Chapter 9. Homeostasis: Active Regulation of the Internal Environment

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By ALISSA J. RUBIN PARIS — When a fledgling alternative press published Gabrielle Deydier’s plaintive memoir of growing up fat in France, there was little expectation that the book would attract much notice. Frenchwomen are among the thinnest in Europe, high fashion is big business, and obesity isn’t often discussed. “To be fat in France is to be a loser,” Ms. Deydier said. So no one, least of all Ms. Deydier, expected “On Ne Naît Pas Grosse” (“One Is Not Born Fat”) to become a media sensation. Using her life as a case in point, bolstered by scientific studies, Ms. Deydier exposes in 150 pages the many ways the obese in France face censure, as well as frequent insensitivity from the medical profession. Soon, the 330-pound author was being interviewed by a broad range of news outlets. The coverage provoked a public reaction, and a variety of comments, including empathy and offers of support for those who are overweight, but also statements denigrating them. Some people complained Ms. Deydier was trying to normalize obesity. “To be close to someone obese in a train or a plane haunts me,” Mathieu B. wrote in a comment on Le Monde’s website. “It’s like being close to someone who smells bad. One has a very bad journey, that’s a fact.” In short, Ms. Deydier had touched a nerve. Her small publisher, which ran a limited first printing, has ordered a second. “A book like this had not been done,” said Clara Tellier Savary, Ms. Deydier’s publisher at Éditions Goutte d’Or. “For an obese person to be aware of all the issues and step back is very rare.” Unlike in the United States, where TV regularly features programs urging viewers to take a positive view of their bodies and where a plus-size clothing industry is booming, celebrating one’s girth is almost unheard-of in France. © 2017 The New York Times Company

Keyword: Obesity
Link ID: 24228 - Posted: 10.21.2017

By Alice Klein A protein injection that decreases appetite helps obese monkeys to slim down fast and cuts their risk of diabetes. Excitement is growing about a protein called GDF15, which naturally regulates body weight in humans and animals. When extra amounts are injected into mice, they eat less, lose weight and have fewer signs of diabetes. Several research teams have tried developing GDF15 as an obesity treatment, but it breaks down too quickly in the bloodstream to work. Now a team led by Murielle Véniant at pharmaceutical company Amgen has found a way to make GDF15 last longer in the body. The team added an antibody fragment onto GDF15. Antibodies are immune proteins that help recognise foreign molecules in the body. They found that this hybrid protein caused obese monkeys to eat about 40 per cent less. When given weekly injections, the monkeys lost 10 per cent of their body weight over 6 weeks. Their glucose tolerance also improved, making them less likely to develop type 2 diabetes. In comparison, the five obesity medications that are currently approved by the FDA for long-term weight management help patients to lose an average of 7 to 12 per cent of their body weight over the course of a year. Bariatric surgery – the gold standard for weight loss – usually results in 20 to 30 per cent weight loss in obese patients in the first year, but is expensive and can have complications and side-effects. © Copyright New Scientist Ltd.

Keyword: Obesity
Link ID: 24213 - Posted: 10.19.2017

Tina Hesman Saey Fungi may affect gut health in unexpected ways, new research suggests. High-fat diets may alter relationships between bacteria and fungi in mice’s intestines, contributing to obesity, researchers report October 11 in mSphere. In independent work, researchers report that a fungus teams up with two types of bacteria to fuel gut inflammation in people with Crohn’s disease. That work was summarized October 4 in Digestive and Liver Disease. Together, the studies are part of a growing body of research indicating that relationships between the bacterial and fungal kingdoms can affect health, says David Andes, a fungal biologist at the University of Wisconsin School of Medicine and Public Health in Madison. Andes wasn’t involved in either study. Scientists have already described links between health issues, including obesity, and gut bacteria — often called the microbiome. But far less is known about the role of the gut’s fungal mix, or mycobiome. “To get the whole picture,” says Andes, “we’re going to need to start looking at the mycobiome in addition to the microbiome.” As part of that picture, fungal biologist and pediatrician Cheryl Gale of the University of Minnesota in Minneapolis wanted to know whether high-fat diets change fungal communities as they do bacterial mixes. |© Society for Science & the Public 2000 - 2017.

