Links for Keyword: Obesity

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Study shows brain and stomach connections are a two-way street

By David Templeton For much of the 20th century, most people thought that stress caused stomach ulcers. But that belief was largely dismissed 38 years ago when a study, which led to a Nobel Prize in 2016, described the bacterium that generates inflammation in the gastrointestinal tract and causes peptic ulcers and gastritis. “The history of the idea that stress causes ulcers took a side step with the discovery of Helicobacter pylori,” said Dr. David Levinthal, director of the University of Pittsburgh Neurogastroenterology & Motility Center. “For the longest time — most of the 20th century — the dominant idea was that stress was the cause of ulcers until the early 1980s with discovery of Helicobacter pylori that was tightly linked to the risk of ulcers. That discovery was critical but maybe over-generalized as the only cause of ulcers.” Now in an important world first, a study co-authored by Levinthal and Peter Strick, both from the Pitt School of Medicine, has explained what parts of the brain’s cerebral cortex influence stomach function and how it can affect health. “Our study shows that the activity of neurons in the cerebral cortex, the site of conscious mental function, can impact the ability of bacteria to colonize the stomach and make the person more sensitive to it or more likely to harbor the bacteria,” Levinthal said. The study goes far beyond ulcers by also providing evidence against the longstanding belief that the brain’s influence on the stomach was more reflexive and with limited, if any, involvement of the thinking brain. And for the first time, the study also provides a general blueprint of neural wiring that controls the gastrointestinal tract. © 2020 StarTribune.

Obesity Linked to Severe Coronavirus Disease, Especially for Younger Patients

By Roni Caryn Rabin Obesity may be one of the most important predictors of severe coronavirus illness, new studies say. It’s an alarming finding for the United States, which has one of the highest obesity rates in the world. Though people with obesity frequently have other medical problems, the new studies point to the condition in and of itself as the most significant risk factor, after only older age, for being hospitalized with Covid-19, the illness caused by the coronavirus. Young adults with obesity appear to be at particular risk, studies show. The research is preliminary, and not peer reviewed, but it buttresses anecdotal reports from doctors who say they have been struck by how many seriously ill younger patients of theirs with obesity are otherwise healthy. No one knows why obesity makes Covid-19 worse, but hypotheses abound. Some coronavirus patients with obesity may already have compromised respiratory function that preceded the infection. Abdominal obesity, more prominent in men, can cause compression of the diaphragm, lungs and chest capacity. Obesity is known to cause chronic, low-grade inflammation and an increase in circulating, pro-inflammatory cytokines, which may play a role in the worst Covid-19 outcomes. Some 42 percent of American adults — nearly 80 million people — live with obesity. That is a prevalence rate far exceeding those of other countries hit hard by the coronavirus, like China and Italy. The new findings about obesity risks are bad news for all Americans, but particularly for African-Americans and other people of color, who have higher rates of obesity and are already bearing a disproportionate burden of Covid-19 deaths. High rates of obesity are also prevalent among low-income white Americans, who may also be adversely affected, experts say. More than half of Covid-19 deaths in the United States so far have been in New York and New Jersey, but the new findings mean the coronavirus could exact a steep toll in regions like the South and the Midwest, where obesity is more prevalent than in the Northeast. © 2020 The New York Times Company

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 11: Emotions, Aggression, and Stress
Link ID: 27205 - Posted: 04.17.2020

