Why do arteries age? Study explores link to gut bacteria, diet
July 1, 2020
Science Daily/University of Colorado at Boulder
Eat a slab of steak and your resident gut bacteria get to work immediately to break it down. But new research shows that a metabolic byproduct, called TMAO, produced in the process can be harmful to the lining of arteries, making them age faster.
A compound produced in the gut when we eat red meat damages our arteries and may play a key role in boosting risk of heart disease as we get older, according to new University of Colorado Boulder research.
The study, published this month in the American Heart Association journal Hypertension, also suggests that people may be able to prevent or even reverse such age-related decline via dietary changes and targeted therapies, like novel nutritional supplements.
"Our work shows for the first time that not only is this compound directly impairing artery function, it may also help explain the damage to the cardiovascular system that naturally occurs with age," said first author Vienna Brunt, a postdoctoral researcher in the Department of Integrative Physiology.
Eat a slab of steak or a plate of scrambled eggs, and your resident gut bacteria get to work immediately to break it down. As they metabolize the amino acids L-carnitine and choline, they churn out a metabolic byproduct called trimethylamine, which the liver converts to trimethylamine-N-Oxide (TMAO) and sends coursing through your bloodstream.
Previous studies have shown that people with higher blood levels of TMAO are more than twice as likely to have a heart attack or stroke and tend to die earlier.
But to date, scientists haven't completely understood why.
Drawing on animal and human experiments, Brunt and her team set out to answer three questions: Does TMAO somehow damage our vascular system? If so, how? And could it be one reason why cardiovascular health gets worse -- even among people who exercise and don't smoke -- as we get older?
The researchers measured the blood and arterial health of 101 older adults and 22 young adults and found that TMAO levels significantly rise with age. (This falls in line with a previous study in mice, showing the gut microbiome -- or your collection of intestinal bacteria -- changes with age, breeding more bacteria that help produce TMAO).
Adults with higher blood levels of TMAO had significantly worse artery function, the new study found, and showed greater signs of oxidative stress, or tissue damage, in the lining of their blood vessels.
When the researchers fed TMAO directly to young mice, their blood vessels swiftly aged.
"Just putting it in their diet made them look like old mice," said Brunt. She noted that 12-month-old mice (the equivalent of humans about 35 years old) looked more like 27-month-old mice (age 80 in people) after eating TMAO for several months.
Preliminary data also show that mice with higher levels of TMAO exhibit decreases in learning and memory, suggesting the compound could also play a role in age-related cognitive decline.
On the flip side, old mice that ate a compound called dimethyl butanol, (found in trace amounts in olive oil, vinegar and red wine) saw their vascular dysfunction reverse. Scientists believe that this compound prevents the production of TMAO.
Brunt notes that everyone -- even a young vegan -- produces some TMAO. But over time, eating a lot of animal products may take a toll.
"The more red meat you eat, the more you are feeding those bacteria that produce it," she said.
Senior author Doug Seals, director of the Integrative Physiology of Aging Laboratory, said the study is an important breakthrough because it sheds light on why our arteries erode with age, even in the healthiest people.
"Aging is the single greatest risk factor for cardiovascular disease, primarily as a result of oxidative stress to our arteries," said Seals. "But what causes oxidative stress to develop in our arteries as we age? That has been the big unkown. This study identifies what could be a very important driver."
The research team is now further exploring compounds that might block production of TMAO to prevent age-related vascular decline.
For now, they said, a plant-based diet may also keep levels in check.
https://www.sciencedaily.com/releases/2020/07/200701100019.htm
Changes in the immune system can promote healthy aging
July 10, 2020
Science Daily/Max-Planck-Gesellschaft
As we age, the immune system gradually becomes impaired. One aspect of this impairment is chronic inflammation in the elderly, which means that the immune system is constantly active and sends out inflammatory substances. Such chronic inflammation is associated with multiple age-related diseases including arthritis and Alzheimer's disease, and impaired immune responses to infection. One of the questions in ageing research is whether chronic inflammation is a cause of ageing, or a consequence of the ageing process itself? Scientists in the laboratory of Director Adam Antebi at the Max Planck Institute for Biology of Ageing in Cologne, Germany have found evidence suggesting that increased inflammation causes the ageing process to speed up, and that there is a fine balance between maintaining immune system function and longevity.
From their work in the tiny roundworm, Caenorhabditis elegans, the scientists discovered a change in an evolutionarily conserved gene called PUF60, which made the worms long lived but at the same time dampened the immune response. Worms with this change lived about 20% longer than normal worms, but when they were infected with certain bacteria, they succumbed more quickly to the infection. This means that an overactive immune system also has a price: it shortens life span. Conversely, a less active immune system pays off as longer life span -- as long as the animal does not die from an infection.
How does PUF60 regulate this fine balance between a maintained immune system and longevity? PUF60 works as a so-called "splicing factor," and is involved in the removal (or "splicing out") of segments in the ribonucleic acid, RNA. This process is essential to generate functional proteins.
