High intake of dietary fiber and whole grains associated with reduced risk of non-communicable diseases
January 10, 2019
Science Daily/The Lancet
Observational studies and clinical trials conducted over nearly 40 years reveal the health benefits of eating at least 25g to 29g or more of dietary fiber a day, according to a series of systematic reviews and meta-analyses.
People who eat higher levels of dietary fibre and whole grains have lower rates of non-communicable diseases compared with people who eat lesser amounts, while links for low glycaemic load and low glycaemic index diets are less clear. Observational studies and clinical trials conducted over nearly 40 years reveal the health benefits of eating at least 25g to 29g or more of dietary fibre a day, according to a series of systematic reviews and meta-analyses published in The Lancet.
The results suggest a 15-30% decrease in all-cause and cardiovascular related mortality when comparing people who eat the highest amount of fibre to those who eat the least. Eating fibre-rich foods also reduced incidence of coronary heart disease, stroke, type 2 diabetes and colorectal cancer by 16-24%. Per 1,000 participants, the impact translates into 13 fewer deaths and six fewer cases of coronary heart disease.
In addition, a meta-analysis of clinical trials suggested that increasing fibre intakes was associated with lower bodyweight and cholesterol, compared with lower intakes.
The study was commissioned by the World Health Organization to inform the development of new recommendations for optimal daily fibre intake and to determine which types of carbohydrate provide the best protection against non-communicable diseases (NCDs) and weight gain.
Most people worldwide consume less than 20 g of dietary fibre per day. In 2015, the UK Scientific Advisory Committee on Nutrition recommended an increase in dietary fibre intake to 30 g per day, but only 9% of UK adults manage to reach this target. In the US, fibre intake among adults averages 15 g a day. Rich sources of dietary fibre include whole grains, pulses, vegetables and fruit.
"Previous reviews and meta-analyses have usually examined a single indicator of carbohydrate quality and a limited number of diseases so it has not been possible to establish which foods to recommend for protecting against a range of conditions," says corresponding author Professor Jim Mann, the University of Otago, New Zealand.
"Our findings provide convincing evidence for nutrition guidelines to focus on increasing dietary fibre and on replacing refined grains with whole grains. This reduces incidence risk and mortality from a broad range of important diseases."
The researchers included 185 observational studies containing data that relate to 135 million person years and 58 clinical trials involving 4,635 adult participants. They focused on premature deaths from and incidence of coronary heart disease, cardiovascular disease and stroke, as well as incidence of type 2 diabetes, colorectal cancer and cancers associated with obesity: breast, endometrial, esophageal and prostate cancer. The authors only included studies with healthy participants, so the findings cannot be applied to people with existing chronic diseases.
For every 8g increase of dietary fibre eaten per day, total deaths and incidence of coronary heart disease, type 2 diabetes and colorectal cancer decreased by 5-27%. Protection against stroke, and breast cancer also increased. Consuming 25g to 29g each day was adequate but the data suggest that higher intakes of dietary fibre could provide even greater protection.
For every 15g increase of whole grains eaten per day, total deaths and incidence of coronary heart disease, type 2 diabetes and colorectal cancer decreased by 2-19%. Higher intakes of whole grains were associated with a 13-33% reduction in NCD risk -- translating into 26 fewer deaths per 1,000 people from all-cause mortality and seven fewer cases of coronary heart disease per 1,000 people. The meta-analysis of clinical trials involving whole grains showed a reduction in bodyweight. Whole grains are high in dietary fibre, which could explain their beneficial effects.
The study also found that diets with a low glycaemic index and low glycaemic load provided limited support for protection against type 2 diabetes and stroke only. Foods with a low glycaemic index or low glycaemic load may also contain added sugars, saturated fats, and sodium. This may account for the links to health being less clear.
"The health benefits of fibre are supported by over 100 years of research into its chemistry, physical properties, physiology and effects on metabolism. Fibre-rich whole foods that require chewing and retain much of their structure in the gut increase satiety and help weight control and can favourably influence lipid and glucose levels. The breakdown of fibre in the large bowel by the resident bacteria has additional wide-ranging effects including protection from colorectal cancer." says Professor Jim Mann.
While their study did not show any risks associated with dietary fibre, the authors note that high intakes might have ill-effects for people with low iron or mineral levels, for whom high levels of whole grains can further reduce iron levels. They also note that the study mainly relates to naturally-occurring fibre rich foods rather than synthetic and extracted fibre, such as powders, that can be added to foods.
Commenting on the implications and limitations of the study, Professor Gary Frost, Imperial College London, UK, says, "[The authors] report findings from both prospective cohort studies and randomised controlled trials in tandem. This method enables us to understand how altering the quality of carbohydrate intake in randomised controlled trials affects non-communicable disease risk factors and how these changes in diet quality align with disease incidence in prospective cohort studies. This alignment is seen beautifully for dietary fibre intake, in which observational studies reveal a reduction in all-cause and cardiovascular mortality, which is associated with a reduction in bodyweight, total cholesterol, LDL cholesterol, and systolic blood pressure reported in randomised controlled trials... There are some important considerations that arise from this Article. First, total carbohydrate intake was not considered in the systematic review and meta-analysis... Second, although the absence of association between glycaemic index and load with non-communicable disease and risk factors is consistent with another recent systematic review, caution is needed when interpreting these data, as the number of studies is small and findings are heterogeneous. Third, the absence of quantifiable and objective biomarkers for assessing carbohydrate intake means dietary research relies on self-reported intake, which is prone to error and misreporting. Improving the accuracy of dietary assessment is a priority area for nutrition research. The analyses presented by Reynolds and colleagues provides compelling evidence that dietary fibre and whole grain are major determinants of numerous health outcomes and should form part of public health policy."
https://www.sciencedaily.com/releases/2019/01/190110184737.htm
Long-term exposure to road traffic noise may increase the risk of obesity
New evidence on the damaging effects of noise on health
November 16, 2018
Science Daily/Barcelona Institute for Global Health (ISGlobal)
Long term exposure to road traffic noise is associated with increased risk of obesity. This was the conclusion of a study involving the participation of the Barcelona Institute for Global Health (ISGlobal), a research centre supported by the "la Caixa" Banking Foundation. The study has been published in Environment International.
The authors of this study wanted to find out whether new research would confirm the results of the few earlier studies that had demonstrated associations between traffic noise and several markers for obesity. To do this, they studied 3796 adults who took part in the population-based Swiss SAPALDIA cohort study and had attended at least two follow-up visits between 2001 and 2011. The study is based on objective measures, such as the participants' weight, height, body mass index, waist circumference, and abdominal fat. These data were analysed together with estimates of exposure to transportation noise developed in the context of the Swiss SiRENE project.
"Our analysis shows that people exposed to the highest levels of traffic noise are at greater risk of being obese" explains ISGlobal research Maria Foraster, first author of the study. "For example, we observed that a 10 dB increase in mean noise level was associated with a 17% increase in obesity."
The study authors also analysed exposure to noise generated by aircraft and railway traffic and found no significant associations except in the case of long-term exposure to railway noise, which was associated with a higher risk of overweight but not of obesity.
The methodology and design of the study were chosen to allow the authors to look at the data from two different perspectives. Cross-sectional analysis was used to study the participant population at a specific time point in the study and to examine more objective measures. The longitudinal design, on the other hand, allowed the authors to evaluate how the risk of obesity evolved over the study period. The associations with traffic-related noise pollution were consistent in both cases. Overweight was only associated with exposure to traffic-related noise in the cross-sectional analysis. The authors found no association between noise exposure and body mass index measured continuously throughout the longitudinal analysis.