Your brain evolved to hoard supplies and shame others for doing the same

Stephanie Preston The media is replete with COVID-19 stories about people clearing supermarket shelves – and the backlash against them. Have people gone mad? How can one individual be overfilling his own cart, while shaming others who are doing the same? As a behavioral neuroscientist who has studied hoarding behavior for 25 years, I can tell you that this is all normal and expected. People are acting the way evolution has wired them. The word “hoarding” might bring to mind relatives or neighbors whose houses are overfilled with junk. A small percentage of people do suffer from what psychologists call “hoarding disorder,” keeping excessive goods to the point of distress and impairment. But hoarding is actually a totally normal and adaptive behavior that kicks in any time there is an uneven supply of resources. Everyone hoards, even during the best of times, without even thinking about it. People like to have beans in the pantry, money in savings and chocolates hidden from the children. These are all hoards. Most Americans have had so much, for so long. People forget that, not so long ago, survival often depended on working tirelessly all year to fill root cellars so a family could last through a long, cold winter – and still many died. Similarly, squirrels work all fall to hide nuts to eat for the rest of the year. Kangaroo rats in the desert hide seeds the few times it rains and then remember where they put them to dig them back up later. A Clark’s nutcracker can hoard over 10,000 pine seeds per fall – and even remember where it put them. © 2010–2020, The Conversation US, Inc.

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 18: Attention and Higher Cognition
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 14: Attention and Higher Cognition
Link ID: 27149 - Posted: 03.30.2020

How to Lose Weight and Keep It Off

By Jane E. Brody Many people who have struggled for years with excess weight know that the hardest and often the most frustrating job is not getting it off but keeping it off. Recent decades have seen countless popular diet schemes that promised to help people shed unwanted pounds, and as each of these diets failed in the long run, they spawned their successors. A diet, after all, is something people go on to go off. Most people think of a diet as a means to an end, and few who go on a food-restricted diet to lose weight expect to have to eat that way indefinitely. And therein lies the rub, with the current unchecked epidemic of obesity as the sorry result. We live in a land of incredible excess. Rich or poor, most of us are surrounded by calorie-rich vittles, many of them tasty but deficient in ingredients that nourish healthy bodies. “We can’t go two minutes without being assaulted by a food cue,” said Suzanne Phelan, lead author of an encouraging new study in the journal Obesity. Even the most diligent dieters can find it hard to constantly resist temptation. And once people fall off the diet wagon, they often stay off, and their hard-lost pounds reappear a lot faster than it took to shed them. But these facts need not discourage anyone from achieving lasting weight loss. Researchers have identified the strategies and thought processes that have enabled many thousands of people to lose a significant amount of weight and keep it off for many years, myself among them. The new study led by Dr. Phelan, professor of kinesiology and public health at California Polytechnic State University, identified habits and strategies that can be keys to success for millions. Yes, like most sensible weight-loss plans, they involve healthful eating and regular physical activity. But they also include important self-monitoring practices and nonpunitive coping measures that can be the crucial to long-term weight management. © 2020 The New York Times Company

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 27119 - Posted: 03.16.2020

A common artificial sweetener might be making you fatter and sicker,

Laura Reiley A study published in the journal Cell Metabolism by a group of Yale researchers found that the consumption of the common artificial sweetener sucralose (which is found in Splenda, Zerocal, Sukrana, SucraPlus and other brands) in combination with carbohydrates can swiftly turn a healthy person into one with high blood sugar. From whole grain English muffins to reduced-sugar ketchup, sucralose is found in thousands of baked goods, condiments, syrups and other consumer packaged goods — almost all of them containing carbs. The finding, which researchers noted has yet to be replicated in other studies, raises new questions about the use of artificial sweeteners and their effects on weight gain and overall health. In the Yale study, researchers took 60 healthy-weight individuals and separated them into three groups: A group that consumed a regular-size beverage containing the equivalent of two packets of sucralose sweetener, a second group that consumed a beverage sweetened with table sugar at the equivalent sweetness, and a third control group that had a beverage with the artificial sweetener as well as a carbohydrate called maltodextrin. The molecules of maltodextrin don’t bind to taste receptors in the mouth and are impossible to detect. While the sensation of the third group’s beverage was identical to the Splenda-only group, only this group exhibited significant adverse health effects. The artificial sweetener by itself seemed to be fine, the researchers discovered, but that changed when combined with a carbohydrate. Seven beverages over two weeks and the previously healthy people in this group became glucose intolerant, a metabolic condition that results in elevated blood glucose levels and puts people at an increased risk for diabetes.

