Chapter 9. Homeostasis: Active Regulation of the Internal Environment
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By Deborah Kotz, Globe Staff Is Alzheimer’s disease really a form of diabetes? Let’s call it type 3, because that’s what a Brown Medical School researcher dubbed it back in 2005 when she autopsied the brains of Alzheimer’s patients and found that they had signs of insulin resistance -- an early indicator of diabetes. Since then, however, we haven’t seen a sea-change in preventive treatments based on this idea. Those who carry the gene for hereditary Alzheimer’s aren’t given diabetes drugs to help stave off dementia. Nor are Alzheimer’s patients given insulin injections. What has been getting attention, however, is whether we should make extra efforts to eat a low glycemic diet -- which is low in processed foods, sugar, and starchy carbohydrates that cause quick spikes in blood sugar -- to help protect our brains from developing those gunky amyloid plaques associated with Alzheimer’s. The September issue of the New Scientist advocates for changing our eating patterns with a frightening image of a cracked chocolate brain on its cover. (Chocolate consumption, though, hasn’t been linked to cognitive decline, much to my relief.) New York Times food columnist Mark Bittman pointed out in a recent post that the latest studies provide some persuasive evidence linking diet to the development of Alzheimer’s. I’ve covered those studies too, including this one that measured a smaller Alzheimer’s risk in people who eat a diet rich in fish, veggies, and fruit compared with those who eat a diet centered on processed foods containing trans fats. © 2012 NY Times Co.
Link ID: 17328 - Posted: 10.03.2012
By Janet Raloff Most people would never equate downing a well-dressed salad or a fried chicken thigh with toking a joint of marijuana. But to Joseph Hibbeln of the National Institutes of Health, the comparison isn’t a big stretch. New animal experiments by Hibbeln and his colleagues have recently shown that the body uses a major constituent in most vegetable oils to make its own versions of the psychoactive ingredient in marijuana. Called endocannabinoids, these natural compounds play a role in heightening appetite. So overproducing them unnecessarily boosts hunger, similarly to how pot triggers the munchies (SN: 6/19/10, p. 16). If what happens in people mirrors what happens in animals, then the prevalence of soybean oil, corn oil and other polyunsaturated vegetable oils in today’s Western diet means your body is “dumping out a lot of these marijuana-like molecules into your brain,” explains Hibbeln, a nutritional neuroscientist. “You’re chronically a little bit stoned.” Vegetable oil’s link to endocannabinoids is just one example of newfound and surprising ways that foods can confuse calorie-sensing networks and foster obesity — in some cases by damaging the brain. Especially troubling: Excess body weight itself can exaggerate the risk of the brain telling a well-fueled body that it is running on empty. By understanding what messes with the body’s satiety meters and why, scientists hope to identify tactics for reducing a diner’s likelihood of becoming another statistic in the obesity epidemic. © Society for Science & the Public 2000 - 2012
By RONI CARYN RABIN Amid fervid criticism that New York City risks becoming a nanny state, city health officials this month banned the sale of supersize sugar-laden drinks in restaurants and movie theaters. Now scientists have handed the ban’s advocates a potent weapon: strong evidence that replacing sugared drinks with sugar-free substitutes or water really can slow weight gain in children. Two-thirds of all American adults and one-third of children in the United States are overweight or obese. The contribution of sugary sodas and fruit drinks to this epidemic has been hotly disputed. But two new randomized clinical trials published on Friday in The New England Journal of Medicine lend credence to the idea that limiting access to these beverages may help reduce obesity. Beverage industry officials denounced the research, which may fuel wider efforts to curb consumption through taxes or other restrictions. In one of the new trials, researchers at Boston Children’s Hospital randomly assigned 224 overweight or obese teenagers to receive home deliveries of bottled water and diet drinks for one year. The children also were regularly encouraged to avoid sugary drinks. Those who received the shipments gained only 3.5 pounds on average during that year, while a comparison group of similar teenagers gained 7.7 pounds. The differences between the groups evaporated after the deliveries stopped. In the second trial, researchers at VU University Amsterdam randomly assigned 641 normal-weight schoolchildren ages 4 to 11 to drink eight ounces of a 104-calorie sugar-sweetened or noncaloric sugar-free fruit-flavored drink every day from identical cans. Over 18 months, children in the sugar-free group gained 13.9 pounds on average, while those drinking the sugar-added version gained 16.2 pounds. © 2012 The New York Times Company
