Eating processed meat could increase dementia risk

March 21, 2021

Science Daily/University of Leeds

Scientists from the University's Nutritional Epidemiology Group used data from 500,000 people, discovering that consuming a 25g serving of processed meat a day, the equivalent to one rasher of bacon, is associated with a 44% increased risk of developing the disease.

But their findings also show eating some unprocessed red meat, such as beef, pork or veal, could be protective, as people who consumed 50g a day were 19% less likely to develop dementia. 

The researchers were exploring whether there is a link between consumption of meat and development of dementia, a health condition which affects 5%-8% of over 60s worldwide.

Their results, titled Meat consumption and risk of incident dementia: cohort study of 493,888 UK Biobank participants, are published today in the American Journal of Clinical Nutrition.

Lead researcher Huifeng Zhang, a PhD student from Leeds' School of Food Science and Nutrition, said: "Worldwide, the prevalence of dementia is increasing and diet as a modifiable factor could play a role.

"Our research adds to the growing body of evidence linking processed meat consumption to increased risk of a range of non-transmissible diseases." 

The research was supervised by Professors Janet Cade and Laura Hardie, both at Leeds.

The team studied data provided by UK Biobank, a database containing in-depth genetic and health information from half a million UK participants aged 40 to 69, to investigate associations between consuming different types of meat and risk of developing dementia.  

The data included how often participants consumed different kinds of meat, with six options from never to once or more daily, collected in 2006-2010 by the UK Biobank. The study did not specifically assess the impact of a vegetarian or vegan diet on dementia risk, but it included data from people who said they did not eat red meat. 

Among the participants, 2,896 cases of dementia emerged over an average of eight years of follow up. These people were generally older, more economically deprived, less educated, more likely to smoke, less physically active, more likely to have stroke history and family dementia history, and more likely to be carriers of a gene which is highly associated with dementia. More men than women were diagnosed with dementia in the study population.  

Some people were three to six times more likely to develop dementia due to well established genetic factors, but the findings suggest the risks from eating processed meat were the same whether or not a person was genetically predisposed to developing the disease. 

Those who consumed higher amounts of processed meat were more likely to be male, less educated, smokers, overweight or obese, had lower intakes of vegetables and fruits, and had higher intakes of energy, protein, and fat (including saturated fat). 

Meat consumption has previously been associated with dementia risk, but this is believed to be the first large-scale study of participants over time to examine a link between specific meat types and amounts, and the risk of developing the disease. 

There are around 50 million dementia cases globally, with around 10 million new cases diagnosed every year. Alzheimer's Disease makes up 50% to 70% of cases, and vascular dementia around 25%. Its development and progression are associated with both genetic and environmental factors, including diet and lifestyle.  

Ms Zhang said: "Further confirmation is needed, but the direction of effect is linked to current healthy eating guidelines suggesting lower intakes of unprocessed red meat could be beneficial for health."

Professor Cade said: "Anything we can do to explore potential risk factors for dementia may help us to reduce rates of this debilitating condition. This analysis is a first step towards understanding whether what we eat could influence that risk."

https://www.sciencedaily.com/releases/2021/03/210321215434.htm

CBD reduces plaque, improves cognition in model of familial Alzheimer's

March 9, 2021

Science Daily/Medical College of Georgia at Augusta University

A two-week course of high doses of CBD helps restore the function of two proteins key to reducing the accumulation of beta-amyloid plaque, a hallmark of Alzheimer's disease, and improves cognition in an experimental model of early onset familial Alzheimer's, investigators report.

The proteins TREM2 and IL-33 are important to the ability of the brain's immune cells to literally consume dead cells and other debris like the beta-amyloid plaque that piles up in patients' brains, and levels of both are decreased in Alzheimer's.

The investigators report for the first time that CBD normalizes levels and function, improving cognition as it also reduces levels of the immune protein IL-6, which is associated with the high inflammation levels found in Alzheimer's, says Dr. Babak Baban, immunologist and associate dean for research in the Dental College of Georgia and the study's corresponding author.

There is a dire need for novel therapies to improve outcomes for patients with this condition, which is considered one of the fastest-growing health threats in the United States, DCG and Medical College of Georgia investigators write in the Journal of Alzheimer's Disease.

"Right now we have two classes of drugs to treat Alzheimer's," says Dr. John Morgan, neurologist and director of the Movement and Memory Disorder Programs in the MCG Department of Neurology. One class increases levels of the neurotransmitter acetylcholine, which also are decreased in Alzheimer's, and another works through the NMDA receptors involved in communication between neurons and important to memory. "But we have nothing that gets to the pathophysiology of the disease," says Morgan, a study coauthor.

The DCG and MCG investigators decided to look at CBD's ability to address some of the key brain systems that go awry in Alzheimer's.

They found CBD appears to normalize levels of IL-33, a protein whose highest expression in humans is normally in the brain, where it helps sound the alarm that there is an invader like the beta-amyloid accumulation. There is emerging evidence of its role as a regulatory protein as well, whose function of either turning up or down the immune response depends on the environment, Baban says. In Alzheimer's, that includes turning down inflammation and trying to restore balance to the immune system, he says.

That up and down expression in health and disease could make IL-33 both a good biomarker and treatment target for disease, the investigators say.

CBD also improved expression of triggering receptor expressed on myeloid cells 2, or TREM2, which is found on the cell surface where it combines with another protein to transmit signals that activate cells, including immune cells. In the brain, its expression is on the microglial cells, a special population of immune cells found only in the brain where they are key to eliminating invaders like a virus and irrevocably damaged neurons.

Low levels of TREM2 and rare variations in TREM2 are associated with Alzheimer's, and in their mouse model TREM2 and IL-33 were both low.

Both are essential to a natural, ongoing housekeeping process in the brain called phagocytosis, in which microglial cells regularly consume beta amyloid, which is regularly produced in the brain, the result of the breakdown of amyloid-beta precursor protein, which is important to the synapses, or connection points, between neurons, and which the plaque interrupts.

They found CBD treatment increased levels of IL-33 and TREM2 -- sevenfold and tenfold respectively.

CBD's impact on brain function in the mouse model of early onset Alzheimer's was assessed by methods like the ability to differentiate between a familiar item and a new one, as well as observing the rodents' movement.

People with Alzheimer's may experience movement problems like stiffness and an impaired gait, says Dr. Hesam Khodadadi, a graduate student working in Baban's lab. Mice with the disease run in an endless tight circle, behavior which stopped with CBD treatment, says Khodadadi, the study's first author.

Next steps include determining optimal doses and giving CBD earlier in the disease process. The compound was given in the late stages for the published study, and now the investigators are using it at the first signs of cognitive decline, Khodadadi says. They also are exploring delivery systems including the use of an inhaler that should help deliver the CBD more directly to the brain. For the published studies, CBD was put into the belly of the mice every other day for two weeks.

A company has developed both animal and human inhalers for the investigators who also have been exploring CBD's effect on adult respiratory distress syndrome, or ARDS, a buildup of fluid in the lungs that is a major and deadly complication of COVID-19, as well as other serious illnesses like sepsis and major trauma. The CBD doses used for the Alzheimer's study were the same the investigators successfully used to reduce the "cytokine storm" of ARDS, which can irrevocably damage the lungs.

Familial disease is an inherited version of Alzheimer's in which symptoms typically surface in the 30s and 40s and occurs in about 10-15% of patients.

