Chapter 13. Homeostasis: Active Regulation of the Internal Environment

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Jennifer Couzin-Frankel What if you could trick your body into thinking you were racing on a treadmill—and burning off calories at a rapid clip—while simply walking down the street? Changing our rate of energy expenditure is still far into the future, but work in mice explores how this might happen. Two teams of scientists suggest that activating immune cells in fat can convert the tissue from a type of fat that stores energy to one that burns it, opening up potential new therapies for obesity and diabetes. There are two types of fat in humans: white adipose tissue, which makes up nearly all the fat in adults, and brown adipose tissue, which is found in babies but disappears as they age. Brown fat protects against the cold (it’s also common in animals that hibernate), and researchers have found that mice exposed to cold show a temporary “browning” of some of their white fat. The same effect occurred in preliminary studies of people, where the browning—which creates a tissue known as beige fat—helps generate heat and burn calories. But cold is “the only stimulus we know that can increase beige fat mass or brown fat mass,” says Ajay Chawla, a physiologist at the University of California (UC), San Francisco. He wanted to better understand how cold caused this change in the tissue and whether there was a way to mimic cold and induce browning some other way. A few years ago, Chawla’s group had reported that cold exposure activated macrophages, a type of immune cell, in white adipose tissue. To further untangle what was going on, Chawla, his postdoc Yifu Qiu, and their colleagues used mice that lacked interleukin-4 (IL-4) and interleukin-13, proteins that help activate macrophages. When they exposed these mice to the cold, the animals developed far fewer beige fat cells than did normal animals, suggesting that macrophages were key to browning of white fat. © 2014 American Association for the Advancement of Science

Keyword: Obesity
Link ID: 19732 - Posted: 06.14.2014

by Lauren Hitchings Being cold can burn calories but no one wants to freeze just to sculpt their muffin-top. Soon we may not have to. Researchers have identified immune molecules triggered by cold temperatures that make obese mice lose weight – without the need for the mercury to drop. Humans and other mammals respond to cold in two ways. On the surface, we shiver to burn energy and produce a quick burst of heat. On a deeper level, as Ajay Chawla at the University of California, San Francisco, and his colleagues recently discovered, cold temperatures send signals to immune molecules called macrophages. They, in turn, release other molecules that convert energy-storing white fat into another type that burns energy. Babies and some hibernating animals have lots of these energy-burning cells – known as brown fat – but it almost all disappears as people age. We now know that cold temperatures can trigger a "browning" of white fat in adults – converting some of their white fat into an intermediate form called beige fat. It may seem counterintuitive for our bodies to use up fat stores when we get cold, but think of the white fat as the wooden walls of a log cabin – having them there is a good way to keep warm generally, but when the cold sets in, you're going to want firewood – brown or beige fat, to burn. Now Chawla's team have identified interleukin-4 and interleukin-13 as the signalling molecules that kick-start the transition of white fat to its darker counterpart. What's more, by injecting mice with interleukin-4 four times over a period of eight days, the team was able to bypass the physical cold stimulus and activate the pathway biochemically. © Copyright Reed Business Information Ltd.

Keyword: Obesity
Link ID: 19719 - Posted: 06.10.2014

Jennifer Couzin-Frankel What if you could trick your body into thinking you were racing on a treadmill—and burning off calories at a rapid clip—while simply walking down the street? Changing our rate of energy expenditure is still far into the future, but work in mice explores how this might happen. Two teams of scientists suggest that activating immune cells in fat can convert the tissue from a type of fat that stores energy to one that burns it, opening up potential new therapies for obesity and diabetes. There are two types of fat in humans: white adipose tissue, which makes up nearly all the fat in adults, and brown adipose tissue, which is found in babies but disappears as they age. Brown fat protects against the cold (it’s also common in animals that hibernate), and researchers have found that mice exposed to cold show a temporary “browning” of some of their white fat. The same effect occurred in preliminary studies of people, where the browning—which creates a tissue known as beige fat—helps generate heat and burn calories. But cold is “the only stimulus we know that can increase beige fat mass or brown fat mass,” says Ajay Chawla, a physiologist at the University of California (UC), San Francisco. He wanted to better understand how cold caused this change in the tissue and whether there was a way to mimic cold and induce browning some other way. A few years ago, Chawla’s group had reported that cold exposure activated macrophages, a type of immune cell, in white adipose tissue. To further untangle what was going on, Chawla, his postdoc Yifu Qiu, and their colleagues used mice that lacked interleukin-4 (IL-4) and interleukin-13, proteins that help activate macrophages. When they exposed these mice to the cold, the animals developed far fewer beige fat cells than did normal animals, suggesting that macrophages were key to browning of white fat. © 2014 American Association for the Advancement of Science

