Chapter 13. Homeostasis: Active Regulation of the Internal Environment

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By Alex Therrien Health reporter, BBC News A low-carb diet could shorten life expectancy by up to four years, a study suggests. Low-carb diets, such as Atkins, have become increasingly popular for weight loss and have shown promise for lowering the risk of some illnesses. But a US study over 25 years indicates that moderate carb consumption - or switching meat for plant-based protein and fats - is healthier. The study relied on people remembering the amount of carbohydrates they ate. 'Gaining widespread popularity' In the study, published in The Lancet Public Health, 15,400 people from the US filled out questionnaires on the food and drink they consumed, along with portion sizes. From this, scientists estimated the proportion of calories they got from carbohydrates, fats, and protein. After following the group for an average of 25 years, researchers found that those who got 50-55% of their energy from carbohydrates (the moderate carb group and in line with UK dietary guidelines) had a slightly lower risk of death compared with the low and high-carb groups. Carbohydrates include vegetables, fruit and sugar but the main source of them is starchy foods, such as potatoes, bread, rice, pasta and cereals. The NHS Eatwell Guide provides details on how to achieve this kind of healthy, balanced diet and reduce the risk of serious illnesses in the long term. Researchers estimated that, from the age of 50, people in the moderate carb group were on average expected to live for another 33 years. © 2018 BBC

Keyword: Obesity
Link ID: 25342 - Posted: 08.17.2018

By Nicholas Bakalar When it comes to losing weight, more can be better. A lot better, according to a new study. Researchers studied 7,670 overweight or obese people who wanted to lose weight. Using data on current weight, weight a year ago and maximum lifetime weight, they tested the association of long-term weight loss with lowering the risk for metabolic syndrome — a constellation of unhealthy conditions that includes high blood pressure, insulin resistance, excess fat around the waist, high triglycerides and low HDL, or “good,” cholesterol. Compared to people who maintained less than a 5 percent weight loss for one year, those who lost 5 to 10 percent lowered their risk for metabolic syndrome by 22 percent. A 15 to 19 percent loss was associated with a 37 percent lower risk, and those who maintained a loss of 20 percent or more had a 53 percent lower risk. The study is in the Mayo Clinic Proceedings. Only 5.5 percent of the participants succeeded in holding a 20 percent or greater weight loss for one year. “Any weight loss is beneficial,” said the lead author, Gregory Knell of the University of Texas School of Public Health in Houston. “You don’t have to reach 20 percent to have a benefit. But if you are able to lose more weight, you get some really significant numbers related to metabolic health.” © 2018 The New York Times Company

Keyword: Obesity
Link ID: 25335 - Posted: 08.16.2018

By Gretchen Reynolds Don’t skip drinking during exercise in hot weather, a new study reminds us. This advice might seem obvious. But apparently some athletes, especially in team sports, have begun to eschew fluids during hot weather workouts, in hopes that the privation might somehow make them stronger. But the new study finds that it is likely only to make them more physically stressed. And very, very thirsty. Working out in the heat is inherently difficult, as any of us who exercise outside in summer knows. When ambient temperatures are high, we generate internal heat more quickly than if the weather is cool. To remove this heat and maintain a safe body temperature, our hearts pump warm blood toward the skin’s surface, where heat can dissipate, and we sweat copiously, providing evaporative heat loss. These reactions become more pronounced and effective with practice, a process known as heat acclimation (also referred to as acclimatization). During heat acclimation, which can require several weeks of sultry exercise, we begin to sweat earlier and in greater volume. This and other changes help our hearts to labor less, so that, in general, the effort of being physically active in high temperatures starts to feel less wearing. A run on a sizzling summer day in August should feel easier than a similar run on an equally hot evening in June, if we have been running outside in the meantime, because our bodies will have acclimated to the heat. But athletes being athletes, some of them and their coaches began to wonder in recent years whether, if heat acclimation taxes the body and makes it stronger, would exacerbating the physical difficulties of acclimation lead to greater adaptations, in approved Machiavellian style? © 2018 The New York Times Company