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 27113 - Posted: 03.12.2020

Your Kids Are Heavier Than You Think

By Susana Martinez-Conde Parents tend to be just a bit biased about their children’s looks (not me though—my kids are objectively beautiful), but as it turns out, this type of self-deception is not as benign as one might think. According to recent research, many parents appear to suffer from a sort of denial concerning their kids’ weights, which poses a considerable obstacle to remediating childhood obesity by way of promoting healthy eating habits at home. The latest of such studies was published last month in the American Journal of Human Biology, and conducted by a team of scientists at the University of Coimbra in Portugal. Daniela Rodrigues and her collaborators, Aristides Machado-Rodrigues and Cristina Padez, recruited hundreds of parents and children for their research. All the participating children were between 6 and 10 years old and attended elementary school in Portugal. A total of 834 parents completed questionnaires that included a variety of questions, such as whether they thought that their children’s weight was a bit too little, a bit too much, way too much, or just fine. In turn, the team collected the weights and heights of the 793 participating children, at their respective schools. The results were in line with the researchers’ predictions, but nonetheless remarkable. Of the 33% parents who misperceived their children’s weight, 93% underestimated it. Moreover, parents who underestimated their kids’ weights were 10 to 20 times more likely to have an obese child. Several factors were associated with the parental weight underestimation, including a higher BMI (body mass index) for the mothers, younger ages for the children, lower household income (for girls) and urban living (for boys). However, such associations did not explain why parents underestimated their children’s weights to begin with. © 2020 Scientific American

Related chapters from BN: Chapter 18: Attention and Higher Cognition; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 14: Attention and Higher Cognition; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 27106 - Posted: 03.09.2020

How Exercise Might Affect Our Food Choices, and Our Weight

By Gretchen Reynolds Taking up exercise could alter our feelings about food in surprising and beneficial ways, according to a compelling new study of exercise and eating. The study finds that novice exercisers start to experience less desire for fattening foods, a change that could have long-term implications for weight control. The study also shows, though, that different people respond quite differently to the same exercise routine and the same foods, underscoring the complexities of the relationship between exercise, eating and fat loss. I frequently write about exercise and weight, in part because weight control is a pressing motivation for so many of us to work out, myself included. But the effects of physical activity on waistlines are not straightforward and coherent. They are, in fact, distressingly messy. Both personal experience and extensive scientific studies tell us that a few people will lose considerable body fat when they start exercising; others will gain; and most will drop a few pounds, though much less than would be expected given how many calories they are burning during their workouts. At the same time, physical activity seems to be essential for minimizing weight gain as we age and maintaining weight loss if we do manage to shed pounds. Precisely how exercise influences weight in this topsy-turvy fashion is uncertain. On the one hand, most types of exercise increase appetite in most people, studies show, tempting us to replace calories, blunting any potential fat loss and even initiating weight creep. But other evidence suggests that physical fitness may affect people’s everyday responses to food, which could play a role in weight maintenance. In some past studies, active people of normal weight displayed less interest in high-fat, calorie-dense foods than inactive people who were obese. © 2020 The New York Times Company