Children and teens with higher levels of BPA, a chemical used in canned foods, are more likely to be overweight and obese but whether the chemical caused the weight gain can’t be answered. The issue of obesity is addressed in Tuesday's online edition of the Journal of the American Medical Association. In one U.S. study, researchers wanted to test the idea that hormone-like chemicals like bisphenol A, also called BPA, could be contributing to childhood obesity by disrupting kids' metabolism. BPA is used to make hard plastics for food and beverage containers. It also found in the lining of many metal cans. Dr. Leonardo Trasande of the New York University School of Medicine and his co-authors looked at BPA concentrations in the urine of 2,838 Americans aged six to 19 as well as body mass index scores. "Urinary BPA concentrations was significantly associated with obesity in this cross-sectional study of children and adolescents," the study's authors concluded. The researchers weren't able to tell which came first, the obesity or BPA concentrations. © CBC 2012
Some people who are severely obese and have gastric bypass surgery may be able to keep weight off for six years, giving them reduced risks of cardiovascular problems and diabetes, a U.S. study finds. The study focused on 1,156 adults with a body mass index of 35 or higher — which is considered severely obese — and who had the bypass surgery. They were compared with 739 other severely obese people in two groups who did not get the surgery. "At six years, 96 per cent of surgical patients had maintained more than 10 per cent weight loss from baseline and 76 per cent had maintained more than 20 per cent weight loss," Ted Adams of the University of Utah School of Medicine and his co-authors wrote in Tuesday’s issue of the Journal of the American Medical Association. All cardiovascular risk factors improved or stayed the same among those who received a type of gastric bypass surgery called Roux-en-Y compared with those who did not, Adams said. Other differences at the end of the study included: Mortality rate three per cent for surgery patients, three per cent for obese patients who were evaluated and one per cent among the control group of obese adults. Diabetes remission 62 per cent for surgery, eight per cent in control group 1 and six per cent in control group 2. © CBC 2012
Link ID: 17279 - Posted: 09.19.2012
By GRETCHEN REYNOLDS Most people who start working out in hopes of shedding pounds wind up disappointed, a lamentable circumstance familiar to both exercisers and scientists. Multiple studies, many of them covered in this column, have found that without major changes to diet, exercise typically results in only modest weight loss at best (although it generally makes people much healthier). Quite a few exercisers lose no weight. Some gain. But there is encouraging news about physical activity and weight loss in a new study by researchers at the University of Copenhagen. It found that exercise does seem to contribute to waist-tightening, provided that the amount of exercise is neither too little nor, more strikingly, too much. To reach that conclusion, the Danish scientists rounded up a group of pudgy and sedentary young men, a segment of the population increasingly common in Denmark, as elsewhere in the world. The volunteers, most in their 20s or early 30s, visited the scientists’ lab to undergo baseline measurements of their aerobic fitness, body fat, metabolic rates and general health. None had diabetes, high blood pressure or heart disease and, while heavy, they were not obese. The men were then randomly assigned to exercise or not. The non-exercisers, who served as controls, returned to their former routines, with no change to their diets or sedentary ways. A second group began 13 weeks of almost daily moderate workouts, consisting of jogging, cycling or otherwise sweating for about 30 minutes, or until each man had burned 300 calories (based on his individual metabolic rate). Copyright 2012 The New York Times Company
Link ID: 17278 - Posted: 09.19.2012
By HARRIET BROWN A few years ago, Mercedes Carnethon, a diabetes researcher at the Feinberg School of Medicine at Northwestern University, found herself pondering a conundrum. Obesity is the primary risk factor for Type 2 diabetes, yet sizable numbers of normal-weight people also develop the disease. Why? In research conducted to answer that question, Dr. Carnethon discovered something even more puzzling: Diabetes patients of normal weight are twice as likely to die as those who are overweight or obese. That finding makes diabetes the latest example of a medical phenomenon that mystifies scientists. They call it the obesity paradox. In study after study, overweight and moderately obese patients with certain chronic diseases often live longer and fare better than normal-weight patients with the same ailments. The accumulation of evidence is inspiring some experts to re-examine long-held assumptions about the association between body fat and disease. Dr. Carl Lavie, medical director of cardiac rehabilitation and prevention at the John Ochsner Heart and Vascular Institute in New Orleans, was one of the first researchers to document the obesity paradox, among patients with heart failure in 2002. He spent more than a year trying to get a journal to publish his findings. “People thought there was something wrong with the data,” he recalled. “They said, ‘If obesity is bad for heart disease, how could this possibly be true?’ ” But there were hints everywhere. One study found that heavier dialysis patients had a lower chance of dying than those whose were of normal weight or underweight. Overweight patients with coronary disease fared better than those who were thinner in another study; mild to severe obesity posed no additional mortality risks. © 2012 The New York Times Company
Link ID: 17270 - Posted: 09.18.2012