Keyword: Obesity
Link ID: 19709 - Posted: 06.07.2014

A moderate dose of MDMA. commonly known as Ecstasy or Molly, that is typically nonfatal in cool, quiet environments can be lethal in rats exposed to conditions that mimic the hot, crowded, social settings where the drug is often used by people, a study finds. Scientists have identified the therapeutically-relevant cooling mechanism to enable effective interventions when faced with MDMA-induced hyperthermia. The study, publishing tomorrow in the Journal of Neuroscience, was conducted by researchers at the National Institute on Drug Abuse’s Intramural Research Program (NIDA IRP). NIDA is a part of the National Institutes of Health. While MDMA can have a range of adverse health effects, previous studies have shown that high doses of MDMA increase body temperature, while results with moderate doses were inconsistent. This has led some people to assume that the drug is harmless if taken in moderation. However, this study shows that in rats even moderate doses of MDMA in certain environments can be dangerous because it interferes with the body’s ability to regulate temperature. “We know that high doses of MDMA can sharply increase body temperature to potentially lead to organ failure or even death,” said NIDA Director Dr. Nora D. Volkow. “However, this current study opens the possibility that even moderate doses could be deadly in certain conditions.” It is impossible to predict who will have an adverse reaction even to a low dose of MDMA. However, in this study scientists gave the rats low to moderate doses that have been shown in past studies to not be fatal. They monitored the rats to determine drug-induced changes in brain and body temperature and in the body’s ability to cool itself through blood vessel dilation. When rats were alone and in a room-temperature environment, a moderate dose of MDMA modestly increased brain and body temperature and moderately diminished the rats’ ability to eliminate excessive heat. However, when researchers injected the same dose in rats that were either in a warmer environment or in the presence of another rat in the cage, brain temperature increased, causing death in some rats. These fatal temperature increases were because the drug interfered with the body’s ability to eliminate heat.

Keyword: Drug Abuse
Link ID: 19695 - Posted: 06.05.2014

By GRETCHEN REYNOLDS If you are aiming to lose weight by revving up your exercise routine, it may be wise to think of your workouts not as exercise, but as playtime. An unconventional new study suggests that people’s attitudes toward physical activity can influence what they eat afterward and, ultimately, whether they drop pounds. For some time, scientists have been puzzled — and exercisers frustrated — by the general ineffectiveness of exercise as a weight-loss strategy. According to multiple studies and anecdotes, most people who start exercising do not lose as much weight as would be expected, given their increased energy expenditure. Some people add pounds despite burning hundreds of calories during workouts. Past studies of this phenomenon have found that exercise can increase the body’s production of appetite hormones, making some people feel ravenous after even a light workout and prone to consume more calories than they expended. But that finding, while intriguing, doesn’t fully explain the wide variability in people’s post-exercise eating habits. So, for the new study, published in the journal Marketing Letters, French and American researchers turned to psychology and the possible effect that calling exercise by any other name might have on people’s subsequent diets. In that pursuit, the researchers first recruited 56 healthy, adult women, the majority of them overweight. The women were given maps detailing the same one-mile outdoor course and told that they would spend the next half-hour walking there, with lunch to follow. Half of the women were told that their walk was meant to be exercise, and they were encouraged to view it as such, monitoring their exertion throughout. The other women were told that their 30-minute outing would be a walk purely for pleasure; they would be listening to music through headphones and rating the sound quality, but mostly the researchers wanted them to enjoy themselves. When the women returned from walking, the researchers asked each to estimate her mileage, mood and calorie expenditure. © 2014 The New York Times Company