Keyword: Miscellaneous
Link ID: 25313 - Posted: 08.10.2018

Lee Daniel Kravetz In 1972, a woman checked into London’s Royal Free Hospital to be treated for anorexia. “I found her symptoms to be unique,” Gerald Russell, the British psychologist who treated her, tells me. “They didn’t match the diagnostic criteria for anorexia at all.” Unlike his emaciated patients with sallow skin and big eyes, Russell’s new patient was of average weight. Her face was full. Her cheeks were pink as the skin of an onion. She was the first of roughly thirty instances of this unusual condition that crossed the threshold of his clinic over the next seven years, each person presenting with perplexing purging behaviors secondary to binge eating. Russell wasn’t dealing with anorexia nervosa, he realized, but something as yet undefined by psychology or medicine. In fact, he had stumbled upon a condition that science had yet to see in large numbers or identify at any time in the long history of eating disorders. Psychological Medicine published Russell’s ensuing paper on these unusual cases; in it, he described the key features of this novel mental illness he was now referring to as bulimia nervosa. Many in the scientific community objected to Russell’s conclusions, pointing to the limited and problematic sample size he’d used. At the time, however, there were simply too few cases for Russell to draw from. The pool in the 1970s was just too small. As bulimia gained further diagnostic legitimacy in 1980 with its inclusion in the third edition of the Diagnostic and Statistical Manual of Mental Disorders, Russell ruefully tracked its unexpectedly swift spread across Europe and North America, where it infiltrated college campuses, affecting 15 percent of female students in sororities, all-women dormitories, and female collegiate sports teams. The disease moved through the halls of American high schools, where binging, fasting, diet pill use, and other eating disorder symptoms easily clustered. He chased its dispersion across Egypt, where the number of new cases grew to 400,000. In Canada, it swelled to 600,000. In Russia, 800,000. In India, 6 million. In China, 7 million. In the UK, one out of every one hundred women was now developing the disorder. © 2018, New York Media LLC.

Keyword: Anorexia & Bulimia
Link ID: 25271 - Posted: 07.30.2018

By Jane E. Brody Eating disorders pose serious hazards to adolescents and young adults and are often hidden from family, friends and even doctors, sometimes until the disorders cause lasting health damage and have become highly resistant to treatment. According to the Family Institute at Northwestern University, nearly 3 percent of teenagers between the ages of 13 and 18 have eating disorders. Boys as well as girls may be affected. Even when the disorder does not reach the level of a clinical diagnosis, some studies suggest that as many as half of teenage girls and 30 percent of boys have seriously distorted eating habits that can adversely affect them physically, academically, psychologically and socially. Eating disorders can ultimately be fatal, said Dr. Laurie Hornberger, a specialist in adolescent medicine at Children’s Mercy Kansas City. “People with eating disorders can die of medical complications, but they may be even more likely to die of suicide. They become tired of having their lives controlled by eating and food issues.” The problem is especially common among, though not limited to, gymnasts, dancers, models, wrestlers and other athletes, who often struggle to maintain ultra-slim bodies or maintain restrictive weight limits. The transgender population is also at higher risk for eating disorders. It is not unusual for teenagers to adopt strange or extreme food-related behaviors, prompting many parents to think “this too shall pass.” But experts say an eating disorder — anorexia, bulimia or binge-eating — should not be considered “normal” adolescent behavior, and they urge the adults in the youngsters’ lives to be alert to telltale signs and take necessary action to stop the problem before it becomes entrenched. © 2018 The New York Times Company