The scientists found that the genetically changed PUF60 perturbs this process and alters the regulation of other genes that are involved in immune functions. "We're excited by this finding because it implicates a very fundamental process in the cell to immunity," says Adam Antebi. "These observations of course raise further questions. Notably pinpointing how PUF60 activity affects immunity and longevity, and how these two processes are balanced will be central to understanding the relationship between inflammation and ageing."
https://www.sciencedaily.com/releases/2020/07/200710121810.htm
Among older adults, statin use tied to decreased risk of early death
July 7, 2020
Science Daily/Brigham and Women's Hospital
Study after study has shown that statins can prevent heart attacks, strokes and death in middle-aged adults. But in 28 major clinical trials of statins, only 2 percent of participants have been 75 years or older. This means that even though older adults are at greater risk of heart disease and death, there is scant data on whether statins should be prescribed for them. A new study led by investigators from Brigham and Women's Hospital and VA Boston Healthcare System leverages national data from the U.S. Veterans Health Administration Services and Centers for Medicare & Medicaid Services to shed new light on the role statins may play for older adults who have not yet experienced a heart attack, stroke or other cardiovascular event. In their retrospective analysis, the researchers found that the risk of dying from any cause was lower by 25 percent among veterans who were using statins compared to those who were not treated with statins. The risk of dying from a cardiovascular event, such as a heart attack or stroke, was lower by 20 percent. The team's results are published in JAMA.
"Based on these data, age is not a reason to not prescribe statins," said lead and corresponding author Ariela Orkaby, MD, MPH, a physician scientist at VA Boston Health Care System and in the Division of Aging at the Brigham . "Statins are commonly studied and prescribed for middle-aged adults but understudied in people over age 75. One of the most remarkable things about our results is that we found the benefit of statins held true regardless of whether a person was older or younger or had a condition such as dementia."
Orkaby and colleagues looked at data on veterans who used VA services between 2002 and 2012, were 75 years or older, and had not previously had a heart attack, stroke or other cardiovascular event. Of the more than 300,000 eligible veterans, the team identified more than 57,000 who began taking statins during this time. Using propensity scoring, the authors compared individuals who began taking statins to those who had the same likelihood of being prescribed a statin based on clinical characteristics but did not receive a prescription for the drug.
Overall, taking statins was significantly associated with lower risk of death from a cardiovascular event or death from any cause. And the benefits remained for veterans at advanced age, including those who were 90 years or older. Lower death rates extended to those with other conditions such as dementia -- individuals who have been excluded from previous studies. In secondary analyses, the team found that starting a statin was also significantly associated with a lower risk of cardiovascular events such as heart attacks and strokes. Orkaby notes that it was particularly intriguing to see a marked decline in rate of strokes among the study's black participants.
"There are many interesting leads to follow up on," said Orkaby, "but it's important to keep in mind that this is not a randomized, clinical trial. Instead, it's a retrospective analysis using real world data that helps us explore where the truth lies."
The study focused only on veterans, a predominantly white and male population, which may limit its generalizability, but the study's size made it possible to glean statistically meaningful information on underrepresented groups. During the study's timeframe, the most commonly prescribed statin was simvastatin, but currently, higher-dose and higher-intensity statins have become more frequently prescribed. While statins are generally well tolerated, many people report aches and pains as a side effect, which may lead some to stop taking the drug. The current study did not evaluate whether patients discontinued statin use.
Two randomized, clinical trials of statins among older adults are now underway with results from one of the studies expected later this year. Orkaby and colleagues plan to follow up on their study by exploring the effects of statin dosing and examining outcomes for sub-populations included in their analysis.
https://www.sciencedaily.com/releases/2020/07/200707113222.htm
Disrupted circadian rhythms linked to later Parkinson's diagnoses
Researchers probe brain's 24-hour biological clock for neurodegenerative risks
June 15, 2020
Science Daily/University of California - San Francisco
Older men who have a weak or irregular circadian rhythm guiding their daily cycles of rest and activity are more likely to later develop Parkinson's disease, according to a new study by scientists at the UC San Francisco Weill Institute for Neurosciences who analyzed 11 years of data for nearly 3,000 independently living older men.
The scientists said their discovery of the link between circadian rhythms and Parkinson's -- a disease characterized by loss of control over movement, balance and other brain functions -- suggests these circadian disruptions may reflect neurodegenerative disease processes already affecting the brain's internal clock well before a Parkinson's diagnosis, and that they could be considered an early warning sign of the disease.
"The strength of the circadian rhythm activity seems to have a really important effect on health and disease, particularly in aging. In this latest study we found that even small changes in circadian rhythm in older men were associated with a greater likelihood of getting Parkinson's down the line," said study senior author Kristine Yaffe, MD, the Roy and Marie Scola Endowed Chair and vice chair of the Department of Psychiatry at UCSF, a professor of psychiatry, neurology, and epidemiology and biostatistics, and a member of the UCSF Memory and Aging Center.
The results -- published June 15, 2020 in JAMA Neurology -- merit follow-up, according to the study authors, to investigate whether physiological changes set off by disruptions in circadian rhythms might themselves be a trigger for neurodegeneration, and whether strengthening these rhythms could lower risk for developing Parkinson's.
Parkinson's is the second most common neurodegenerative disorder after Alzheimer's disease. 500,000 individuals in the United States have been diagnosed with Parkinson's disease, and many with the disease are undiagnosed, according to the National Institute of Neurological Disorders and Stroke. Most who have Parkinson's are diagnosed after age 60. There are no drugs known to prevent the disease, but there are a growing number of treatments to relieve symptoms.
Among older adults, weakened or irregular circadian rhythms of rest and activity are common, according to study lead author Yue Leng, MD, PhD, an assistant professor of psychiatry at UCSF. Other conditions -- constipation or deficits in the sense of smell -- have also been associated with increased likelihood of developing Parkinson's later on.
"Parkinson's is a disease that probably takes decades to develop, and apart from changes in movement, earlier signs might be critical in understanding the disease and its mechanisms," Leng said. "This is the first large, long-term study to find that disrupted circadian rhythms might be linked to Parkinson's that emerges years later."