CBD should be at least equally effective in the more common, nonfamilial type Alzheimer's, which likely have more targets for CBD, Baban notes. They already are looking at its potential in a model of this more common type and moving forward to establish a clinical trial.

Plaques as well as neurofibrillary tangles, a collection of the protein tau inside neurons, are the main components of Alzheimer's, Morgan says. Beta-amyloid generally appears in the brain 15-20 years or more before dementia, he says, and the appearance of tau tangles, which can occur up to 10 years afterward, correlates with the onset of dementia. There is some interplay between beta amyloid and tau that decrease the dysfunction of each, Morgan notes.

The Food and Drug Administration is scheduled to make a ruling by early June on a new drug aducanumab, which would be the first to attack and help clear beta amyloid, Morgan says.

https://www.sciencedaily.com/releases/2021/03/210309192548.htm

Head injury 25 years later: Study finds increased risk of dementia

March 9, 2021

Science Daily/University of Pennsylvania School of Medicine

Head injury in the United States is common, with over 23 million adults age 40 or older reporting a history of head injury with loss of consciousness. Many head injuries can be caused by a host of different situations -- from car and motorcycle accidents to sports injuries. What's more, it has become increasingly recognized that the effects from head injuries are long-lasting. New research led by the Perelman School of Medicine at the University of Pennsylvania shows that a single head injury could lead to dementia later in life. This risk further increases as the number of head injuries sustained by an individual increases. The findings also suggest stronger associations of head injury with risk of dementia among women compared to among men and among white as compared to among Black populations.

The researchers, whose findings were published today in Alzheimer's & Dementia: The Journal of the Alzheimer's Association, conducted the investigation using data from the Atherosclerosis Risk in Communities (ARIC) Study, which aimed to uncover associations between head injury and dementia over the span of 25 years in a diverse population in the United States. Previously, data on traumatic brain injury has been limited to select populations, such as military and medical claims databases. These are among the first findings to specifically investigate head injury and dementia risk in both Black and white populations, as well as among both males and females, in a community-based setting.

"Head injury is a significant risk factor for dementia, but it's one that can be prevented. Our findings show that the number of head injuries matter -- more head injuries are associated with greater risk for dementia," said lead investigator, Andrea L.C. Schneider, MD, PhD, an assistant professor of Neurology at Penn. "The dose-dependence of this association suggests that prevention of head injury could mitigate some risk of dementia later in life. While head injury is not the only risk factor for dementia, it is one risk factor for dementia that is modifiable by behavior changes such as wearing helmets and seat belts."

The findings show that compared to participants who never experienced a head injury, a history of a single prior head injury was associated with a 1.25 times increased risk of dementia, and a history of two or more prior head injuries was associated with over 2 times increased risk of dementia compared to individuals without a history of head injury. Overall, 9.5 percent of all dementia cases in the study population could be attributed to at least one prior head injury.

To illustrate the relationship between dementia and head injuries, the authors gathered data from a diverse cohort with a mean baseline age of 54 years, comprised of 56 percent female and 27 percent Black participants from four different communities across the United States. Participants were followed for a median of 25 years through up to six in-person visits and semi-annual telephone follow-ups. Data on head injuries of participants was drawn from hospital records, as well as self-reporting from some participants.

Previous research on dementia and traumatic brain injuries suggests that women are at higher risk for dementia compared to men. Additionally, Black populations overall are at higher risk for dementia compared to people who are white. However, few prior studies have evaluated for possible differences in associations of head injury with dementia risk by sex and race.

This data from the ARIC study found evidence that females were more likely to experience dementia as a result of head injury than males. Further, the study showed that although there is increased dementia risk associated with head injury among both White and Black participants, White participants were at higher risk for dementia after head injury compared to Black participants. The authors conclude that more research is needed to better understand reasons for these observed sex and race differences in the association of head injury with dementia risk.

"Given the strong association of head injury with dementia, there is an important need for future research focused on prevention and intervention strategies aimed at reducing dementia after head injury," Schneider said. "The results of this study have already led to several ongoing research projects, including efforts to uncover the causes of head injury-related dementia as well as investigations into reasons underlying the observed sex and race differences in the risk of dementia associated with head injury."

https://www.sciencedaily.com/releases/2021/03/210309091257.htm

Why odors trigger powerful memories

Smell travels on superhighway to hippocampus in the brain

March 8, 2021

Science Daily/Northwestern University

A new Northwestern Medicine paper is the first to identify a neural basis for how the brain enables odors to so powerfully elicit those memories. The paper shows unique connectivity between the hippocampus -- the seat of memory in the brain -- and olfactory areas in humans.

This new research suggests a neurobiological basis for privileged access by olfaction to memory areas in the brain. The study compares connections between primary sensory areas -- including visual, auditory, touch and smell -- and the hippocampus. It found olfaction has the strongest connectivity. It's like a superhighway from smell to the hippocampus.

"During evolution, humans experienced a profound expansion of the neocortex that re-organized access to memory networks," said lead investigator Christina Zelano, assistant professor of neurology at Northwestern University Feinberg School of Medicine. "Vision, hearing and touch all re-routed in the brain as the neocortex expanded, connecting with the hippocampus through an intermediary -- association cortex -- rather than directly. Our data suggests olfaction did not undergo this re-routing, and instead retained direct access to the hippocampus."

The paper, "Human hippocampal connectivity is stronger in olfaction than other sensory systems" was published March 4 in the journal Progress in Neurobiology.

Epidemic loss of smell in COVID-19 makes research more urgent In COVID-19, smell loss has become epidemic, and understanding the way odors affect our brains -- memories, cognition and more -- is more important than ever, Zelano noted.

"There is an urgent need to better understand the olfactory system in order to better understand the reason for COVID-related smell loss, diagnose the severity of the loss and to develop treatments," said first author Guangyu Zhou, research assistant professor of neurology at Northwestern. "Our study is an example of the basic research science that our understanding of smell, smell loss and future treatments is built on."

Below is a Q & A with Zelano about the importance of the sense of smell, olfactory research and the link to COVID-19.

Why do smells evoke such vivid memories? 

"This has been an enduring mystery of human experience. Nearly everyone has been transported by a whiff of an odor to another time and place, an experience that sights or sounds rarely evoke. Yet, we haven't known why. The study found the offactory parts of the brain connect more strongly to the memory parts than other senses. This is a major piece of the puzzle, a striking finding in humans. We believe our results will help future research solve this mystery.'

How does smell research relate to COVID-19?

"The COVID-19 epidemic has brought a renewed focus and urgency to olfactory research. While our study doesn't address COVID smell loss directly, it does speak to an important aspect of why olfaction is important to our lives: smells are a profound part of memory, and odors connect us to especially important memories in our lives, often connected to loved ones. The smell of fresh chopped parsley may evoke a grandmother's cooking, or a whiff of a cigar may evoke a grandfather's presence. Odors connect us to important memories that transport us back to the presence of those people."

Loss of smell linked to depression and poor quality of life

"Loss of the sense of smell is underestimated in its impact. It has profound negative effects of quality of life, and many people underestimate that until they experience it. Smell loss is highly correlated with depression and poor quality of life.

"Most people who lose their smell to COVID regain it, but the time frame varies widely, and some have had what appears to be permanent loss. Understanding smell loss, in turn, requires research into the basic neural operations of this under-studied sensory system.