Keyword: Anorexia & Bulimia
Link ID: 25270 - Posted: 07.30.2018

Allison Aubrey Was it hard to concentrate during that long meeting? Or, does the crossword seem a little tougher? You could be mildly dehydrated. A growing body of evidence finds that being just a little dehydrated is tied to a range of subtle effects — from mood changes to muddled thinking. "We find that when people are mildly dehydrated they really don't do as well on tasks that require complex processing or on tasks that require a lot of their attention," says Mindy Millard-Stafford, director of the Exercise Physiology Laboratory at Georgia Institute of Technology. She published an analysis of the evidence this month, based on 33 studies. Heat Making You Lethargic? Research Shows It Can Slow Your Brain, Too Shots - Health News Heat Making You Lethargic? Research Shows It Can Slow Your Brain, Too How long does it take to become mildly dehydrated in the summer heat? Not long at all, studies show, especially when you exercise outdoors. "If I were hiking at moderate intensity for one hour, I could reach about 1.5 percent to 2 percent dehydration," says Doug Casa, a professor of kinesiology at the University of Connecticut, and CEO of the Korey Stringer Institute. For an average-size person, 2 percent dehydration equates to sweating out about a liter of water. "Most people don't realize how high their sweat rate is in the heat," Casa says. If you're going hard during a run, you can reach that level of dehydration in about 30 minutes. And, at this level of dehydration the feeling of thirst, for many of us, is only just beginning to kick in. "Most people can't perceive that they're 1.5 percent dehydrated," Casa says. © 2018 npr

Keyword: Learning & Memory; Attention
Link ID: 25269 - Posted: 07.30.2018

By Emily Willingham Of all of our organs, our brains and hearts get the most attention. But the liver once held top billing, preeminent over the heart and mind as the seat of emotion and even the soul. As its name implies, we need our liver to live—not only because it works hard as a detox unit but also because it quietly processes components our brains need to thrive. The Alzheimer’s disease (AD) research community is turning its attention to this liver–brain connection. That newfound interest turns up in a quartet of new studies presented July 24 at the Alzheimer’s Association International Conference 2018. The results may help provide clues to both the basic biology of AD and how diet is linked to brain health. More specifically, it may give insight into why human clinical trials of fish oil have failed to protect against AD and other forms of dementia. In the four studies, blood levels of molecules associated with the liver and production of fats, or lipids, were tied to AD risk—a first step toward deeper examination of the liver–brain link. “There seem to be some positive results correlating levels of lipids with cognition and cognitive progression,” says Paul Schulz, director of the Dementia and Memory Disorders Clinic at The University of Texas McGovern Medical School, who was not involved in the studies. “The challenge will be to establish cause and effect.” The brain consists mostly of fats, which contribute to both its form and function. These lipids facilitate communication from neuron to neuron and make up much of the insulation that sheaths these cells. It is the liver that builds the fats the brain needs—and many genes tied to AD are linked to fat production or transport, including a version of a gene associated with high AD risk—APOE ε4. © 2018 Scientific American

Keyword: Alzheimers
Link ID: 25253 - Posted: 07.26.2018

By Anahad O’Connor Nutrition scientists have long debated the best diet for optimal health. But now some experts believe that it’s not just what we eat that’s critical for good health, but when we eat it. A growing body of research suggests that our bodies function optimally when we align our eating patterns with our circadian rhythms, the innate 24-hour cycles that tell our bodies when to wake up, when to eat and when to fall asleep. Studies show that chronically disrupting this rhythm — by eating late meals or nibbling on midnight snacks, for example — could be a recipe for weight gain and metabolic trouble. That is the premise of a new book, “The Circadian Code,” by Satchin Panda, a professor at the Salk Institute and an expert on circadian rhythms research. Dr. Panda argues that people improve their metabolic health when they eat their meals in a daily 8- to 10-hour window, taking their first bite of food in the morning and their last bite early in the evening. This approach, known as early time-restricted feeding, stems from the idea that human metabolism follows a daily rhythm, with our hormones, enzymes and digestive systems primed for food intake in the morning and afternoon. Many people, however, snack and graze from roughly the time they wake up until shortly before they go to bed. Dr. Panda has found in his research that the average person eats over a 15-hour or longer period each day, starting with something like milk and coffee shortly after rising and ending with a glass of wine, a late night meal or a handful of chips, nuts or some other snack shortly before bed. That pattern of eating, he says, conflicts with our biological rhythms. Scientists have long known that the human body has a master clock in the brain, located in the hypothalamus, that governs our sleep-wake cycles in response to bright light exposure. A couple of decades ago, researchers discovered that there is not just one clock in the body but a collection of them. Every organ has an internal clock that governs its daily cycle of activity. © 2018 The New York Times Company

