Chapter 9. Homeostasis: Active Regulation of the Internal Environment

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By JANE E. BRODY When The New York Times hired me to write about science and health 52 years ago, I was 40 pounds overweight. I’d spent the previous three years watching my weight rise as I hopped from one diet to the next in a futile attempt to shed the pounds most recently gained. No amount of exercise, and I did plenty of it, could compensate for how much I ate when I abandoned the latest weight loss scheme. I had become a living example of the adage: A diet is something one goes on to go off. Even daylong fasting failed me. When I finally ate supper, I couldn’t stop eating until I fell asleep, and sometimes awoke the next morning with partly chewed food in my mouth. I had dieted myself into a binge-eating disorder, and that really scared me. Clearly, something had to change. I finally regained control when I stopped dieting. I decided that if I was going to be fat, at least I could be healthy. I made a plan to eat three nutritious, satisfying meals every day with one small snack, which helped me overcome the temptation to binge in response to deprivation. Much to my surprise, a month later I had lost 10 pounds — eating! Eating good food, that is, and plenty of it. I continued the regimen without difficulty because it was not a diet. It was a way to live and a healthy one at that. And I continued to lose, about two pounds a month. Two years later, all the excess weight was gone. I never gained it back and never again went on a diet. (Even with a twin pregnancy, I gained only 36 pounds and lost them all when my sons were born at 6 pounds 13 ounces each.) The greatest challenge to lasting weight loss, especially for someone like me with a food addiction, is the fact that no one can give up eating. Rather, one has to learn a better — and permanent — way to handle food. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24723 - Posted: 03.06.2018

By VERONIQUE GREENWOOD If you think about being thirsty at all, it seems like a fairly simple thought process: Find water. Drink it. Move on. But in fact there is something rather profound going on as you take that long, refreshing drink after a run or a hot day in the garden. As you become dehydrated, there is less water in your blood, and neurons in your brain send out the word that it’s time to look for water. Then, once you take a drink, you feel almost instantly satisfied. But if that is obvious, it is also mysterious. You aren’t pouring water directly into your bloodstream, after all. It will take at least 10 or 15 minutes, maybe longer, for the water in your stomach to make its way into the blood. And yet somehow, the brain knows. Sometimes that process isn’t as straightforward as it should be: People with a syndrome called polydipsia feel excessive thirst and drink enormous quantities of water. That can be dangerous, because if the blood is diluted too much, a person can die — a victim of water intoxication. As neuroscientists ponder how and why we thirst, a group of researchers at the California Institute of Technology has shed light on one small corner of the problem. Interested in how the brain keeps track of what the body is drinking, they have identified a set of neurons that receive messages as thirsty mice gulp down water. Passed around in the brain’s thirst centers, these messages seem to be behind the sensation of swift satisfaction that comes after a drink, and also suggest that it’s not just what is drunk, but how it is slurped down, that affects the brain. If the circuits work the same way in people, it may be key to understanding the neuroscience of what happens as we feel thirsty. In the last few years, biologists have been mapping the neurons within an area in the brain that regulates thirst, said Yuki Oka, a professor at Caltech and senior author of the new paper, which was published Wednesday in Nature. Cells in this region had been observed going quiet after an animal had water, but it was not clear exactly why. © 2018 The New York Times Company

Keyword: Miscellaneous
Link ID: 24715 - Posted: 03.01.2018

By NICHOLAS BAKALAR Some experts have suggested that there is an “obesity paradox,” the idea that obese people live longer than those of normal weight. But a new study found that obesity was associated with an increased risk for cardiovascular disease and a two- to three-year shorter life span. The study, in JAMA Cardiology, pooled data from 10 studies of 190,672 people followed from 1964 to 2015. Compared with those of normal weight, overweight men (body mass index of 25 to 29.9) had a 21 percent higher lifetime risk of cardiovascular disease and women a 32 percent higher risk. Among the obese (B.M.I. of 30 to 39.9), the risk was 67 percent higher for men and 85 percent higher for women, with even higher risk for those with a B.M.I. over 40. Longevity in men who were overweight but not obese was similar to that of men of normal weight. But they had an increased risk of cardiovascular disease at a younger age. “We were able to measure how much time is spent in healthy life years rather than just life span,” said the study’s senior author, Dr. Sadiya S. Khan, an assistant professor of medicine at Northwestern. “Maintaining a healthy B.M.I. is associated with a longer, healthier life, with less risk for cardiovascular disease.” © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24712 - Posted: 03.01.2018