"Research like ours moves understanding of the olfactory parts of the brain forward, with the goal of providing the foundation for translational work on, ultimately, interventions."

https://www.sciencedaily.com/releases/2021/03/210308140743.htm

A weak heart makes a suffering brain

Evidence of disturbed gene activity in the brain as a result of heart problems

February 26, 2021

Science Daily/DZNE - German Center for Neurodegenerative Diseases

Heart problems cause disturbed gene activity in the brain's memory center, from which cognitive deficits arise. Researchers at the German Center for Neurodegenerative Diseases (DZNE), the University Medical Center Göttingen (UMG) and the German Center for Cardiovascular Research (DZHK) come to this conclusion based on laboratory studies. They consider that they have found a possible cause for the increased risk of dementia in people with heart problems. In mice, a specific drug which is known to affect gene activity alleviated the mental deficits. The involved experts see these results as potential approaches for therapies. The study data are published in the scientific journal EMBO Molecular Medicine.

In Germany, about four million people are affected by what is called "heart failure": Their heart muscle is too weak to pump enough blood through the body and is therefore abnormally enlarged. Physical fitness and quality of life suffer as a result. Moreover, affected individuals have an increased risk of developing dementia. "People with cardiological problems and heart failure in particular may experience noticeable cognitive deficits and increased risk of developing Alzheimer's disease. Possible reasons include impaired blood supply to the brain and dysfunction of the hippocampus, which is the memory's control center," explained André Fischer, research group leader at the DZNE's Göttingen site and professor at the Department of Psychiatry and Psychotherapy at UMG. "Yet, there is a lack of therapies to effectively treat cognitive deficits in people with heart problems. This is because it is completely unclear which deficiencies are triggered in neurons. There was no data on this so far."

Stressed Cells

Now, a team led by Prof. André Fischer and Prof. Karl Toischer (Clinic of Cardiology and Pneumology at UMG and DZHK's Göttingen site) is presenting findings on this subject for the first time. The researchers observed in mice that impaired gene activity developed in the hippocampus as a result of heart problems. "In memory tests, mice with heart failure performed significantly worse than their healthy mates," Fischer explained. "We then examined the neurons of the hippocampus. In the mice with heart failure, we found increased cellular stress pathways and altered gene activity in neurons."

Tight Windings

The genome of a mouse -- and also of humans -- comprises around 20,000 genes. In any given cell, however, only a part of them is active, switched on, so to speak. This is not a mere on or off state: the activity can be strong or less strong. This depends, among other things, on how tightly the DNA (the thread-like molecule that carries the genome) is wound and how accessible the genes on it are. In both mice and humans, the DNA is more than a meter long. But in a cell, the molecule is so tightly packed that it fits into the nucleus. "Genes can only be active if they are accessible to the cell's machinery. To this end, the DNA needs to be wound a little more loosely at the relevant sites. This is similar to a ball of yarn with loops sticking out of it," said Fischer. In the current study, the DNA was found to be more tightly wound in neurons of mice with heart problems than in healthy mates. Various genes important for hippocampal function were therefore less active than in healthy mice.

A Drug Improved Memory

The scientists identified chemical changes in the histones as the cause of the tight winding. Histones are special proteins: The DNA wraps around them, much like yarn around a spool of thread. Fischer's research group has been studying histones and other players that influence gene activity for quite some time -- in technical jargon they are called "epigenetic mechanisms." In this context, the researchers are also investigating drugs. In previous studies, they were able to show that the cancer drug "vorinostat" can alleviate genetically driven as well as age-related memory problems in mice. Currently, vorinostat is being investigated for the therapy of people with Alzheimer's in a clinical trial of the DZNE. In the current study, the scientists treated mice with heart failure with this drug. They found that the heart's pumping capacity did not change significantly, but memory performance improved.

Interdisciplinary Cooperation

"Vorinostat has been shown to act on histones and thus on gene activity. Our study thereby provides initial clues about the molecular processes that contribute to cognitive dysfunction following heart problems, and it indicates potential approaches for therapy," Fischer commented on the results. "Fact is, however, that we do not yet understand why, as a result of heart failure, gene activity in the hippocampus is disturbed. What is the role of the deficient blood supply to the brain? Does the troubled heart release substances that affect the histones? We intend to investigate this in patients with heart problems. As with our current study, which involved experts from neuroscience and cardiac research, we aim to address these questions in an interdisciplinary way."

https://www.sciencedaily.com/releases/2021/02/210226121252.htm

Sleep is vital to associating emotion with memory

February 22, 2021

Science Daily/University of Michigan

When you slip into sleep, it's easy to imagine that your brain shuts down, but University of Michigan research suggests that groups of neurons activated during prior learning keep humming, tattooing memories into your brain.

U-M researchers have been studying how memories associated with a specific sensory event are formed and stored in mice. In a study conducted prior to the coronavirus pandemic and recently published in Nature Communications, the researchers examined how a fearful memory formed in relation to a specific visual stimulus.

They found that not only did the neurons activated by the visual stimulus keep more active during subsequent sleep, sleep is vital to their ability to connect the fear memory to the sensory event.

Previous research has shown that regions of the brain that are highly active during intensive learning tend to show more activity during subsequent sleep. But what was unclear was whether this "reactivation" of memories during sleep needs to occur in order to fully store the memory of newly learned material.

"Part of what we wanted to understand was whether there is communication between parts of the brain that are mediating the fear memory and the specific neurons mediating the sensory memory that the fear is being tied to. How do they talk together, and must they do so during sleep? We would really like to know what's facilitating that process of making a new association, like a particular set of neurons, or a particular stage of sleep," said Sara Aton, senior author of the study and a professor in the U-M Department of Molecular, Cellular and Developmental Biology. "But for the longest time, there was really no way to test this experimentally."

Now, researchers have the tools to genetically tag cells that are activated by an experience during a specific window of time. Focusing on a specific set of neurons in the primary visual cortex, Aton and the study's lead author, graduate student Brittany Clawson, created a visual memory test. They showed a group of mice a neutral image, and expressed genes in the visual cortex neurons activated by the image.

To verify that these neurons registered the neutral image, Aton and her team tested whether they could instigate the memory of the image stimulus by selectively activating the neurons without showing them the image. When they activated the neurons and paired that activation with a mild foot shock, they found that their subjects would subsequently be afraid of visual stimuli that looked similar to the image those cells encode. They found the reverse also to be true: after pairing the visual stimulus with a foot shock, their subjects would subsequently respond with fear to reactivating the neurons.

"Basically, the precept of the visual stimulus and the precept of this completely artificial activation of the neurons generated the same response," Aton said.

The researchers found that when they disrupted sleep after they showed the subjects an image and had given them a mild foot shock, there was no fear associated with the visual stimulus. Those with unmanipulated sleep learned to fear the specific visual stimulus that had been paired with the foot shock.

"We found that these mice actually became afraid of every visual stimulus we showed them," Aton said. "From the time they go to the chamber where the visual stimuli are presented, they seem to know there's a reason to feel fear, but they don't know what specifically they're afraid of."

This likely shows that, in order for them to make an accurate fear association with a visual stimulus, they have to have sleep-associated reactivation of the neurons encoding that stimulus in the sensory cortex, according to Aton. This allows a memory specific to that visual cue to be generated.The researchers think that at the same time, that sensory cortical area must communicate with other brain structures, to marry the sensory aspect of the memory to the emotional aspect.