Keyword: Biological Rhythms; Obesity
Link ID: 25246 - Posted: 07.25.2018

By Frankie Schembri Do you ever find yourself scouring the web for pizza delivery services to satisfy those late-night cravings? You’re not alone: A new study reveals that hungry web surfers around the world all start searching for food-related information at two peak times, 7 p.m. and 2 a.m. Wanting to see if they could spot trends in human behavior based on a massive database of Google searches, a team of scientists analyzed hourly food-related queries from five countries: the United States, Canada, India, Australia, and the United Kingdom. For two 1-week periods, they looked for general food-related keywords such as “pizza delivery” or “Chinese delivery” and country-specific delivery companies like India’s “Swiggy” and “Just Eat,” which serves the United Kingdom and Australia. They also analyzed 5 years of data to see if they could discover seasonal trends. The two spikes in food-related searches occurred across all countries, keywords, days of the week, and seasons, the researchers report today in Royal Society Open Science. They say the peaks likely represent two different groups of people searching for nighttime nourishment, one older (the early birds) and one younger (the night owls). Another hypothesis is that the two groups are simply running on different internal body clocks, which affects when they want their evening calories. © 2018 American Association for the Advancement of Science.

Keyword: Obesity; Biological Rhythms
Link ID: 25245 - Posted: 07.25.2018

A record number of primary school children are leaving school severely obese, according to new figures from Public Health England. Data for 2016/17 shows one in 25 10 to 11 year olds were severely obese. That's more than 22,000 children, and the highest level since records began. Levels of childhood obesity have remained fairly stable in recent years, but the new analysis shows that severe obesity has been on an upward trend over the last decade. The data from the National Child Measurement Programme (NCMP) for children for the year 2016/17 has detailed the trends in severe obesity for the first time. The programme found: More deprived areas have a much higher rate of overweight and obese children, compared to the most well-off areas. This disparity is happening at a faster rate in school leavers in year 6, than in reception age. The figures did however show a downward trend of reception age boys being overweight and obese. When records began in 2006/07, one in 32 primary school leavers were severely obese. Severe obesity is BMI on or above the 99.6th percentile for a child's age and sex. Dr Alison Tedstone, chief nutritionist at Public Health England, said the trends were "extremely worrying and have been decades in the making - reversing them will not happen overnight." She said "bold measures are needed to tackle this threat to our children's health". The Department of Health recently announced the second phase of its childhood obesity plan to help halve childhood obesity by 2030. As part of that, sweets and high-fat snacks will be banned from supermarket checkouts, and there will be tighter restrictions on junk food ads on TV. © 2018 BBC

Keyword: Obesity; Development of the Brain
Link ID: 25239 - Posted: 07.24.2018

Tina Hesman Saey MADISON, Wis. — Giving children with autism a healthier mix of gut bacteria as a way to improve behavioral symptoms continued to work even two years after treatment ended. The finding may solidify the connection between tummy troubles and autism, and provide more evidence that the gut microbiome — the collection of bacteria and other microbes that live in the intestines — can influence behavior. “It’s a long way from saying there’s a cure for autism,” says Michael Hylin, a neuroscientist at Southern Illinois University in Carbondale who was not involved in the work. “But I think it’s a promising approach. It’s one that’s worthwhile.” Children with autism spectrum disorders often have gastrointestinal problems. In previous studies, environmental engineer Rosa Krajmalnik-Brown of Arizona State University in Tempe and colleagues discovered that children with autism had fewer types of bacteria living in their guts than typically developing children did. And many of the kids were missing Prevotella bacteria, which may help regulate immune system actions. The researchers wondered whether altering the children’s cocktail of gut microbes to get a more diverse and healthier mix might help fix both the digestive issues and the behavioral symptoms associated with autism. In a small study of 18 children and teenagers with autism, the scientists gave kids fecal transplants from healthy donors over eight weeks. During and two months after the treatment, the kids had fewer gastrointestinal problems, including diarrhea, constipation, abdominal pain and indigestion than before the therapy. Autism symptoms, such as hyperactivity, repetitive actions and irritability, also improved and seemed to be getting even better at the end of the trial than immediately after treatment ended, the team reported last year in Microbiome. But no one knew whether the improvements would last. |© Society for Science & the Public 2000 - 2018.