The Benefits of Intermittent Fasting

By Jane E. Brody I’ve long thought the human body was not meant to run on empty, that fasting was done primarily for religious reasons or political protest. Otherwise we needed a reliably renewed source of fuel to function optimally, mentally and emotionally as well as physically. Personal experience reinforced that concept; I’m not pleasant to be around when I’m hungry. There’s even an official name for that state of mind, confirmed by research: Hangry! But prompted by recent enthusiasm for fasting among people concerned about their health, weight or longevity, I looked into the evidence for possible benefits — and risks — of what researchers call intermittent fasting. Popular regimens range from ingesting few if any calories all day every other day or several times a week to fasting for 16 hours or more every day. A man I know in his early 50s said he had lost 12 pounds in about two months on what he calls the 7-11 diet: He eats nothing from 7 p.m. until 11 a.m. the next morning, every day. I was skeptical, but it turns out there is something to be said for practicing a rather prolonged diurnal fast, preferably one lasting at least 16 hours. Mark P. Mattson, neuroscientist at the National Institute on Aging and Johns Hopkins University School of Medicine, explained that the liver stores glucose, which the body uses preferentially for energy before it turns to burning body fat. “It takes 10 to 12 hours to use up the calories in the liver before a metabolic shift occurs to using stored fat,” Dr. Mattson told me. After meals, glucose is used for energy and fat is stored in fat tissue, but during fasts, once glucose is depleted, fat is broken down and used for energy. Most people trying to lose weight should strive for 16 calorie-free hours, he said, adding that “the easiest way to do this is to stop eating by 8 p.m., skip breakfast the next morning and then eat again at noon the next day.” (Caffeine-dependent people can have sugar- free black coffee or tea before lunch.) But don’t expect to see results immediately; it can take up to four weeks to notice an effect, he said. © 2020 The New York Times Company

Half of Us Face Obesity, Dire Projections Show

By Jane E. Brody Climate change is not the only source of dire projections for the coming decade. Perhaps just as terrifying from both a health and an economic perspective is a predicted continued rise in obesity, including severe obesity, among American adults. A prestigious team of medical scientists has projected that by 2030, nearly one in two adults will be obese, and nearly one in four will be severely obese. The estimates are thought to be particularly reliable, as the team corrected for current underestimates of weight given by individuals in national surveys. In as many as 29 states, the prevalence of obesity will exceed 50 percent, with no state having less than 35 percent of residents who are obese, they predicted. Likewise, the team projected, in 25 states the prevalence of severe obesity will be higher than one adult in four, and severe obesity will become the most common weight category among women, non-Hispanic black adults and low-income adults nationally. Given the role obesity plays in fostering many chronic, disabling and often fatal diseases, these are dire predictions indeed. Yet, as with climate change, the powers that be in this country are doing very little to head off the potentially disastrous results of expanding obesity, obesity specialists say. Well-intentioned efforts like limiting access to huge portions of sugar-sweetened soda, the scientists note, are effectively thwarted by well-heeled industries able to dwarf the impact of educational efforts by health departments that have minuscule budgets by comparison. With rare exceptions, the sugar and beverage industries have blocked nearly every attempt to add an excise tax to sugar-sweetened beverages. Claims that such a tax is regressive and unfairly targets low-income people is shortsighted, according to Zachary J. Ward, public health specialist at Harvard and the lead author of the new report, published in The New England Journal of Medicine in December. © 2020 The New York Times Company

Do Our Babies Need to Move More?

By Gretchen Reynolds In a world that encourages inactivity, even our babies may be moving too little, according to an innovative new study of physical activity patterns during a child’s first year of life. The study, which used tiny activity trackers to monitor babies’ movements, found associations between infants’ squirming, kicking, crawling or stillness and the levels of fat around their middles, raising provocative questions about just how early any links between inactivity and obesity might begin. We already have considerable evidence, of course, that children in the Western world tend to be sedentary. According to recent estimates, most school-age children in the United States sit for more than eight hours a day, while children as young as 2 or 3 years of age can be sedentary for 90 percent or more of their waking hours. These statistics are concerning, because other studies suggest that inactive children face much higher risks of becoming overweight or obese than children who move more often. But little has been known about how much — or little — tiny babies move and if there might be correlations between their activities and their rotundity, and if such correlations matter. So, for the new study, which was published this month in Obesity, a group of researchers from Johns Hopkins University and other institutions decided to fit baby-size trackers to infants’ ankles and watch how they wiggled. They began by turning to new mothers already participating in a large, ongoing study of the health of mothers and newborns and asking if they could now track their babies’ activities. The researchers wound up recruiting 506 young boys and girls from various socioeconomic levels, more than half of them African-American. The researchers visited these infants in their homes when the babies were 3, 6, 9 and 12 months old, weighing and measuring the children, gently checking their body fat with calipers and fitting them with tiny accelerometers. © 2020 The New York Times Company