Aton says their findings could have implications for how anxiety and post-traumatic stress disorder are understood.

"To me this is kind of a clue that says, if you're linking fear to some very specific event during sleep, sleep disruption may affect this process. In the absence of sleep, the brain seems to manage processing the fact that you are afraid, but you may be unable to link that to what specifically you should be afraid of," Aton said. "That specification process may be one that goes awry with PTSD or generalized anxiety."

https://www.sciencedaily.com/releases/2021/02/210222164216.htm

How the 'noise' in our brain influences our behavior

Neural variability provides an essential basis for how we perceive the world and react to it

February 17, 2021

Science Daily/Max Planck Institute for Human Development

The brain's neural activity is irregular, changing from one moment to the next. To date, this apparent "noise" has been thought to be due to random natural variations or measurement error. However, researchers at the Max Planck Institute for Human Development have shown that this neural variability may provide a unique window into brain function. In a new Perspective article out now in the journal Neuron, the authors argue that researchers need to focus more on neural variability to fully understand how behavior emerges from the brain.

When neuroscientists investigate the brain, its activity seems to vary all the time. Sometimes activity is higher or lower, rhythmic or irregular. Whereas averaging brain activity has served as a standard way of visualizing how the brain "works," the irregular, seemingly random patterns in neural signals have often been disregarded. Strikingly, such irregularities in neural activity appear regardless of whether single neurons or entire brain regions are assessed. Brains simply always appear "noisy," prompting the question of what such moment-to-moment neural variability may reveal about brain function.

Across a host of studies over the past 10 years, researchers from the Lifespan Neural Dynamics Group (LNDG) at the Max Planck Institute for Human Development and the Max Planck UCL Centre for Computational Psychiatry and Ageing Research have systematically examined the brain's "noise," showing that neural variability has a direct influence on behavior. In a new Perspective article published in the journal Neuron, the LNDG in collaboration with the University of Lübeck highlights what is now substantial evidence supporting the idea that neural variability represents a key, yet under-valued dimension for understanding brain-behavior relationships. "Animals and humans can indeed adapt successfully to environmental demands, but how can such behavioral success emerge in the face of neural variability? We argue that neuroscientists must grapple with the possibility that behavior may emerge because of neural variability, not in spite of it," says Leonhard Waschke, first author of the article and LNDG postdoctoral fellow.

A recent LNDG study published in the journal eLife exemplifies the direct link between neural variability and behavior. Participants' brain activity was measured via electroencephalography (EEG) while they responded to faint visual targets. When people were told to detect as many visual targets as possible, neural variability generally increased, whereas it was downregulated when participants were asked to avoid mistakes. Crucially, those who were better able to adapt their neural variability to these task demands performed better on the task. "The better a brain can regulate its 'noise,' the better it can process unknown information and react to it. Traditional ways of analyzing brain activity simply disregard this entire phenomenon." says LNDG postdoctoral fellow Niels Kloosterman, first author of this study and co-author of the article in Neuron.

The LNDG continues to demonstrate the importance of neural variability for successful human behavior in an ongoing series of studies. Whether one is asked to process a face, remember an object, or solve a complex task, the ability to modulate moment-to-moment variability seems to be required for optimal cognitive performance. "Neuroscientists have seen this 'noise' in the brain for decades but haven't understood what it means. A growing body of work by our group and others highlights that neural variability may indeed serve as an indispensable signal of behavioral success in its own right. With the increasing availability of tools and approaches to measure neural variability, we are excited that such a hypothesis is now immediately testable," says Douglas Garrett, Senior Research Scientist and LNDG group leader. In the next phases of their research, the group plans to examine whether neural variability and behavior can be optimized through brain stimulation, behavioral training, or medication.

https://www.sciencedaily.com/releases/2021/02/210217134848.htm

Study suggests role of sleep in healing traumatic brain injuries

Technique developed at OHSU measures brain's waste-clearance system through MRIs

March 12, 2021

Science Daily/Oregon Health & Science University

Sound sleep plays a critical role in healing traumatic brain injury, a new study of military veterans suggests.

The study, published in the Journal of Neurotrauma, used a new technique involving magnetic resonance imaging developed at Oregon Health & Science University. Researchers used MRI to evaluate the enlargement of perivascular spaces that surround blood vessels in the brain. Enlargement of these spaces occurs in aging and is associated with the development of dementia.

Among veterans in the study, those who slept poorly had more evidence of these enlarged spaces and more post-concussive symptoms.

"This has huge implications for the armed forces as well as civilians," said lead author Juan Piantino, M.D., MCR, assistant professor of pediatrics (neurology) in the OHSU School of Medicine and Doernbecher Children's Hospital. "This study suggests sleep may play an important role in clearing waste from the brain after traumatic brain injury -- and if you don't sleep very well, you might not clean your brain as efficiently."

Piantino, a physician-scientist with OHSU's Papé Family Pediatric Research Institute, studies the effects of poor sleep on recovery after traumatic brain injuries.

The new study benefited from a method of analyzing MRIs developed by study co-author Daniel Schwartz and Erin Boespflug, Ph.D., under the direction of Lisa Silbert, M.D., M.C.R., professor of neurology in the OHSU School of Medicine. The technique measures changes in the brain's perivascular spaces, which are part of the brain's waste clearance system known as the glymphatic system.

"We were able to very precisely measure this structure and count the number, location and diameter of channels," Piantino said.

Co-author Jeffrey Iliff, Ph.D., professor of psychiatry and behavioral sciences and of neurology at the University of Washington and a researcher at the VA Puget Sound Health Care System, has led scientific research into the glymphatic system and its role in neurodegenerative conditions such as Alzheimer's disease. During sleep, this brain-wide network clears away metabolic proteins that would otherwise build up in the brain.

The study used data collected from a group of 56 veterans enrolled by co-authors Elaine Peskind, M.D., and Murray Raskind, M.D., at the Mental Illness Research, Education and Clinical Center at the VA Puget Sound between 2011 and 2019.

"Imagine your brain is generating all this waste and everything is working fine," Piantino said. "Now you get a concussion. The brain generates much more waste that it has to remove, but the system becomes plugged."

Piantino said the new study suggests the technique developed by Silbert could be useful for older adults.

"Longer term, we can start thinking about using this method to predict who is going to be at higher risk for cognitive problems including dementia," he said.

The study is the latest in a growing body of research highlighting the importance of sleep in brain health.

Improving sleep is a modifiable habit that can be improved through a variety of methods, Piantino said, including better sleep hygiene habits such as reducing screen time before bed. Improving sleep is a focus of research of other OHSU scientists, including Piantino's mentor, Miranda Lim, M.D., Ph.D., associate professor of neurology, medicine and behavioral neuroscience in the OHSU School of Medicine.

"This study puts sleep at the epicenter of recovery in traumatic brain injury," Piantino said.

https://www.sciencedaily.com/releases/2021/03/210312155435.htm

High rates of depression, anxiety, PTSD worldwide among health workers during COVID-19

Sixty five-study analysis includes research published in English and Chinese

March 10, 2021

Science Daily/PLOS

A new systematic review of 65 studies from around the world involves a total of 97,333 health care workers and finds that 1 in 5 have experienced depression, anxiety, and/or PTSD during the ongoing COVID-19 pandemic. Yufei Li, Nathaniel Scherer, and colleagues at the London School of Hygiene & Tropical Medicine, U.K., present these findings in the open-access journal PLOS ONE on March 10.