Keyword: Autism; Hormones & Behavior
Link ID: 25202 - Posted: 07.13.2018

by Jennifer MacCormack Many people feel more irritable, annoyed or negative when hungry — an experience colloquially called being “hangry.” The idea that hunger affects our feelings and behaviors is widespread. But surprisingly little research investigates how feeling hungry transforms into feeling hangry. Psychologists have traditionally thought of hunger and emotions as separate, with hunger and other physical states as basic drives with different physiological and neural underpinnings from emotions. But growing scientific evidence suggests that your physical states can shape your emotions and cognition in surprising ways. Prior studies show that hunger itself can influence mood, probably because it activates many of the same bodily systems — such as the autonomic nervous system and hormones — that are involved in emotion. For example, when you’re hungry, your body releases a host of hormones including cortisol and adrenaline, often associated with stress. The result is that hunger, especially at greater intensity, can make you feel more tense, unpleasant and primed for action. But is feeling hangry just these hunger-induced feelings, or is there more to it? This question inspired the studies that psychologist Kristen Lindquist and I conducted at the University of North Carolina at Chapel Hill. We wanted to know whether ­hunger-induced feelings can transform how people experience their emotions and the world around them. © 1996-2018 The Washington Post

Keyword: Emotions; Obesity
Link ID: 25191 - Posted: 07.11.2018

Layal Liverpool Working night shifts can mess up the body’s natural rhythms so much that the brain and digestive system end up completely out of kilter with one another, scientists say. Three night shifts in a row had little impact on the body’s master clock in the brain, researchers found, but it played havoc with gut function, throwing the natural cycle out by a full 12 hours. The finding highlights the dramatic impact that night shifts can have on the different clocks that govern the natural rhythms of organs and systems throughout the human body. Internal disagreements over night and day may explain why people on night shifts, and those with jet lag, can suffer stomach pains and other gut problems, which clear up once their body has had time to adjust. “One of the first symptoms people experience when traveling across time zones is gastrointestinal discomfort and that’s because you knock their gut out of sync from their central biological clock,” said Hans Van Dongen, director of the Sleep and Performance Research Center at Washington State University. For the study, Van Dongen invited 14 healthy volunteers aged 22 to 34 into his sleep lab and split them into two groups. The first spent three days on a simulated day shift and could sleep from 10pm to 6am each night. Those in the second group stayed awake for three nights in a row and were only allowed to sleep from 10am to 6pm. © 2018 Guardian News and Media Limited

Keyword: Biological Rhythms; Obesity
Link ID: 25188 - Posted: 07.10.2018

Laura Sanders Mouse mothers can transmit stress signals to offspring, changing the way the pups’ bodies and brains develop. Some of these stress messages get delivered during birth, scientists suggest July 9 in Nature Neuroscience. Researchers suspected that vaginal microbes from stressed-out moms could affect male pups in ways that leave them vulnerable to stress later in life (SN: 12/14/2013, p. 13). But earlier studies hadn’t demonstrated whether those microbes, picked up during birth, actually caused some of the changes seen in offspring, or if other aspects of life in utero were to blame. Tracy Bale of the University of Maryland School of Medicine in Baltimore and colleagues subjected pregnant mice to stressful trials that included smelling the scent of a fox for an hour, listening to unusual sounds overnight and being restrained in a tube for 15 minutes. Other pregnant mice didn’t experience these stressors. Then, researchers delivered pups by cesarean section, so that the pups weren’t exposed to their mothers’ community of vaginal microorganisms, or microbiome. After delivery, researchers dosed the pups with vaginal fluid taken from stressed or unstressed mothers. For male pups not exposed to stress in the womb, vaginal microbes from a stressed mother changed the amount of certain kinds of gut bacteria. (Just as in earlier studies, female pups didn’t show effects of their mothers’ stress.) When those male pups were older, being restrained led them to release more of the stress hormone corticosteroid than mice dosed with microbiota from unstressed moms. And in the brains of adult mice that had experienced chronic stress, genes involved in metabolism and the development of nerve cells behaved differently depending on whether early microbes came from stressed or unstressed mothers. |© Society for Science & the Public 2000 - 2018