By MyHealthNewsDaily staff In common weight-loss advice, "get more sleep," should figure just as prominently as "eat less" and "move more," two researchers in Canada argue. There is strong evidence that lack of sleep is contributing to the obesity epidemic, they said, and factors that contribute to obesity that have been given less attention than diet and exercise may at least partly explain why weight-loss efforts fail, according to the researchers. "Among the behavioural factors that have been shown to impede weight loss, insufficient sleep is gaining attention and recognition," the researchers write in their editorial published today (Sept. 17) in the Canadian Medical Association Journal. The researchers pointed to a 2010 study in which participants were randomly assigned to sleep either 5.5 hours or 8.5 hours every night for 14 days. They all cut their daily calorie intake by 680 calories, and slept in a lab. Participants who slept for 5.5 hours lost 55 percent less body fat, and 60 percent more of their lean body mass than those who slept for longer. In other words, the sleep-deprived people held onto their fat tissue, and instead lost muscle. In another study, published in July, researchers looked at 245 women in a six-month weight loss program and found that those who slept more than seven hours a night, and those who reported better quality sleep, were 33 percent more likely to succeed in their weight-loss efforts. © 2012 NBCNews.com
By Scicurious It’s often interesting to look over the scientific literature, and to see, for lack of a better term, “fashion trends”. Not what style of kahkis the PIs are wearing this fall, but rather neurotransmitters, techniques, behaviors, or models that you can watch go in and out of fashion. There are lots of different reasons for why this occurs, sometimes a new, better model comes along, sometimes the technique is not a versatile as first thought, sometimes the new neurotransmitter field gets extremely “crowded” and people feel they need to branch out. But it’s interesting to see things wax and wane, and to try and see if you can predict where some things are going. For example, when it first appeared on the scene, the technique of optogenetics (stimulating cells to fire by hitting them with light, because you have infected them with a light sensitive channel) was the new hot thing. Optogenetics is still very “now”, and promises to stick around for a bit, as the flexibility of the technique is still being tested. Knockout mice, on the other hand, though they were wildly popular (and are still), are being replaced with things like targeted knockouts of genes that are localized to specific regions, or inducible knockouts that will only become knockouts when you stimulate the system with something in the diet. It’s a more specific technique and so the older technique is gradually becoming less popular. It works the same way for neurotransmitters, the chemicals released between neurons to convey messages. And I’ve been noticing a new one that I think is going to be an up and comer. This chemical is called orexin (or hypocretin, two groups characterized it at the same time and the name war has continued for years now. It looks like orexin is winning out, for while hypocretin is more functionally accurate…orexin sounds a lot better and is easier to say). Orexin was originally noticed due to two main behaviors: sleep, and appetite. Orexin is a powerful mediator of something called arousal (what you might also call attention or wakefulness, though it’s not quite the same as either). In fact, the most common form of narcolepsy is due to a lack of orexin in the brain. © 2012 Scientific American
By Amr Abouelleil Twenty years ago I joined my high school’s football team and over the next four years became intimately acquainted with pasta – the delicious flavor and al dente texture, the margherita and alfredo sauces that could drown it, and the marvelous butter and garlic soaked breads that could accompany it. I owed the joys of these team-bonding dinners to one of the coaches of my team. What I was too meatball-addled to realize then was that like a pig for Christmas dinner, we were being fattened up – not for the December dinner table, but for the football field. All this because my high school football team had a size problem. Our affluent little town – full of band geeks, video game nerds and lean soccer stars, couldn’t find but a few mountains to hold the line of scrimmage (and those few were bused in from the city). Most of our players were smaller than our opponents – some who produced players who’d later play for Notre Dame. Though it took years of parental indoctrination, I was finally convinced – my coaches had decided to solve the team’s size problem by fattening us up with all-you-can-eat pasta dinners. Ever since then, it’s been my size problem. I’ve done battle with the self-esteem and social issues obesity presents. I’ve had surgery on a disc that ruptured simply because I bent to pick up my jacket from the floor, and every backache since has me worried that I’ll end up under the knife again. Last year, I was diagnosed with sleep apnea. Then there are the risks I have yet to experience: diabetes, stroke, and coronary artery disease, to name a few. I don’t blame my coaches for this – I doubt they knew any better. © 2012 Scientific American
