Chapter 13. Homeostasis: Active Regulation of the Internal Environment

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By ANAHAD O’CONNOR Anyone who has ever been on a diet knows that the standard prescription for weight loss is to reduce the amount of calories you consume. But a new study, published Tuesday in JAMA, may turn that advice on its head. It found that people who cut back on added sugar, refined grains and highly processed foods while concentrating on eating plenty of vegetables and whole foods — without worrying about counting calories or limiting portion sizes — lost significant amounts of weight over the course of a year. The strategy worked for people whether they followed diets that were mostly low in fat or mostly low in carbohydrates. And their success did not appear to be influenced by their genetics, a finding that casts doubt on the increasingly popular idea that different diets should be recommended to people based on their DNA makeup. The research lends strong support to the notion that diet quality, not quantity, is what helps people lose and manage their weight most easily in the long run. It also suggests that health authorities should shift away from telling the public to obsess over calories and instead encourage Americans to avoid processed foods that are made with refined starches and added sugar, like bagels, white bread, refined flour and sugary snacks and beverages, said Dr. Dariush Mozaffarian, a cardiologist and dean of the Friedman School of Nutrition Science and Policy at Tufts University. “This is the road map to reducing the obesity epidemic in the United States,” said Dr. Mozaffarian, who was not involved in the new study. “It’s time for U.S. and other national policies to stop focusing on calories and calorie counting.” The new research was published in JAMA and led by Christopher D. Gardner, the director of nutrition studies at the Stanford Prevention Research Center. It was a large and expensive trial, carried out on more than 600 people with $8 million in funding from the National Institutes of Health, the Nutrition Science Initiative and other groups. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24685 - Posted: 02.21.2018

By KAREN CROUSE — Shortly before Adam Rippon’s breakthrough victory at the United States figure skating championships, Brian Boitano crossed paths with him and asked how he was doing. Boitano, the 1988 Olympic gold medalist, expected Rippon to rave about his jumps or his signature spins. Instead, Boitano said, Rippon pulled back his shoulders, puffed out his chest and proudly proclaimed, “I’ve never been thinner.” It was 2016, and Rippon was subsisting mostly on a daily diet of three slices of whole grain bread topped with miserly pats of the spread I Can’t Believe It’s Not Butter. He supplemented his “meals” with three cups of coffee, each sweetened with six packs of Splenda. “It makes me dizzy now to think about it,” Rippon said in a interview last month. In the lead up to the men’s singles competition at the Olympics this week, Rippon has been celebrated for his robust thigh and gluteal muscles, not to mention his tight abs. He weighs 150 pounds, 10 more than he did in 2016, when he took drastic measures to stretch his 5-foot-7 body, as if it were putty, into a leaner frame that he thought would be more aesthetically pleasing to the judges. Rippon, 28, remembers wanting to resemble skaters like Nathan Chen and Vincent Zhou, his teenage Olympic teammates, whose matchstick bodies facilitate explosive quadruple jumps. “I looked around and saw my competitors, they’re all doing these quads, and at the same time they’re a head shorter than me, they’re 10 years younger than me and they’re the size of one of my legs,” Rippon said. © 2018 The New York Times Company

Keyword: Anorexia & Bulimia
Link ID: 24654 - Posted: 02.13.2018

Nicola Davis While you might be tempted to wolf down a sandwich or gobble up your dinner, researchers say there may be advantages to taking your time over a meal. According to a study looking at type 2 diabetics, eating slowly could help prevent obesity, with researchers finding a link to both lower waist circumference and body mass index (BMI). “Interventions aimed at altering eating habits, such as education initiatives and programmes to reduce eating speed, may be useful in preventing obesity and reducing the risk of non-communicable diseases,” the authors write. The latest study is not the first to suggest that taking a sedate pace at the dinner table could be beneficial: various pieces of work have hinted that those who eat quickly are more likely to be overweight, have acid reflux and have metabolic syndrome. The latest study, published in the journal BMJ Open by researchers in Japan, looked at data collected though health checkups and claims from more than 59,700 individuals as part of health insurance plans, with data spanning from 2008 to mid-2013. As part of the health checkup, participants were asked seven questions about their lifestyle, including whether their eating speed was fast, normal or slow, whether they snacked after dinner three times or more a week, and whether they skipped breakfast three times or more a week. © 2018 Guardian News and Media Limited