Keyword: Obesity
Link ID: 24207 - Posted: 10.18.2017

Hannah Devlin Forget negotiations over who takes out the bin, new research suggests that the ideal home temperature is the vexed question most likely to split households down gender lines. A study found that one third of couples dispute this issue and that four in 10 women covertly turn up the heating behind their partner’s back. The research, which was sponsored by Corgi Homeplan, a company that installs and maintains boilers and thermostats, probably falls short of the rigours of peer-reviewed science. However, there is strong evidence to back up the idea that women are more sensitive to the cold. A 2015 study by Dutch scientists, for instance, found that women are comfortable at a temperature 2.5C warmer than men, typically between 24-25C. Men and women have roughly the same core body temperature, at over 37C; in fact, some studies have found the female core body temperature is slightly higher. However, our perception of temperature depends more on skin temperature, which, for women, tends to be lower. One study reported that the average temperature of women’s hands exposed to cold was nearly 3C degrees lower than that observed in men. The female hormone oestrogen contributes to this because it slightly thickens the blood, reducing the flow to capillaries that supply the body’s extremities. This means that, in women, blood flow to the tips of fingers and toes tends to shut off more readily when it is cold. Research has shown that women tend to feel colder around ovulation, when estrogen levels are high. © 2017 Guardian News and Media Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 24181 - Posted: 10.12.2017

By Jessica Hamzelou For the first time, researchers have shown that being born by C-section can contribute to obesity in mice. This probably happens because the procedure disrupts a newborn’s microbiome. Until fairly recently, babies were thought to be born with sterile guts free from bacteria. But we now know that babies are born with a gutful of microbes, and that at least some of these come from a mother’s vaginal canal during birth. Babies born by C-section are thought to miss out on these bacteria, which could explain why their microbiomes look different. The ecosystem of microbes that live inside us has been implicated in a range of health issues, so this may explain why babies born by C-section are more likely to grow up overweight, and to develop allergies and asthma in later life. To test if C-sections really do lead to heavier babies, Maria Dominguez-Bello at New York University and her colleagues performed C-sections on 34 pregnant mice, and compared the resulting pups to 35 that were born vaginally. By the time the mice had grown into adults 15 weeks later, there were stark difference in body weight between the two groups. The mice born by C-section were, on average, 33 per cent heavier than those born vaginally. Females seemed particularly affected, says Dominguez-Bello. While the C-section males were around 20 per cent heavier than their vaginally-born counterparts, the females were 70 per cent heavier, she says. “We were very surprised to see this,” she says. “We have no idea why it’s happening.” © Copyright New Scientist Ltd.

Keyword: Obesity
Link ID: 24180 - Posted: 10.12.2017

By Ann Gibbons The insult "You're a Neandertal!" has taken on dramatic new meaning in the past few years, as researchers have begun to identify the genes many of us inherited from our long-extinct relatives. By sequencing a remarkably complete genome from a 50,000-year-old bone fragment of a female Neandertal found in Vindija Cave in Croatia, researchers report online today in Science a new trove of gene variants that living people outside of Africa obtained from Neandertals. Some of this DNA could influence cholesterol levels, the accumulation of belly fat, and the risk of schizophrenia and other diseases. The genome is only the second from a Neandertal sequenced to such high quality that it can reliably reveal when, where, and what DNA was passed from Neandertals to modern humans—and which diseases it may be causing or preventing today. "It's really exciting because it's more than two times better to have two Neandertal genomes," says evolutionary genomicist Tony Capra of Vanderbilt University in Nashville. The first Neandertal genome was a composite drawn from three individuals from Vindija Cave. Then, over the past few years, ancient DNA researchers sequenced two more Neandertal genomes, including another high-quality sequence from an individual that lived 122,000 years ago in the Altai Mountains of Siberia. Together, the genomes showed that living Europeans and Asians carry traces of DNA from Neandertals who mated with members of Homo sapiens soon after our species left Africa. (Most Africans lack Neandertal DNA as a result.) © 2017 American Association for the Advancement of Science.