Keyword: Obesity; Emotions
Link ID: 19691 - Posted: 06.04.2014

by Catherine de Lange Could your ideal diet be written in your genes? That's the promise of nutrigenomics, which looks for genetic differences in the way people's bodies process food so that diets can be tailored accordingly. The field had a rocky start after companies overhyped its potential, but with advances in genetic sequencing, and a slew of new studies, the concept is in for a reboot. Last week, Nicola Pirastu at the University of Trieste, Italy, and his colleagues told the European Society of Human Genetics meeting in Milan that diets tailored to genes that are related to metabolism can help people lose weight. The team used the results of a genetic test to design specific diets for 100 obese people that also provided them with 600 fewer calories than usual. A control group was placed on a 600-calorie deficit, untailored diet. After two years, both groups had lost weight, but those in the nutrigenetic group lost 33 per cent more. They also took only a year to lose as much weight as the group on the untailored diet lost in two years. If this is shown to work in bigger, randomised trials, it would be fantastic, says Ana Valdes, a genetic epidemiologist at the University of Nottingham, UK. Some preliminary information will soon be available from Europe's Food4Me project. It is a study of 1200 people across several countries who were given either standard nutrition advice, or a similarly genetically tailored diet. "It's testing whether we can get bigger changes in diet using a personalised approach, and part of that is using genetic information," says team member John Mathers, director of the Human Nutrition Research Centre at Newcastle University, UK. © Copyright Reed Business Information Ltd.

Keyword: Chemical Senses (Smell & Taste); Obesity
Link ID: 19690 - Posted: 06.04.2014

By SANFORD E. DeVOE IN recent years we have seen plenty of studies of the impact of fast food on our bodies. But what about our psychological health? It stands to reason that fast food would have an effect on our mental state. From its production to its consumption, fast food both embodies and symbolizes speed and instant gratification. Moreover, through extensive franchising and large advertising budgets, fast-food companies shape many of the cues in our everyday environment. While the ubiquity of fast food is undoubtedly driven by consumer demand for instant gratification, it may also play a role in exacerbating that very impatience — and not just for food, but in many facets of our lives. In a series of recent papers, I joined two of my colleagues at the University of Toronto, Julian House and Chen-Bo Zhong, in examining this question. We began our experiments by prompting participants with reminders of fast food, like pictures of fast-food logos or having them recall recent experiences of eating fast food. We then gave them a number of tasks to complete. Across several studies, we found that thoughts of fast food spurred participants to hurry through reading a paragraph describing their city; express a greater desire for timesaving products; report less happiness from savoring a beautiful opera duet; and save less for tomorrow. These findings — that our associations with fast food can induce greater impatience — are interesting in their own right, but they are especially important because of the pervasiveness of fast food in our modern environment. We also took our investigation a step further, to consider whether the prevalence of fast-food restaurants in our neighborhoods might undercut our well-being. There is a lengthy epidemiology literature demonstrating a link between the number of fast-food restaurants and obesity. While the consequences of fast food for our health seem quite obvious, we wondered what these same methods might reveal regarding impatience. © 2014 The New York Times Company

Keyword: Obesity
Link ID: 19680 - Posted: 06.02.2014

By NICHOLAS BAKALAR Several observational studies have suggested that drinking diet soda may encourage weight gain, but a new randomized trial finds that it is not so. The study, published in the June issue of Obesity and paid for by the American Beverage Association, suggests that diet drinks may be better for weight loss than plain water. The study tested 303 men and women who followed the same diet for 12 weeks. But half were randomly assigned to drink at least 24 ounces of water daily, and the rest the same amount of artificially sweetened drinks. After controlling for age, sex, ethnicity and initial weight and blood pressure, researchers found that those who drank diet drinks lost an average of 14.2 pounds, compared with a 10-pound loss for the water drinkers. The mechanism, the authors write, is unclear, but the group on diet drinks reported slightly lower scores on a questionnaire measuring the degree of feelings of hunger. “There’s no magic in diet soda,” said the lead author, James O. Hill, a professor of health and wellness at the University of Colorado. But the less intense feelings of hunger among the drinkers, he said, may have made it easier for them to adhere to the diet. “From everything we know about diet soda,” he continued, “this result was totally expected. There’s not a single randomized controlled trial that shows the opposite.” © 2014 The New York Times Company