Keyword: Obesity; Attention
Link ID: 24653 - Posted: 02.13.2018

By ANDREW JACOBS SANTIAGO, Chile — They killed Tony the Tiger. They did away with Cheetos’ Chester Cheetah. They banned Kinder Surprise, the chocolate eggs with a hidden toy. The Chilean government, facing skyrocketing rates of obesity, is waging war on unhealthy foods with a phalanx of marketing restrictions, mandatory packaging redesigns and labeling rules aimed at transforming the eating habits of 18 million people. Nutrition experts say the measures are the world’s most ambitious attempt to remake a country’s food culture, and could be a model for how to turn the tide on a global obesity epidemic that researchers say contributes to four million premature deaths a year. “It’s hard to overstate how significant Chile’s actions are — or how hard it has been to get there in the face of the usual pressures,” said Stephen Simpson, director of the Charles Perkins Centre, an organization of scholars focused on nutrition and obesity science and policy. The multibillion dollar food and soda industries have exerted those pressures to successfully stave off regulation in many other countries. Since the food law was enacted two years ago, it has forced multinational behemoths like Kellogg to remove iconic cartoon characters from sugary cereal boxes and banned the sale of candy like Kinder Surprise that use trinkets to lure young consumers. The law prohibits the sale of junk food like ice cream, chocolate and potato chips in Chilean schools and proscribes such products from being advertised during television programs or on websites aimed at young audiences. Beginning next year, such ads will be scrubbed entirely from TV, radio and movie theaters between 6 a.m. and 10 p.m. In an effort to encourage breast-feeding, a ban on marketing infant formula kicks in this spring. The linchpin of the initiative is a new labeling system that requires packaged food companies to prominently display black warning logos in the shape of a stop sign on items high in sugar, salt, calories or saturated fat. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24633 - Posted: 02.08.2018

By RONI CARYN RABIN Most dieters know the hard truth: Sticking to a weight loss regimen gets more difficult as the day wears on. But while those who give in to food cravings and binge at night may blame flagging willpower, a new study suggests the problem could lie in the complex orchestra of hormones that drive hunger and signal feelings of satiety, or fullness. The small study of 32 obese men and women, half of whom had a habit of binge eating, suggests that satiety hormones may be lower during the evening hours, while hunger hormones rise toward nightfall and may be stoked even higher by stressful situations. Overweight binge eaters may be particularly susceptible to the influence of fluctuations in these appetite-regulating hormones, the researchers found. “There’s more opportunity to eat in the evening, but this study is showing that hormonal responses are setting them up to do this,” said Susan Carnell, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins University School of Medicine who was a first author of the study along with Charlotte Grillot of Florida State University. It’s not clear whether these hormonal patterns precede and cause the binge eating behaviors or are conditioned by an individual’s eating habits, Dr. Carnell said. But either way, “you can get stuck in the cycle.” The study is an important reminder that myriad factors contribute to weight gain, and that shaming and blaming people for their weight problems is inappropriate, said Kelly Costello Allison, director of the Center for Weight and Eating Disorders at the University of Pennsylvania, who was not involved in the new research. © 2018 The New York Times Company