The study, which enrolled 2,930 men with an average age of 76.3 when the research began, was part of the larger, population-based Osteoporotic Fractures in Men Study (MRoS), which began in 2000 and enrolled men at six medical centers nationwide. None of the participants in the subset of the MRoS cohort initially had Parkinson's, and all were living in community-based settings (i.e. not in nursing homes). Their status for many health-related factors was assessed at the start, and they were monitored through follow-up visits and questionnaires.
As part of the study, researchers monitored circadian rhythms of rest and activity over three separate 24-hour periods by having participants wear an actigraph -- a watch-like device that detects and records even slight wrist movements. The data collected from these devices were independently associated with the later development of Parkinson's.
In a previous study, Leng and Yaffe identified an association between daytime napping and the later development of Parkinson's. But the link between circadian rhythms and Parkinson's is not just a matter or disrupted sleep, according to the new study. The association held true even after accounting for indicators of sleep disturbances -- including loss of sleep; sleep inefficiency (time spent asleep after turning off the lights); leg movement during sleep; and the chronic, temporary cessation of breathing known as sleep apnea.
In drawing this conclusion, the researchers took into account numerous other variables collected as part of the MRoS study, including regional differences in study sites and participant demographics, education, baseline cognitive performance, chronic diseases, physical activity, symptoms of depression, body mass index, smoking, and use of benzodiazepines, alcohol, and caffeine.
Leng and Yaffe evaluated four parameters of participants' rest-activity rhythms as measured by actigraph: amplitude, the difference between the period of greatest to least activity; mesor, the average activity; robustness, how well the measured cyclical rest-activity matched a regular curve similar to a cosine wave; and acrophase, a measure of advance or delay in the 24-hour cycle relative to the population average.
During follow-up, 78 of the 2,930 study participants were diagnosed with Parkinson's. Those who scored lowest in actigraph amplitude, mesor or robustness had triple the risk of developing Parkinson's compared to those who scored highest. The researchers did not find an association between acrophase and Parkinson's risk.
Animal models of Parkinson's have shown that cells controlling the brain's circadian rhythm pacemaker often begin to degenerate even before cells in the part of the brain that are traditionally associated with Parkinson's symptoms, suggesting that weakening of circadian rhythm may in some cases represent an early stage of disease.
Leng also does not rule out the possibility that disruptions in circadian rhythm, already known to cause metabolic changes and inflammation, might themselves contribute to neurodegenerative disease. Leng hopes to investigate whether weakened circadian rhythms trigger inflammation or the abnormal accumulation of proteins seen in affected brain tissue in both Parkinson's and Alzheimer's.
"These neurodegenerative diseases are not reversible," she said. "But if research points to sleep or circadian problems being risk factors for neurodegeneration prior to traditional symptoms, then we may be able to use that information for early detection and diagnosis, or we might be able to intervene in ways that prevent development of neurodegenerative loss of function."
https://www.sciencedaily.com/releases/2020/06/200615142802.htm
Cognition and gait speed often decline together
Mexican Americans at higher risk
May 5, 2020
Science Daily/University of Texas Health Science Center at San Antonio
Measures of cognition and gait speed largely paralleled each other in a San Antonio study of 370 participants that included 9½ years of follow-up. One-fifth of participants were classified into a cognitive and physical vulnerability group. Mexican American participants were almost four times more likely than European Americans to be in the cognitive and physical vulnerability group.
Do thinking and walking go hand in hand in determining the health course of senior adults? A study published by UT Health San Antonio researchers found that, indeed, the two functions often parallel each other in determining a person's health trajectory.
The researchers analyzed data from 370 participants in the San Antonio Longitudinal Study of Aging (SALSA) and found that they grouped into three distinct trajectories. These classifications were based on the participants' changes on a cognitive measure and a gait speed task over an average of 9½ years:
Stable cognition and gait class (65.4% of the participants).
Cognitive and physical vulnerability class (22.2%).
Physical vulnerability class (12.4%).
"In our community-based sample of Mexican American and European American older adults aged 65 to 74 years old at baseline, the majority of individuals began the study with higher scores in both domains, cognition and gait speed. During follow-up, this group demonstrated resilience to age-related declines and continued to be functionally independent," said study senior author Helen Hazuda, Ph.D., professor in UT Health San Antonio's Long School of Medicine and the principal investigator of SALSA.
"In contrast, one-fifth of individuals began the study with lower scores in cognition and gait speed. They experienced deterioration in each domain during the follow-up period," Dr. Hazuda said.
The third group of individuals, termed the physical vulnerability class, demonstrated stable cognition throughout the study, but their gait speed slowed over time.
2 effects, 1 root?
Cognition was assessed using English or Spanish versions of the Folstein Mini-Mental State Examination, a 30-item tool that assesses orientation to time and place, attention, recall, language and other aspects. Gait speed was measured with a timed 10-foot walk.
"For most of the population we studied, changes in cognition and gait speed were parallel, which suggests shared mechanisms," said Mitzi M. Gonzales, Ph.D., lead author of the study and a neuropsychologist with the Glenn Biggs Institute for Alzheimer's and Neurodegenerative Diseases, which is part of UT Health San Antonio.
Cognition and gait speed may be altered by blood vessel disease, brain tissue insults, hormone regulation, and abnormal deposits of amyloid beta and tau proteins in the brain, Dr. Gonzales said. Amyloid beta and tau deposits are well-known indicators of Alzheimer's disease but may impact gait, too.