Keyword: Obesity; Evolution
Link ID: 24156 - Posted: 10.06.2017

Amazon has been described as "irresponsible" for selling a hoodie that describes anorexia as "like bulimia, except with self control". One woman living with anorexia said it could "damage" the mental health of those with the conditions. Anorexia expert Dr Susie Orbach told the BBC's Victoria Derbyshire programme the online retailer should "remove it immediately". Amazon said the hoodie was not sold on its UK website. It has previously been criticised for stocking T-shirts which say: "Keep calm and rape a lot". Beth Grant, who has lived with anorexia for 13 years, said selling the product was "absolutely disgraceful". "It could be extremely damaging to anyone suffering with either bulimia or anorexia," she told the BBC's Victoria Derbyshire programme. "I think it could damage their mental health even further and cause them to potentially harm their life." Dr Susie Orbach, a psychotherapist and expert on anorexia, described the hoodie as "a way to make people feel really awful" when they were "already anguished enough". "This is terribly irresponsible on Amazon's part," she said. "We're breeding a culture [where people think] you should transform your body, you should comment on it, and if it isn't the way you want it to be it's got to be some other way." Dr Orbach called for Amazon to "remove it immediately". © 2017 BBC.

Keyword: Anorexia & Bulimia
Link ID: 24144 - Posted: 10.04.2017

By DIONNE SEARCEY and MATT RICHTEL ACCRA, Ghana — After finishing high school a decade ago, Daniel Awaitey enrolled in computer courses, dropped out to work in a hotel, then settled into a well-paying job in the booming oil sector here. He has an apartment, a car, a smartphone and a long-distance girlfriend he met on a dating website. So he had reasons and the means to celebrate his 27th birthday in late July. His boss and co-workers joined him for an evening of laughter and selfies, lingering over dinner at his favorite restaurant: KFC. Mr. Awaitey first learned about the fried chicken chain on Facebook. The “finger lickin’ good” slogan caught his attention and it has lived up to expectations. “The food is just ——” he said, raising his fingertips to his mouth and smacking his lips. “When you taste it you feel good.” Ghana, a coastal African country of more than 28 million still etched with pockets of extreme poverty, has enjoyed unprecedented national prosperity in the last decade, buoyed by offshore oil. Though the economy slowed abruptly not long ago, it is rebounding and the signs of new fortune are evident: millions moving to cities for jobs, shopping malls popping up and fast food roaring in to greet people hungry for a contemporary lifestyle. Chief among the corporate players is KFC, and its parent company, YUM!, which have muscled northward from South Africa — where KFC has about 850 outlets and a powerful brand name — throughout sub-Saharan Africa: to Angola, Tanzania, Nigeria, Uganda, Kenya, Ghana and beyond. The company brings the flavors that have made it popular in the West, seasoned with an intangible: the symbolic association of fast food with rich nations. But KFC’s expansion here comes as obesity and related health problems have been surging. Public health officials see fried chicken, french fries and pizza as spurring and intensifying a global obesity epidemic that has hit hard in Ghana — one of 73 countries where obesity has at least doubled since 1980. In that period, Ghana’s obesity rates have surged more than 650 percent, from less than 2 percent of the population to 13.6 percent, according to the Institute for Health Metrics and Evaluation, an independent research center at the University of Washington. © 2017 The New York Times Company