"Our study contributes additional evidence to support the hypothesis that traffic-related noise affects obesity because the results we obtained in a different population were the same as those reported by the authors of earlier studies. Nevertheless, more longitudinal studies are needed to confirm the association and to examine certain inconsistencies in the data which, to date, have prevented us from formulating an explanation accepted by the scientific community as a whole," explains Maria Foraster.
Unfortunately, sustained exposure to noise pollution is a widespread public health problem that is more serious than previously thought. Noise generates stress and affects our sleep. It alters hormone levels and increases blood pressure. Moreover, among other effects, sleep disturbance deregulates glucose metabolism and alters the appetite. "In the long term, these effects could give rise to chronic physiological alterations, which would explain the proven association between persistent exposure to traffic-related noise and cardiovascular disease or the more recently discovered associations with diabetes and obesity. Our findings suggest that reducing traffic-related noise could also be a way of combating the obesity epidemic" adds Maria Foraster.
https://www.sciencedaily.com/releases/2018/11/181116110615.htm
Should you eat a low-gluten diet?
November 15, 2018
Science Daily/University of Copenhagen The Faculty of Health and Medical Sciences
When healthy people eat a low-gluten and fiber-rich diet compared with a high-gluten diet they experience less intestinal discomfort including less bloating which researchers show are due to changes of the composition and function of gut bacteria. The new study also shows a modest weight loss following low-gluten dieting. The researchers attribute the impact of diet on healthy adults more to change in composition of dietary fibers than gluten itself.
An increasing number of people choose a low-gluten diet, even though they are not allergic to the dietary substance. This trend has sparked public debate about whether or not low-gluten diets are recommendable for people without allergies. Now, researchers from University of Copenhagen among others have looked into just that.
In an intervention study of healthy Danish adults, reported today in Nature Communications, an international team of scientists shows that a low-gluten but fibre-rich diet changes the community of gut bacteria and decreases gastrointestinal discomfort such as bloating and is linked to a modest weight loss. The changes in intestinal comfort and body weight relate to changes in gut bacteria composition and function.
"We demonstrate that, in comparison with a high-gluten diet, a low-gluten, fibre-rich diet induces changes in the structure and function of the complex intestinal ecosystem of bacteria, reduces hydrogen exhalation, and leads to improvements in self-reported bloating. Moreover, we observed a modest weight loss, likely due to increased body combustion triggered by the altered gut bacterial functions," explains the leading principal investigator of the trial, Professor Oluf Pedersen, Novo Nordisk Foundation Center for Basic Metabolic Research at University of Copenhagen.
Change in dietary fibre composition seems to be the cause
The researchers undertook a randomised, controlled, cross-over trial involving 60 middle-aged healthy Danish adults with two eight week interventions comparing a low-gluten diet (2 g gluten per day) and a high-gluten diet (18 g gluten per day), separated by a washout period of at least six weeks with habitual diet (12 g gluten per day).
The two diets were balanced in number of calories and nutrients including the same amount of dietary fibres. However, the composition of fibres differed markedly between the two diets.
Based on their observations of altered food fermentation patterns of the gut bacteria, the researchers conclude that the effects of low-gluten dieting in healthy people may not be primarily due to reduced intake of gluten itself but rather to a change in dietary fibre composition by reducing fibres from wheat and rye and replacing them with fibres from vegetables, brown rice, corn, oat and quinoa.
No basis for change of diet recommendation yet
A low-gluten diet has previously been proposed to diminish gastrointestinal symptoms in patients with inflammatory bowel diseases and irritable bowel syndrome, disorders which occur in up to 20 percent of the general Western population.
The present study suggests that even some healthy individuals may prefer a low-gluten diet to combat intestinal discomfort or excess body weight.
"More long-term studies are definitely needed before any public health advice can be given to the general population. Especially, because we find dietary fibres -- not the absence of gluten alone -- to be the primary cause of the changes in intestinal discomfort and body weight. By now we think that our study is a wake-up call to the food industry. Gluten-free may not necessarily be the healthy choice many people think it is.
Most gluten-free food items available on the market today are massively deprived of dietary fibers and natural nutritional ingredients. Therefore, there is an obvious need for availability of fibre-enriched, nutritionally high-quality gluten-free food items which are fresh or minimally processed to consumers who prefer a low-gluten diet. Such initiatives may turn out to be key for alleviating gastro-intestinal discomfort and in addition to help facilitating weight control in the general population via modification of the gut microbiota," concludes senior lead investigator, Professor Oluf Pedersen.
https://www.sciencedaily.com/releases/2018/11/181115115340.htm
Curry spice boosts exercise performance in mice with heart failure
Curcumin treatment improved muscle function, exercise capacity in mice with heart failure and healthy controls
November 29, 2018
Science Daily/American Physiological Society
New research suggests that curcumin, a main ingredient in curry, may improve exercise intolerance related to heart failure.
Curcumin, a chemical that comes from the turmeric plant, has been used as a traditional Asian medicine for centuries, primarily to treat gastrointestinal ailments and skin wounds. Studies increasingly suggest that the compound may prevent or limit muscle wasting associated with a number of health conditions, including heart failure.
Heart failure affects more than 6 million people living in the U.S. People with heart failure have a reduced function of the left ventricle -- the chamber of the heart that pumps blood out to the rest of the body -- called reduced ejection fraction. A decreased ability to exercise (exercise intolerance) is another significant characteristic of heart failure. Previous research has found that higher than normal levels of oxidative stress -- an imbalance of two different kinds of molecules that can result in cell damage -- contribute to exercise intolerance in people with heart failure. Heart failure is also associated with lower than normal expression of antioxidant enzymes in the muscles, but the reason for this is unclear. Antioxidant enzymes both prevent and repair damage from oxidative stress. Boosting enzyme levels may improve exercise performance in people in heart failure.
Researchers from the University of Nebraska Medical Center theorized that a reduction in the normal signaling of Nrf2, a protein that regulates the expression of antioxidant enzymes, may play a role in the impaired expression of antioxidant enzymes. They examined the effects of curcumin, which is known to promote activation of Nrf2, on a mouse model of heart failure with reduced ejection fraction. One group of mice with heart failure received daily doses of curcumin for 12 weeks, and another group did not receive treatment. The heart failure groups were compared to a control group of healthy mice that received curcumin and an untreated control group.
The research team measured the exercise capacity of all the mice before and after curcumin treatment. The researchers also examined muscle fiber samples to assess enzyme expression levels. They found that expression of Nrf2 increased and levels of antioxidant enzymes improved in the animals with heart failure that were given curcumin. In addition, both groups that received curcumin -- even the animals without heart failure -- had improved exercise capacity when compared with the untreated groups, suggesting the effects of curcumin on skeletal muscle is not exclusive to heart failure.
"These data suggest that activation of Nrf2 in skeletal muscle may represent a novel therapeutic strategy to improve ... quality of life" in people with heart failure with reduced ejection fraction, the researchers wrote.
https://www.sciencedaily.com/releases/2018/11/181129122448.htm
Vitamin D levels in the blood linked to cardiorespiratory fitness
October 30, 2018
Science Daily/European Society of Cardiology
Vitamin D levels in the blood are linked to cardiorespiratory fitness, according to a study published today in the European Journal of Preventive Cardiology, a publication of the European Society of Cardiology (ESC).
"Our study shows that higher levels of vitamin D are associated with better exercise capacity," said Dr Amr Marawan, assistant professor of internal medicine, Virginia Commonwealth University, Virginia, US. "We also know from previous research that vitamin D has positive effects on the heart and bones. Make sure your vitamin D levels are normal to high. You can do this with diet, supplements, and a sensible amount of sun exposure."