Keyword: Obesity
Link ID: 19677 - Posted: 05.31.2014

Carl Zimmer All animals do the same thing to the food they eat — they break it down to extract fuel and building blocks for growing new tissue. But the metabolism of one species may be profoundly different from another’s. A sloth will generate just enough energy to hang from a tree, for example, while some birds can convert their food into a flight from Alaska to New Zealand. For decades, scientists have wondered how our metabolism compares to that of other species. It’s been a hard question to tackle, because metabolism is complicated — something that anyone who’s stared at a textbook diagram knows all too well. As we break down our food, we produce thousands of small molecules, some of which we flush out of our bodies and some of which we depend on for our survival. An international team of researchers has now carried out a detailed comparison of metabolism in humans and other mammals. As they report in the journal PLOS Biology, both our brains and our muscles turn out to be unusual, metabolically speaking. And it’s possible that their odd metabolism was part of what made us uniquely human. When scientists first began to study metabolism, they could measure it only in simple ways. They might estimate how many calories an animal burned in a day, for example. If they were feeling particularly ambitious, they might try to estimate how many calories each organ in the animal’s body burned. Those tactics were enough to reveal some striking things about metabolism. Compared with other animals, we humans have ravenous brains. Twenty percent of the calories we take in each day are consumed by our neurons as they send signals to one another. Ten years ago, Philipp Khaitovich of the Max Planck Institute of Evolutionary Anthropology and his colleagues began to study human metabolism in a more detailed way. They started making a catalog of the many molecules produced as we break down food. “We wanted to get as much data as possible, just to see what happened,” said Dr. Khaitovich. To do so, the scientists obtained brain, muscle and kidney tissues from organ donors. They then extracted metabolic compounds like glucose from the samples and measured their concentrations. All told, they measured the levels of over 10,000 different molecules. © 2014 The New York Times Company

Keyword: Evolution
Link ID: 19670 - Posted: 05.28.2014

By JANE E. BRODY Bowels, especially those that don’t function properly, are not a popular topic of conversation. Most of the 1.4 million Americans with inflammatory bowel disease — Crohn’s disease or ulcerative colitis — suffer in silence. But scientists are making exciting progress in understanding the causes of these conditions and in developing more effective therapies. And affected individuals have begun to speak up to let others know that they are not alone. Abby Searfoss, 21, who just graduated from the University of Connecticut, shared her story not in a support group, but online. She was a high school senior in Ridgefield, Conn., when she became ill. After she researched her symptoms on the Internet, she realized that, like her father, she had developed Crohn’s disease. Her father had been very ill, losing 40 pounds, spending weeks in the hospital and undergoing surgery. Soon after Ms. Searfoss’s own diagnosis, her two younger sisters learned that they, too, had the condition. In Crohn’s disease, the immune system attacks cells in the digestive tract, most often the end of the small intestine and first part of the colon, or large intestine. Sufferers may experience bouts of abdominal pain, cramps and diarrhea, often accompanied by poor appetite, fatigue and anxiety. “You don’t go anywhere without checking where the bathroom is and how many stalls it has,” said Dr. R. Balfour Sartor, a gastroenterologist at the University of North Carolina School of Medicine and a patient himself. “The fear of incontinence is huge.” Neither Crohn’s disease nor its less common relative ulcerative colitis, which affects only the large intestine, is curable (except, in the latter instance, by removing the entire colon). But research into what predisposes people to develop these conditions has resulted in more effective treatments and has suggested new ways to prevent the diseases in people who are genetically susceptible. © 2014 The New York Times Company