Keyword: Obesity
Link ID: 24133 - Posted: 10.02.2017

By Amanda Onion Belly fat can be deadly, and is linked to a host of chronic diseases, including heart disease and type 2 diabetes. But as many of us probably know, it can be hard to lose weight in this area. Now it seems that inflammation of immune cells may be to blame, and we may be able to use drugs to help us burn off our belly flab. Christina Cammel, of the Yale School of Medicine, and her colleagues have been investigating macrophages – immune cells that normally track down and gobble up pathogens in the body. But as we age, there’s evidence that the macrophages in belly fat become inflamed. To see what effect this might have, Cammel’s team isolated macrophages from the fat tissue of young and old mice, and sequenced the DNA from these cells. They found that the genomes of the aged macrophages expressed more genes that hinder a group of molecules that spread signals between nerve cells, called catecholamines. The genes do this by activating an enzyme that suppresses these neurotransmitters. The boosted activity of this enzyme in aged immune cells in the belly fat of older mice effectively block signals telling the body that there is fat there that is available to burn for energy. “We found [that] macrophages in belly fat interfere with signals in a way that’s new to us,” says Cammel. © Copyright New Scientist Ltd.

Keyword: Obesity; Depression
Link ID: 24120 - Posted: 09.28.2017

By GRETCHEN REYNOLDS For most of us, temptations are everywhere, from the dessert buffet to the online shoe boutique. But a new study suggests that exercise might be a simple if unexpected way to increase our willpower and perhaps help us to avoid making impulsive choices that we will later regret. Self-control is one of those concepts that we all recognize and applaud but do not necessarily practice. It requires forgoing things that entice us, which, let’s face it, is not fun. On the other hand, lack of self-control can be consequential for health and well-being, often contributing to problems like weight gain, depression or money woes. Given these impacts, scientists and therapists have been interested in finding ways to increase people’s self-restraint. Various types of behavioral therapies and counseling have shown promise. But such techniques typically require professional assistance and have for the most part been used to treat people with abnormally high levels of impulsiveness. There have been few scientifically validated options available to help those of us who might want to be just a little better at resisting our more devilish urges. So for the new study, which was published recently in Behavior Modification, a group of researchers at the University of Kansas in Lawrence began wondering about exercise. Exercise is known to have considerable psychological effects. It can raise moods, for example, and expand people’s sense of what they are capable of doing. So perhaps, the researchers speculated, exercise might alter how well people can control their impulses. To find out, the scientists decided first to mount a tiny pilot study, involving only four men and women. © 2017 The New York Times Company

Keyword: Obesity; Attention
Link ID: 24119 - Posted: 09.28.2017

By Amy Lewis Stress, anxiety, and depression are emotions we all feel at some point in our lives, some people to a greater degree than others. Part of the human experience, right? “It may seem odd that my research focuses on the gut if I’m interested in the brain,” says John Cryan, a researcher at the APC Microbiome Institute at University College Cork in Ireland. “But when we think of how we express emotion in language, through sayings like ‘butterflies in your tummy’ and ‘gut feeling,’ it isn’t surprising that they’re connected.” In a recent study, Cryan and his colleagues reported a link between the microbiome and fear. By examining mice with and without gut bacteria, they discovered that the germ-free mice had blunted fear responses (Mol Psychiatr, doi:10.1038/mp.2017.100, 2017). Their findings may pave the way for the development of novel treatments for anxiety-related illnesses, including posttraumatic stress disorder. Researchers at Kyushu University in Japan were the first to show, in 2004, that bacteria in the gut can influence stress responses, prompting many subsequent investigations. Yet despite mounting research, scientists remain uncertain about exactly how the gut microbiome affects the brain. While some bacteria influence the brain through the vagus nerve, other strains seem to use different pathways. It is known, however, that the population of the gut microbiome begins in early life, and recent research suggests that disruptions to its normal development may influence future physical and mental health (Nat Commun, 6:7735, 2015). Researchers are finding that this gut-brain connection could have clinical implications, as influencing the gut microbiome through diet may serve to ameliorate some psychiatric disorders. Together with University College Cork colleague Ted Dinan, Cryan coined the term “psychobiotics” in 2013 to describe live organisms that, when ingested, produce health benefits in patients with psychiatric illness. These include foods containing probiotics, live strains of gut-friendly bacteria. © 1986-2017 The Scientist