It is well established that vitamin D is important for healthy bones, but there is increasing evidence that it plays a role in other areas of the body including the heart and muscles.
Cardiorespiratory fitness, a reliable surrogate for physical fitness, is the ability of the heart and lungs to supply oxygen to the muscles during exercise. It is best measured as the maximal oxygen consumption during exercise, referred to as VO2 max. People with higher cardiorespiratory fitness are healthier and live longer.
This study investigated whether people with higher levels of vitamin D in the blood have improved cardiorespiratory fitness. The study was conducted in a representative sample of the US population aged 20-49 years using the National Health and Nutrition Survey (NHANES) in 2001-2004. Data was collected on serum vitamin D and VO2 max. Participants were divided into quartiles of vitamin D levels.
Of 1,995 participants, 45% were women, 49% were white, 13% had hypertension, and 4% had diabetes. Participants in the top quartile of vitamin D had a 4.3-fold higher cardiorespiratory fitness than those in the bottom quartile. The link remained significant, with a 2.9-fold strength, after adjusting for factors that could influence the association such as age, sex, race, body mass index, smoking, hypertension, and diabetes.
Dr Marawan said: "The relationship between higher vitamin D levels and better exercise capacity holds in men and women, across the young and middle age groups, across ethnicities, regardless of body mass index or smoking status, and whether or not participants have hypertension or diabetes."
Each 10 nmol/L increase in vitamin D was associated with a statistically significant 0.78 mL/kg/min increase in VO2 max. "This suggests that there is a dose response relationship, with each rise in vitamin D associated with a rise in exercise capacity," said Dr Marawan.
Dr Marawan noted that this was an observational study and it cannot be concluded that vitamin D improves exercise capacity. But he added: "The association was strong, incremental, and consistent across groups. This suggests that there is a robust connection and provides further impetus for having adequate vitamin D levels, which is particularly challenging in cold, cloudy places where people are less exposed to the sun."
On the other hand, Vitamin D toxicity can lead to excess calcium in the blood, which can cause nausea, vomiting, and weakness. "It is not the case that the more vitamin D, the better," said Dr Marawan. "Toxicity is caused by megadoses of supplements rather than diet or sun exposure, so caution is needed when taking tablets."
Regarding further research, Dr Marawan said: "We know the optimum vitamin D levels for healthy bones but studies are required to determine how much the heart needs to function at its best. Randomised controlled trials should be conducted to examine the impact of differing amounts of vitamin D supplements on cardiorespiratory fitness. From a public health perspective, research should look into whether supplementing food products with vitamin D provides additional benefits beyond bone health."
https://www.sciencedaily.com/releases/2018/10/181030091449.htm
Modeling the microbiome
Physicists develop new mathematical approaches to analyze interactions between gut bacteria
December 5, 2018
Science Daily/University of California - Santa Barbara
The gut microbiome -- the world of microbes that inhabit the human intestinal tract -- has captured the interest of scientists and clinicians for its critical role in health. However, parsing which of those microbes are responsible for effects on our wellbeing remains a mystery.
Taking us one step closer to solving this puzzle, UC Santa Barbara physicists Eric Jones and Jean Carlson have developed a mathematical approach to analyze and model interactions between gut bacteria in fruit flies. This method could lead to a more sophisticated understanding of the complex interactions between human gut microbes.
Their finding appear in the Proceedings of the National Academy of Sciences.
"Especially over the past 20 years or so, scientists have been finding that the microbiome interacts with the rest of your body, with your immune system, with your brain," said Jones, a graduate student researcher in Carlson's lab. "Many diseases are associated with certain microbial compositions in the gut."
The human gut microbiome as yet is too diverse to fully analyze. Instead, the research team, led by Carnegie Institution for Science biologist Will Ludington, used the fruit fly as a model organism to tease apart how the presence of particular gut bacteria could lead to physical and behavioral effects in the host organism.
In their paper, "Microbiome interactions shape host fitness," Carlson, Jones, Ludington and colleagues examine the interactions between five core species of bacteria found in the fly gut, and calculate how the presence or absence of individual species influences aspects of the fly's fitness, including lifespan, fertility and development. "The classic way we think about bacterial species is in a black-and-white context as agents of disease -- either you have it or you don't," Ludington said. "Our work shows that isn't the case for the microbiome. The effects of a particular species depend on the context of which other species are also present."
Building on previous research that found the presence versus the absence of bacteria affected the longevity of an organism (sterile hosts lived longer), the researchers' work on this project revealed that the situation is far more nuanced. For example, the presence of certain bacteria might increase the host's fecundity, while others might decrease longevity. "As we examined the total of what we call a fly's fitness -- it's chances of surviving and creating offspring -- we found that there was a tradeoff between having a short lifespan with lots of offspring, versus having a long lifespan with few offspring," Ludington explained. "This tradeoff was mediated by microbiome interactions."
To decipher these interactions, Ludington performed a combinatorial assay, rearing 32 batches of flies each inhabited by a unique combination of the five bacteria. For each bacterial combination, Ludington measured the fly's development, fecundity and longevity. The analysis of the interactions required Carlson and Jones to develop new mathematical approaches.
"One model that often would be a starting point would be to consider the interactions between pairs of bacteria," said Carlson, whose research delves into the physics of complex systems. "This research shows us that a strictly pairwise model does not capture all of the observed fly traits."
What the study shows, the researchers said, is that the interactions between the bacterial populations are as significant to the host's overall fitness as their presence -- the microbiome's influence cannot be solely attributed to the presence or absence of individual species. "In a sense," said Jones, "the microbiome's influence on the host is more than the sum of its parts."
The newly developed models could be extended to better understand the interactions of the thousands of different species of bacteria in the human microbiome, which could, in turn, shed light on the many connections to microbiome-affiliated diseases including mood disorders, neurological dysfunctions, autoimmune diseases and antibiotic-resistant superbugs.
"In many cases infections are caused by bacteria that we all have in ourselves all the time, and are kept in check by native gut bacteria," Carlson said. It's not so much that the infection is some new, horrible bacteria, she explained, but that the populations of other bacteria have changed, resulting in unrestricted growth for the infectious bacteria.
"It's really about understanding the population dynamics of these systems," she said.
https://www.sciencedaily.com/releases/2018/12/181205152208.htm
Exploring the connection between hearing loss and cognitive decline
Eight-year study reveals association that may indicate early stage changes in cognition
January 29, 2019
Science Daily/Brigham and Women's Hospital
Hearing loss affects tens of millions of Americans and its global prevalence is expected to grow as the world's population ages. A new study led by investigators at Brigham and Women's Hospital adds to a growing body of evidence that hearing loss is associated with higher risk of cognitive decline. These findings suggest that hearing loss may help identify individuals at greater risk of cognitive decline and could provide insights for earlier intervention and prevention.
"Dementia is a substantial public health challenge that continues to grow. There is no cure, and effective treatments to prevent progression or reverse the course of dementia are lacking," said lead author Sharon Curhan, MD, MSc, a physician and epidemiologist in the Channing Division for Network Medicine at the Brigham. "Our findings show that hearing loss is associated with new onset of subjective cognitive concerns which may be indicative of early stage changes in cognition. These findings may help identify individuals at greater risk of cognitive decline."
Curhan and colleagues conducted an eight-year longitudinal study among 10,107 men aged ?62 years in the Health Professionals Follow-up Study (HFPS). They assessed subjective cognitive function (SCF) scores based on responses to a six-item questionnaire administered in 2008, 2012 and 2016. SCF decline was defined as a new report of at least one SCF concern during follow-up.