Keyword: Stress; Neuroimmunology
Link ID: 19655 - Posted: 05.25.2014

By ANAHAD O'CONNOR Americans have long been told that the cure for obesity is simple: Eat fewer calories and exercise more. But a new documentary challenges that notion, making the case that Americans have been misled by the idea that we get fat simply because we consume more calories than we expend. The film explores what it sees as some of the more insidious corporate and political forces behind the rise of childhood obesity, and it examines whether increasing levels of sugar consumption have played an outsized role in the epidemic. The film, called “Fed Up,” has as executive producers Katie Couric, the former anchor of “The CBS Evening News,” and Laurie David, who was also a producer of the global warming documentary “An Inconvenient Truth.” Ms. Couric, who narrates the film, said she came up with the idea after years of covering the obesity epidemic left her with more questions than answers. “What struck me was that the more I reported on childhood obesity and the longer I was in this business, the worse the problem seemed to be getting,” Ms. Couric said in an interview. “I felt like we were never really giving people a handle on what was causing this and why the rates were skyrocketing the way they were.” The film draws on commentary from obesity experts and nutrition scientists, and it tells the stories of several obese children around the country who struggle to lose weight despite strict dieting and in some cases hours of daily exercise. But at the heart of the film is a question that is widely debated among scientists: Are all calories equal? Dr. David Ludwig, the director of the obesity program at Boston Children’s Hospital, argues in the film that they are not. In recent studies, Dr. Ludwig has shown that high-carbohydrate diets appear to slow metabolic rates compared to diets higher in fat and protein, so that people expend less energy even when consuming the same number of calories. Dr. Ludwig has found that unlike calories from so-called low glycemic foods (like beans, nuts and non-starchy vegetables), those from high glycemic foods (such as sugar, bread and potatoes) spike blood sugar and stimulate hunger and cravings, which can drive people to overeat. © 2014 The New York Times Company

Keyword: Obesity
Link ID: 19596 - Posted: 05.10.2014

Brian Owens Surveys of people's eating habits have suggested a link between fibre intake and weight loss, but exactly how fibre helps to regulate weight has been unclear. A study of mouse metabolism suggests that a product of fibre fermentation may be directly affecting the hypothalamus, a region of the brain involved in regulating appetite. People have long been told that a diet high in fibre can help to fight obesity, but how it does so has been unclear. “There has been lots of epidemiological information showing a relationship between fibre and obesity, but no one has been able to connect the epidemiological results with actual mechanisms,” says Jimmy Bell, a biochemist at Imperial College London who worked on the research, published today in Nature Communications1. Until now, a high-fibre diet was thought to help keep weight down by stimulating the release of appetite-suppressing hormones in the gut2, says Bell, but humans do not seem to show the same increase in these hormones that mice do. So Bell and his colleagues decided to look elsewhere. An obvious candidate, they thought, might be one of the products of fibre fermentation in the gut. In particular they focused on the short-chain fatty acid acetate, because it is the most abundant and is known to circulate throughout the bloodstream. They fed mice fibre labelled with carbon-13, which has an additional neutron from the more common carbon-12 that gives its nuclei a magnetic spin and therefore makes it easy to track as it progresses through the body's chemical reactions. The fibre was fermented as usual into acetate, which turned up not only in the gut, but also in the hypothalamus, a part of the brain known to be involved in regulating appetite. There, the researchers found, it was metabolized through the glutamine-glutamate cycle, which is involved in controlling the release of neurotransmitters associated with appetite control. The same model has been proposed for acetate metabolism after drinking alcohol. © 2014 Nature Publishing Group,

