierce protector of America’s health, and now it’s nothing more than a patsy for polluters” [Washington Post].

Currently, the government advises young children, pregnant women, and women of child-bearing age to restrict overall fish consumption to 12 ounces per week and to avoid shark, swordfish, king mackerel and tilefish, which are known to have particularly high mercury levels. Mercury in the environment accumulates in fish and studies have linked the element to developmental problems in fetuses and young children as well as cardiovascular disease in adults. However, the new FDA report says recent studies suggest “a beneficial impact on fetal neurodevelopment from the mother’s consumption of fish, even though they contain methylmercury…The net effect is not necessarily adverse, and could in fact be beneficial” [AP]. The report argued that nutrients in fish, including omega-3 fatty acids, selenium and other minerals could boost a child’s IQ by three points [Washington Post]. The new analysis places ideal fish consumption—for optimal IQ-boosting—somewhere above 12 ounces per week.

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Researchers recently went to an Amish community in Pennsylvania with an odd request: Will you drink milkshakes for the sake of science? In a study about cardiovascular health and genetics that had more than 800 Amish people slurping high-fat shakes, researchers discovered that about five percent of their subjects had a genetic mutation that defends the heart against the effects of a high-fat diet—specifically, breaking down triglycerides, those fats that clog arteries like hair in your bathroom drain [Newsweek].

In the study, published in Science [subscription required], Amish men and women agreed to drink a rich milkshake that was made mostly of heavy cream. Over the next six hours, a group of investigators took samples of their blood, determining how much fat was churning through their bloodstreams. Most of the study participants responded as expected — their levels of triglycerides, a common form of fat in the blood, rose steadily for three to four hours and then declined. But about 5 percent had an extraordinary reaction: their triglyceride levels started out low and hardly budged [The New York Times].

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The fear surrounding nut allergies among children has gotten so out of control, one doctor says, that it could be considered an outbreak of mass psychogenic illness (MPI), more informally known as mass hysteria. Writing in the British Medical Journal, medical sociologist Nicholas Christakis argues that a tiny fraction of hospital admissions and deaths are due to allergic reactions to nuts yet ever more draconian measures are being brought in to prevent any child coming into contact with nuts [Telegraph]. Those draconian measures fuel parents’ anxieties, Christakis says, in what he calls a “cycle of over-reaction.”

Christakis cites the extreme example of when a potentially fatal peanut was “spotted on the floor of a school bus, whereupon the bus was evacuated and cleaned (I am tempted to say decontaminated), even though it was full of 10-year-olds who, unlike two-year-olds, could actually be told not to eat food off the floor” [The Register]. He also mentions some school policies of banning all nuts, peanut butter, and even baked goods that may have come into contact with nuts. While he acknowledges that nut allergies can be serious and even deadly, Christakis says that reasonable preventative measures could protect vulnerable children without scaring the bejesus out of everyone else.

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You may not want to think about what goes into your fast food, but a new study may at least put your overactive imagination to rest: It’s mostly corn. The researchers analyzed hamburgers, chicken sandwiches, and fries from McDonald’s, Burger King, and Wendy’s and determined that nearly all of them could be traced to the corn industry– in the form of corn feed or corn-based oil. “If you put any money into fast food, it all goes back to corn, everything. The first step to making hamburgers is making an ear of corn,” said Hope Jahren, lead author of the study [Des Moines Register].

The researchers traveled to Los Angeles, San Francisco, Denver, Detroit, Boston and Baltimore, purchasing feasts of fast food at multiple restaurants in each city. Samples of beef, chicken, and fries were then ground up and analyzed for levels of isotopes. Specifically, they were looking for carbon-13, which is a unique signature of corn, and nitrogen-15, which is found in fertilizers and animal excrement. Based on the high levels of carbon and nitrogen isotopes found in the meat products, the authors claim that the cattle and poultry were predominantly fed corn, which makes them as fat as possible in as short a time as possible, and were raised in extreme confinement [Forbes.com], keeping the animals in close contact with their own excrement. The high nitrogen-15 content also suggests the corn fields were heavily fertilized with nitrogen-based fertilizers.