By NICHOLAS BAKALAR Overweight mothers are more likely to have overweight babies, and the gut bacteria the babies inherit may in part be to blame. Researchers report that overweight mothers are more likely to have a cesarean section, and that babies born by cesarean to those mothers have species of gut bacteria different from those in babies born to normal weight women. And that difference in the gut microbiome — specifically an abundance of bacteria of the family Lachnospiraceae in infants of overweight mothers — may contribute to an increased risk for obesity. The study included 935 mother-infant pairs. Compared to children born to normal weight mothers, those born vaginally to overweight women were more than three times as likely to be overweight by age 3. But C-section babies born to overweight mothers were more than five times as likely to be overweight. For normal weight mothers, vaginal or C-section delivery made no difference in the risk for overweight babies. The study, in JAMA Pediatrics, controlled for breast-feeding, antibiotic exposure and other factors. The senior author, Anita L. Kozyrskyj, a professor of pediatrics at the University of Alberta, said that there is no probiotic that would lead to a positive change in gut bacteria. “If a cesarean is unavoidable, there is no easy answer,” she added, “but breast-feeding is effective in helping to prevent infants from becoming overweight.” © 2018 The New York Times Company

Keyword: Obesity
Link ID: 24711 - Posted: 03.01.2018

By Aaron E. Carroll I remember the first time my daughter discovered her hand. The look of amazement on her face was priceless. It wasn’t long before she was putting that discovery to use, trying to put everything she could find into her mouth. Babies want to feed themselves. It sometimes feels as if parents spend more time trying to stop them than encouraging them. Over the last few years, however, some people have begun to ask if we are doing the right thing. Baby-led weaning is an approach to feeding that encourages infants to take control of their eating. It’s based on the premise that infants might be better self-regulators of their food consumption. It has even been thought that baby-led weaning might lead to reductions in obesity. While babies have been spoon-fed for a long time, the explosion of commercial foods for them might be making it too easy to overfeed them, an idea that the results from a cohort study in 2015 seemed to hint at. Those weaned in a baby-led approach seemed to be more responsive to being sated and were less likely to be overweight. A case-control study from 2012 also argued that baby-led weaning was associated with a lower body mass index (B.M.I). Such trials cannot establish causality, however, and may be confounded in unmeasured ways. A recent randomized controlled trial accomplished what previous work could not. Pregnant women in New Zealand were recruited before they gave birth and randomly assigned to one of two groups. Both got standard midwifery and child care. But one group received eight more contacts, from pregnancy to the newborn’s ninth month. Five of these were with a lactation consultant, who encouraged the mothers to prolong breast-feeding and delay the introduction of solid foods until 6 months of age. The three other contacts were with research staffers who encouraged parents to read hunger and fullness cues from their infants and provide their babies (starting at 6 months) with foods that were high in energy and iron — easy to grab but hard to choke on. © 2018 The New York Times Company

Keyword: Obesity; Development of the Brain
Link ID: 24701 - Posted: 02.27.2018

By Alexandra Rosati The shift to a cooked-food diet was a decisive point in human history. The main topic of debate is when, exactly, this change occurred. All known human societies eat cooked foods, and biologists generally agree cooking could have had major effects on how the human body evolved. For example, cooked foods tend to be softer than raw ones, so humans can eat them with smaller teeth and weaker jaws. Cooking also increases the energy they can get from the food they eat. Starchy potatoes and other tubers, eaten by people across the world, are barely digestible when raw. Moreover, when humans try to eat more like chimpanzees and other primates, we cannot extract enough calories to live healthily. Up to 50 percent of women who exclusively eat raw foods develop amenorrhea, or lack of menstruation, a sign the body does not have enough energy to support a pregnancy—a big problem from an evolutionary perspective. Such evidence suggests modern humans are biologically dependent on cooking. But at what point in our evolutionary history was this strange new practice adopted? Some researchers think cooking is a relatively recent innovation—at most 500,000 years old. Cooking requires control of fire, and there is not much archaeological evidence for hearths and purposefully built fires before this time. The archaeological record becomes increasingly fragile farther back in time, however, so others think fire may have been controlled much earlier. Anthropologist Richard Wrangham has proposed cooking arose before 1.8 million years ago, an invention of our evolutionary ancestors. If the custom emerged this early, it could explain a defining feature of our species: the increase in brain size that occurred around this time. © 2018 Scientific American,

Keyword: Evolution
Link ID: 24698 - Posted: 02.26.2018

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