Keyword: Obesity
Link ID: 19557 - Posted: 04.30.2014

By Lenny Bernstein FILE - In this Oct. 7, 2013 file photo, workers collect red grapes in the vineyards of the famed Chateau Haut Brion, a Premier Grand Cru des Graves, during the grape harvest in Pessac-Leognan, near Bordeaux, southwestern France. Global warming makes feeding the world harder and more expensive, a United Nations scientific panel said. A warmer world will push food prices higher, trigger Red wine gets all the good press for the cardiovascular benefits of the flavonoids it contains, but U.S. Department of Agriculture researchers are reporting that one white wine grape has the reds beat when it comes to slowing weight gain and lowering cholesterol, at least in laboratory animals. The researchers put hamsters on a high-fat diet supplemented by flour made from the seeds of grapes used for chardonnay, syrah and cabernet sauvignon wines. They found that the white grapes easily beat the reds in slowing the hamsters’ weight gain and limiting production of cholesterol. They believe the higher levels of flavonoids in the chardonnay grape seeds altered the work of genes related to fat metabolism. They also had an anti-inflammatory effect, according to a study the USDA scientists published in the Journal of Agricultural and Food Chemistry in February. In part, the researchers say in another paper yet to be published, the anti-oxidant compounds in the chardonnay grape seeds may work with bacteria in the gut to produce beneficial effects. The flour production also provides grape-growers a way to use seeds that currently are discarded and dumped during the chardonnay production. The Mayo Clinic has begun human trials to determine whether the same results can be achieved, said Wally Yokoyama, a research chemist for the USDA in Albany, Calif., and one of the authors of the two studies. The innovation is one of many in a new USDA report released this week. © 1996-2014 The Washington Post

Keyword: Obesity
Link ID: 19545 - Posted: 04.29.2014

By LAWRENCE K. ALTMAN Douglas L. Coleman, a Canadian-born scientist who upset scientific dogma by discovering that genes — not willpower, eating habits or other behaviors — could cause obesity in some people, died on April 16 at his home in Lamoine, Me. He was 82. The cause was aggressive basal cell cancer, said a spokeswoman for the Jackson Laboratory in Bar Harbor, Me., where Dr. Coleman spent his entire research career. Beginning in the 1960s, Dr. Coleman’s research showed that a blood-borne substance could curb hunger. In the 1990s, his findings led Dr. Jeffrey M. Friedman’s team at the Rockefeller University in Manhattan to identify the gene that produces the appetite suppressant leptin, which is released by fat cells. For their work, Dr. Coleman and Dr. Friedman shared the prestigious Lasker Award for basic medical research in 2010. Their discoveries upended the conventional wisdom that fat cells are simply energy storage bins, and demonstrated that fat tissue is an endocrine organ required for normal development. Scientists have learned from their research and others’ that fat produces a variety of hormones, cytokines and other chemicals in the body’s natural weight-control system. Douglas Leonard Coleman was born on Oct. 6, 1931, in Stratford, Ontario. Influenced by his father, Leonard, who repaired radios and refrigerators for a living, Douglas spent much of his youth investigating how things worked by taking them apart. He earned a chemistry degree from McMaster University in Hamilton, Ontario, and a doctorate in biochemistry from the University of Wisconsin. In 1958, facing poor employment prospects in academia or industry in Canada, he became a research scientist at the Jackson Laboratory, which studies mouse genetics to learn about human disease. He intended to spend a year or two there to gain experience in genetics and immunology, but stayed until he retired in 1991. After retiring, he turned a tract of land he owned into a nature preserve. © 2014 The New York Times Company

Keyword: Obesity; Genes & Behavior
Link ID: 19538 - Posted: 04.26.2014

Victoria Colliver, Erin Allday Women who gain too much or too little weight during pregnancy can greatly increase their baby's risk of being overweight or obese as a young child, according to a study by Kaiser Permanente researchers. Researchers examined the health records from 4,145 Northern California Kaiser members who filled out a health survey between 2007 and 2009 and subsequently gave birth. They found that women who exceeded the Institute of Medicine's revised 2009 guidelines for weight gain during pregnancy were 46 percent more likely than women who met the guidelines to have an obese or overweight child between the ages of 2 and 5 years old. Under the new guidelines, women who are obese - defined as those with a body mass index, or BMI, of 30 or higher - should gain 11 to 20 pounds. Overweight women - with BMIs between 25 and 29 - can gain 15 to 25 pounds. And normal-weight women are recommended to gain between 25 and 35 pounds. Those who are underweight - with BMIs under 18.5 - are to gain 28 to 40 pounds. Women who had a healthy BMI before their pregnancy but gained less weight than recommended were 63 percent more likely than those who met the guidelines to have an obese or overweight child. Meanwhile, healthy-weight women who exceeded the guidelines were 79 percent more likely to have an overweight child. Researchers suggested gaining too little or too much weight may permanently affect the body's mechanisms that manage energy balance and metabolism. The study, which is considered the largest to examine the new guidelines in relationship to childhood obesity, was published April 14 in the American Journal of Obstetrics and Gynecology. © 2014 Hearst Communications, Inc.