The team found that hearing loss was associated with higher risk of subjective cognitive decline. Compared with men with no hearing loss, the relative risk of cognitive decline was 30 percent higher among men with mild hearing loss, 42 percent higher among men with moderate hearing loss, and 54 percent higher among men with severe hearing loss but who did not use hearing aids.
Researchers were interested to see if hearing aids might modify risk. Although the found that among men with severe hearing loss who used hearing aids, the risk of cognitive decline was somewhat less (37 percent higher), it was not statistically significantly different from the risk among those who did not use hearing aids. The authors note that this may have been due to limited power or could suggest that if a difference truly exists, the magnitude of the effect may be modest.
The authors also note that the study was limited to predominantly older white male health professionals. This allowed for greater control of variability but further studies in additional populations would be helpful. In addition, the study relies on self-reported hearing loss and subjective measures of cognitive function. In the future, the team plans to investigate the relationships between self-reported hearing loss, change in audiometric hearing thresholds, and changes in cognition in women using several different assessment measures.
"Whether there is a temporal association between hearing loss and cognitive decline and whether this relation is causal remains unclear," said Curhan. "We plan to conduct further longitudinal studies of the relation of hearing loss and cognition in women and in younger populations, which will be informative."
https://www.sciencedaily.com/releases/2019/01/190129081936.htm
Poor sleep at night, more pain the next day
January 29, 2019
Science Daily/Society for Neuroscience
After one night of inadequate sleep, brain activity ramps up in pain-sensing regions while activity is scaled back in areas responsible for modulating how we perceive painful stimuli. This finding provides the first brain-based explanation for the well-established relationship between sleep and pain.
In two studies -- one in a sleep laboratory and the other online -- Matthew Walker and colleagues show how the brain processes pain differently when individuals are sleep deprived and how self-reported sleep quality and pain sensitivity can change night-to-night and day-to-day. When the researchers kept healthy young adults awake through the night in the lab, they observed increased activity in the primary somatosensory cortex and reduced activity in regions of the striatum and insula cortex during a pain sensitivity task. Participants in the online study, recruited via the crowdsourcing marketplace Amazon Mechanical Turk, reported increased pain during the day after reporting poor sleep the night before.
These results suggest improving sleep quality, especially in hospital settings, could be an effective approach for pain management. More generally, the research highlights the interrelationship between sleep and pain, which is decreasing and increasing, respectively, in societies around the world.
https://www.sciencedaily.com/releases/2019/01/190129093714.htm
Lowering blood pressure reduces risk of cognitive impairment
January 28, 2019
Science Daily/Wake Forest Baptist Medical Center
Intensive control of blood pressure in older people significantly reduced the risk of developing mild cognitive impairment (MCI), a precursor of early dementia, in a clinical trial led by scientists at Wake Forest School of Medicine, part of Wake Forest Baptist Health. However, the National Institutes of Health-supported Systolic Blood Pressure Intervention Trial (SPRINT) Memory and Cognition in Decreased Hypertension (SPRINT MIND) study did not prove that treating blood pressure to a goal of 120 mm Hg or less statistically reduced the risk of dementia. This result may have been due to too few new cases of dementia occurring in the study, the authors noted.
The results were reported in the Jan. 28 edition of the Journal of the American Medical Association.
MCI is defined as a decline in memory and thinking skills that is greater than expected with normal aging and is a risk factor for dementia. Dementia is defined as a group of symptoms associated with a decline in memory or other thinking skills severe enough to reduce a person's ability to perform everyday activities.
"As doctors treating older patients, we are encouraged to finally have a proven intervention to lower someone's risk for MCI," said the study's principal investigator, Jeff Williamson, M.D., professor of gerontology and geriatric medicine at Wake Forest School of Medicine. "In the study, we found that just three years of lowering blood pressure not only dramatically helped the heart but also helped the brain."
The objective of SPRINT MIND was to evaluate the effect of intensive blood pressure control on risk of dementia. Hypertension, which affects more than half of people over age 50 and more than 75 percent of those older than 65, has been identified as a potentially modifiable risk factor for MCI and dementia in previous observational studies.
The clinical trial, which enrolled 9361 volunteers, was conducted at 102 sites in the United States and Puerto Rico among adults 50 and older with hypertension but without diabetes or history of stroke. The participating group was 35.6 percent female, 30 percent black and 10.5 percent Hispanic and thus representative of the broader U.S. population.
Participants were randomly assigned to a systolic blood pressure goal of either less than 120 mm HG (intensive treatment) or less than 140 mm HG (standard treatment). They were then classified after five years as having no cognitive impairment, MCI or probable dementia.
"Although the study showed a 15 percent reduction in dementia in the intensively controlled group, we were disappointed that the results did not achieve statistical significance for this outcome," Williamson said. "Last week the Alzheimer's Association agreed to fund additional follow-up of SPRINT MIND participants in the hope that sufficient dementia cases will accrue, allowing for a more definitive statement on these outcomes."
SPRINT was stopped early due to the success of the trial in reducing cardiovascular disease. As a result, participants were on intensive blood pressure lowering treatment for a shorter period than originally planned. The authors concluded that the shorter time may have made it difficult to accurately determine the role of intensive blood pressure control on dementia cases.
Williamson said some caution should be exercised in interpreting the study result both because MCI was not the primary cognitive focus of the trial and because it is not clear what intensive blood pressure control may mean for the longer-term incidence of dementia. Although MCI considerably increases the risk of dementia, this progression is not inevitable and reversion to normal cognition is possible, he said.
https://www.sciencedaily.com/releases/2019/01/190128111703.htm
Gut bacteria may control movement
Study suggests that bacteria may regulate neuronal circuits behind movement in flies
November 1, 2018
Science Daily/NIH/National Institute of Neurological Disorders and Stroke
A new study puts a fresh spin on what it means to 'go with your gut.' The findings suggest that gut bacteria may control movement in fruit flies and identify the neurons involved in this response.
"This study provides additional evidence for a connection between the gut and the brain, and in particular outlines how gut bacteria may influence behavior, including movement," said Margaret Sutherland, Ph.D., program director at NINDS.
Researchers led by Sarkis K. Mazmanian, Ph.D., professor of microbiology at the California Institute of Technology in Pasadena, and graduate student Catherine E. Schretter, observed that germ-free flies, which did not carry bacteria, were hyperactive. For instance, they walked faster, over greater distances, and took shorter rests than flies that had normal levels of microbes. Dr. Mazmanian and his team investigated ways in which gut bacteria may affect behavior in fruit flies.
"Locomotion is important for a number of activities such as mating and searching for food. It turns out that gut bacteria may be critical for fundamental behaviors in animals," said Dr. Mazmanian.
Fruit flies carry between five and 20 different species of bacteria and Dr. Mazmanian's team treated the germ-free animals with individual strains of those microbes. When the flies received Lactobacillus brevis, their movements slowed down to normal speed. L. brevis was one of only two species of bacteria that restored normal behavior in the germ-free flies.
Dr. Mazmanian's group also discovered that the molecule xylose isomerase (Xi), a protein that breaks down sugar and is found in L. brevis, may be critical to this process. Isolating the molecule and treating germ-free flies with it was sufficient to slow down the speedwalkers.
Additional experiments showed that Xi may regulate movement by fine-tuning levels of certain carbohydrates, such as trehalose, which is the main sugar found in flies and is similar to mammalian glucose. Flies that were given Xi had lower levels of trehalose than did untreated germ-free flies. When Xi-treated flies, which showed normal behavior, were given trehalose alone, they resumed fast movements suggesting that the sugar was able to reverse the effects of Xi.