Related chapters from BN: Chapter 13: Homeostasis: Active Regulation of the Internal Environment; Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 9: Homeostasis: Active Regulation of the Internal Environment; Chapter 4: Development of the Brain
Link ID: 26978 - Posted: 01.22.2020

Childhood Obesity Is a Major Problem. Research Isn’t Helping

By Aaron E. Carroll Childhood obesity is a major public health problem, and has been for some time. Almost 20 percent of American children are affected by obesity, as well as about 40 percent of adults. Over all, this costs the United States around $150 billion in health care spending each year. Pediatricians like me, and many other health professionals, know it’s a problem, and yet we’ve been relatively unsuccessful in tackling it. About six years ago, some reports seemed to show that rates had stabilized in children and even decreased in those ages 2 to 5. Later studies showed this trend to be an illusion. If anything, things have gotten worse. Efforts to help can backfire. People on diets often gain weight. Although individual studies have pointed to potential interventions and solutions, these have not yet translated into actual improvements. Part of the problem may be flawed research. A recent paper in Pediatric Obesity provided a guide on how to do better. Its suggestions fall into five general themes. 1) When things look better, it’s critical to ask “compared to what?” In short, you need a control group. Over time, changes in behaviors or measurements often follow a pattern known as regression toward the mean. Outliers (in this case those who are more overweight) tend to move toward the average. Thus, interventions might look as if they’re working when they’re not. Control groups — participants who don’t receive the intervention — can help ensure that we’re seeing real effectiveness. Even then, things can get tricky. In a randomized controlled trial, it’s important to keep the comparisons directly between the intervention and control groups. A common mistake is comparing each group after the intervention with the same group before the intervention. In other words, people could compare a dieting group to itself, before and after, and compare the control group to itself, before and after, to see if the © 2020 The New York Times Company

Brain differences may be tied to obesity, kids' study says

New results from the largest long-term study of brain development and children's health raise provocative questions about obesity and brain function. Does excess body weight somehow reduce brain regions that regulate planning and impulse control? Is obesity a result of that brain difference? Or are eating habits, lifestyle, family circumstances and genetics to blame? Previous studies in children and adults have had conflicting results. The new research doesn't settle the matter and outside experts cautioned that misinterpreting it could unfairly perpetuate weight stigma. But an editorial published with the study Monday in JAMA Pediatrics called it an important addition to mounting evidence of a link between weight, brain structure and mental function. If follow-up research confirms the findings, it could lead to new ways to prevent obesity that target improved brain function. "We don't know which direction these relationships go nor do they suggest that people with obesity are not as smart as people at a healthy weight,"said Dr. Eliana Perrin, a Duke University pediatrics professor who co-wrote the editorial. The federally-funded study involved 3,190 U.S. children aged 9 and 10. They had height and weight measurements, MRI brain scans and computer-based tests of mental function including memory, language, reasoning and impulse control. Nearly 1,000 kids — almost 1 in 3 —were overweight or obese, similar to national statistics. Inflammatory changes early in life ©2019 CBC/Radio-Canada