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Eating red meat could make your body more vulnerable to a dangerous bacterial toxin, according to a new study. A sugar molecule, Neu5Gc, found in beef, lamb, pork, and unpasteurized milk can attach itself to the cells lining the human intestines and act as a magnet for toxins produced by certain strains of E. coli, often carried in the same meats. The result is bloody diarrhea and sometimes death. “This uncovered the first example of bacterium causing disease in humans by targeting a molecule which is incorporated into our bodies through what we eat,” [ABC Science] says researcher Travis Beddoe.

The study, published in Nature [subscription required], was conducted in petri dishes using mouse tissues and human cells. The scientists tested human gut and kidney cells steeped in these sugar molecules and discovered that the toxin was about seven times more likely to bind to these cells if the sugar was present. It is still “not clear how to extrapolate this precisely to the human body,” [Science News] says co-author Ajit Varki. That is, researchers don’t know exactly what it means for human health yet. (more…)

The toxic chemical melamine that has already contaminated Chinese milk and eggs may also have been widely used in animal feed, according to new reports from the Chinese state media. Chinese consumers were horrified when it was revealed in September that four babies had died and more than 50,000 were sickened due to tainted infant formula, and the outrage grew in October when eggs from four large companies were also found to be tainted. Since then, the widening scandal has caused companies across Asia to recall products made with Chinese milk or eggs, and the new reports suggest that there may be broader recalls to come.

Melamine can be used to make food products appear to have a higher protein content, and the new admission from the state-run media, which usually suppresses bad news, shows that the trick was commonly used. “The feed industry seems to have acquiesced to agree on using the chemical to reduce production costs while maintaining the protein count for quality inspections,” the state-run China Daily said in an editorial. “We cannot say for sure if the same chemical has made its way into other types of food,” the newspaper added [BBC News].

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Using a gene from a snapdragon flower, researchers have created a purple tomato rich in antioxidants, and a new study has shown that cancer-prone mice that were fed the altered tomatoes had significantly longer lifespans than those that dined on regular tomatoes. The tomatoes’ purple hue was a side effect of the type of antioxidants produced, called anthocyanins.

The tomatoes produce levels of anthocyanins about on par with blackberries, blueberries and currants, which recent research has touted as miracle fruits. But because of the high cost and infrequent availability of such berries, tomatoes might be a better source, says [lead researcher Cathie] Martin [USA Today].

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A preliminary study has shown that large doses of vitamin C may decrease the effectiveness of chemotherapy drugs, bringing new confusion into the debate over whether vitamin C supplements can help or harm cancer patients. In the study, researchers treated cancer cells with very high doses of vitamin C and then tried to kill the cells with various cancer drugs; they found that all the drugs were less effective on the pretreated cancer cells than on cells that had received no vitamin dose.

While the effect was only tested in cancer cells and mice, researchers say further studies should look for a parallel effect in humans. “There’s a possibility that taking supplemental vitamin C could have a detrimental effect on cancer treatment,” said study author Dr. Mark L. Heaney…. However, there’s no indication that smaller doses of vitamin C, such as those found in food and ordinary multivitamins, might be a problem, he said [HealthDay News].

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Meat and milk from the offspring of cloned animals may already be part of the U.S. food supply, the Food and Drug Administration announced this week. While the cloning process is too expensive (about $20,000 per animal) to justify creating clones that will be turned into hamburgers, some ranchers have cloned animals with desirable traits, which they then breed the old-fashioned way to create offspring. Officials said it is impossible to differentiate between cloned animals, their offspring and conventionally bred animals, making it difficult to know if offspring are in the food supply [Reuters].

The use of cloned livestock–particularly cows, swine, and sheep–has been fiercely debated in the United States and Europe. In January, the FDA declared that cloned animals and their offspring were as safe to eat as conventionally bred animals; regulators still ask that food companies follow a voluntary moratorium on using cloned animals for food production, but no such moratorium exists for the clones’ natural offspring. Those offspring may have made it into the food supply, a U.S. Agriculture Department spokesman said, but “they would be a very limited number because of the very few number of clones that are out there and relatively few of those clones are at an age where they would be parenting” [Reuters].