The pandemic has posed significant challenges for health care workers, with many fearing for their own safety while facing a high workload and limited psychological support. Previous analyses of data from multiple studies have revealed high rates of depression, anxiety, and PTSD among health care workers during the pandemic. However, those reviews did not adequately address the many relevant studies conducted in China, where the first COVID-19 outbreak occurred.

To address that gap, Li, Scherer, and colleagues carried out a systematic search of studies in both English and Chinese that were conducted from December 2019 to August 2020 and addressed prevalence of mental disorders in health care workers. They identified 65 suitable studies from 21 countries, involving a total of 97,333 health care workers.

By pooling and statistically analyzing data from all 65 studies, the researchers estimated that 21.7 percent of the health care workers involved in the studies have experienced depression during the pandemic, 22.1 percent anxiety, and 21.5 percent PTSD. Studies conducted in the Middle East showed the highest pooled rates of depression (34.6 percent) and anxiety (28.9 percent).

These findings suggest that the COVID-19 pandemic has significantly impacted the mental health of health care workers. For comparison, the World Health Organization estimates that 4.4 percent of the entire world population experience depression, and 3.6 percent experience anxiety disorders, including PTSD. However, those estimates were determined through different methods and prior to the pandemic.

Nonetheless, the authors note, the new findings could help inform policy and initiatives to provide urgently needed psychological support to health care workers.

The authors add: "This systematic review and meta-analysis provides, to date, the most comprehensive synthesis of depression, anxiety and PTSD prevalence amongst health care workers during the COVID-19 pandemic, with the unique inclusion of publications in both English and Chinese."

https://www.sciencedaily.com/releases/2021/03/210310150402.htm

Study identifies potential link between Soldiers exposed to blasts, Alzheimer's

February 25, 2021

Science Daily/U.S. Army Research Laboratory

Research shows that Soldiers exposed to shockwaves from military explosives are at a higher risk for developing Alzheimer's disease -- even those that don't have traumatic brain injuries from those blasts. A new Army-funded study identifies how those blasts affect the brain.

Researchers at the University of North Carolina at Pembroke in collaboration with the U.S. Army Combat Capabilities Development Command, now known as DEVCOM, the Army Research Laboratory, and the National Institutes of Health found that the mystery behind blast-induced neurological complications when traumatic damage is undetected may be rooted in distinct alterations to the tiny connections between neurons in the hippocampus, the part of the brain particularly involved in memory encoding and social behavior.

The research published in Brain Pathology, the medical journal of the International Society of Neuropathology, was funded by the lab's Army Research Office.

"Blasts can lead to debilitating neurological and psychological damage but the underlying injury mechanisms are not well understood," said Dr. Frederick Gregory, program manager, ARO. "Understanding the molecular pathophysiology of blast-induced brain injury and potential impacts on long-term brain health is extremely important to understand in order to protect the lifelong health and well-being of our service members."

The research team tested slices of rat hippocampus by exposing the healthy tissue to controlled military blast waves. In the experimental brain explants (tissue slices maintained alive in culture dishes), the rapid blast waves produced by the detonated military explosives led to selective reductions in components of brain connections needed for memory, and the distinct electrical activity from those neuronal connections was sharply diminished.

The research showed that the blast-induced effects were evident among healthy neurons with subtle synaptic pathology, which may be an early indicator of Alzheimer's-type pathogenesis occurring independent of overt brain damage.

"This finding may explain those many blast-exposed individuals returning from war zones with no detectable brain injury, but who still suffer from persistent neurological symptoms, including depression, headaches, irritability and memory problems," said Dr. Ben Bahr, the William C. Friday distinguished professor of Molecular Biology and Biochemistry at UNC-Pembroke.

The researchers believe that the increased risk of developing Alzheimer's disease is likely rooted in the disruption of neuronal communication instigated by blast exposures.

"Early detection of this measurable deterioration could improve diagnoses and treatment of recurring neuropsychiatric impediments, and reduce the risk of developing dementia and Alzheimer's disease later in life," Bahr said.

https://www.sciencedaily.com/releases/2021/02/210225112922.htm

Changes in mouth bacteria after drinking beetroot juice may promote healthy aging

March 30, 2021

Science Daily/University of Exeter

Drinking beetroot juice promotes a mix of mouth bacteria associated with healthier blood vessels and brain function, according to a new study of people aged 70-80.

Beetroot -- and other foods including lettuce, spinach and celery -- are rich in inorganic nitrate, and many oral bacteria play a role in turning nitrate to nitric oxide, which helps to regulate blood vessels and neurotransmission (chemical messages in the brain).

Older people tend to have lower nitric oxide production, and this is associated with poorer vascular (blood vessel) and cognitive (brain) health.

In the new study, by the University of Exeter, 26 healthy older people took part in two ten-day supplementation periods: one with nitrate-rich beetroot juice and another with nitrate-free placebo juice, which they drank twice a day.

The results showed higher levels of bacteria associated with good vascular and cognitive health, and lower levels of bacteria linked to disease and inflammation.

Systolic blood pressure dropped on average by five points (mmHg) after drinking the beetroot juice.

"We are really excited about these findings, which have important implications for healthy ageing," said lead author Professor Anni Vanhatalo, of the University of Exeter.

"Previous studies have compared the oral bacteria of young and older people, and healthy people compared to those with diseases, but ours is the first to test nitrate-rich diet in this way.

"Our findings suggest that adding nitrate-rich foods to the diet -- in this case via beetroot juice -- for just ten days can substantially alter the oral microbiome (mix of bacteria) for the better.

"Maintaining this healthy oral microbiome in the long term might slow down the negative vascular and cognitive changes associated with ageing."

The researchers ran tests to identify clusters (or "modules") of oral bacteria that tend to thrive together in similar conditions.

A module (Prevotella-Veillonella) that has been associated with inflammation was reduced after nitrate supplementation, including a decrease of Clostridium difficile (which can infect the bowel and cause diarrhea).

Professor Vanhatalo stressed that more research is needed to confirm the findings and see whether similar effects are found in other groups.

"Our participants were healthy, active older people with generally good blood pressure," she said. "Dietary nitrate reduced their blood pressure on average, and we are keen to find out whether the same would happen in other age groups and among people in poorer health.

"We are working with colleagues in the University of Exeter Medical School to investigate interactions between the oral bacteria and cognition to better understand the how diet could be used to delay cognitive decline in older age."

Much research has been conducted into the benefits of a healthy gut microbiome, but far less is known about the oral microbial community, which plays a crucial role in "activating" the nitrate from a vegetable-rich diet.

https://www.sciencedaily.com/releases/2021/03/210330121231.htm

Should you take fish oil? Depends on your genotype

March 25, 2021

Science Daily/University of Georgia

Fish oil supplements are a billion-dollar industry built on a foundation of purported, but not proven, health benefits. Now, new research from a team led by a University of Georgia scientist indicates that taking fish oil only provides health benefits if you have the right genetic makeup.

The study, led by Kaixiong Ye and published in PLOS Genetics, focused on fish oil (and the omega-3 fatty acids it contains) and its effect on triglycerides, a type of fat in the blood and a biomarker for cardiovascular disease.

"We've known for a few decades that a higher level of omega-3 fatty acids in the blood is associated with a lower risk of heart disease," said Ye, assistant professor of genetics in the Franklin College of Arts and Sciences. "What we found is that fish oil supplementation is not good for everyone; it depends on your genotype. If you have a specific genetic background, then fish oil supplementation will help lower your triglycerides. But if you do not have that right genotype, taking a fish oil supplement actually increases your triglycerides."