Full intestines, more than full stomachs, may tell mice to stop eating

By Laura Sanders Bulging stomachs often take the blame for ending holiday indulging. But bulging guts might be the real appetite killer, a study in mice suggests. The results, published November 14 in Cell, could point out new ways to treat obesity, or even help explain how gastric bypass surgeries limit eating. Those procedures result in food moving faster through the stomach into the intestines, stretching the gut in a way that might signal fullness, the authors speculate. Zachary Knight, a neuroscientist at the University of California, San Francisco, and colleagues identified and studied nerve cells in mice’s intestines that sense mechanical stretching. To simulate full intestines, the team activated these nerve cells with light and chemicals. As a result, the mice ate less food. Physically stretching the mice’s intestines with a salty liquid or a diuretic also caused the mice to eat less. Different stretch-sensing cells in the stomach also curbed mice’s appetites, but to a lesser extent, the researchers found. These nerve cell endings relay messages up the vagus nerve (SN: 11/13/15), which then zips signals to the brain. These messages about intestinal stretching help influence the eat-or-not decision, researchers suspect. L. Bai et al. Genetic identification of vagal sensory neurons that control feeding. Cell. Vol. 179, November 14, 2019, p. 1129. doi: 10.1016/j.cell.2019.10.031 © Society for Science & the Public 2000–2019.

Why Diet Research Is So Spectacularly Thin

By David S. Ludwig and Steven B. Heymsfield Most diet trials in the best journals fail even the most basic of quality control measures. That’s the finding of a study by us to be published today in JAMA Network Open. Investigators receiving funding for any clinical trial from the National Institutes of Health must register in advance what they plan to test, among other design features, to ensure that the data are fairly analyzed. Comparing the original registries with the final published studies, we found that diet trials in the past decade were about four times as likely as drug trials to have a discrepancy in the main outcome or measurement — raising concern for bias. This quality-control problem of diet trials in comparison to ones on pharmaceuticals leads to a bigger issue: underinvestment in nutrition research and in how we tackle the mysteries of a healthy diet. Although the problems with observational studies have received much attention (“Association doesn’t prove causation,” as scientists say), clinical trials can suffer from equally important limitations. In a clinical trial, investigators assign volunteers to receive different treatments — such as a a low-carbohydrate versus low-fat diet — ideally in random order. Beyond registry issues, trials may provide misleading results for many reasons, including small size, short duration and weak interventions (they lack power to actually make the intended change in behavior). These failures are disturbing because epidemics of diet-related disease will shorten life expectancy and impose huge economic costs on the United States in coming years. We continue to lack effective dietary prevention, in part because clinical trials have been too poorly designed and conducted to reach definitive conclusions. We’re still debating questions that have raged for decades: Should we focus on reducing carbs or fat? Is red meat harmful? Is sugar toxic? What about artificially sweetened beverages or moderate amounts of alcohol? © 2019 The New York Times Company

Sugary Drink Ban Tied to Health Improvements at Medical Center

By Anahad O’Connor In recent years, hospitals and medical centers across the country have stopped selling sugar-sweetened beverages in an effort to reduce obesity and diabetes. Now a new study carried out at the University of California, San Francisco, has documented the health impact of a soda sales ban on its employees. Ten months after a sales ban went into effect, U.C.S.F. workers who tended to drink a lot of sugary beverages had cut their daily intake by about half. By the end of the study period, the group had, on average, reduced their waist sizes and belly fat, though they did not see any changes in their body mass index. Those who cut back on sugary beverages also tended to see improvements in insulin resistance, a risk factor for Type 2 diabetes. The new research, published on Monday in JAMA Internal Medicine, is the first peer-reviewed study to examine whether a workplace sales ban on sugary drinks could lead to reduced consumption of the beverages and improve employee health. At least nine other University of California campuses have said they are going to adopt similar initiatives to reduce sugary beverage sales and promote water consumption. “This was an intervention that was easy to implement,” said Elissa Epel, an author of the study and director of the Aging, Metabolism, and Emotions Center at U.C.S.F. “It’s promising because it shows that an environmental change can help people over the long run, particularly those who are consuming large-amounts of sugary beverages, and possibly even lead to a reduction in their risk of cardiometabolic disease.” In recent years, the link between sugar and obesity has drawn increasing scientific attention. Health authorities say that Americans have gotten fatter because they are consuming too many calories of all kinds. But some experts have singled out the role of added sugar consumption, which increased more than 30 percent between 1977 and 2010. © 2019 The New York Times Company

Why Isn’t There a Diet That Works for Everyone?