Keyword: Obesity; Hormones & Behavior
Link ID: 24591 - Posted: 01.31.2018

By JANE E. BRODY The media love contrarian man-bites-dog stories that purport to debunk long-established beliefs and advice. Among the most popular on the health front are reports that saturated fats do not cause heart disease and that the vegetable oils we’ve been encouraged to use instead may actually promote it. But the best-established facts on dietary fats say otherwise. How well polyunsaturated vegetable oils hold up health-wise when matched against saturated fats like butter, beef fat, lard and even coconut oil depends on the quality, size and length of the studies and what foods are eaten when fewer saturated fats are consumed. So before you succumb to wishful thinking that you can eat well-marbled steaks, pork ribs and full-fat dairy products with abandon, you’d be wise to consider the findings of what is probably the most comprehensive, commercially untainted review of the dietary fat literature yet published. They are found in a 26-page advisory prepared for the American Heart Association and published last June by a team of experts led by Dr. Frank M. Sacks, professor of cardiovascular disease prevention at the Harvard T.H. Chan School of Public Health. The report helps to explain why the decades-long campaign to curb cardiovascular disease by steering the American diet away from animal fats has been less successful than it might have been and how it inadvertently promoted expanding waistlines and an epidemic of Type 2 diabetes. When people cut back on a particular nutrient, they usually replace it with something else to maintain their needed caloric input. Unfortunately, in too many cases, saturated fats — and fats in general — gave way to refined carbohydrates and sugars, the so-called SnackWell phenomenon that prompted fat-wary eaters to overindulge in high-calorie, low-nutrient foods. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24585 - Posted: 01.30.2018

Laura Sanders Nerve cells in the brain make elaborate connections and exchange lightning-quick messages that captivate scientists. But these cells also sport simpler, hairlike protrusions called cilia. Long overlooked, the little stubs may actually have big jobs in the brain. Researchers are turning up roles for nerve cell cilia in a variety of brain functions. In a region of the brain linked to appetite, for example, cilia appear to play a role in preventing obesity, researchers report January 8 in three studies in Nature Genetics. Cilia perched on nerve cells may also contribute to brain development, nerve cell communication and possibly even learning and memory, other research suggests. “Perhaps every neuron in the brain possesses cilia, and most neuroscientists don’t know they’re there,” says Kirk Mykytyn, a cell biologist at Ohio State University College of Medicine in Columbus. “There’s a big disconnect there.” Most cells in the body — including those in the brain — possess what’s called a primary cilium, made up of lipid molecules and proteins. The functions these appendages perform in parts of the body are starting to come into focus (SN: 11/3/12, p. 16). Cilia in the nose, for example, detect smell molecules, and cilia on rod and cone cells in the eye help with vision. But cilia in the brain are more mysterious. © Society for Science & the Public 2000 - 2017.

Keyword: Obesity
Link ID: 24546 - Posted: 01.20.2018

By GRETCHEN REYNOLDS Our skeletons may help to keep our weight stable, according to a fascinating new study with animals. The study suggests that bones could be much more intimately involved in tracking weight and controlling appetite than scientists realized. It also raises interesting questions about whether a sedentary lifestyle could cause us to pack on pounds in part by discombobulating our sensitive bones. There is no question that our bodies like to maintain whatever weight they have sustained for any period of time. This is in large part because of our biological predilection for homeostasis, or physiological stability, which prompts our bodies to regain any weight that we lose and, in theory, lose any weight that we gain. To achieve this stability, however, our bodies have to be able to sense how much we weigh, note when that weight changes, and respond accordingly, as if we contained an internal bathroom scale. It has not been clear how our bodies manage this trick. Some years ago, scientists did discover one of the likely mechanisms, which involves leptin, a hormone released by fat cells. In broad terms, when people add fat, they produce more leptin, which then jump-starts processes in the brain that reduce appetite and should cause their bodies to drop that new weight. But obviously this system is not perfect or no one would hold on to added pounds. So for the new study, which was published this month in Proceedings of the National Academy of Sciences, an international group of researchers began to wonder whether there might be other processes at work. To find out, they first gathered groups of mice and rats. They chose both species, hoping that, if any results were common to each, this might indicate that they also could occur in other mammals, including, potentially, us. Then the scientists implanted tiny capsules into each rodent’s abdomen. Some contained weights equaling about 15 percent of each animal’s body mass. Others were empty. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24534 - Posted: 01.17.2018