Keyword: Obesity; Development of the Brain
Link ID: 19524 - Posted: 04.23.2014

by Bethany Brookshire Many of us have experienced that depressing sight: The bottom of the ice cream pint. You get to the end of your favorite movie and suddenly realize the ice cream is gone — and you’re far too full for comfort. We’re left wondering why we did it. But when it comes to forgetting ourselves and bingeing on the pint, the power of habit can be strong. It could be that our previous eating experiences make us helpless to our habits. A new study in rats, published April 2 in the Journal of Neuroscience, shows that long-term exposure to bursts of sweet, fatty foods produces animals that appear to seek food not out of hunger, but out of habit. And neural changes associated with habit formation accompany the behavioral changes. The results suggest that repeated binges on sugar and fat could tilt the neural balance from taking a few scoops of Cherry Garcia toward mindlessly reaching the bottom of the bowl. But while the results show us the power of habit, bad habits don’t necessarily make us food addicts. Teri Furlong and her colleagues at the University of Sydney in Australia were interested in how animals control behaviors. Some behaviors are goal-directed, while others are more efficiently taken care of with habits. Furlong describes habits as “behaviors where we are not thinking about the consequences as we do them.” Many habits can be useful things to develop — eating breakfast daily or brushing your teeth, for example. But other habits can become maladaptive, such as drug abuse — or binge eating. © Society for Science & the Public 2000 - 2013.

Keyword: Anorexia & Bulimia; Drug Abuse
Link ID: 19519 - Posted: 04.22.2014

Feeling peeved at your partner? You may want to check your blood sugar. A new study suggests that low levels of glucose in the blood may increase anger and aggression between spouses. The researchers say their findings suggest a connection between glucose and self-control, but other experts disagree about the study’s implications. Glucose is a source of fuel for the body, and its levels in the blood rise and fall throughout the day, as the body metabolizes meals that include carbohydrates. Researchers have suspected since the 1960s that low glucose or swings in glucose may play a role in human aggression. In two 2010 studies, psychologist Brad Bushman of Ohio State University, Columbus, attempted to figure out just what that role is, first by measuring vengefulness among people with symptoms of type 2 diabetes (a disease in which the body can’t regulate glucose levels properly), and then by providing sweetened drinks to strangers competing on a computerized task. Both studies suggested that higher glucose levels can make strangers less likely to treat each other aggressively. Bushman wondered about the relationship between glucose levels and aggression among romantic couples. So he and colleagues at the University of Kentucky and the University of North Carolina recruited 107 married couples and equipped them with blood glucose meters, voodoo dolls, and 51 pins to record their glucose and anger levels over time. For 21 days, the couples used the meters to measure their glucose levels each morning before breakfast and each evening before bed. They also assessed how angry they were at their spouse at the end of each day, by recording how many of the 51 pins they stuck into their voodoo dolls just before bed when their partner wasn’t looking. After 21 days, the couples were invited into the lab. There, they played a computer game that allowed them to blast their spouse with an unpleasant noise—a mixture of fingernails scratching a chalkboard, ambulance sirens, and dentist drills—as loudly and for as long as he or she wanted, as a proxy for their willingness to act aggressively and make their partner suffer. © 2014 American Association for the Advancement of Science.