By Kim Tingley In the United States and other Western countries, diet and nutrition researchers face an urgent imperative: Figure out how to solve the crisis of obesity. About 40 percent of the adults and 19 percent of the children and adolescents in the United States have obesity, according to the Centers for Disease Control and Prevention. More and more of them face the increased risks of suffering from diabetes, cardiovascular disease and countless other negative health effects. This situation looks like a single problem from a population standpoint — one that simple guidelines for balancing calorie consumption and expenditure should be able to solve. Instead, a seeming infinitude of variables influence what each of us eats and how the body responds. That is: Obesity, like cancer, “is not one disease,” says Elizabeth Mayer-Davis, a professor of nutrition and medicine at the University of North Carolina at Chapel Hill. In order to treat it, “you really have to be thinking about biology and behavior and society and culture and policy all at the same time. Because if you miss any one of those pieces, your intervention or your diet — it’s less likely to actually work.” The same diet can affect even identical twins differently. “It’s also why there have been so many conflicting studies in nutrition,” Mayer-Davis says. “The public is very frustrated.” Indeed, just last month a paper in Annals of Internal Medicine created controversy when it argued that there’s not enough evidence to say whether red and processed meats are bad for us, despite years of guidance claiming just that. It also reignited a growing debate: How valuable can universal diet guidelines be for individuals? In recent decades, popular weight-loss plans have largely seesawed between low-fat strategies, which U.S. health agencies have also promoted, and low-carbohydrate ones. Many of them appear to work especially well for some people and not well for others; on average, however, in studies comparing the two kinds of regimens, participants lose the same moderate amount of weight. In those cases when opposing diets produce equivalent results, Kevin Hall, a researcher at the National Institutes of Health, wondered if there was, in fact, an explanation other than the nutrients. He noticed that many of those diets tended to have at least one rule in common: Avoid ultraprocessed food, the sort of packaged fare containing artificial flavorings and ingredients you wouldn’t find in your kitchen that make processed food cheap, convenient, tasty and shelf-stable — and popular. It currently accounts for 57 percent of the American diet (a proportion that is rising). Previous studies have found correlations between ultraprocessed-food consumption and obesity but no proof that it’s a cause. © 2019 The New York Times Company

Chemicals released by bacteria may help gut control the brain, mouse study suggests

By Elizabeth Pennisi The more researchers look, the more connections they find between the microbes in our intestines and those in our brain. Gut bacteria appear to influence everything from depression to autism. Now, a study on how mice overcome fear is starting to reveal more about the mysterious link between gut and mind. “This work is amazing,” says Peng Zheng, a neuroscientist at Chongqing Medical University in China who was not involved with the research. The study, he says, could provide new insight into several mental disorders. The research used a classic Pavlovian test: Shock a mouse on the foot while playing a tone and the rodent will quickly learn to associate the noise with pain, flinching whenever it hears the sound. But the association doesn’t last forever. After several sessions of hearing the tone but not getting the shock, the mouse will forget the association, and the sound will have no effect. This “forgetting” is important for people as well; it’s impaired, for example, in those with chronic anxiety and post-traumatic stress disorder. David Artis, an immunologist and microbiologist at Weill Cornell Medicine in New York City, wondered whether gut bacteria played any role in the learning and forgetting responses. He and colleagues treated mice with antibiotics to totally rid them of the bacteria in their gut, collectively known as the microbiome. They then played a tone and right after gave the mouse a mild shock, doing this multiple times. © 2019 American Association for the Advancement of Science.