by Andy Coghlan Muscles that burn energy without contracting have yielded new clues about how the body retains a constant temperature – and they may provide new targets for combating obesity. Traditionally, the body's main thermostat was thought to be brown fat. It raids the body's white fat stores in cold conditions to burn energy and keep the body warm. Muscles also play a role in keeping the body warm by contracting and triggering the shiver response – but this is only a short-term fix because prolonged shivering damages muscles. Now it seems that muscles have another way to turn up the heat. "Our findings demonstrate for the first time that muscle, which accounts for 40 per cent of body weight in humans, can generate heat independent of shivering," says Muthu Periasamy of Ohio State University in Columbus. Surviving the chill Through experiments on mice that had their usual thermostat – brown fat – surgically removed, Periasamy and his colleagues proved that a protein called sarcolipin helps muscle cells keep the body warm by burning energy, almost like an idling motor car, even if the muscles do not contract. All of the mice had their brown fat removed, but some of them had been genetically engineered to lack sarcolipin too. These rodents could not survive when held at 4 °C, and died of hypothermia within 10 hours. By contrast, mice that could make sarcolipin were able to survive the chilly temperatures and maintained their core body temperature – despite having no brown fat. © Copyright Reed Business Information Ltd.
Analysis by Sheila Eldred Kids with metabolism problems may be at risk of brain impairment, a new study in the journal Pediatrics suggests. Researchers at the NYU School of Medicine linked adolescents who experienced a few years of problems with metabolism to brain complications. "The kids with MetS [metabolic syndrome] took longer to do tasks, could not read as well and had poorer math scores," lead investigator Dr. Antonio Convit, professor of psychiatry and medicine, said in a press release. "These findings indicate that kids with MetS do not perform well on things that are very relevant to school performance." Children are diagnosed with metabolic syndrome when they have at least three of five health issues: abdominal obesity, low HDL (good cholesterol), high triglycerides, high blood pressure and pre-diabetic insulin resistance. The syndrome, which increases the risk of type 2 diabetes, stroke and coronary artery disease, has risen along with the increase in childhood obesity. To determine how metabolic syndrome might affect brain development, the researchers compared 49 kids with the syndrome to 62 without the syndrome, balancing the groups according to age, socioeconomic status, gender and ethnicity. © 2012 Discovery Communications, LLC.
By Nathan Seppa Decades of research have linked low-calorie diets with extended survival, but a new report finds that rhesus monkeys on strict diets don’t live longer than their counterparts getting a standard diet. The findings, reported August 29 in Nature, run counter to a 2009 study from the University of Wisconsin–Madison that showed a clear survival advantage in a calorie-restricted group of similar rhesus monkeys. Scientists suspect that differences in the two studies’ designs might explain the discordant findings, leaving the question of longevity still dangling. Both research groups will need to wait another decade or more before all the monkeys live out their lives. But the authors of the new study, conducted at a National Institute on Aging laboratory in Baltimore, say their data are unlikely to change, since calculations show that the chance of a survival difference arising in the remaining monkeys is exceedingly low. “I don’t think one study overturns 75 years of research,” says Steven Austad, a bio-gerontologist at the University of Texas Health Science Center in San Antonio, who isn’t part of either study team. But he notes that most previous calorie-restriction studies have been done in short-lived animals. “It’s always been possible that whatever you used to increase their lives might not work the same in long-lived animals.” © Society for Science & the Public 2000 - 2012
Link ID: 17221 - Posted: 08.30.2012
by Kai Kupferschmidt Farmers have long used antibiotics to make cows, pigs, and turkeys gain weight faster. Now, scientists claim that receiving antibiotics early in life may also make children grow fat. The researchers believe the drugs change the composition of the bacterial population in the gut in a crucial developmental stage that may have a long-lasting impact. Other scientists are casting doubt on the conclusions, however. The new data are "not convincing," says Michael Blaut, a microbiologist at the German Institute of Human Nutrition in Potsdam, Germany. And David Relman, a microbiologist at the Stanford University School of Medicine in Palo Alto, California, calls the work "provocative" but says some of the data are "a bit vague and unclear." Billions of microbial cells live in the guts of humans and other animals. Research on these vast bacterial populations, called microbiomes, is just getting started, but scientists already know that some microbial boarders play a crucial role in breaking down nutrients in our diet. Some have also suspected that low-dose antibiotics, given to farm animals to make them grow bigger, could work by altering the gut microbiome. To test this hypothesis, a team led by microbiologist Martin Blaser of the New York University School of Medicine in New York City added antibiotics to the drinking water of mice that had just been weaned. The medicine—either penicillin, vancomycin, a combination of the two, or chlortetracycline—was given at doses comparable to those approved by the U.S. Food and Drug Administration as growth promoters in farm animals. © 2010 American Association for the Advancement of Science.