Next, the researchers looked into the flies' nervous system to see what cells were involved in bacteria-directed movement. When Dr. Mazmanian's team turned on neurons that produce the chemical octopamine, that activation canceled out the effect of L. brevis on the germ-free flies. As a result, the flies, which had previously slowed down after receiving the bacterium or Xi, resumed their speedwalking behavior. Turning on octopamine-producing nerve cells in flies with normal levels of bacteria also caused them to move faster. However, activating neurons that produce other brain chemicals did not influence the flies' movements.
According to Dr. Mazmanian, Schretter and their colleagues, Xi may be monitoring the flies' metabolic state, including levels of nutrients, and then signaling to octopamine neurons whether they should turn on or off, resulting in changes in behavior.
Instead of octopamine, mammals produce a comparable chemical called noradrenaline, which has been shown to control movement.
"Gut bacteria may play a similar role in mammalian locomotion, and even in movement disorders such as Parkinson's disease," said Dr. Mazmanian.
More research is needed to see whether bacteria control movement in other species, including mammals. In addition, future studies will further investigate how Xi is involved in these behaviors.
https://www.sciencedaily.com/releases/2018/11/181101085302.htm
Inflammation can lead to circadian sleep disorders
Novel technology turns inflammation on and off, affecting body clock in mice
October 31, 2018
Science Daily/Northwestern University
Inflammation, which is the root cause of autoimmune disorders including arthritis, type 1 diabetes, irritable bowel syndrome and Crohn's disease, has unexpected effects on body clock function and can lead to sleep and shiftwork-type disorders, a new study in mice found.
The study was published in the journal Genes & Development.
The study used a new technology -- a genetic switch -- to turn inflammation on and off in genetically modified mouse models. When researchers deactivated inflammation, the mouse was unable to tell what time it was and was unable to keep an intact rest-activity cycle.
In addition to this new technology, the study was novel because, for the first time, scientists saw a link between what causes inflammation and what controls the body's clock.
In inflammatory diseases, the body experiences an excess of a genetic factor known as NF-kappa beta (NFKB), the study found. NFKB is a catalyst for a set of chain reactions, or pathway, that leads to the pain and tissue destruction patients feel in inflammatory diseases. That same chain-reaction catalyst also controls the body's clock.
"NFKB alters the core processor through which we tell time, and now we know that it is also critical in linking inflammation to rest-activity patterns," said senior author Dr. Joseph Bass, the Charles F. Kettering Professor of Medicine and director of the Center for Diabetes and Metabolism at Northwestern University Feinberg School of Medicine.
When people have sore muscles and take an ibuprofen to reduce the inflammation, they are essentially trying to turn down the activation of inflammation, which is similar to what the authors did in this study, Bass said.
The findings also have implications for diet and provide a detailed roadmap to understanding the fundamental mechanisms by which inflammation -- including the inflammation that occurs when someone chronically consumes a high-fat diet -- and likely other instigators lead to circadian disorders.
The scientists sought to understand how a high-fat diet might affect the perception of time at the tissue level, which is what led to their study of inflammation, said first author Hee-Kyung Hong, research assistant professor of endocrinology at Feinberg.
One of the reasons Western diet contributes to diabetes, cardiovascular disease and even certain cancers is thought to be the inappropriate trigger of inflammation, so a unifying idea is that impaired time-keeping may be one of the links between diet and disease.
"We don't know the reasons, but this interaction between the inflammation and clocks is not only relevant to understanding how inflammation affects the brain and sleep-wake cycle but also how immune or fat cells work," Hong said.
https://www.sciencedaily.com/releases/2018/10/181031124858.htm
Three types of depression identified
October 31, 2018
Science Daily/Okinawa Institute of Science and Technology (OIST) Graduate University
Scientists have used brain imaging to identify three sub-types of depression -- including one that is unresponsive to commonly prescribed serotonin boosting drugs.
According to the World Health Organization, nearly 300 million people worldwide suffer from depression and these rates are on the rise. Yet, doctors and scientists have a poor understanding of what causes this debilitating condition and for some who experience it, medicines don't help.
Scientists from the Neural Computational Unit at the Okinawa Institute of Science and Technology Graduate University (OIST), in collaboration with their colleagues at Nara Institute of Science and Technology and clinicians at Hiroshima University, have for the first time identified three sub-types of depression. They found that one out of these sub-types seems to be untreatable by Selective Serotonin Reuptake Inhibitors (SSRIs), the most commonly prescribed medicines for the condition. The study was published in the journal Scientific Reports.
Serotonin is a neurotransmitter that influences our moods, interactions with other people, sleep patterns and memory. SSRIs are thought to take effect by boosting the levels of serotonin in the brain. However, these drugs do not have the same effect on everyone, and in some people, depression does not improve even after taking them. "It has always been speculated that different types of depression exist, and they influence the effectiveness of the drug. But there has been no consensus," says Prof. Kenji Doya.
For the study, the scientists collected clinical, biological, and life history data from 134 individuals -- half of whom were newly diagnosed with depression and the other half who had no depression diagnosis- using questionnaires and blood tests. Participants were asked about their sleep patterns, whether or not they had stressful issues, or other mental health conditions.
Researchers also scanned participants' brains using magnetic resonance imaging (MRI) to map brain activity patterns in different regions. The technique they used allowed them to examine 78 regions covering the entire brain, to identify how its activities in different regions are correlated. "This is the first study to identify depression sub-types from life history and MRI data," says Prof. Doya.
With over 3000 measurable features, including whether or not participants had experienced trauma, the scientists were faced with the dilemma of finding a way to analyze such a large data set accurately. "The major challenge in this study was to develop a statistical tool that could extract relevant information for clustering similar subjects together," says Dr. Tomoki Tokuda, a statistician and the lead author of the study. He therefore designed a novel statistical method that would help detect multiple ways of data clustering and the features responsible for it. Using this method, the researchers identified a group of closely-placed data clusters, which consisted of measurable features essential for accessing mental health of an individual. Three out of the five data clusters were found to represent different sub-types of depression.
The three distinct sub-types of depression were characterized by two main factors: functional connectivity patterns synchronized between different regions of the brain and childhood trauma experience. They found that the brain's functional connectivity in regions that involved the angular gyrus -- a brain region associated with processing language and numbers, spatial cognition, attention, and other aspects of cognition -- played a large role in determining whether SSRIs were effective in treating depression.
Patients with increased functional connectivity between the brain's different regions who had also experienced childhood trauma had a sub-type of depression that is unresponsive to treatment by SSRIs drugs, the researchers found. On the other hand, the other two subtypes -- where the participants' brains did not show increased connectivity among its different regions or where participants had not experienced childhood trauma -- tended to respond positively to treatments using SSRIs drugs.
This study not only identifies sub-types of depression for the first time, but also identifies some underlying factors and points to the need to explore new treatment techniques. "It provides scientists studying neurobiological aspects of depression a promising direction in which to pursue their research," says Prof. Doya. In time, he and his research team hope that these results will help psychiatrists and therapists improve diagnoses and treat their patients more effectively.
https://www.sciencedaily.com/releases/2018/10/181031093337.htm
Lifespan and sexual maturity depend on your brain more than your body
'Brain Soup' research connects number of neurons to longevity
October 30, 2018
Science Daily/Vanderbilt University
New research finds how long humans and other warm-blooded animals live -- and when they reach sexual maturity -- may have more to do with their brain than their body. More specifically, it is not animals with larger bodies or slower metabolic rates that live longer; it is animals with more neurons in the cerebral cortex, whatever the size of the body.
"Whether you're looking at birds or primates or humans, the number of neurons that you find in the cortex of a species predicts around 75 percent of all of the variation in longevity across species," said study author associate professor of psychology and biological sciences Suzana Herculano-Houzel.