Keyword: Obesity
Link ID: 24108 - Posted: 09.25.2017

“Bad fat” could be made to turn over a new leaf and combat obesity by blocking a specific protein, scientists have discovered. Most fat in the body is unhealthy “white” tissue deposited around the waist, hips and thighs. But smaller amounts of energy-hungry “brown” fat are also found around the neck and shoulders. Brown fat generates heat by burning up excess calories. Now scientists experimenting on lab mice have found a way to transform white fat into “beige” fat – a healthier halfway stage also capable of reducing weight gain. Dr Irfan Lodhi, from Washington University School of Medicine in the US, said: “Our goal is to find a way to treat or prevent obesity. “Our research suggests that by targeting a protein in white fat, we can convert bad fat into a type of fat that fights obesity.” Beige fat was discovered in adults in 2015 and shown to function in a similar way to brown fat. Lodhi’s team found that blocking a protein called PexRAP caused white fat in mice to be converted to beige fat that burned calories. The discovery, published in the journal Cell Reports, raises the prospect of more effective treatments for obesity and diabetes. The next step will be to find a safe way of blocking PexRAP in white fat cells in humans. Lodhi said: “The challenge will be finding safe ways to do that without causing a person to overheat or develop a fever, but drug developers now have a good target.” © 2017 Guardian News and Media Limited

Keyword: Obesity
Link ID: 24079 - Posted: 09.20.2017

By Consumer Reports Fasting every other day doesn’t lead to bigger weight loss than daily calorie-cutting and is more difficult to maintain, suggests a University of Illinois at Chicago study published recently in JAMA Internal Medicine. The researchers followed 100 obese people for a year, making this the largest and longest study so far to examine ­alternate-day fasting. The alternate-day diet in this study called for participants to take in 25 percent of their needed calories on fast days and 125 percent on feast days. It’s a type of intermittent fasting that involves drastically reducing your calorie intake on some days or during certain hours and eating whatever you like on others. The theory is that it is easier to focus on reducing calorie intake only some of the time and that the eating pattern improves cardiovascular risk factors — such as blood pressure, cholesterol and insulin levels — more than daily calorie-cutting does. In this study, those who took the intermittent-fasting approach lost the same amount of weight, on average, as those who cut back on calories — to 75 percent of their needs — every day. Both groups dropped about 7 percent of their body weight after six months and regained about 1 percent of their weight during the six-month weight-maintenance phase. “We can say that alternate-day fasting does produce clinically significant weight loss after a year, but it’s not better than a typical calorie-restricted diet,” says study researcher Krista A. Varady, an associate professor of nutrition at the University of Illinois at Chicago. © 1996-2017 The Washington Post

Keyword: Obesity
Link ID: 24069 - Posted: 09.18.2017

By Giorgia Guglielmi The trillions of bacteria that live in our intestines, known collectively as the gut microbiome, have been linked to maladies from eye disease to rheumatoid arthritis. Now, two new studies have added another disease: multiple sclerosis (MS), an autoimmune disorder that strips away nerve cells’ protective covers, leading to muscle weakness, blindness, and even death. What’s more, the studies suggest how our gut microbes make the immune system turn against nerve cells—a finding that could lead to treatments, like drugs based on microbial byproducts, that might improve the course of the disease. MS affects 2.5 million people worldwide, but little is known about what causes the disease, which progressively disrupts information flow from and within the brain. Most researchers think it starts when genetically predisposed people encounter an as-yet-unknown environmental trigger. Previous studies have identified particular bacteria present in increased amounts in the guts of MS patients. But the new papers “took it to the next level” in trying to understand how these bacteria affect the immune system, says Francisco Quintana, a neuroimmunologist at Brigham and Women’s Hospital in Boston not involved with the work. “These are going to be landmark studies.” In the first paper, a team of researchers led by Sergio Baranzini, a human geneticist at the University of California, San Francisco, analyzed the microbiomes of 71 people with MS and 71 healthy individuals, aged 19 to 71. They found that two bacterial groups, Acinetobacter and Akkermansia, were four times more abundant in MS patients than in individuals with no disease. Another group, Parabacteroides, was four times as abundant in healthy people. © 2017 American Association for the Advancement of Science