Ye's team, including first author and graduate student Michael Francis, examined four blood lipids (fats) -- high-density lipoprotein, low-density lipoprotein, total cholesterol and triglycerides -- that are biomarkers for cardiovascular disease. The data for their sample of 70,000 individuals was taken from UK Biobank, a large-scale cohort study collecting genetic and health information from half a million participants.

The team divided the sample into two groups, those taking fish oil supplements (about 11,000) and those not taking fish oil supplements. Then they performed a genome-wide scan for each group, testing for 8 million genetic variants to compare. After running over 64 million tests, their results revealed a significant genetic variant at gene GJB2. Individuals with the AG genotype who took fish oil decreased their triglycerides. Individuals with the AA genotype who took fish oil slightly increased their triglycerides. (A third possible genotype, GG, was not evident in enough study volunteers to draw conclusions.)

Determining your genotype is not as far-fetched as it sounds, thanks to direct-to-consumer genetic testing companies. Companies may not report that specific genetic variant yet, but a tech-savvy consumer should be able to download the raw data and look at the specific position to discover the genotype, according to Ye. The ID for the variant is rs112803755 (A>G).

The study's findings may also shed light on previous trials, most of which found that fish oil provides no benefit in preventing cardiovascular disease.

"One possible explanation is that those clinical trials didn't consider the genotypes of the participants," Ye said. "Some participants may benefit, and some may not, so if you mix them together and do the analysis, you do not see the impact."

Now that Ye has identified a specific gene that can modify an individual's response to fish oil supplementation, his next step will be directly testing the effects of fish oil on cardiovascular disease.

"Personalizing and optimizing fish oil supplementation recommendations based on a person's unique genetic composition can improve our understanding of nutrition," he said, "and lead to significant improvements in human health and well-being."

https://www.sciencedaily.com/releases/2021/03/210325115253.htm

Green leafy vegetables essential for muscle strength

March 24, 2021

Science Daily/Edith Cowan University

Eating just one cup of leafy green vegetables every day could boost muscle function, according to new Edith Cowan University (ECU) research.

The study, published today in the Journal of Nutrition, found that people who consumed a nitrate-rich diet, predominantly from vegetables, had significantly better muscle function of their lower limbs.

Poor muscle function is linked to greater risk of falls and fractures and is considered a key indicator of general health and wellbeing.

Researchers examined data from 3,759 Australians taking part in Melbourne's Baker Heart and Diabetes Institute AusDiab study over a 12-year period. They found those with the highest regular nitrate consumption had 11 per cent stronger lower limb strength than those with the lowest nitrate intake. Up to 4 per cent faster walking speeds were also recorded.

Lead researcher Dr Marc Sim from ECU's Institute for Nutrition Research said the findings reveal important evidence for the role diet plays in overall health.

"Our study has shown that diets high in nitrate-rich vegetables may bolster your muscle strength independently of any physical activity," he said.

"Nevertheless, to optimise muscle function we propose that a balanced diet rich in green leafy vegetables in combination with regular exercise, including weight training, is ideal."

Muscle function is vital for maintaining good overall health, especially bone strength later in life.

"With around one in three Australians aged over 65 suffering a fall each year, it's important to find ways of preventing these events and their potentially serious consequences," said Dr Sim.

Go for green

While leafy greens may be some of our least favourite vegetables, they could be the most important, according to Dr Sim.

The research found nitrate-rich vegetables, such as lettuce, spinach, kale and even beetroot, provided the greatest health benefits.

"Less than one in ten Australians eat the recommended five to six serves of vegetables per day," Dr Sim said.

"We should be eating a variety of vegetables every day, with at least one of those serves being leafy greens to gain a range of positive health benefits for the musculoskeletal and cardiovascular system."

"It's also better to eat nitrate-rich vegetables as part of a healthy diet rather than taking supplements. Green leafy vegetables provide a whole range of essential vitamins and minerals critical for health."

Building knowledge

The study, a collaboration with Deakin University's Institute of Physical Activity and Nutrition and the Baker Heart and Diabetes Institute, builds on Dr Sim's previous research into nitrate and muscle function in older women.

It also adds to growing evidence linking vegetables with cardiovascular health, including a recent ECU study into cruciferous vegetables and blood vessel health.

Dr Sim said the next step of his research will be exploring strategies to increase leafy green vegetable consumption in the general population.

"We are currently recruiting for the MODEL Study, which examines how knowledge of disease can be used to prompt people in making long-term improvements to their diet and exercise," said Dr Sim.

https://www.sciencedaily.com/releases/2021/03/210324132309.htm

Consumption of added sugar doubles fat production

March 16, 2021

Science Daily/University of Zurich

Sugar is added to many common foodstuffs, and people in Switzerland consume more than 100 grams of it every day. The high calorie content of sugar causes excessive weight and obesity, and the associated diseases. But does too much sugar have any other harmful effects if consumed regularly? And if so, which sugars in particular?

Even moderate amounts of sugar increase fat synthesis

Researchers at the University of Zurich (UZH) and the University Hospital Zurich (USZ) have been investigating these questions. Compared to previous studies, which mainly examined the consumption of very high amounts of sugar, their results show that even moderate amounts lead to a change in the metabolism of test participants. "Eighty grams of sugar daily, which is equivalent to about 0,8 liters of a normal soft drink, boosts fat production in the liver. And the overactive fat production continues for a longer period of time, even if no more sugar is consumed," says study leader Philipp Gerber of the Department of Endocrinology, Diabetology and Clinical Nutrition.

Ninety-four healthy young men took part in the study. Every day for a period of seven weeks, they consumed a drink sweetened with different types of sugar, while the control group did not. The drinks contained either fructose, glucose or sucrose (table sugar which is a combination of fructose and glucose). The researchers then used tracers (labeled substances that can be traced as they move through the body) to analyze the effect of the sugary drinks on the lipid metabolism.

Fructose and sucrose double fat production beyond food intake

Overall, the participants did not consume more calories than before the study, as the sugary drink increased satiety and they therefore reduced their calorie intake from other sources. Nevertheless, the researchers observed that fructose has a negative effect: "The body's own fat production in the liver was twice as high in the fructose group as in the glucose group or the control group -- and this was still the case more than twelve hours after the last meal or sugar consumption," says Gerber. Particularly surprising was that the sugar we most commonly consume, sucrose, boosted fat synthesis slightly more than the same amount of fructose. Until now, it was thought that fructose was most likely to cause such changes.

Development of fatty liver or diabetes more likely

Increased fat production in the liver is a significant first step in the development of common diseases such as fatty liver and type-2 diabetes. From a health perspective, the World Health Organization recommends limiting daily sugar consumption to around 50 grams or, even better, 25 grams. "But we are far off that mark in Switzerland," says Philipp Gerber. "Our results are a critical step in researching the harmful effects of added sugars and will be very significant for future dietary recommendations."

https://www.sciencedaily.com/releases/2021/03/210316100709.htm

Stress reduction as a path to eating less fast food

Intervention's effect of lowering stress linked to dietary improvement

March 11, 2021

Science Daily/Ohio State University

Overweight low-income mothers of young kids ate fewer fast-food meals and high-fat snacks after participating in a study -- not because researchers told them what not to eat, but because the lifestyle intervention being evaluated helped lower the moms' stress, research suggests.