Body size and metabolism, in comparison, to usual standards for comparing animals, only predicted between 20-30 percent of longevity depending on species, and left many inconsistencies, like birds that live ten times longer than mammals of same size.
Most importantly, humans were considered to be a "special" evolutionary oddity, with long childhood and postmenopausal periods. But this research, published in the Journal of Comparative Neurology, finds that's not accurate. Humans take just as long to mature as expected of their number of cortical neurons -- and live just as long as expected thereafter.
THE STUDY
In the study, Herculano-Houzel examined more than 700 warm-blooded animal species from the AnAge database which collects comprehensive longevity records. She then compared these records with her extensive data on the number of neurons in the brains of different species of animals.
Herculano-Houzel color-coded the data for hundreds of species and found that parrots and songbirds, including corvids, live systematically longer than primates of similar body mass, which in turn live longer than non-primate mammals of similar body mass.
"Likewise, for similar specific basal metabolic rates, parrots and songbirds live longer and take longer to reach sexual maturity than many mammalian species, especially non-primates," said Herculano-Houzel.
She had seen that pattern before: her previous studies determining what brains are made of showed that parrots and songbirds have more cortical neurons than similar-sized primates, which have more cortical neurons than any other mammal of comparable body size.
Her new analysis confirmed her suspicion: that longevity increases uniformly across warm-blooded species together with the absolute number of neurons in the cerebral cortex.
"The more cortical neurons a species has, the longer it lives -- doesn't matter if it is a bird, a primate or some other mammal, how large it is, and how fast it burns energy," says Herculano-Houzel.
ARE HUMANS UNIQUE? ASK GRANDMA
Anthropologists and researchers interested in evolution and human behavior have been working under the assumption that one of the ways the human species is unique is that humans have an uncommonly long childhood and adolescent period to allow for learning and social interactions. If larger animals live longer, then gorillas should live longer than humans -- but they don't: humans outlive them. One favored hypothesis is that being cared for by grandmothers could have led humans to delayed sexual maturity and increased postmenopausal longevity beyond the expected.
But Herculano-Houzel's new data show that humans are not an exception from other mammalian species. Given the number of neurons in our cortex, humans take as long as they should to reach sexual maturity -- and live just as long as expected for their number of neurons. Body size, it turns out, is irrelevant in matters of longevity.
"Now we can say that humans spend just as long in childhood and live exactly as long after reaching maturity as you would expect for the number of neurons in our cerebral cortex," said Herculano-Houzel.
Which is longer, compared to other species -- gorillas included -simply because humans have the most neurons in the cerebral cortex.
"It makes sense that the more neurons you have in the cortex, the longer it should take a species to reach that point where it's not only physiologically mature, but also mentally capable of being independent," says Herculano-Houzel. "The delay also gives those species with more cortical neurons more time to learn from experience, as they interact with the environment."
And if longer lives also accompany more cortical neurons, those species will also enjoy a greater overlap between generations, and so more opportunities to pass along what they learned.
"Which means that grandma is still fundamental in the lives of those with plenty of cortical neurons; she's just probably not the reason why our species is long-lived," argues Herculano-Houzel.
FUNCTION OF THE CORTEX
What is the link between having more neurons in the cortex and living longer lives? Herculano-Houzel says that's the new big question researchers need to tackle.
"The data suggest that warm-blooded species accumulate damages at the same rate as they age. But what curtails life are damages to the cerebral cortex, not the rest of the body; the more cortical neurons you have, the longer you will still have enough to keep your body functional," she says.
Contrary to the rest of the body, which gets new cells that replenish old ones, cortical neurons are thought to have to last a lifetime.
While the cortex is usually associated with cognition, Herculano-Houzel believes a much more basic function of the cortex is key to longevity.
"The cortex is the part of your brain that is capable of making our behavior complex and flexible, yes, but that extends well beyond cognition and doing mental math and logic reasoning," said Herculano-Houzel. "The cerebral cortex also gives your body adaptability, as it adjusts and learns how to react to stresses and predict them. That includes keeping your physiological functions running smoothly and making sure your heart rate, your respiratory rate, and your metabolism are on track with what you're doing, with how you feel, and with what you expect to happen next. And that, apparently, is a key factor that impacts longevity," she adds.
BRAIN SOUP
Herculano-Houzel pioneered the method for rapidly and accurately measuring the number of neurons in brains. She creates "brain soup" by taking brain tissue and breaking down the cells, then applying fluorescent tags to the nuclei floating in the "brain soup" and counting them.
In collaboration with Vanderbilt Distinguished Professor of Psychology Jon Kaas, she studied how many neurons compose different primate brains, including great apes. With colleagues in Brazil, she produced the first accurate count of the number of neurons in the human brain -- an average 86 billion, which makes it simply an enlarged primate brain.
TAKE CARE OF YOUR BRAIN!
Aging starts once humans and other species reach adolescence, and there's no way to gain back neurons. In fact, research shows humans can lose neurons in the prefrontal cortex. So Herculano-Houzel says taking good care of your mind, and keeping those cortical neurons healthy and busy, is the best bet to live long and well.
https://www.sciencedaily.com/releases/2018/10/181030150718.htm
Air pollution and noise increase risk for heart attacks
October 24, 2018
Science Daily/Swiss Tropical and Public Health Institute
Air pollution and transportation noise are both associated with an increased risk of heart attacks. Studies on air pollution, which do not take into account traffic noise, tend to overestimate the long-term effect of air pollution on heart attacks.
Where air pollution is high, the level of transportation noise is usually also elevated. Not only air pollution negatively impacts on health, but also car, train and aircraft noise increases the risk for cardiovascular diseases and diabetes, as previous research has demonstrated. Studies investigating the effect of air pollution without sufficiently taking into account the impact that noise exhibits on health, might overestimate the effect of air pollution. These are the results of a comprehensive study conducted by the Swiss Tropical and Public Health Institute (Swiss TPH), which was published today in the peer-reviewed European Heart Journal.
The study looked at the combined effects of air pollution and transportation noise for heart attack mortality, by considering all deaths that occurred in Switzerland between 2000 and 2008. Analyses that only included fine particulates (PM2.5) suggest that the risk for a heart attack rises by 5.2% per 10 ?g/m³ increase in the long-term concentration at home. Studies which also account for road, railway and aircraft noise reveal that the risk for a heart attack attributable to fine particulates in fact increases considerably less; 1.9% per 10 ?g/m³ increase. These findings indicate that the negative effects of air pollution may have been overestimated in studies which fail to concurrently consider noise exposure.
"Our study showed that transportation noise increases the risk for a heart attack by 2.0 to 3.4% per 10 decibels increase in the average sound pressure level at home." said Martin Röösli, Head of the Environmental Exposures and Health Unit at Swiss TPH, and lead author of the published research. "Strikingly, the effects of noise were independent from air pollution exposure."
Effect of noise and air pollution are additive
The study also found that people exposed to both air pollution and noise are at highest risk of heart attack. Hence, the effects of air pollution and noise are additive. "Public discussions often focus on the negative health effects of either air pollution or noise but do not consider the combined impact." said Röösli. "Our research suggests that both exposures must be considered at the same time." This has implications for both policy as well as future research. Hence, Röösli and co-researchers recommend including transportation noise exposure in any further research related to air pollution and health to avoid overestimating the negative effects of air pollution on the cardiovascular system.