Nicola Davis Obese patients undergoing stomach-shrinking surgery have half the risk of death in the years that follow compared with those tackling their weight through diet and behaviour alone, new research suggests. Experts say obesity surgery is cost-effective, leads to substantial weight loss and can help tackle type 2 diabetes. But surgeons say not enough of the stomach-shrinking surgeries are carried out in the UK, with figures currently lagging behind other European countries, including France and Belgium – despite the latter having a smaller population. “We don’t think this [new study] alone is sufficient to conclude that obese patients should push for bariatric surgery, but this additional information certainly seems to provide additional support,” said Philip Greenland, co-author of the latest study from Northwestern University. In the new study, one of several on obesity surgery published in the Journal of the American Medical Association, researchers sought to explore whether stomach-shrinking operations, known as bariatric surgery, had a long-term impact on the risk of death among obese individuals, compared with non-surgical approaches to weight loss. In total, more than 33,500 participants were involved in the study – 8,385 of whom had one of three types of bariatric surgery between 2005 and 2014. The majority of participants had a BMI greater than 35; obesity is defined as a BMI of 30 or higher. © 2018 Guardian News and Media Limited

Keyword: Obesity
Link ID: 24533 - Posted: 01.17.2018

By Asha Tomlinson, Tyana Grundig, CBC News Barb Litt, 49, decided to have gastric band surgery at a private clinic in Toronto two years ago because she'd hit a low point in her life. She was depressed, unemployed and desperate to lose weight. But rather than shedding a few pounds, the mother of two ended up gaining a $12,000 debt she can't shake and a shooting pain in her side that ultimately required a second operation in hospital to remove the silicone band around her stomach that was supposed to shrink her appetite. A new Marketplace investigation reveals Litt's painful experience is hardly unique. The clinic that performed Litt's surgery, Slimband, no longer offers the procedure. Its former chief surgeon had his licence temporarily suspended by the Ontario College of Physicians and Surgeons last April, following years of complaints from clients. But the financing company linked to the clinic, Credit Medical, is still busy collecting money from clients like Litt, who took out high-interest loans to pay for the procedure. Because of the many complications with gastric bands, including erosion, bleeding, slippage and blockages, 2,363 of the devices have had to be surgically removed in public hospitals across Canada, excluding Quebec, since 2010, according to the Canadian Institute for Health Information. Each removal costs between $3,000 and $14,000, meaning taxpayers are on the hook for up to $33 million. ©2018 CBC/Radio-Canada.

Keyword: Obesity
Link ID: 24521 - Posted: 01.12.2018

By LISA FOGARTY The last time I tasted my birthday cake was the spring I turned 13, a few months before I discovered the elimination game. The game went like this: first, stop eating sweets. Second, blot sauces, oils and dressings with paper towels while no one was looking. Third, count grams of fat, reject any food with over 3 grams, and keep a calorie tally in the back of your math notebook (where, if someone found it, they’d assume it was just math). The elimination game also involved adding. Add the toilet bowl and the sewer down the street to the list of places you could discard food. Add candy bar wrappers and empty full-fat yogurt containers to your bedroom nightstand as evidence that you’re not sick. Finally, add up the pounds you’ve lost that week that signify victory. So easy. Repeat. At 38, I am a former anorexic in recovery. Over the years, I’ve discovered my strengths — making my two children feel loved, encouraging sources to open up for stories I write as a magazine reporter — but I’ve never been as good at anything as I was at the elimination game. Growing up in leafy suburban Queens, N.Y., I became obsessed with made-for-TV movies from the ’80s and ’90s about anorexia. All of my early eating disorder role models — a nightmarish choice of words, but when you’re in the grip of this mental disorder, that’s what they are — were scared, sad and relatable. They were also all very, very young. My stars were Karen Carpenter, Tracy Gold and my favorite, Jennifer Jason Leigh, who, in the 1981 movie “The Best Little Girl in the World,” appeared appealingly helpless in high-waisted jeans. With one exception, these movies wrapped up anorexia in tidy boxes where therapy, feeding tubes, weight gain, finding release from a controlling mother’s grip and discovering the joys of food led to a happy ending. I was a kid who no longer ate dessert when I watched Ms. Leigh’s character jovially lick an ice cream cone beside her therapist. But even I knew then that ice cream was neither the problem nor the solution. © 2018 The New York Times Company