The 16-week program was aimed at preventing weight gain by promoting stress management, healthy eating and physical activity. The methods to get there were simple steps tucked into lessons on time management and prioritizing, many demonstrated in a series of videos featuring mothers like those participating in the study.

"We used the women's testimonies in the videos and showed their interactions with their families to raise awareness about stressors. After watching the videos, a lot of intervention participants said, 'This is the first time I've realized I am so stressed out' -- because they've lived a stressful life," said Mei-Wei Chang, lead author of the study and associate professor of nursing at The Ohio State University.

"Many of these women are aware of feeling impatient, and having head and neck pain and trouble sleeping -- but they don't know those are signs of stress."

An analysis of the study data showed that the women's lowered perceived stress after participating in the intervention was the key factor influencing their eventual decrease in consumption of high-fat and fast foods.

"It's not that these women didn't want to eat healthier," Chang said. "If you don't know how to manage stress, then when you are so stressed out, why would you care about what you eat?"

The research is published in a recent issue of the journal Nutrients.

The 338 participants, overweight or obese moms between the ages of 18 and 39, were recruited from the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC), which serves low-income mothers and children up to age 5. Those eligible for the program must have an annual household income no higher than 185 percent of the federal poverty line.

Chang said these women are likely to face a number of challenges that could cause them stress: financial difficulties, living in run-down neighborhoods, frequent moves, unstable romantic relationships and households bustling with little kids. It's also common for this population to retain 10 or more pounds of pregnancy weight after childbirth and risk life-long obesity and potential problems for themselves and new babies if they become pregnant again.

During the trial, the 212 participants randomized into the intervention group watched a total of 10 videos in which women like them gave unscripted testimonials about healthy eating and food preparation, managing their stress and being physically active. Participants also dialed in to 10 peer support group teleconferences over the course of the study.

Chang and colleagues previously reported that as a group, the women in the intervention arm of the study were more likely to have reduced their fat consumption than women in a comparison group who were given print materials about lifestyle change.

This newer analysis showed that the intervention's lessons alone did not directly affect that change in diet. When the researchers assessed the potential role of stress as a mediator, the indirect effect of the intervention -- reducing participants' perceived stress -- was associated with less consumption of high-fat foods, including fast food. A 1-point reduction in the scale measuring stress was linked to a nearly 7% reduction in how frequently the women ate high-fat foods.

The intervention focused on showing the women examples of how they could achieve a healthier and less stressful lifestyle rather than telling them what they had to change.

"I learned a lot from those women," Chang said. "Everything needs to be practical and applicable to daily life -- anytime, anywhere."

Some examples: Comparing a bag of chips to a bag of apples -- the chips might be half the price, but they supply far fewer family snacks. Or using a household responsibility chart to assign tasks to young children, and encouraging moms to reward kids with a hug or individual attention when they follow the instructions. And taking deep breaths to counter the feeling of being overwhelmed.

When it came to stress management, the researchers focused on advising the women to shift their thinking, and not to blame themselves when things go wrong, rather than to take on solving the problems that caused them stress.

"We raised their awareness about stressors in their lives, and unfortunately a lot of these problems are not within their control," Chang said. "So we teach them ways to control their negative emotions -- remember that this is temporary, and you can get through it. And give them confidence to look to the future."

The videos from the intervention are now part of WIC's continuing education series for mothers. This work was supported by the National Institutes of Health. Co-authors included Duane Wegener from Ohio State and Roger Brown from the University of Wisconsin-Madison.

https://www.sciencedaily.com/releases/2021/03/210311185957.htm

Two servings of fish per week can help prevent recurrent heart disease

March 8, 2021

Science Daily/McMaster University

An analysis of several large studies involving participants from more than 60 countries, spearheaded by researchers from McMaster University, has found that eating oily fish regularly can help prevent cardiovascular disease (CVD) in high-risk individuals, such as those who already have heart disease or stroke.

The critical ingredient is omega-3 fatty acids, which researchers found was associated with a lower risk of major CVD events such as heart attacks and strokes by about a sixth in high-risk people who ate two servings of fish rich in omega-3 each week.

"There is a significant protective benefit of fish consumption in people with cardiovascular disease," said lead co-author Andrew Mente, associate professor of research methods, evidence, and impact at McMaster and a principal investigator at the Population Health Research Institute.

No benefit was observed with consumption of fish in those without heart disease or stroke.

"This study has important implications for guidelines on fish intake globally. It indicates that increasing fish consumption and particularly oily fish in vascular patients may produce a modest cardiovascular benefit."

Mente said people at low risk for cardiovascular disease can still enjoy modest protection from CVD by eating fish rich in omega-3, but the health benefits were less pronounced than those high-risk individuals.

The study was published in JAMA Internal Medicine on March 8.

The findings were based on data from nearly 192,000 people in four studies, including about 52,000 with CVD, and is the only study conducted on all five continents. Previous studies focused mainly on North America, Europe, China and Japan, with little information from other regions.

"This is by far the most diverse study of fish intake and health outcomes in the world and the only one with sufficient numbers with representation from high, middle and low income countries from all inhabited continents of the world," said study co-lead Dr. Salim Yusuf, professor of medicine at the Michael G. DeGroote School of Medicine and executive director of the PHRI.

https://www.sciencedaily.com/releases/2021/03/210308131709.htm

Eating more refined grains increases risk of heart attack, early death

The researchers examined diets from diverse populations in low, middle and high-income countries.

February 19, 2021

Science Daily/Simon Fraser University

A new study published in The British Medical Journal by researchers including SFU health sciences professor Scott Lear found consuming a high number of refined grains, such as croissants and white bread, is associated with a higher risk of major cardiovascular disease, stroke and early death.

The Prospective Urban Rural Epidemiology (PURE) study has been examining diets from diverse populations in low-, middle- and high-income countries around the world. Over 16 years of analysis of 137,130 participants in 21 countries, including Canada, the researchers found the intake of refined grains and added sugars have greatly increased over the years.

Grains were categorized into three groups: refined grains, whole grains and white rice. Refined grains included goods made with refined (e.g. white) flour, including white bread, pasta/noodles, breakfast cereals, crackers, and bakery products/desserts containing refined grains. Whole grains included whole grain flours (e.g. buckwheat) and intact or cracked whole grains (eg. steel cut oats).

The study found that having more than seven servings of refined grains per day was associated with a 27 per cent greater risk for early death, 33 percent greater risk for heart disease and 47 per cent greater risk for stroke.

"This study re-affirms previous work indicating a healthy diet includes limiting overly processed and refined foods," says Lear.

No significant adverse health effects were found with consuming whole grains or white rice.

The study suggests eating whole grain foods like brown rice and barley, and having fewer cereal grains and refined wheat products. Reducing one's overall consumption of refined grains and having better quality carbohydrates is essential for optimal health outcomes.

https://www.sciencedaily.com/releases/2021/02/210219155857.htm

Study links prolonged sedentary time to distractibility in adults with obesity, overweight

February 17, 2021

Science Daily/University of Illinois at Urbana-Champaign, News Bureau

Scientists used accelerometers to track daily activity levels for a week in 89 adults with obesity or overweight and, in a series of tests, measured their ability to multitask and maintain their attention despite distractions. The study revealed that individuals who spent more sedentary time in bouts lasting 20 minutes or more were less able to overcome distractions.