Keyword: Multiple Sclerosis
Link ID: 24059 - Posted: 09.13.2017

By NICHOLAS BAKALAR High carbohydrate intake is associated with a higher risk of mortality, and high fat intake with a lower risk, researchers report. An international team of scientists studied diet and mortality in 135,335 people between 35 and 70 years old in 18 countries, following them for an average of more than seven years. Diet information depended on self-reports, and the scientists controlled for factors including age, sex, smoking, physical activity and body mass index. The study is in The Lancet. Compared with people who ate the lowest 20 percent of carbohydrates, those who ate the highest 20 percent had a 28 percent increased risk of death. But high carbohydrate intake was not associated with cardiovascular death. People with the highest 20 percent in total fat intake — an average of 35.3 percent of calories from fat — had about a 23 percent reduced risk of death compared with the lowest 20 percent (an average of 10.6 percent of calories from fat). Consuming higher saturated fat, polyunsaturated fat and monounsaturated fat were all associated with lower mortality. Higher fat diets were also associated with a lower risk of stroke. “Guidelines recommend low saturated fat, and some recommend really low amounts,” said a co-author, Andrew Mente, an epidemiologist at McMaster University in Ontario. “Our study, which captures intake at the lowest levels, shows that this may be harmful.” Current federal guidelines recommend a diet that provides no more than 35 percent of calories from fat. © 2017 The New York Times Company

Keyword: Obesity
Link ID: 24050 - Posted: 09.09.2017

By Bob Grant Eating a diet high in fat and low in carbohydrates keeps mice living longer, healthier lives, according to two separate studies published in Cell Metabolism today (September 5). One of the studies, conducted by researchers at the University of California, San Francisco, and the Buck Institute for Research on Aging in California, cycled mice on and off a ketogenic diet, which forces the body to produce fatty acids called ketone bodies to fuel metabolism through the severe limiting of carbohydrates. Those mice, which were given non-ketogenic diets one week and ketogenic diets the next, avoided obesity and memory decline and displayed reductions in midlife mortality, compared to mice on a control diet. The other study, performed by scientists at the Buck Institute in collaboration with researchers at the University of California, Davis, kept mice on a ketogenic diet for 14 months and showed similar results, with the addition of improvements in motor function, grip strength, and other indicators of muscle mass. “The fact that we had such an effect on memory and preservation of brain function is really exciting,” Eric Verdin, CEO of the Buck Institute and coauthor of the study that alternated ketogenic and non-ketogenic diets, says in a statement. “The older mice on the ketogenic diet had a better memory than the younger mice. That’s really remarkable.” © 1986-2017 The Scientist

Keyword: Obesity
Link ID: 24043 - Posted: 09.07.2017

Ian Sample Science editor A drug that mimics a zero-carbohydrate diet could help people live longer, healthier lives and have better memories in old age, US researchers claim. Scientists hope to develop a medication after two independent studies showed that mice fed on a diet stripped of all carbohydrate lived longer and performed better on a range of physical and mental tasks than those that had regular meals. Because the diet is hard to stick to, the researchers are working on a compound that aims to deliver the same benefits for humans. If they are successful, it would amount to an extra seven to ten years of life on average, and protection against the weakening muscles and faltering memories that are defining aspects of human ageing. “I’m excited about this, and it’s hard not to be after what we’ve seen that it does. These are pretty profound effects,” said Eric Verdin, a physician who led one of the studies at the Buck Institute for Research on Aging in California. The zero carb diet was designed to induce a dramatic change in metabolism, by fooling the mice into thinking they were fasting. When deprived of carbohydrate, the body shifts from using glucose as its main energy source to burning fat and producing chemicals in the liver known as ketone bodies. In 2013, Verdin showed that a ketone body called BHB served as fuel in the body and might also protect animals against the microscopic damage that builds up in cells as part of the natural ageing process. © 2017 Guardian News and Media Limited