"Abnormal protein deposition promotes neurodegeneration and synaptic loss, which may induce dysfunction in brain regions governing cognition and gait," said study coauthor Sudha Seshadri, M.D., professor of neurology in the Long School of Medicine and director of the Biggs Institute. "Another possibility is damage to white matter in regions integral to both cognition and gait coordination."
Groundbreaking San Antonio research
SALSA investigators led by Dr. Hazuda launched the study in 1992 and completed the baseline examination in 1996. Follow-up examinations were conducted at 18-month intervals between 2000 and 2005.
Among the 370 participants in this new analysis, 182 were Mexican American and 188 were European American. The Mexican American participants were almost four times more likely than European Americans to be in the cognitive and physical vulnerability class, even after statistical adjustment for educational attainment, income and chronic medical conditions, Dr. Gonzales said.
Prevalence of a key risk factor in this group, diabetes, was significantly higher in Mexican Americans (23%) than in European Americans (7%). Diabetes was associated with a 4½ times higher likelihood of being part of the cognitive and physical vulnerability class.
Poor start, poor course
Individuals who entered the study with poorer cognition and slower gait speed went on to decline in both domains at an accelerated pace through the years of follow-up, Dr. Hazuda said.
"In this at-risk group, we observed steeper rates of decline over and above the low starting point," Dr. Hazuda said. "This suggests that preventive efforts should ideally target young and middle-aged adults in which there is still time to intervene to alter the trajectories."
Overall, individuals in the cognitive and physical vulnerability class and the physical vulnerability class had a five- to sevenfold increased risk of mortality in comparison to the stable cognition and gait class.
https://www.sciencedaily.com/releases/2020/05/200505121717.htm
Excessive sugar intake linked with unhealthy fat deposits
June 29, 2020
Science Daily/European Society of Cardiology
Sugar consumption is linked with larger fat deposits around the heart and in the abdomen, which are risky for health. That's the finding of a study published today in the European Journal of Preventive Cardiology, a journal of the European Society of Cardiology (ESC).
"When we consume too much sugar the excess is converted to fat and stored," said study author Ms. So Yun Yi, a PhD student at the University of Minnesota School of Public Health. "This fat tissue located around the heart and in the abdomen releases chemicals into the body which can be harmful to health. Our results support limiting added sugar intake."
Excess sugar consumption is a worldwide problem. The six countries with the highest sales of sugary drinks per capita are Chile, Mexico, Argentina, Peru, the US, and Saudi Arabia. The demand for sugar is expected to increase in Asia, Africa, and Russia.
This observational study examined both sugar-sweetened beverages (such as soft drinks, fruit drinks, energy drinks) and sugar added to foods and beverages for sweetness (for example when cooking or in processed foods). The researchers analysed the association between long-term sugar consumption and fat stores around the heart and other organs.
Data were obtained from Coronary Artery Risk Development in Young Adults (CARDIA), an ongoing cohort study in the US that includes centres in Alabama, California, Illinois, and Minnesota. A total of 3,070 healthy participants aged 18 to 30 were included in this study.
Food and beverage intakes were measured three times over a 20-year period (1985 to 2005). After 25 years (in 2010) computed tomography (CT) scans of the chest and abdomen were performed to measure fat volumes in the abdomen and around the heart.
The researchers found that sugar intake over the 20-year period was related to fat volumes later in life. Higher intakes of both sugar-sweetened beverages and added sugar were related to greater fat stores around organs in a stepwise fashion.
"Our findings provide more evidence that consuming too much added sugar and sugary drinks is related to a higher amount of fat tissue," said study author Dr. Lyn Steffen of the University of Minnesota School of Public Health. "And, we know that fat deposits are connected with higher risks of heart disease and diabetes."
She advised reducing the amount of added sugar consumed each day. "Have water instead of sugary drinks and choose healthier snacks over foods rich in added sugar like cakes," she said. "Read food labels to check the amount of added sugar in what you are buying. Look for ingredients like syrups, glucose, fructose, sucrose, and maltose. Being more aware of hidden sugar will help you cut back."
Dr. Steffen said: "On top of our individual efforts, governments, food manufacturers, restaurants, schools, and workplaces have a role to play in increasing consumer awareness of the sugar content in foods and beverages and offering healthier alternatives."
https://www.sciencedaily.com/releases/2020/06/200629120243.htm
Raw milk may do more harm than good
Not properly stored, it's a source of antibiotic-resistant microbes
June 29, 2020
Science Daily/University of California - Davis
Raw or unpasteurized cows' milk from U.S. retail stores can hold a huge amount of antimicrobial-resistant genes if left at room temperature, according to a new study from researchers at the University of California, Davis. The study also found bacteria that harbored antimicrobial-resistant genes can transfer them to other bacteria, potentially spreading resistance if consumed. The study was published in the journal Microbiome.
"We don't want to scare people, we want to educate them. If you want to keep drinking raw milk, keep it in your refrigerator to minimize the risk of it developing bacteria with antibiotic-resistant genes," said lead author Jinxin Liu, a postdoctoral researcher in the Department of Food Science and Technology at UC Davis.
Lacking in Probiotics
An estimated 3 percent of the U.S. population consumes unpasteurized, or raw, milk, which has not been heated to kill pathogens and extend shelf life. Raw milk is often touted to consumers as having an abundant supply of probiotics, or healthy bacteria, compared with pasteurized milk. UC Davis researchers did not find that to be the case.