Data from across Switzerland
The study included all deaths (19,261) reported across Switzerland from the period 2000 to 2008. The air pollution (PM2.5) was modelled using satellite and geographic data, calibrated with air pollution measurements from 99 measurement sites throughout Switzerland. Nitrogen dioxides (NO2) were also modelled using 9,469 biweekly passive sampling measurements collected between 2000 and 2008 at 1,834 locations in Switzerland. Transportation noise was modelled by well-established noise propagation models (sonRoad, sonRAIL and FLULA 2) by Empa and n-sphere. The air pollution and the transportation noise models were applied for each address of the 4.4 million Swiss adult citizen (aged 30 years and above).
https://www.sciencedaily.com/releases/2018/10/181024112244.htm
Brain wave device enhances memory function
October 22, 2018
Science Daily/University of California - Davis
The entrainment of theta brain waves with a commercially available device not only enhances theta wave activity, but also boosts memory performance, according to new research.
Electrical activity in the brain causes different types of brain waves that can be measured on the outside of the head. Theta waves occur at about five to six cycles per second, often associated with a brain that is actively monitoring something -- such as the brain of a rat navigating a maze.
In an earlier study, Charan Ranganath, professor of psychology, and colleagues at the Center for Neuroscience found that high levels of theta wave activity immediately before a memory task predicted better performance.
"Entrainment" devices use a combination of sound and lights to stimulate brain wave activity. The idea is that oscillating patterns in sensory inputs will be reflected in brain activity. The devices are marketed to address a range of problems such as anxiety, sleep issues, "low mood" and learning. However, there is very little published scientific evidence to support these claims.
Brooke Roberts, a postdoctoral researcher in Ranganath's lab, obtained a theta wave entrainment device and decided to test it. She had 50 volunteers either use the device for 36 minutes, or listen to 36 minutes of white noise, then do a simple memory test.
Improved memory performance
The subjects who had used the device showed both improved memory performance and enhanced theta wave activity, she found.
Roberts showed her results to Ranganath, who was intrigued but cautious and suggested new controls. They repeated the experiment with another 40 volunteers, but this time the control group received beta wave stimulations. Beta waves are a different type of brain wave pattern, occurring at about 12 to 30 cycles per second, associated with normal waking consciousness.
Once again, theta wave entrainment enhanced theta wave activity and memory performance.
Ranganath's lab also conducted a separate study using electrical stimulation to enhance theta waves. However, this actually had the opposite effect, disrupting theta wave activity, and temporarily weakened memory function.
Ranganath said he's surprised the devices work as well as they appear to do.
"What's surprising is that the device had a lasting effect on theta activity and memory performance for over half an hour after it was switched off," he said.
There is debate among neuroscientists over the function and role of these brain waves. Some researchers argue that they are simply a product of normal brain function with no particular role. Ranganath, however, thinks that they may play a role in coordinating brain regions.
"The neurons are more excitable at the peak of the wave, so when the waves of two brain regions are in sync with each other, they can talk to each other," he said.
Other authors on the paper are Alex Clarke, now at the University of Cambridge and Anglia Ruskin University, U.K.; and Richard Addante, now at California State University San Bernardino. Roberts is now a research scientist at QUASAR Inc., San Diego. The work was supported by a Guggenheim Fellowship and a Vannevar Bush Fellowship from the Office of Naval Research.
https://www.sciencedaily.com/releases/2018/10/181022172959.htm
The smell of lavender is relaxing
October 23, 2018
Science Daily/Frontiers
A new review reveals how lavender mellows us out -- and why some day psychiatrists and surgeons might be prescribing patients a whiff of the purple stuff.
Research published in Frontiers in Behavioral Neuroscience shows for the first time that the vaporized lavender compound linalool must be smelt -- not absorbed in the lungs- to exert its calming effects, which could be used to relieve preoperative stress and anxiety disorders.
Soothing scents
"In folk medicine, it has long been believed that odorous compounds derived from plant extracts can relieve anxiety," says co-author Dr Hideki Kashiwadani of Kagoshima University, Japan.
Modern medicine has overlooked these scented settlers, despite a need for safer alternatives to current anxiolytic (anxiety-relieving) drugs like benzodiazepines.
Numerous studies now confirm the potent relaxing effects of linalool, a fragrant alcohol found in lavender extracts.
"However, the sites of action of linalool were usually not addressed in these studies," Kashiwadani points out.
Many assumed that absorption into bloodstream via the airway led to direct effects on brain cell receptors such as GABAARs -- also the target of benzodiazepines. But establishing the true mechanism of linalool's relaxing effects is a key step in moving towards clinical use in humans.
A nose for success
Kashiwadani and colleagues tested mice to see whether it is the smell of linalool -- i.e. stimulation of olfactory (odor-sensitive) neurons in the nose -- that triggers relaxation.
"We observed the behavior of mice exposed to linalool vapor, to determine its anxiolytic effects. As in previous studies, we found that linalool odor has an anxiolytic effect in normal mice. Notably, this did not impair their movement." This contrasts with benzodiazepines, and linalool injections, whose effects on movement are similar to those of alcohol.
However, crucially there was no anxiolytic effect in anosmic mice -- whose olfactory neurons have been destroyed -- indicating that the relaxation in normal mice was triggered by olfactory signals evoked by linalool odor.
What's more, the anxiolytic effect in normal mice disappeared when they were pretreated with flumazenil, which blocks benzodiazepine-responsive GABAA receptors.
"When combined, these results suggest that linalool does not act directly on GABAA receptors like benzodiazepines do -- but must activate them via olfactory neurons in the nose in order to produce its relaxing effects," explains Kashiwadani.
Coming to theaters near you
"Our study also opens the possibility that relaxation seen in mice fed or injected with linalool could in fact be due to the smell of the compound emitted in their exhaled breath."
Similar studies are therefore needed to establish the targets, safety and efficacy of linalool administered via different routes, before a move to human trials.
"These findings nonetheless bring us closer to clinical use of linalool to relieve anxiety -- in surgery for example, where pretreatment with anxiolytics can alleviate preoperative stress and thus help to place patients under general anesthesia more smoothly. Vaporized linalool could also provide a safe alternative for patients who have difficulties with oral or suppository administration of anxiolytics, such as infants or confused elders."
https://www.sciencedaily.com/releases/2018/10/181023085648.htm
Eating leafy greens could help prevent macular degeneration
October 19, 2018
Science Daily/Westmead Institute for Medical Research
A new study has shown that eating vegetable nitrates, found mainly in green leafy vegetables and beetroot, could help reduce your risk of developing early-stage age-related macular degeneration (AMD).
Researchers at the Westmead Institute for Medical Research interviewed more than 2,000 Australian adults aged over 49 and followed them over a 15-year period.
The research showed that people who ate between 100 to 142 mgs of vegetable nitrates each day had a 35% lower risk of developing early AMD than people who ate less than 69mgs of vegetable nitrates each day.
Lead Researcher Associate Professor Bamini Gopinath from the Westmead Institute and the University of Sydney said the link between vegetable nitrates and macular degeneration could have important implications.
"This is the first time the effects of dietary nitrates on macular degeneration risk has been measured.
"Essentially we found that people who ate 100 to 142 mgs of vegetable nitrates every day had a reduced risk of developing early signs of macular degeneration compared with people who ate fewer nitrates.
"If our findings are confirmed, incorporating a range of foods rich in dietary nitrates -- like green leafy vegetables and beetroot -- could be a simple strategy to reduce the risk of early macular degeneration," Associate Professor Gopinath said.
Spinach has approximately 20mg of nitrate per 100g, while beetroot has nearly 15mg of nitrate per 100g.
The research did not show any additional benefits for people who exceeded 142mgs of dietary nitrate each day. It also did not show any significant connections between vegetable nitrates and late stage AMD, or between non-vegetable nitrates and AMD risk.