Link ID: 17202 - Posted: 08.25.2012
By ANAHAD O'CONNOR For people who are extremely overweight and likely to develop diabetes, surgery may be the best form of prevention. A new study shows that weight-loss surgery not only produced sustained weight loss in obese men and women but substantially reduced their odds of developing Type 2 diabetes. Over the course of a roughly 15-year period, those who had one of three types of bariatric procedures were 80 percent less likely to develop the disease than people who tried losing weight with diet and exercise advice from their doctors. In fact, those who had the worst blood sugar levels at the start of the study, putting them in a high-risk category called prediabetes, benefited the most from surgery. Their risk of becoming diabetic fell by nearly 90 percent. “The message is that bariatric surgery works,” said Dr. Claude Bouchard, an author of the study and a professor at the Pennington Biomedical Research Center in Louisiana. “You can take people on their way to becoming diabetic, and you intervene with bariatric surgery and weight loss, and you have a very, very strong protective effect against Type 2 diabetes.” The findings add to a growing body of literature supporting bariatric surgery as a means for combating diabetes. This year, two studies showed that for people who are obese and already have diabetes, weight-loss surgery was more effective than drugs, diet and exercise in causing a remission of the disease. The new report, published on Wednesday in The New England Journal of Medicine, is the first large study to show a long-term preventive effect of surgery in people who are not yet diabetic but well on their way. Copyright 2012 The New York Times Company
Link ID: 17201 - Posted: 08.25.2012
By Melissa Dahl, NBC News You lost 15 pounds! And gained it back. And lost it! And gained it back. It's been this way for years, so long that you've begun to believe that you've mucked up your metabolism, not to mention your odds of ever taking that weight off permanently. But take heart, yo-yo dieters: A new study suggests that your history of gaining and losing, gaining and losing, actually doesn't screw up your metabolism, nor does it wreck your chances at future weight loss attempts. The new research, recently published in the journal Metabolism, provides some hopeful news for those who've tried a series of diet fads and serious programs -- Weight Watchers, paleo, cleanses -- only to put that weight right back on. Advertise | AdChoices "Just because you didn't reach or keep to a goal before doesn't mean you won't succeed if you try again," says Anne McTiernan, a researcher at Fred Hutchinson Cancer Research Center in Seattle, whose work is primarily concerned with how diet and exercise affect a person's cancer risk. Up to 40 percent of people in Westernized countries like the U.S. have a tendency toward weight cycling, as it's academically termed. Previous studies have turned up mixed findings on the ways our bodies and behavior changes after repeated periods of weight loss and gain. But it's a commonly held belief that yo-yo diets increase our likelihood of gaining weight over time. Still, few studies have been able to prove this, so McTiernan set out to do so. © 2012 NBCNews.com
Link ID: 17182 - Posted: 08.20.2012
By ABBY ELLIN After downing 70 chicken wings in about an hour, Andrew Walen realized he had a problem. Oh, he had known something was wrong over the years. Normal people don’t consume 4,500 calories worth of food in one sitting, or order takeout for four when dining alone. But it took a maniacal feeding frenzy for him to finally accept the reality: He was a binge eater, and he had absolutely no control around food. “Ultimately, it was about numbing out and self-loathing,” said Mr. Walen, now 39 and a therapist in Columbia, Md. “There was this voice in my head that said, ‘You’re no good, worthless,’ and I turned to food.” Mr. Walen is one of an estimated eight million men and women in the United States who struggle with binge eating, defined as consuming large amounts of food within a two-hour period at least twice a week without purging, accompanied by a sense of being out of control. While about 10 percent of patients with anorexia and bulimia are men, binge eating is a problem shared almost equally by both sexes. A study published online in October and then in the March issue of The International Journal of Eating Disorders found that among 46,351 men and women ages 18 to 65, about 11 percent of women and 7.5 percent of men acknowledged some degree of binge eating. “Binge eating among men is associated with significant levels of emotional distress, obesity, depression and work productivity impairment,” said Richard Bedrosian, a study author and director of behavioral health and solution development at Wellness and Prevention Inc., which works with employers and health plans. Copyright 2012 The New York Times Company