"Two things surprised us," said Liu. "We didn't find large quantities of beneficial bacteria in the raw milk samples, and if you leave raw milk at room temperature, it creates dramatically more antimicrobial-resistant genes than pasteurized milk."
Bacteria with antimicrobial-resistant genes, if passed to a pathogen, have the potential to become "superbugs," so that pharmaceuticals to treat infection or disease no longer work. Each year, almost 3 million people get an antibiotic-resistant infection, and more than 35,000 people die, according to the Centers for Disease Control.
The Longer It Sits, the Worse It Gets
UC Davis researchers analyzed more than 2,000 retail milk samples from five states, including raw milk and milk pasteurized in different ways. The study found raw milk had the highest prevalence of antibiotic-resistant microbes when left at room temperature.
"Our study shows that with any temperature abuse in raw milk, whether intentional or not, it can grow these bacteria with antimicrobial resistance genes," said co-author Michele Jay-Russell, research microbiologist and manager with the UC Davis Western Center for Food Safety. "It's not just going to spoil. It's really high risk if not handled correctly."
Some consumers are intentionally letting raw milk sit outside of the refrigerator at room temperature to ferment, in order to make what's known as clabber. Co-author and Peter J. Shields Chair of Dairy Food Science David Mills said if consumers eat raw milk clabber, they are likely adding a high number of antimicrobial-resistant genes to their gut.
"You could just be flooding your gastrointestinal tract with these genes," said Mills. "We don't live in an antibiotic-free world anymore. These genes are everywhere, and we need to do everything we can to stop that flow into our bodies."
While more work is needed to fully understand whether antibiotic-resistant genes in raw milk translate into health risks for humans, Mills suggests that consumers instead use a starter culture if they want to ferment raw milk, which carries specific strains of bacteria to inoculate the milk.
Other authors include Yuanting Zhu of UC Davis and Danielle Lemay of USDA ARS Western Human Nutrition Research Center. This study was funded with support from the National Institutes of Health and the Peter J. Shields Endowed Chair in Dairy Food Science.
https://www.sciencedaily.com/releases/2020/06/200629140054.htm
Higher fruit, vegetable and whole grain intake linked to lower risk of diabetes
Findings further support advice to eat more of these foods to prevent disease
July 8, 2020
Science Daily/BMJ
Higher consumption of fruit, vegetables and whole grain foods are associated with a lower risk of developing type 2 diabetes, according to two studies published by The BMJ today.
The findings suggest that even a modest increase in consumption of these foods as part of a healthy diet could help prevent type 2 diabetes.
In the first study, a team of European researchers examined the association between blood levels of vitamin C and carotenoids (pigments found in colourful fruits and vegetables) with risk of developing type 2 diabetes.
Vitamin C and carotenoid levels are more reliable indicators of fruit and vegetable intake than using dietary questionnaires.
Their findings are based on 9,754 adults who developed new-onset type 2 diabetes and a comparison group of 13,662 adults who remained free of diabetes during follow-up from among 340,234 participants who were taking part in the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct study in eight European countries.
After adjusting for lifestyle, social and dietary risk factors for diabetes, higher blood levels of each of vitamin C and carotenoids and their sum when combined into a "composite biomarker score" were associated with a lower risk of developing type 2 diabetes.
Compared with people who had the lowest composite biomarker score, the risk in people whose biomarker score was in the top 20% of the population was 50% lower. The risk in those with biomarker scores between these two extremes was intermediate.
The researchers calculate that every 66 grams per day increase in total fruit and vegetable intake was associated with a 25% lower risk of developing type 2 diabetes.
In the second study, researchers in the United States examined associations between total and individual whole grain food intake and type 2 diabetes.
Their findings are based on 158,259 women and 36,525 men who were free from diabetes, heart disease and cancer and were taking part in the Nurses' Health Study, Nurses' Health Study II, and Health Professionals Follow-Up Study.
After adjusting for lifestyle and dietary risk factors for diabetes, participants in the highest category for total whole grain consumption had a 29% lower rate of type 2 diabetes compared with those in the lowest category.
For individual whole grain foods, the researchers found that consuming one or more servings a day of whole grain cold breakfast cereal or dark bread was associated with a lower risk of type 2 diabetes (19% and 21% respectively) compared with consuming less than one serving a month.
For other individual whole grains with lower average intake levels, consumption of two or more servings a week compared with less than one serving a month was associated with a 21% lower risk for oatmeal, a 15% lower risk for added bran, and a 12% lower risk for brown rice and wheat germ.
These reductions in risk seemed to plateau at around two servings a day for total whole grain intake, and at around half a serving a day for whole grain cold breakfast cereal and dark bread.
Both studies are observational so can't establish cause, and there's a possibility that some of the results may be due to unmeasured (confounding) factors. However, both studies took account of several well known lifestyle risk factors and markers of dietary quality, and the findings back up other research linking a healthy diet with better health.
As such, both research teams say their findings provide further support for current recommendations to increase fruit, vegetable and whole grain consumption as part of a healthy diet to prevent type 2 diabetes.
And for fruit and vegetables, the findings also suggest that consumption of even a moderately increased amount among populations who typically consume low levels could help to prevent type 2 diabetes.
https://www.sciencedaily.com/releases/2020/07/200708213317.htm
Living close to green space benefits gut bacteria of urban, formula-fed infants
July 9, 2020
Science Daily/University of Alberta Faculty of Medicine & Dentistry
Living close to natural green space can mitigate some of the changes in infant gut bacteria associated with formula feeding, according to new research published in the journal Environment International.