Keyword: Stress; Development of the Brain
Link ID: 25187 - Posted: 07.10.2018

By Jane E. Brody I wonder how we all survived — and even thrived — in our younger years without the plethora of water bottles that nearly everyone seems to carry around these days. In reading about the risks and consequences of dehydration, especially for the elderly and anyone who exercises vigorously in hot weather, it’s nothing short of a miracle that more of us hadn’t succumbed years ago to the damaging physical, cognitive and health effects of inadequate hydration. Even with the current ubiquity of portable water containers, far too many people still fail to consume enough liquid to compensate for losses suffered especially, though not exclusively, during the dehydrating months of summer. For those of you who know or suspect that you don’t drink enough to compensate for daily water losses, the good news is you don’t have to rely entirely on your liquid intake to remain well-hydrated. Studies in societies with limited supplies of drinking water suggest you can help to counter dehydration and, at the same time, enhance the healthfulness of your diet by consuming nutritious foods that are laden with a hidden water source. Plant foods like fruits, vegetables and seeds are a source of so-called gel water — pure, safe, hydrating water that is slowly absorbed into the body when the foods are consumed. That’s the message in a newly published book, “Quench,” by Dr. Dana Cohen, an integrative medicine specialist in New York, and Gina Bria, an anthropologist whose studies of the water challenges faced by desert dwellers led to the establishment of the Hydration Foundation, a nonprofit group that promotes understanding and consumption of nonliquid sources of water. © 2018 The New York Times Company

Keyword: Miscellaneous
Link ID: 25185 - Posted: 07.09.2018

Laura Sanders Newly identified nerve cells deep in the brains of mice compel them to eat. Similar cells exist in people, too, and may ultimately represent a new way to target eating disorders and obesity. These neurons, described in the July 6 Science, are not the first discovered to control appetite. But because of the mysterious brain region where they are found and the potential relevance to people, the mouse results “are worth pursuing,” says neurobiologist and physiologist Sabrina Diano of Yale University School of Medicine. Certain nerve cells in the human brain region called the nucleus tuberalis lateralis, or NTL, are known to malfunction in neurodegenerative diseases such as Huntington’s and Alzheimer’s. But “almost nothing is known about [the region],” says study coauthor Yu Fu of the Singapore Bioimaging Consortium, Agency for Science, Technology and Research. In people, the NTL is a small bump along the bottom edge of the hypothalamus, a brain structure known to regulate eating behavior. But in mice, a similar structure wasn’t thought to exist at all, until Fu and colleagues discovered it by chance. The researchers were studying cells that produce a hormone called somatostatin — a molecular signpost of some NTL cells in people. In mice, that cluster of cells in the hypothalamus seemed to correspond to the human NTL. Not only do these cells exist in mice, but they have a big role in eating behavior. The neurons sprang into action when the mice were hungry, or when the hunger-signaling hormone ghrelin was around, the team found. |© Society for Science & the Public 2000 - 201

Keyword: Obesity
Link ID: 25178 - Posted: 07.06.2018

By Gretchen Reynolds Can working out help us to drop pounds after all? A provocative new study involving overweight men and women suggests that it probably can, undercutting a widespread notion that exercise, by itself, is worthless for weight loss. But the findings also indicate that, to benefit, we may need to exercise quite a bit. In theory, exercise should contribute substantially to weight loss. It burns calories. If we do not replace them, our bodies should achieve negative energy balance, use stored fat for fuel and shed pounds. But life and our metabolisms are not predictable or fair, as multiple exercise studies involving people and animals show. In these experiments, participants lose less weight than would be expected, given the energy they expend during exercise. The studies generally have concluded that the exercisers had compensated for the energy they had expended during exercise, either by eating more or moving less throughout the day. These compensations were often unwitting but effective. Some researchers had begun to wonder, though, if the amount of exercise might matter. Many of the past human experiments had involved about 30 minutes a day or so of moderate exercise, which is the amount generally recommended by current guidelines to improve health. But what if people exercised more, some researchers asked. Would they still compensate for all the calories that they burned? To find out, scientists from the University of North Dakota and other institutions decided to invite 31 overweight, sedentary men and women to a lab for measurements of their resting metabolic rate and body composition. The volunteers also recounted in detail what they had eaten the previous day and agreed to wear a sophisticated activity tracker for a week. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 25172 - Posted: 07.05.2018