By SABRINA TAVERNISE Adolescents in states with strict laws regulating the sale of snacks and sugary drinks in public schools gained less weight over a three-year period than those living in states with no such laws, a new study has found. The study, published Monday in Pediatrics, found a strong association between healthier weight and tough state laws regulating food in vending machines, snack bars and other venues that were not part of the regular school meal programs. Such snacks and drinks are known as competitive foods, because they compete with school breakfasts and lunches. The conclusions are likely to further stoke the debate over what will help reduce obesity rates, which have been rising drastically in the United States since the 1980s. So far, very little has proved effective and rates have remained stubbornly high. About a fifth of American children are obese, according to the Centers for Disease Control and Prevention. Public health experts have urged local and state governments to remove competitive foods from schools, and in recent years states have started to pass laws that restrict their sale, either banning them outright or setting limits on the amount of sugar, fat or calories they contain. The study tracked weight changes for 6,300 students in 40 states between 2004 and 2007, following them from fifth to eighth grade. They used the results to compare weight change over time in states with no laws regulating such food against those in states with strong laws and those with weak laws. © 2012 The New York Times Company
By Judy Stone As expected, the FDA recently announced approval of a second drug for obesity within a month, Vivus’ Qnexa, now renamed Qsymia. This approval is less of a surprise, as the data appeared somewhat stronger than that for Arena’s lorcaserin (Belviq). What was rather curious is that USA Today broke news of the drug’s approval before the FDA had announced their decision. The FDA is responding to the growing crisis of obesity. As noted in my post, “A Glut of Obesity Drugs?” the Centers for Disease Control and Prevention has established that more than one-third of adults in the United States are obese, defined as having a Body-Mass Index of > 30. In the U.S. alone, 78 million U.S. adults are obese; another 34% of adults are overweight > 25-29. So 70% of US adults have a problem with weight. This results in an estimated 300,000 deaths per year. And the burden of obesity is increasing, expected to rise to 42% by 2030, with an additional 11% prevalence of severe obesity (BMI >40, or ~80+ lbs overweight). Obesity is the second cause of preventable deaths, after smoking. The costs of obesity are also staggering, and may be as high as $147 billion per year, or roughly 9% of U.S. annual medical expenditures. The health crisis from obesity is drawing increasing attention, as outlined in the documentary, “The Weight of the Nation,” a project of HBO, the Institute of Medicine (IOM), the Centers for Disease Control and Prevention (CDC) the National Institutes of Health (NIH), the Michael & Susan Dell Foundation, and Kaiser Permanente. In my previous post, we looked at how obesity drugs work and how there are many different targets that are under study. Lorcaserin (Belviq) works by targeting the activation of the serotonin 5HT2C receptor in the brain. © 2012 Scientific American,
Link ID: 17118 - Posted: 08.04.2012
By Winnie Yu If you want to keep your cool, you might want to pass up those greasy wings and gooey dessert. A new study from the University of California, San Diego, suggests that people whose diets are higher in trans fats are more prone to aggression. Trans fats, or hydrogenated oils, have made the news in recent years because studies have strongly linked them to heart disease and cancer, and some locales have passed laws restricting their use. They are still common, however, in restaurant food and many grocery items. Beatrice Golomb, a physician and associate professor of medicine at U.C. San Diego, wondered if trans fats might affect behavior, after noting how they interact with a type of healthy fat. Past studies found that docosahexaenoic acid—or DHA, a long-chain omega-3 fatty acid—has a calming, antidepressant effect. Trans fats disrupt the chemical process that leads to the conversion of fatty acids into DHA, which led Golomb to suspect that trans fats might be linked to aggression. Her study, which was published in March in PLoS ONE, involved 1,018 men and women older than 20 who filled out a food questionnaire and several other surveys that measure impatience, irritability and aggression. Even after considering other influences, Golomb's team found a strong link between the intake of trans fats and aggression. “Trans-fatty acids were a more consistent predictor of aggression than some traditional risk factors such as age, male sex, education and smoking,” Golomb says. The findings were consistent across both sexes and across all ages, ethnicities and socioeconomic groups. © 2012 Scientific American
Link ID: 17110 - Posted: 08.01.2012