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Researchers have found specialized receptors on the tongues of mice that detect calcium, leading them to hypothesize that humans have the calcium-dedicated receptors, too. It may be time to add calcium to the types of tastes — sweet, sour, salty, bitter and savory — that can be detected by humans [HealthDay News].

But in another twist, most mice don’t like the taste, lead researcher Michael Tordoff says. Tordoff and his colleagues gave 40 different strains of mice a choice: They could drink water or a calcium-rich liquid. Most preferred water once they tried both. There was, however, one exception—a mouse strain called PWK actually preferred the calcium-enriched liquid. Those mice, it turned out, had a different version of genes that are responsible for taste receptors on the tongue [Scientific American].

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Injections of high doses of vitamin C slowed the growth of tumors in mice by 50 percent, and also prevented the cancers from metastasizing to other parts of the body. Researchers say the findings form a “firm basis” for trials in humans, with a view to using vitamin C injections alongside conventional drugs, particularly for some of the most lethal tumours, such as pancreatic, ovarian and brain cancer [The Guardian].

But some cancer specialists are sceptical, and fear that desperate patients will be prompted to start taking large doses of the vitamin. That may be dangerous, because antioxidants such as vitamin C could undermine the effectiveness of standard cancer drugs and radiation therapy [New Scientist]. Researchers point out that they were only able to deliver a higher dose of the vitamin through intravenous injection and that patients couldn’t get a similar dose through diet or vitamin supplements, because the digestive system can absorb a limited amount of the vitamin.

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California is striking a blow against obesity and heart disease: On Friday, Governor Arnold Schwarzenegger signed a bill outlawing the use of trans fats in all restaurants and bakeries. The bill creates the first state-wide ban of trans fats, but follows the path set out by cities like New York City and Philadelphia, which have already evicted the substance from restaurants within city limits.

Trans fats are created by pumping hydrogen into liquid oil at high temperature, a process called partial hydrogenation. The process results in an inexpensive fat that prolongs the shelf life and appearance of packaged foods and that, many fast-food restaurants say, helps make cooked food crisp and flavorful [The New York Times]. The artificial fats have been shown to increase levels of “bad” cholesterol and decrease levels of “good” cholesterol, and are therefore linked to heart disease.

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A report from an European Union agency says that while meat and milk from cloned animals appears to be safe for human consumption, more studies are needed to prove the point. While the document from the European Food Safety Authority is not the final word on the matter, it seems to indicate that European consumers won’t be chowing down on steaks from cloned cows anytime soon.

“For cattle and pigs, food safety concerns are considered unlikely. But we must acknowledge that the evidence base is still small. We would like to have a broader data base and we need further clarification” [Reuters], said an agency official. The report also said that cloning has a negative impact on the health and welfare of the animals, as clones are more likely to be born with birth defects and often die younger.

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The results are out from a new study that compared the results of three different diets, and the researchers say that the famously low-carbohydrate, high-fat Atkins diet was the most effective. Lead researcher Meir Stampfer claims: “The low-carb diet was the clear winner in providing the most weight loss” [ABC News]. But many others are less convinced that the study gives the prize to the Atkins diet, and say that the study had some serious flaws.

The study, published in the New England Journal of Medicine, compared the Atkins diet to a low-fat diet that emphasized whole grains, fruits, and vegetables, and also to a “Mediterranean” diet that allows a modicum of fats in the form of olive oil, nuts, and fish. While obese people who stuck with the Atkins diet for two years lost an average of 12 pounds, compared to 10 pounds for the Mediterranean dieters and 7 pounds for the low-fat dieters, some say that focusing on those numbers misses the point. The study… was supposed to determine which of three types of diets works best. Instead, the results highlight the difficulty of weight loss and the fact that most diets do not work well [The New York Times].
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