Keyword: Anorexia & Bulimia
Link ID: 24515 - Posted: 01.11.2018

By Abby Olena Most mammalian cells have a primary cilium, an antenna-like, immobile surface projection that senses the surrounding environment. Researchers report in Nature Genetics today (January 8) that proteins localized to the cilia of neurons in the hypothalamus control food intake in mice. Furthermore, two human genetics studies published in Nature Genetics today tie variants of a neuronal ciliary gene, adenylyl cyclase 3 (ADCY3), identified in people from Pakistan, Greenland, and the United States, to an increased risk of obesity and diabetes. “This [mouse] paper contributes nicely to a consensus that cilia are important in the brain for energy homeostasis and feeding behaviors,” says Nick Berbari, a biologist at Indiana University–Purdue University Indianapolis who did not participate in the study. “It’s interesting to think about how cilia function could be important for the general population, [not] just in rare instances of ciliopathies,” he adds. Ciliopathies—rare diseases caused by mutations in genes that affect the primary cilia—can produce a variety of symptoms, including extra fingers or toes, retinal degeneration, and obesity, coauthor Christian Vaisse, a geneticist at the University of California, San Francisco, tells The Scientist. “Relatively recently, it was found that the obesity in ciliopathies was linked to a role of the primary cilium in neurons because the genetic removal of primary cilia from all neurons in an adult mouse leads to obesity,” he explains. © 1986-2018 The Scientist

Keyword: Obesity
Link ID: 24511 - Posted: 01.10.2018

Want to eat better? Sleep more. Increasing the amount of sleep a person gets has been linked to eating fewer sugary foods, and making better nutritional choices. Wendy Hall, at King’s College London, and her team enlisted 42 volunteers to help them investigate the link between sleep and diet. Half the participants were given advice on how to get more sleep – such as avoiding caffeine before bed, establishing a relaxing routine, and trying not to go to bed too full or hungry. This advice was intended to help them boost the amount of sleep they each got by 90 minutes a night. The remaining 21 volunteers received no such advice. The team found that, of those who were given the advice, 86 per cent spent more time in bed, and around half slept for longer than they used to. These extended sleep patterns were associated with an average reduction in the intake of free sugars of 10 grams a day. People who were getting more sleep also ate fewer carbohydrates. There were no significant changes in diet in the control group. Free sugars include those that are added to foods by manufacturers or during cooking at home, as well as sugars in honey, syrups and fruit juice. “The fact that extending sleep led to a reduction in intake of free sugars suggests that a simple change in lifestyle may really help people to consume healthier diets,” says Hall. © Copyright New Scientist Ltd.

Keyword: Sleep; Obesity
Link ID: 24510 - Posted: 01.10.2018

By Jessica Hamzelou Did you pile on the pounds this Christmas? At least you can take some comfort in the fact that not all fat is bad. Evidence in mice and monkeys suggests it is important for storing important immune cells and may even make them more effective at fighting infection. Yasmine Belkaid at the US National Institutes of Health and her team have found that a type of immune cell – called a memory T-cell – seems to be stored in the body fat of mice. These cells learn to fight infection. Once exposed to a pathogen, they mount a stronger response the next time they encounter it. When the researchers infected mice with parasites or bacteria, they found that memory T-cells clustered densely in the animals’ body fat. Tests showed that these cells seemed to be more effective than those stored in other organs, being better at replicating and at releasing infection-fighting chemicals, for example. After exposing the mice to the same pathogens again, the memory T-cells stored in their fat were the fastest to respond. Belkaid’s team found that monkeys also have plenty of memory T-cells in their body fat, and that these cells worked better than those from other organs. “It means that fat tissue is not only a reservoir for memory cells, but those memory cells have enhanced function,” says Belkaid. “The tissue is like a magic potion that can optimally activate the T-cells.” © Copyright New Scientist Ltd.

