Fad diets can work, but experts find no magic slimming bullet

January 13, 2014

Resolutions to lose weight are often made in January yet almost as frequently abandoned as heavy hopefuls find diets that demand fasting, virtually no carbs or liquid food shakes notoriously hard to stick to. But even "fad" diets can lead to a slimmer, lighter New Year for those whose resolve remains robust, according to doctors and nutritionists analysing them.

Gathering for a London conference to review evidence behind popular weight loss diets - at just the time of year when slimming ideas are in peak demand - specialists concluded that food fads such as the hunter-gatherer "Paleo" plan or the 5:2 diet can deliver. But it's hard work. "If it was easy, our species would have died out years ago. As humans we have a default to eat," said Gary Frost, a professor and chair of nutrition and dietetics at Imperial College London. The results of that default are looming large in a global "wave of obesity", he said. According to the World Health Organisation, worldwide obesity - defined as having a body mass index of more than 30 - has nearly doubled since 1980. The latest global figure is that in 2008, more than 1.4 billion adults were overweight.

WAVE OF OBESITY

According to the US Centers for Disease Control and Prevention, almost 36% of American adults are obese and almost 70% are either obese or overweight. In Britain, a government health study predicts 60% of men, 50% of women and 25% of children will be obese by 2050. Against this background, experts say the search for effective diets must always take account of how easy it is for people to understand and follow, and how likely they are to abide by its restrictions.

Michelle Harvie, a research dietician from the Genesis Prevention Centre at Britain's University Hospital of South Manchester, said that on this front, fasting diets - sometimes called intermittent diets - can be successful. "Energy restriction is difficult to maintain over the long term and people tend to find it easier to follow a diet with intermittent energy restriction," she said. She said that while a regular weight loss plan might require the dieter to take in 25% fewer calories, intermittent diets may suggest two days of a 75% calorie cut interspersed with five days of normal healthy eating. But the key to these diets - such as the 5:2 diet in which followers eat as little as 400 calories on two "fasting" days per week - is that dieters won't succeed if they "pig out" and eat whatever they want on non-fasting days.

Harvie's research shows those who succeed in losing weigh on these diets find the fasting days lead them to also have a lower food intake on normal days - leading to lower calorie intake overall.

HUNTING FOR FOOD

Mark Berry, head of plant biology and biochemistry at the consumer company Unilever's research and development unit, says there are also positive signs in data from studies of "Palaeolithic" or stone-age diets - plans designed to mimic the diet of pre-agricultural hunter-gatherers of that era. A sign of its current popularity is that "Paleo diet" was one of the most "Googled" terms of 2013.

The idea is based around foods that can be hunted, fished or foraged for - meat, seafood, eggs, nuts, seeds, fruits and vegetables. Berry said his research showed little impact on glucose response in the body in people eating a Palaeolithic diet, but did find a significant impact on hormones that signal satiety and tell the brain the eater is full. Alexandra Johnstone of the Rowett Institute of Nutrition and Health, who has been looking into high protein and low carbohydrate diets such as the Atkins diet, said these also had a significant impact on fullness feelings - giving them the potential to help dieters control appetite and lose weight. "The high satiety effects of increased protein in the diet seems to be a contributing factor to the success of high-protein, low-carbohydrate diets," she said.

Johnstone cited data showing the amount of weight lost on high-protein diets is around double that lost on a comparable low-fat diet at the six-month mark. But there is little difference in weight loss after one year, as dieters often lose momentum and their resolve to slim down fades. "There's no magic bullet," she said. Judy Buttriss, head of the British Nutrition Foundation, said the evidence for popular diets was clearly nuanced. While there are several that can be used as tools for effective weight loss and maintenance, she said "there's currently no evidence that one is any better than another in the long term".

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Agencies
July 24,2020

Colorado, Jul 24: A new study has found that physical stress in one's job may be associated with faster brain ageing and poorer memory.

Aga Burzynska, an assistant professor in the Department of Human Development and Family Studies, and her research team connected occupational survey responses with brain-imaging data from 99 cognitively normal older adults, age 60 to 79. They found that those who reported high levels of physical stress in their most recent job had smaller volumes in the hippocampus and performed poorer on memory tasks. The hippocampus is the part of the brain that is critical for memory and is affected in both normal ageing and in dementia.

Their findings were published this summer in Frontiers in Human Neuroscience under the research topic 'Work and Brain Health Across the Lifespan.'

"We know that stress can accelerate physical ageing and is the risk factor for many chronic illnesses," Burzynska said. "But this is the first evidence that occupational stress can accelerate brain and cognitive ageing."

She added that it is important to understand how occupational exposures affect the ageing of our brains.

"An average American worker spends more than eight hours at work per weekday, and most people remain in the workforce for over 40 years," Burzynska said. "By pure volume, occupational exposures outweigh the time we spend on leisure social, cognitive and physical activities, which protect our ageing minds and brains."

Physical demands at work

Burzynska explained that the association between "physical stress" and brain/memory were driven by physical demands at work. These included excessive reaching, or lifting boxes onto shelves, not necessarily aerobic activity. This is important because earlier work by Burzynska and her colleagues showed that leisure aerobic exercise is beneficial for brain health and cognition, from children to very old adults. Therefore, the researchers controlled for the effects of leisure physical activity and exercise.

As expected, leisure physical activity was associated with greater hippocampal volume, but the negative association with physical demands at work persisted.