One in seven Australians over 50 have some signs of macular degeneration.
Age is the strongest known risk factor and the disease is more likely to occur after the age of 50.
There is currently no cure for the disease.
The research compiled data from the Blue Mountains Eye Study, a benchmark population-based study that started in 1992.
It is one of the world's largest epidemiology studies, measuring diet and lifestyle factors against health outcomes and a range of chronic diseases.
"Our research aims to understand why eye diseases occur, as well as the genetic and environmental conditions that may threaten vision," Associate Professor Gopinath concluded.
https://www.sciencedaily.com/releases/2018/10/181019100558.htm
People who commute through natural environments daily report better mental health
This association is even stronger among active commuters
October 18, 2018
Science Daily/Barcelona Institute for Global Health (ISGlobal)
People who commute through natural environments report better mental health. This is the main conclusion of a research based on questionnaires answered by nearly 3,600 participants from four European cities.
According to a new study led by the Barcelona Institute for Global Health (ISGlobal) -- a centre supported by the "la Caixa" Foundation -- , people who commute through natural environments report better mental health. This is the main conclusion of a research based on questionnaires answered by nearly 3,600 participants from four European cities and published in Environment International.
The study was conducted within the Positive Health Effects of the Natural Outdoor Environment in Typical Populations in Different Regions in Europe project (PHENOTYPE). The 3,599 participants from Barcelona (Spain), Doetinchem (the Netherlands), Kaunas (Lithuania) and Stoke-on-Trent (UK) answered a questionnaire about their commuting habits and their mental health. The statistical analysis showed that respondents commuting through natural environments on a daily basis had on average a 2.74 point higher mental health score compared to those who commuted through natural environments less frequently. This association was even stronger among people who reported active commuting (i.e. walking or cycling). In this case, natural environments were defined as all public and private outdoor spaces that contain 'green' and/or 'blue' natural elements such as street trees, forests, city parks and natural parks/reserves, and also included all types of waterbodies.
Other results showed that there were more active commuters among those who declared commuting through natural environments daily. However, the quality of the natural environments in which commuting took place did not influence the results.
"From previous experimental studies we knew that physical activity in natural environments can reduce stress, improve mood and mental restoration when compared to the equivalent activity in urban environments. Although this study is the first of its kind to our knowledge and, therefore, more research will be needed, our data show that commuting through these natural spaces alone may also have a positive effect on mental health," says Wilma Zijlema, ISGlobal researcher and first author of the study.
"Mental health and physical inactivity are two of the main public health problems associated with the life in urban environments. Urban design could be a powerful tool to confront these challenges and create healthier cities. One way of doing so would be investing in natural commuting routes for cycling and walking," states Mark Nieuwenhuijsen, coordinator of the ISGlobal Initiative of Urban Planning, Environment and Health and last author of the study.
https://www.sciencedaily.com/releases/2018/10/181018095349.htm
World's largest sleep study shows too much shut-eye can be bad for your brain
October 9, 2018
Science Daily/University of Western Ontario
Preliminary results from the world's largest sleep study have shown that people who sleep on average between 7 to 8 hours per night performed better cognitively than those who slept less, or more, than this amount.
Neuroscientists from Western University's Brain and Mind Institute released their findings today in the high-impact journal, SLEEP.
The world's largest sleep study was launched in June 2017 and within days more than 40,000 people from around the world participated in the online scientific investigation, which includes an in-depth questionnaire and a series of cognitive performance activities.
"We really wanted to capture the sleeping habits of people around the entire globe. Obviously, there have been many smaller sleep studies of people in laboratories but we wanted to find out what sleep is like in the real world," says Adrian Owen, Western's superstar researcher in Cognitive Neuroscience and Imaging. "People who logged in gave us a lot of information about themselves. We had a fairly extensive questionnaire and they told us things like which medications they were on, how old they were, where they were in the world and what kind of education they'd received because these are all factors that might have contributed to some of the results."
Approximately half of all participants reported typically sleeping less than 6.3 hours per night, about an hour less than the study's recommended amount. One startling revelation was that most participants who slept four hours or less performed as if they were almost nine years older.
Another surprising discovery was that sleep affected all adults equally. The amount of sleep associated with highly functional cognitive behaviour was the same for everyone (7 to 8 hours), regardless of age. Also, the impairment associated with too little, or too much, sleep did not depend on the age of the participants.
"We found that the optimum amount of sleep to keep your brain performing its best is 7 to 8 hours every night and that corresponds to what the doctors will tell you need to keep your body in tip-top shape, as well. We also found that people that slept more than that amount were equally impaired as those who slept too little," says Conor Wild, Owen Lab Research Associate and the study's lead author.
Participants' reasoning and verbal abilities were two of the actions most strongly affected by sleep while short-term memory performance was relatively unaffected. This is different than findings in most scientific studies of complete sleep deprivation and suggests that not getting enough sleep for an extended period affects your brain differently than staying up all night.
On the positive side, there was some evidence that even a single night's sleep can affect a person's ability to think. Participants who slept more than usual the night before participating in the study performed better than those who slept their usual amount or less.
https://www.sciencedaily.com/releases/2018/10/181009135845.htm
Day-time naps help us acquire information not consciously perceived
'I'll sleep on it' proves scientifically sound advice
October 4, 2018
Science Daily/University of Bristol
The age-old adage 'I'll sleep on it' has proven to be scientifically sound advice, according to a new study which measured changes in people's brain activity and responses before and after a nap. The findings support the advice which suggests that a period of sleep may help weighing up pros and cons or gain insight before making a challenging decision.
The Medical Research Council-funded study, led by University of Bristol researchers, aimed to understand whether a short period of sleep can help us process unconscious information and how this might affect behaviour and reaction time.
The findings further reveal the benefits of a short bout of sleep on cognitive brain function and found that even during short bouts of sleep we process information that we are not consciously aware of.
While previous evidence demonstrates that sleep helps problem solving, resulting in enhanced cognition upon awaking; it was not clear whether some form of conscious mental process was required before or during sleep to aid problem solving. In this study, researchers hid information by presenting it very briefly and "masking" it -- so it was never consciously perceived -- the masked prime task. The hidden information, however, was processed at a subliminal level within the brain and the extent to which it interferes with responses to consciously perceived information was measured.
Sixteen healthy participants across a range of ages were recruited to take part in an experiment. Participants carried out two tasks -- the masked prime task and a control task where participants simply responded when they saw a red or blue square on a screen. Participants practiced the tasks and then either stayed awake or took a 90-minute nap before doing the tasks again.
Using an EEG, which records the electrical activity naturally produced in the brain, researchers measured the change in brain activity and response pre-and-post nap.
Sleep (but not wake) improved processing speed in the masked prime task -- but not in the control task -- suggesting sleep-specific improvements in processing of subconsciously presented primes.
The findings suggest that even a short bout of sleep may help improve our responses and process information. Therefore, the results here suggest a potentially sleep-dependent, task-specific enhancement of brain processing that could optimise human goal-directed behaviour.
Importantly, while it is already known that the process of acquiring knowledge and information recall, memory, is strengthened during sleep. This study suggests that information acquired during wakefulness may potentially be processed in some deeper, qualitative way during sleep
Dr LizCoulthard, Consultant Senior Lecturer in Dementia Neurology at the University of Bristol Medical School: Translational Health Sciences, said: "The findings are remarkable in that they can occur in the absence of initial intentional, conscious awareness, by processing of implicitly presented cues beneath participants' conscious awareness.
"Further research in a larger sample size is needed to compare if and how the findings differ between ages, and investigation of underlying neural mechanisms."
https://www.sciencedaily.com/releases/2018/10/181004095929.htm