Keyword: Obesity; Neuroimmunology
Link ID: 24473 - Posted: 12.30.2017

By JOANNA KLEIN Most rodents are just rodents. And the ones with exceptional abilities are usually cartoon rats or mice. But here in the real world of flesh, bones, brains and nerves that we mammals use each second to survive, some woodland rodents really do have a superpower that helps them tolerate cold and endure harsh winters. In grasslands from central Canada to Texas, a species known as thirteen-lined ground squirrels can adjust their body temperature to match the air around them. This is especially important during hibernation: They don’t have to fatten up like bears or find warm hide-outs like conventional mice and rats. They slumber, surviving in bodies just above freezing. Another species, the Syrian hamster, does it too. “They combine warm and cold blooded animals in one,” said Elena Gracheva, a neurophysiologist at Yale University. This uncanny ability to withstand prolonged cold (and even hypothermia) results in part from an adaptation these rodents have developed in molecules they share with other mammals, including us, Dr. Gracheva and her colleagues found in a study published last week in the journal Cell Reports. Unique properties of TRPM8, a cold-sensing protein found in their peripheral nervous systems, shields these rodents from harsh weather. It’s really important because if they’re too cold, they can’t hibernate — just like if you’re too cold, you might have trouble sleeping. The new research brings scientists closer to understanding enigmas of hibernation and solving a mystery of how this molecular sensor works. The work also may lead to therapies for allodynia, a nerve condition that causes some people to misperceive something normally not-so-cold as painful. © 2017 The New York Times Company

Keyword: Pain & Touch
Link ID: 24464 - Posted: 12.28.2017

By Catherine Offord Jerrold Olefsky has spent much of the last decade trying to decipher the connection between obesity and the risk for type 2 diabetes. It’s now known that “in obesity, the adipose tissue becomes highly inflamed and fills up with macrophages and other immune cells,” Olefsky, an endocrinologist at the University of California, San Diego, explains. “This inflammation is very important for causing insulin resistance,” in which cells fail to respond to hormonal signals to take up glucose. But a crucial piece of the puzzle has been missing. “Insulin resistance is a systemic thing,” Olefsky says. For inflamed fat tissue to trigger it, “somehow, all the tissues must talk to each other. We just didn’t know how.” Research has not supported a major role for early suspects such as cytokines. But reading a paper a few years ago on the role of tiny vesicles called exosomes in intercellular communication in cancer, Olefsky was struck by the fact that, “Well, gee, all these cells make exosomes.” Known to carry microRNAs (miRNAs)—small nucleic acids that influence gene expression—exosomes seemed like plausible candidates for an inter-tissue communication system in obesity. Olefsky’s group isolated macrophages from adipose tissue in obese and lean mice and harvested exosomes produced by the cells in vitro. Then, the researchers added these vesicles to cultured muscle, liver, and fat cells—major insulin targets in the body. While lean-type exosomes made recipient cells “super insulin-sensitive,” Olefsky says, obese-type exosomes induced insulin resistance. In vivo work showed a similar effect: lean mice injected with obese-type exosomes became insulin resistant without gaining weight, while obese mice treated with lean-type exosomes stayed obese, but developed normalized insulin sensitivity. © 1986-2017 The Scientist

Keyword: Obesity
Link ID: 24450 - Posted: 12.22.2017

Laurel Hamers The hardy souls who manage to push shorts season into December might feel some kinship with the thirteen-lined ground squirrel. The critter hibernates all winter, but even when awake, it’s less sensitive to cold than its nonhibernating relatives, a new study finds. That cold tolerance is linked to changes in a specific cold-sensing protein in the sensory nerve cells of the ground squirrels and another hibernator, the Syrian hamster, researchers report in the Dec. 19 Cell Reports. The altered protein may be an adaptation that helps the animals drift into hibernation. In experiments, mice, which don’t hibernate, strongly preferred to hang out on a hot plate that was 30° Celsius versus one that was cooler. Syrian hamsters (Mesocricetus auratus) and the ground squirrels (Ictidomys tridecemlineatus), however, didn’t seem to notice the chill until plate temperatures dipped below 10° Celsius, notes study coauthor Elena Gracheva, a neurophysiologist at Yale University. Further work revealed that a cold-sensing protein called TRPM8 wasn’t as easily activated by cold in the squirrels and hamsters as in rats. Found in the sensory nerve cells of vertebrates, TRPM8 typically sends a sensation of cold to the brain when activated by low temperatures. It’s what makes your fingertips feel chilly when you’re holding a glass of ice water. It’s also responsible for the cooling sensation in your mouth after you chew gum made with menthol. |© Society for Science & the Public 2000 - 2017