"This finding suggests that physical demands at work may have parallel yet opposing associations with brain health," Burzynska explained. "Most interventions for postponing cognitive decline focus on leisure, not on your job. It's kind of unknown territory, but maybe future research can help us make some tweaks to our work environment for long-term cognitive health."

She added that the results could have important implications for society.

"Caring for people with cognitive impairment is so costly, on economic, emotional and societal levels," Burzynska said. "If we can support brain health earlier, in middle-aged workers, it could have an enormous impact."

The researchers considered and corrected for several other factors that could be related to work environment, memory and hippocampus, such as age, gender, brain size, educational level, job title, years in the occupation and general psychological stress.

One piece of the puzzle

"The research on this topic is so fragmented," Burzynska said. "One previous study linked mid-life managerial experience with greater hippocampus volume in older age. Another showed that taxi drivers had larger hippocampi than a city's bus drivers, presumably due to the need to navigate. In our study, job complexity and psychological stress at work were not related to hippocampal volume and cognition. Clearly, our study is just one piece of the puzzle, and further research is needed."

The magnetic resonance imaging (MRI) data used for the study was collected at the University of Illinois Urbana-Champaign between 2011 and 2014.

CSU researchers now can collect MRI data with the new 3T scanner at the University's Translational Medicine Institute.

With this new capability, Burzynska, along with Michael Thomas and Lorann Stallones of CSU's Department of Psychology, is launching a new project, "Impact of Occupational Exposures and Hazards on Brain and Cognitive Health Among Aging Agricultural Workers," which will involve collecting MRI brain scans and identifying risk and protective factors that could help the agricultural community age successfully. The project recently obtained funding as an Emerging Issues Short-Term Project from the High Plains Intermountain Center for Agricultural Health and Safety.

The Department of Human Development and Family Studies is part of CSU's College of Health and Human Sciences.

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Agencies
January 25,2020

Washington D.C., Jan 25: A new study conducted by a team of researchers reveals why individuals who have a history of early life adversity (ELA) are disproportionately prone to opioid addiction.

The study conducted examined how early adversities interact with factors such as increased access to opioids to directly influence brain development and function, causing a higher potential for opioid addiction.

The study was lead by UCI researchers and was published in Molecular Psychiatry.

Tallie Z. Baram, MD, PhD, the Danette Shepard Chair in Neurological Sciences at the UCI School of Medicine and one of the senior researchers for the study, was on the take that the widely known factor genetics that plays major role in addiction vulnerability, cannot be solely held responsible for the recent rise in opioid abuse.

To further clarify, the researchers simulated ELA in rats by limiting bedding and nesting materials during a short, postnatal period of time.

In female rats, this led to striking opioid addiction-like characteristics including an increased relapse- behaviour, for example.

As observed in addicted humans, the rats were willing to work very hard (pay a very high price) to obtain the drug.

Baram said: "Ultimately, we found that conditions during sensitive developmental periods can lead to vulnerability to the addictive effects of opioid drugs, especially in females, which is consistent with the prevalence of ELA in heroin-addicted women."

These findings can be used to highlight the importance given to sex differences in future ELA-related studies on opioid addiction, and in future prevention or intervention strategies being developed to address the growing opioid crisis.

The study conducted examined how early adversities interact with factors such as increased access to opioids to directly influence brain development and function, causing a higher potential for opioid addiction.

The study was lead by UCI researchers and was published in Molecular Psychiatry.

The study found that unpredictable, fragmented early life environments may lead to abnormal maturation of certain brain circuits, which profoundly impacts brain function and persists into adolescence and adulthood.

Tallie Z. Baram, MD, PhD, the Danette Shepard Chair in Neurological Sciences at the UCI School of Medicine and one of the senior researchers for the study, was on the take that the widely known factor genetics that plays major role in addiction vulnerability, cannot be solely held responsible for the recent rise in opioid abuse.

To further clarify, the researchers implanted ELA in rats by limiting bedding and nesting materials during a short, postnatal period of time.

In female rats, this led to striking opioid addiction-like characteristics including an increased relapse- behaviour, for example.

As observed in addicted humans, the rats were willing to work very hard (pay a very high price) to obtain the drug.

Baram said: "Ultimately, we found that conditions during sensitive developmental periods can lead to vulnerability to the addictive effects of opioid drugs, especially in females, which is consistent with the prevalence of ELA in heroin-addicted women."

These findings can be used to highlight the importance given to sex differences in future ELA-related studies on opioid addiction, and in future prevention or intervention strategies being developed to address the growing opioid crisis.

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Agencies
July 2,2020

London, Jul 2: The World Health Organisation says smoking is linked to a higher risk of severe illness and death from the coronavirus in hospitalised patients, although it was unable to specify exactly how much greater those risks might be.

In a scientific brief published this week, the U.N. health agency reviewed 34 published studies on the association between smoking and Covid-19, including the probability of infection, hospitalisation, severity of disease and death.

WHO noted that smokers represent up to 18% of hospitalised coronavirus patients and that there appeared to be a significant link between whether or not patients smoked and the severity of disease they suffered, the type of hospital interventions required and patients' risk of dying.

In April, French researchers released a small study suggesting smokers were at less risk of catching Covid-19 and planned to test nicotine patches on patients and health workers — but their findings were questioned by many scientists at the time who cited the lack of definitive data.

WHO says "the available evidence suggests that smoking is associated with increased severity of disease and death in hospitalized Covid-19 patients. It recommends that smokers quit.

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