"Not every infant can be breastfed," said Anita Kozyrskyj, pediatrics professor at the University of Alberta. "This is one of the first pieces of evidence for a nature-related intervention that could possibly help promote healthy gut microbial composition in infants who are not breastfed."
"We consider breastfeeding to be the desirable state, and we know that a breastfed infant is at reduced likelihood of many conditions later in life -- for example, developing respiratory infections and becoming overweight," said Kozyrskyj, who is principal investigator for SyMBIOTA, a research team that studies how changes in infant gut microbiota can lead to the development of obesity, allergies and asthma in children.
The researchers examined fecal samples taken during routine home visits from 355 four-month-old infants who are part of the CHILD Cohort Study -- a national study that is following nearly 3,500 Canadian children from before birth to adolescence with the goal of discovering root causes of allergies, asthma and chronic disease.
The babies' postal codes were then cross-referenced with the City of Edmonton's urban Primary Land and Vegetation Inventory (uPLVI), which maps natural green spaces in the city, including natural forest, grasslands, wetlands, lakes, rivers and ravines.
"We found that the infants who lived within 500 metres of a natural environment were less likely to have higher diversity in their gut bacteria," she said. "It may seem counterintuitive, but a young breastfed infant has lower gut microbial diversity than a formula-fed infant because formula feeding increases the number of different gut bacteria."
The results applied only to infants living close to natural spaces, regardless of whether there was a human-made park in the neighbourhood.
The researchers found the greatest association was for formula-fed infants living in a home with a pet. Though the exact mechanism is not understood, they hypothesize that families who walk their dog may use natural areas more often, or that pets may bring healthy bacteria into the home on their fur.
"We know that when you introduce a pet into the home, it does change the types of microbes that are found in household dust," Kozyrskyj pointed out.
The researchers found that 54 per cent of the infants lived close to a natural environment and 18 per cent of the babies were exclusively formula-fed. Nine per cent were both formula-fed and had pets in the home. The results were adjusted for the type of delivery (caesarean section or natural), the season, and the age and education level of the mothers.
They did not distinguish between the type of pets the families owned, but Kozyrskyj said, "We think it's a dog effect."
"Even if you live in a highrise, if you have a dog you go out and use the natural spaces near your home. It's likely that the pet is the conduit."
The researchers reported an increased presence of Proteobacteria -- the type of bacteria more often found in nature -- in the guts of all of the babies.
While numerous studies have examined the impact of living close to natural green spaces on the skin and gut microbiota of adults, this is the first study to cross-reference proximity to natural green spaces with the gut bacteria of infants.
"We had this wonderful opportunity for data linkage between the unique natural assets map, the home locations of infants in the CHILD birth cohort and information on the composition of their gut bacteria," Kozyrskyj said.
Kozyrskyj said the research team included a geographer, a city planner, pediatrics and obstetrics specialists, and international environmental and microbiome scientists.
"It takes an interdisciplinary team to do this kind of research," she said. "That's what made the project so rich in terms of the interpretation of the results and the kinds of questions that could be asked."
Kozyrskyj said the next step for this research will be to follow the formula-fed infants who are exposed to natural areas throughout childhood and track the impact on their health.
She said she often receives emails from new mothers who are unable to breastfeed and are concerned about their children's futures. Based on these results, she will now advise them to take their babies out to natural areas and consider getting a pet.
The research was funded by the Canadian Institutes of Health Research, the Allergy, Genes and Environment (AllerGen) Networks of Centres of Excellence, the Stollery Children's Hospital Foundation through the Women and Children's Health Research Institute and the Spanish Ministry of Science and Innovation.
https://www.sciencedaily.com/releases/2020/07/200709135616.htm
Hot flushes and night sweats linked to 70% increase in cardiovascular disease
July 2, 2020
Science Daily/University of Queensland
New research from The University of Queensland has found that women who have hot flushes and night sweats after menopause are 70 per cent more likely to have heart attacks, angina and strokes.
School of Public Health PhD student Dr Dongshan Zhu has found women of any age who experience hot flushes and night sweats, also known as vasomotor symptoms or VMS, are more likely to experience non-fatal cardiovascular events.
"Until now, it's been unclear if VMS is associated with cardiovascular disease, but now we know it to be true," Dr Zhu said.
"Further, VMS before menopause increases a woman's chance of cardiovascular events by 40 per cent."
Dr Zhu also found that the risk of cardiovascular events was more related to the severity of the hot flushes and night sweats rather than the frequency or duration.
"We found that women with severe VMS were more than twice as likely to experience a non-fatal cardiovascular event compared with women who had no symptoms," he said.
Dr Zhu used data from InterLACE, a major collaboration of 25 studies of more than 500,000 women around the world.
Senior author on the study Professor Gita Mishra said the findings may have important clinical implications.
"This research helps to identify women who are at a higher risk for the development of cardiovascular events and who may need close monitoring in clinical practice," Professor Mishra said.
https://www.sciencedaily.com/releases/2020/07/200702113707.htm
Air pollution's connection to infant mortality
June 29, 2020
Science Daily/Stanford University
The study of sub-Saharan Africa finds that a relatively small increase in airborne particles significantly increase infant mortality rates. A cost-effective solution may lie in an exotic-sounding proposal.