Keyword: Miscellaneous
Link ID: 24445 - Posted: 12.20.2017

By Simon Makin The brain's reward system learns the actions that produce positive outcomes, such as obtaining food or sex. It then reinforces the desire to initiate those behaviors by inducing pleasure in anticipation of the relevant action. But in some circumstances this system can become oversensitized to pleasurable but harmful behaviors, producing pathological impulses like drug addiction, binge eating and compulsive gambling. But what if we could spot impulsive urges in the brain and intervene to prevent the act? This is the promise of a new study published December 18 in Proceedings of the National Academy of Sciences, led by neurosurgeon Casey Halpern, of Stanford University. His team identified a “signature” of impulsive urges in part of the brain's reward-learning circuitry, the nucleus accumbens. Delivering electrical pulses to this region on detecting this activity reduced binge-eating behavior in mice. They also observed the same signature in a human brain, suggesting the technique has potential for treating a range of conditions involving compulsive behaviors. “We've identified a brain biomarker of loss of control,” Halpern says. “If we can use that to prevent any of these potentially dangerous actions, we can help a lot of people.” Researchers used a variation on deep-brain stimulation (DBS) in their experiments, a well-established treatment to diminish the shaking present in Parkinson's disease that is also showing promise in other conditions including depression and obsessive-compulsive disorder. Exactly how DBS has beneficial effects is still being debated, but there can be side effects. When treating movement disorders, patients may experience tingling and muscle contraction, says neurosurgeon Tipu Aziz of the University of Oxford. The long-term consequences in other regions are unknown but could include seizures, or effects on cognition, he says. © 2017 Scientific American,

Keyword: Drug Abuse; Obesity
Link ID: 24441 - Posted: 12.20.2017

Esther Landhuis Picture this: While reaching for the cookie jar — or cigarette or bottle of booze or other temptation — a sudden slap denies your outstretched hand. When the urge returns, out comes another slap. Now imagine those "slaps" occurring inside the brain, protecting you in moments of weakness. In a report published Monday in the Proceedings of the National Academy of Sciences, Stanford neuroscientists say they've achieved this sort of mind-reading in binge-eating mice. They found a telltale pattern of brain activity that comes up seconds before the animals start to pig out — and delivering a quick zap to that part of the brain kept the mice from overindulging. Whether this strategy could block harmful impulses in people remains unclear. For now the path seems promising. The current study used a brain stimulation device already approved for hard-to-treat epilepsy. And based on the new findings, a clinical trial testing this off-the-shelf system for some forms of obesity could start as early as next summer, says Casey Halpern, the study's leader and an assistant professor of neurosurgery at Stanford. He thinks the approach could also work for eating disorders and a range of other addictive or potentially life-threatening urges. As a physician-researcher, Halpern specializes in deep brain stimulation (DBS), a surgical treatment in which battery-powered implants send electrical pulses to brain areas where signals go awry. © 2017 npr

Keyword: Obesity; Drug Abuse
Link ID: 24440 - Posted: 12.19.2017

Eating is prompted, in part, by brain regions that help to maintain the body’s energy levels. But hunger pangs are not the only motivation for a trip to the snack bar. In an effort to understand how the brain’s emotional and cognitive machinery influences appetite, Yunlei Yang and his colleagues at the State University of New York Upstate Medical University in Syracuse examined the medial septal complex, a group of brain cells that has a role in emotion. Some of the complex’s cells produce a signalling chemical called glutamate. When the scientists turned on these glutamate-producing cells in mice, the animals ate less than half as much as control mice. That makes the region a good starting point for studies of emotionally triggered eating, the team says. Proc. Natl Acad. Sci. USA (2017)

Keyword: Obesity; Emotions
Link ID: 24420 - Posted: 12.14.2017