Keyword: Emotions; Obesity
Link ID: 19488 - Posted: 04.15.2014

By SABRINA TAVERNISE WASHINGTON — Researchers at the University of North Carolina published a paper last week that introduced another wrinkle into the debate about childhood obesity. They disputed recent findings that obesity among young children had fallen since 2004, arguing that a longer view — using data all the way back to 1999 — showed that these youngsters were not really getting any thinner. So which view is correct? The answer seems to be both. Obesity has become a major health problem in the United States, affecting about 17 percent of Americans ages 2 to 19, up from about 5 percent in the early 1970s. The rate rose for years but then leveled off, and the current debate centers on whether obesity has begun to decline in the youngest of these children. The question has drawn considerable attention not just because scientists disagree on the answer, but also because it has a political dimension: The issue has been vigorously championed by Michelle Obama, the first lady. The North Carolina researchers and the federal team that produced the earlier findings both relied on the same data from the National Health and Nutrition Examination Survey. It is considered the gold standard in health research because height and weight are measured by a health professional, not the respondents themselves. But instead of looking only at the past decade of data on children ages 2 to 5, the North Carolina researchers looked at 14 years’ worth. An unusual spike in obesity among these children in 2003 created the false appearance of a later decline, they concluded, so comparing 2012 to 1999 gave a truer view of the trends. © 2014 The New York Times Company

Keyword: Obesity
Link ID: 19487 - Posted: 04.15.2014

by Alix Spiegel It was late, almost 9 at night, when Justin Holden pulled the icy pizza box from the refrigerator at the Brookville Supermarket in Washington, D.C. He stood in front of the open door, scanning the nutrition facts label. A close relative had recently had a heart attack, and in the back of his mind there was this idea stalking him: If he put too much salt in his body, it would eventually kill him. For this reason the information in the label wasn't exactly soothing: 1,110 milligrams of sodium seemed like a lot. But there was even worse-sounding stuff at the bottom of the label. Words like "diglyceride," with a string of letters that clearly had no business sitting next to each other. It suggested that something deeply unnatural was sitting inside the box. "Obviously it's not good for me," the 20ish Holden said. "But, hopefully, I can let it slide in." He tucked the pizza under his arm, and headed one aisle over for a sports drink. Who among us has not had a moment like this? That intimate tete-a-tete with the nutrition label, searching out salt, sugar, fat, trying to discern: How will you affect me? Are you good? Or are you bad? Here's the thing you probably haven't stopped to consider: how the label itself is affecting you. "Labels are not just labels; they evoke a set of beliefs," says , a clinical psychologist who does research at the Columbia Business School in New York. A couple of years ago, Crum found herself considering what seems like a pretty strange question. She wanted to know whether the information conveyed by a nutritional label could physically change what happens to you — "whether these labels get under the skin literally," she says, "and actually affect the body's physiological processing of the nutrients that are consumed." ©2014 NPR

Keyword: Obesity; Attention
Link ID: 19486 - Posted: 04.15.2014

By Helen Briggs BBC News Young men with an eating disorder are not getting the help and support they need because of a perceptions about a "women's illness", say researchers. Men are underdiagnosed and undertreated for anorexia and other eating disorders, despite making up about a quarter of cases, a UK study suggests. Frontline health workers have a key role in identifying eating disorders in young men, they report in BMJ Open. Men are under pressure to have the "ideal" body image, says a charity. Researchers from the University of Oxford and University of Glasgow interviewed 39 young people aged 16 to 25, including 10 men, about their experiences of diagnosis, treatment and support for eating disorders. They say young men with eating disorders were "underdiagnosed, undertreated and underresearched". This is partly because the men themselves were unaware of the symptoms, despite purging, not eating for days or obsessive calorie counting, they said. "Our findings suggest that men may experience particular problems in recognising that they may have an eating disorder as a result of the continuing cultural construction of eating disorders as uniquely or predominantly a female problem," said Dr Ulla Raisanen and Dr Kate Hunt. One man said he thought eating disorders only affected "fragile teenage girls"; another said he thought eating disorders were "something girls got"; while one was told by his doctor to "man up". Others said they often had to wait a long time for specialist referral and had sometimes been misdiagnosed. GPs and other professionals such as teachers have a key role in improving the outlook for men with eating disorders by challenging misconceptions, the researchers said. BBC © 2014

Keyword: Anorexia & Bulimia; Sexual Behavior
Link ID: 19469 - Posted: 04.10.2014