Dust sweeping across the Southeast U.S. in recent days warns of a growing risk to infants and children in many parts of the world. A Stanford-led study focuses on this dust, which travels thousands of miles from the Sahara Desert, to paint a clearer picture than ever before of air pollution's impact on infant mortality in sub-Saharan Africa. The paper, published June 29 in Nature Sustainability, reveals how a changing climate might intensify or mitigate the problem, and points to seemingly exotic solutions to reducing dust pollution that could be more effective and affordable than current health interventions in improving child health.
"Africa and other developing regions have made remarkable strides overall in improving child health in recent decades, but key negative outcomes such as infant mortality remain stubbornly high in some places," said study senior author Marshall Burke, an associate professor of Earth system science in Stanford's School of Earth, Energy & Environmental Sciences. "We wanted to understand why that was, and whether there was a connection to air pollution, a known cause of poor health."
Understanding airborne danger
Children under 5 are particularly vulnerable to the tiny particles, or particulate, in air pollution that can have a range of negative health impacts, including lower birth weight and impaired growth in the first year of life. In developing regions, exposure to high levels of air pollution during childhood is estimated to reduce overall life expectancy by 4-5 years on average.
Quantifying the health impacts of air pollution -- a crucial step for understanding global health burdens and evaluating policy choices -- has been a challenge in the past. Researchers have struggled to adequately separate out the health effects of air pollution from the health effects of activities that generate the pollution. For example, a booming economy can produce air pollution but also spur developments, such as lower unemployment, that lead to better healthcare access and improved health outcomes.
To isolate the effects of air pollution exposure, the Stanford-led study focuses on dust carried thousands of miles from the Bodélé Depression in Chad -- the largest source of dust emissions in the world. This dust is a frequent presence in West Africa and, to a lesser extent, across other African regions. The researchers analyzed 15 years of household surveys from 30 countries across Sub-Saharan Africa covering nearly 1 million births. Combining birth data with satellite-detected changes in particulate levels driven by the Bodélé dust provided an increasingly clear picture of poor air quality's health impacts on children.
Sobering findings and surprising solutions
The researchers found that a roughly 25 percent increase in local annual mean particulate concentrations in West Africa causes an 18 percent increase in infant mortality. The results expand on a 2018 paper by the same researchers that found exposure to high particulate matter concentrations in sub-Saharan Africa accounted for about 400,000 infant deaths in 2015 alone.
The new study, combined with previous findings from other regions, makes clear that air pollution, even from natural sources, is a "critical determining factor for child health around the world," the researchers write. Emissions from natural sources could change dramatically in a changing climate, but it's unclear how. For example, the concentration of dust particulate matter across Sub-Saharan Africa is highly dependent on the amount of rainfall in the Bodélé Depression. Because future changes in rainfall over the Bodélé region due to climate change are highly uncertain, the researchers calculated a range of possibilities for sub-Saharan Africa that could result in anywhere from a 13-percent decline in infant mortality to a 12-percent increase just due to changes in rainfall over the desert. These impacts would be larger than any other published projections for climate change impact on health across Africa.
Safeguarding children against air pollution is nearly impossible in many developing regions because many homes have open windows or permeable roofs and walls, and infants and young children are unlikely to wear masks. Instead, the researchers suggest exploring the possibility of dampening sand with groundwater in the Bodélé region to stop it from going airborne -- an approach that has been successful at small scale in California.
The researchers estimate that deploying solar-powered irrigation systems in the desert area could avert 37,000 infant deaths per year in West Africa at a cost of $24 per life, making it competitive with many leading health interventions currently in use, including a range of vaccines and water and sanitation projects.
"Standard policy instruments can't be counted on to reduce all forms of air pollution," said study lead author Sam Heft-Neal, a research scholar at Stanford's Center on Food Security and the Environment. "While our calculation doesn't consider logistical constraints to project deployment, it highlights the possibility of a solution that targets natural pollution sources and yields enormous benefits at a modest cost."
https://www.sciencedaily.com/releases/2020/06/200629120215.htm
Prenatal stress associated with infant gut microbes
June 23, 2020
Science Daily/University of Turku
Mother's chronic prenatal psychological distress and elevated hair cortisol concentrations are associated with gut microbiota composition of the infant, according to a new publication from the FinnBrain research project of the University of Turku, Finland. The results help to better understand how prenatal stress can be connected to infant growth and development. The study has been published in the Psychoneuroendocrinology journal.
Prenatal stress can be associated with infant growth and development. However, the mechanisms underlying this association are not yet fully understood.
"We were able to show that maternal chronic psychological distress and elevated hair cortisol concentrations during pregnancy are associated with infant gut microbiota composition but not diversity," says Doctoral Candidate, Doctor Anna Aatsinki.
The study used hair cortisol analysis which enabled measuring the concentration averages of stress hormone cortisol over several months. In addition, the symptoms of the mother were assessed three times during pregnancy. The infant gut microbiota was analysed early at the age of 2.5 months with next generation sequencing.
Previously, similar studies have focused on animals and two have been smaller human studies making this data consisting of 399 mothers and their infants the largest in the world so far. The received results provide significant new information on the phenomenon. In addition, this study was able to confirm previously made observations.
Studying the Role of Microbes as Mediators of Stress
Both Proteobacteria and Lactobacillus are common infant gut microbes.
"We discovered, for instance, that mother's chronic prenatal psychological distress was linked to increased abundances of Proteobacteria genera in infant microbiota. In addition, chronic psychological symptoms were connected to decreased abundances of Akkermansia genera which is considered to promote health at least in adults," summarises Aatsinki.