Reported in the International Journal of Obesity, the research adds to the evidence linking sedentary behaviors and cognition, said University of Illinois Urbana-Champaign kinesiology and community health professor Dominika Pindus, who led the work on the paper.

"Several studies have examined the relationship between different types of sedentary behaviors such as TV viewing and cognitive functions in children and adults," Pindus said. "The relationships they observed varied with the type of sedentary behavior. These studies primarily measured sedentary behaviors during leisure time."

The research found that regularly sitting for extended periods is linked to increased mortality and cardiovascular disease, Pindus said. People who do not engage in at least 60 minutes per day of moderate-to-vigorous physical activity and sit for eight hours or more have an increased health risk. Other studies suggest that bouts of prolonged sitting lasting 20 minutes or more negatively affect levels of blood sugar after a meal.

"Few studies, however, have examined the relationship between prolonged sedentary time and cognitive functions," Pindus said. To address this gap in research, she and her colleagues focused on the associations between objectively measured, prolonged sedentary time and cognition in adults 25-45 years old with obesity or overweight.

"We know from previous research that people with obesity or overweight don't do as well on certain types of cognitive tasks," Pindus said. "These tasks engage executive functions -- cognitive functions that are important for reasoning and staying focused on a goal."

Some studies have found that long-term physical activity interventions in preadolescent children or older adults can improve those functions.

"But we don't have much data on how prolonged sedentary time is linked to executive functions in working-age people with obesity or overweight," she said. "If we can show how sedentary time and physical activity in everyday life relate to executive functions in those individuals, we may be able to design more targeted lifestyle interventions to improve cognition in this population."

The researchers collected baseline information for all participants, tested their cognitive ability and calculated each person's body mass index and percent body fat. Participants wore accelerometers on their waists during waking hours for seven days. They also completed cognitive tasks and measures of brain function in a laboratory setting.

"We used EEG recordings to measure electrical potentials that are generated in the brain while participants engaged in tasks that challenged them to focus, ignore distractions and flexibly switch attention between tasks," Pindus said. A controller connected to a computer allowed participants to respond to problems while the speed and accuracy of their responses was recorded.

A statistical analysis of participants' sedentariness in relation to their speed and accuracy on a task that measures distractibility found a relationship between the two, Pindus said.

"Our key finding was that people who spent more time in prolonged sedentary bouts were more easily distracted," she said.

More research is needed to determine how the structure of a person's sedentary time influences cognition, Pindus said.

"If you make sure to break up your sitting time with brief bouts of physical activity, could that reduce how distracted you will be?" she said. "And if it does, what is driving this effect? This is something we want to explore."

https://www.sciencedaily.com/releases/2021/02/210217132335.htm

Women 'risk' grey hair to feel authentic

April 12, 2021

Science Daily/University of Exeter

Many women "risk" allowing natural grey hair to show in order to feel authentic, a new study shows.

Researchers from the University of Exeter surveyed women who chose not to dye their grey hair, and found a "conflict" between looking natural and being seen as competent.

Participants in the study -- mostly from English-speaking countries -- belonged to online groups whose members allow their natural grey hair to show, and the researchers noted "solidarity and sisterhood" among these women.

"We are all constrained by society's norms and expectations when it comes to appearance, but expectations are more rigorous for women -- especially older women," said lead author Vanessa Cecil, of the University of Exeter.

"The 'old woman' is an undesirable character in Western societies, being seen as incompetent or unpleasant -- if she is seen at all.

"In our study, we wanted to understand why some women choose natural grey hair.

"In the face of impossible standards to be natural and remain youthful forever, these women are doing what they can to retain status.

"Although many reported negative consequences such as being ignored or treated as less competent, they also felt happier to be 'flying my natural flag'.

"We also found that women chose to compensate for going grey by using other beauty practices -- so embracing grey isn't the same as embracing looking old.

"Grey-haired and youthfully glamorous is one thing, but in Western societies it's still not OK to look old."

Responses from the 80 participants, members of two Facebook groups about transitioning to natural grey hair, suggested the key trade-off was between authenticity and being seen as competent.

Women reported being shamed -- including by family and friends -- for being too natural ("let oneself go") but also wanted to avoid looking as if they have tried too hard to conceal their age ("mutton dressed as lamb").

Those who were supported by partners, family and friends had an "easier time" of the transition to grey, Cecil said.

Many women have chosen natural grey hair during COVID lockdowns -- both because hairdressers have been closed and due to spending less time in public, including at work.

"This appears to have accelerated a shift that was already happening, with more and more women choosing not to dye their hair," Cecil said.

https://www.sciencedaily.com/releases/2021/04/210412114815.htm

Stress from work and social interactions put women at higher coronary heart disease risk

April 9, 2021

Science Daily/Drexel University

Psychosocial stress -- typically resulting from difficulty coping with challenging environments -- may work synergistically to put women at significantly higher risk of developing coronary heart disease, according to a study by researchers at Drexel University's Dornsife School of Public Health, recently published in the Journal of the American Heart Association.

The study specifically suggests that the effects of job strain and social strain -- the negative aspect of social relationships -- on women is a powerful one-two punch. Together they are associated with a 21% higher risk of developing coronary heart disease. Job strain occurs when a woman has inadequate power in the workplace to respond to the job's demands and expectations.

The study also found that high-stress life events, such as a spouse's death, divorce/separation or physical or verbal abuse, as well as social strain, were each independently linked with a 12% and 9% higher risk of coronary heart disease, respectively.

The Drexel study used data from a nationally representative sample of 80,825 postmenopausal women from the Women's Health Initiative Observational Study, which tracked participants from 1991 to 2015, to find better methods of preventing cancer, heart disease and osteoporosis in women. In the current follow-up study, Drexel researchers evaluated the effect of psychosocial stress from job strain, stressful life events and social strain (through a survey), and associations among these forms of stress, on coronary heart disease.

Nearly 5% of the women developed coronary heart disease during the 14-year, seven-month study. Adjusting for age, time at a job, and socioeconomic characteristics, high-stress life events were associated with a 12% increased coronary heart disease risk, and high social strain was associated with a 9% increased risk of coronary heart disease. Work strain was not independently associated with coronary heart disease.

Coronary heart disease, the leading cause of death in the United States, occurs with the heart's arteries become narrow and cannot bring sufficient oxygenated blood to the heart. The latest work builds on earlier studies linking psychosocial stress to coronary heart disease by finding out how job strain and social strain work together to compound disease risk.

"The COVID-19 pandemic has highlighted ongoing stresses for women in balancing paid work and social stressors. We know from other studies that work strain may play a role in developing CHD, but now we can better pinpoint the combined impact of stress at work and at home on these poor health outcomes," said senior author Yvonne Michael, ScD, SM, an associate professor in the Dornsife School of Public Health. "My hope is that these findings are a call for better methods of monitoring stress in the workplace and remind us of the dual-burden working women face as a result of their unpaid work as caregivers at home ."

The study's authors say that future studies should look at the effects of shift work on coronary heart disease and explore the effects of job demands according to gender.

"Our findings are a critical reminder to women, and those who care about them, that the threat of stress to human health should not go ignored," said lead author Conglong Wang, PhD, a recent Dornsife graduate who conducted the research while at Drexel. "This is particularly pertinent during the stressors caused by a pandemic."

https://www.sciencedaily.com/releases/2021/04/210409124746.htm