David Cyranoski An ambitious Chinese study tracking tens of thousands of babies and their mothers has begun to bear fruit — just six years after the study’s leaders recruited their first sets of mothers and babies. Researchers have already published results based on the cohort study, which collects biological, environmental and social data, some with important public-health implications. And many more investigations are under way. One, in particular, will examine infants’ microbiomes, the collections of bacteria and other microorganisms that inhabit their bodies — a hot topic in health research and a key goal of the cohort study. The Born in Guangzhou Cohort Study has recruited about 33,000 babies and their mothers since 20121. The study’s leaders are hoping to reach 50,000 baby–mother sets by 2020. And this year, investigators started recruiting 5,000 maternal grandmothers to the project, enabling studies across multiple generations. “The data is vast, and there is space for many different groups globally to mine this information,” says Maria Gloria Dominguez-Bello, a microbiologist at Rutgers, The State University of New Jersey, in New Brunswick, who is not involved in the study. “I really admire this effort from the Chinese team. Very few countries can achieve this scale.” © 2018 Macmillan Publishers Limited,

Keyword: Obesity; Schizophrenia
Link ID: 25170 - Posted: 07.03.2018

By Nicholas Bakalar Obesity is more common in rural areas than in cities in the United States, two new studies have found. The two analyses, one of adults and the other of children, used data on weight, height and where people lived that was gathered in a series of nationally representative surveys from 2001 to 2016. They were published online together in JAMA. The adult study included 10,792 men and women 20 and older. In the 2013-16 survey period, 39 percent were obese — defined as having a body mass index of 30 or above — including 8 percent who were severely obese, with a B.M.I. of 40 or more. Prevalence of obesity was 36.5 percent among men and 40.8 percent among women, including severe obesity of 5.5 percent for men and 9.8 percent for women. In the study of 6,863 children 2 to 19 years old, 17.8 percent were obese, including 5.8 percent who were severely obese. “I want to emphasize that this survey — the National Health and Nutrition Examination Survey — is the gold standard” in accuracy for obesity rates, said Cynthia L. Ogden, an epidemiologist with the Centers for Disease Control and Prevention and an author on both studies. “When people report their own measurements, they exaggerate their height and minimize their weight,” she said. “This survey has measured heights and weights.” About 38 percent of women living in urban areas with a population greater than a million were obese, as were 42.5 percent of those living in urban areas smaller than a million. But in rural areas, the obesity rate for women was 47.2 percent. Rates for men showed a similar, although not identical, pattern — 31.8 percent in large urban areas, 42.4 percent in small metropolitan areas, and 38.9 percent in rural regions. These differences could not be explained by age, education level, race, ethnicity or smoking status. © 2018 The New York Times Company

Keyword: Obesity
Link ID: 25118 - Posted: 06.22.2018

Alex Fox Northern fur seals (Callorhinus ursinus) can forgo rapid eye movement sleep for up to two weeks while at sea with no visible hardship, according to new research. This flies in the face of previous studies on land mammals such as rats, in which depriving the animals of rapid eye movement (REM) sleep for a week or more led to problems including weight loss, hypothermia and eventually, death. Nearly all land mammals and birds experience REM sleep. This is the brain's most active sleep phase and has been associated with learning and processing memories. But now, results1 published on 7 June in Current Biology point to another function: regulating brain temperature. Like whales and dolphins, northern fur seals switch off half of their brain to catch some Zs at sea in order to maintain a low level of alertness. The researchers wanted to see whether the seals skipped REM sleep in the water, as whales and dolphins do2. They also thought that the fur seals could offer a good way of investigating the functions of REM sleep without causing the stress of interrupted sleep that can muddy the results of similar studies in other mammals. The study authors used four captive northern fur seals, fitting them with electrodes that recorded electrical activity in the animals’ brains, eyes, muscles and hearts. The scientists allowed or prevented the seals from sleeping on land by raising or lowering the water level in their pool — thereby exposing or submerging a platform they could use to rest. © 2018 Macmillan Publishers Limited,

Keyword: Sleep
Link ID: 25073 - Posted: 06.09.2018