Trans Fats, Bad for the Heart, May Be Bad for the Brain as Well

By Nicholas Bakalar Trans fatty acids, known to increase the risk for heart disease, stroke and diabetes, have now been linked to an increased risk for dementia. Researchers measured blood levels of elaidic acid, the most common trans fats, in 1,628 men and women 60 and older and free of dementia. Over the following 10 years, 377 developed some type of dementia. Trans fats, which are added to processed food in the form of partially hydrogenated vegetable oils, increase levels of LDL, or “bad” cholesterol. Meat and dairy products naturally contain small amounts of trans fats, but whether these fats raise bad cholesterol is unknown. After controlling for other factors, the scientists found that compared with those in the lowest one-quarter in blood levels of elaidic acid, those in the highest were 50 percent more likely to develop any form of dementia and 39 percent more likely to develop Alzheimer’s disease in particular. Elaidic acid levels were not associated with vascular dementia considered alone. The study is in Neurology. The senior author, Dr. Toshiharu Ninomiya, a professor of public health at Kyushu University in Japan, said the study is observational so cannot prove cause and effect. “It is difficult to avoid trans fats completely, and the risk of a small amount of trans fats is unclear,” he said. “But it would be better to try to avoid them as much as possible.” © 2019 The New York Times Company

The Problem With Labeling Gut Troubles ‘Dysbiosis’

/ By Elizabeth Preston On the first page of Heinz Koop’s fecal analysis test results, a bar showed where he fell on a gradient from green to red. A label above said, in German: “Overall dysbiosis.” Koop was not in the green or even the yellow regions, but a worrisome orange. It was a bad result — but, he says, “I was kind of happy.” Doctors hadn’t given him a satisfying answer about his recurring bloody diarrhea and other gut troubles. But Koop had learned on Facebook that he could test his gut microbiome — the community of bacteria and other organisms living in his gastrointestinal tract — to look for problems. Koop ordered a test from a German laboratory called Medivere. The results said his gut microbes were imbalanced, which was something he thought he could treat. Soon he would be attempting to correct this imbalance by chauffering a friend’s fresh stool samples home to implant up his own colon. Trillions of microbes living on and in our bodies, especially our guts, make up our microbiome. The bugs in our bowel are not just there to slow down our poop, as one researcher speculated in 1970, but are intricately connected to our health. Gut microbes help us digest our food, make critical vitamins, and keep pathogens out. Over the past decade or so, research into the microbiome has exploded as researchers have tried to tease apart the complex connections between our diseases and our resident microbes. Today, at least 10 percent of published microbiome papers use the term dysbiosis to describe changes in the microbiome, estimates Katarzyna Hooks, a computational biologist now at Evotec, a global biotechnology company headquartered in Germany. Some scientists say the term is useful for communicating a specific finding, though they acknowledge its limitations. Other scientists hate it. Copyright 2019 Undark

Fat found in overweight people's lungs

Fatty tissue has been found in the lungs of overweight and obese people for the first time. Australian researchers analysed lung samples from 52 people and found the amount of fat increased in line with body mass index. They said their findings could explain why being overweight or obese increased asthma risk. Lung experts said it would be interesting to see if the effect could be reversed by weight loss. In the study, published in the European Respiratory Journal, scientists looked at post-mortem samples of lung donated for research. Fifteen had had no reported asthma, 21 had asthma but died of other causes and 16 died of the condition. The scientists used dyes to carry out detailed analyses of almost 1,400 airways from the lung samples under the microscope. The researchers found adipose (fatty) tissue in the walls of airways, with more present in people with a higher body mass index, And they say the increase in fat appears to alter the normal structure of the airways and cause inflammation in the lungs - which could explain the increased risk of asthma in overweight or obese people. Dr Peter Noble, an associate professor at the University of Western Australia, in Perth who worked on the study, said: "Being overweight or obese has already been linked to having asthma or having worse asthma symptoms. "Researchers have suggested that the link might be explained by the direct pressure of excess weight on the lungs or by a general increase in inflammation created by excess weight." But, he said, their study suggested "another mechanism is also at play". © 2019 BBC.

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