Keyword: Obesity
Link ID: 24040 - Posted: 09.06.2017

By Ryan Cross Weight loss seems to come easiest to those who want it least. Every year, hundreds of thousands suffer from the loss of appetite that comes with tumor-induced anorexia, which can accompany many late-stage cancers. Now, researchers from three major pharmaceutical companies have independently published papers showing that the culprit behind this condition—a protein called growth differentiation factor-15 (GDF15)—helps mice, rats, and monkeys lose weight without any apparent side effects. “The idea of having another medication to add to our armamentarium is exciting news,” says Katherine Saunders, an obesity medicine physician at Weill Cornell Medicine in New York City who was not involved with the work. There are currently five U.S. Food and Drug Administration–approved obesity medications for long-term weight management, which can help patients lose 5% to 8% of their body weight on average. “That’s very limited,” Saunders says, adding that many drugs used to treat obesity don’t have the same level of specificity as GDF15. GDF15’s potential as a weight-loss agent was first discovered by Samuel Breit, an immunologist and physician at St. Vincent's Hospital in Sydney, Australia. He saw levels of the protein rise 10 to 100 times higher than normal during tumor-induced anorexia in mice with prostate tumors and in humans with advanced prostate cancer. Breit also showed that GDF15 likely exerts its effects through the brain—though he says that until now the protein’s target has befuddled scientists. © 2017 American Association for the Advancement of Science

Keyword: Obesity
Link ID: 24018 - Posted: 08.31.2017

BY Patrick Skerrett, An international study is casting doubt on the wisdom of eating lots of carbohydrates. Photo by Flickr user Dani Armengol Garreta Fat, once a dirty word when it came to diet, has been edging back toward respectability. New results from a huge international study help continue to reshape its image while at the same time casting doubt on the wisdom of eating lots of carbohydrates and questioning the “more is better” recommendations for eating fruits and vegetables. The latest evidence comes from data released Tuesday by the international Prospective Urban Rural Epidemiology (PURE) study. Its research team recorded the eating habits of 135,000 adults in 18 countries — including high-income, medium-income, and low-income nations — and followed the participants’ health for more than seven years on average. Among the PURE participants, those with the highest intake of dietary fat (35 percent of daily calories) were 23 percent less likely to have died during the study period than those with the lowest fat intake (10 percent of calories). The rates of various cardiovascular diseases were essentially the same across fat intake, while strokes were less common among those with a high fat intake. Upending conventional wisdom, the findings for carbohydrate intake went in the opposite direction. PURE participants with the highest carbohydrate intake (77 percent of daily calories) were 28 percent more likely to have died than those with the lowest carbohydrate intake (46 percent of calories). The results were presented at the European Society of Cardiology meeting in Barcelona, and published in the Lancet. © 1996 - 2017 NewsHour Productions LLC.

Keyword: Obesity
Link ID: 24015 - Posted: 08.31.2017

Maria Temming Bacteria living in the human gut have strange influence over mood, depression and more, but it has been unclear exactly how belly-dwelling bacteria exercise remote control of the brain (SN: 4/2/16, p. 23). Now research in rodents suggests that gut microbes may alter the inventory of microRNAs — molecules that help keep cells in working order by managing protein production — in brain regions involved in controlling anxiety. The findings, reported online August 25 in Microbiome, could help scientists develop new treatments for some mental health problems. Mounting evidence indicates “that the way we think and feel might be able to be controlled by our gut microbiota,” says study coauthor Gerard Clarke, a psychiatrist at University College Cork in Ireland. For instance, the presence or absence of gut bacteria can influence whether a mouse exhibits anxiety-like behaviors, such as avoiding bright lights or open spaces. Clarke and colleagues compared normal mice, whose gastrointestinal tracts were teeming with bacteria, with mice bred in sterile environments, whose guts didn’t contain any microbes. The researchers discovered that in brain regions involved in regulating anxiety — the amygdala and prefrontal cortex — microbe-free mice had an overabundance of some types of microRNA and a shortage of others compared with normal mice. After scientists exposed some sterilized mice to microbes, the rodents’ microRNA levels more closely matched those of normal mice. |© Society for Science & the Public 2000 - 2017.

Keyword: Emotions; Stress
Link ID: 24012 - Posted: 08.30.2017