According to Aatsinki, it was also interesting that low cortisol concentrations were associated with increased abundances of Lactobacillus in infant gut microbiota. Lactobacillus bacteria are considered to promote health.
However, Proteobacteria also contain species that are able to cause inflammation in the body. Proteobacteria can also be associated with the child's disease risk later in life. Therefore, researchers consider it important to study how the observed changes are connected to later child development.
"Our study does not explain the cause-effect relationship, or whether prenatal psychological stress is linked to differences in microbial metabolic products or e.g. in immune system function. In other words, important questions still need to be answered," notes Aatsinki.
The study is part of the FinnBrain research project and its gut-brain axis sub-project. The sub-project led by Docent, Child and Adolescent Psychiatrist Linnea Karlsson studies how prenatal stress affects infant microbiota development and how infant gut microbes affect later brain development.
The FinnBrain research project of the University of Turku studies the combined influence of environmental and genetic factors on the development of children. Over 4,000 families participate in the research project and they are followed from infancy long into adulthood.
https://www.sciencedaily.com/releases/2020/06/200623145346.htm
Childhood trauma affects the timing of motherhood
June 4, 2020
Science Daily/University of Turku
Women who have experienced childhood trauma become mothers earlier than those with a more stable childhood environment shows a new study conducted in collaboration between the University of Turku and the University of Helsinki in Finland. The trauma children experience form living in war zones, natural disasters or perhaps even epidemics can have unexpected effects that resurface later in their lives.
During the Second World War, thousands of Finnish women and girls volunteered to aid in the war effort as part of the paramilitary organisation 'Lotta Svärd' exposing some to the trauma of war. Researcher and lead author of the study Robert Lynch from the University of Turku used extensive data collected on these volunteers to study the effects of childhood trauma on adults.
The study showed that young girls and women who served in the war became mothers earlier and had more children compared to women of the same age who did not participate in the war effort.
"If we can measure the effects of trauma on basic things such as the timing of motherhood, then it almost certainly has major effects on many of our other important behaviours, such as overall aversion to risk, sociality or the pace of sexual development," explains Lynch.
"This study is groundbreaking because it overcomes many of the pitfalls of research on humans that has made it difficult to know whether trauma is actually the root cause of starting a family at a younger age. The extensive dataset made it possible for us to compare women before and after the war and also take family background into account by comparing sisters. This is strong evidence in support of the idea that trauma affects reproductive schedules," adds senior author, Researcher John Loehr from the University of Helsinki.
The study has clear relevance for the millions of children and adults worldwide who experience trauma through wars. However, relevance likely also extends to other sources of trauma, such as natural disasters or even the current COVID-19 epidemic.
Evolutionary theory predicts that individuals experiencing an unstable environment with high mortality are better off reproducing sooner rather than taking the risk of not having the chance later.
"There appears to be a sensitivity window that extends from childhood into early adulthood where behaviour adjusts to match the circumstances experienced. The consequences can be far-reaching even after the situation stabilises. A childhood trauma can influence people's adult lives in ways that they are unaware of, such as the timing of their motherhood," explains Academy Professor Virpi Lummaa from the University of Turku.
Background:
Prior to and during the Second World War, many Finnish girls and women volunteered for the 'Lotta Svärd' organisation that was a major part of the war effort. Tasks within the organisation varied greatly, and many of the women performed duties that exposed them to the trauma of war. Towards the end of the war, girls as young as fourteen years of age were entrusted with some of the more demanding jobs usually reserved for adults. The project was funded by the Kone Foundation with data from Karjala Liitto registers and digitised church register data provided by Karjalan tietokantasäätiö.
https://www.sciencedaily.com/releases/2020/06/200604120546.htm
Poor sleep at night 'spills over' into children's emotional lives
July 7, 2020
Science Daily/University of Houston
In a new study published in the Journal of Child Psychology and Psychiatry, Candice Alfano, University of Houston professor of psychology and director of the Sleep and Anxiety Center of Houston, reports the results from an innovative, experimental study showing inadequate nighttime sleep alters several aspects of children's emotional health.
Although plenty of correlational research links inadequate sleep with poor emotional health, experimental studies in children are rare. Alfano and her team studied 53 children ages 7-11 over more than a week. The children completed an in-lab emotional assessment twice, once after a night of healthy sleep and again after two nights where their sleep was restricted by several hours.
"After sleep restriction, we observed changes in the way children experience, regulate and express their emotions," reports Alfano. "But, somewhat to our surprise, the most significant alterations were found in response to positive rather than negative emotional stimuli."
The multi-method assessment had children view a range of pictures and movie clips eliciting both positive and negative emotions while the researchers recorded how children responded on multiple levels. In addition to subjective ratings of emotion, researchers collected respiratory sinus arrhythmias (a non-invasive index of cardiac-linked emotion regulation) and objective facial expressions. Alfano points out the novelty of these data. "Studies based on subjective reports of emotion are critically important, but they don't tell us much about the specific mechanisms through which insufficient sleep elevates children's psychiatric risk."
Alfano highlights the implications of her findings for understanding how poor sleep might "spill over" into children's everyday social and emotional lives. "The experience and expression of positive emotions are essential for children's friendships, healthy social interactions and effective coping. Our findings might explain why children who sleep less on average have more peer-related problems," she said.
Another important finding from the study is that the impact of sleep loss on emotion was not uniform across all children. Specifically, children with greater pre-existing anxiety symptoms showed the most dramatic alterations in emotional responding after sleep restriction.
According to Alfano, these results emphasize a potential need to assess and prioritize healthy sleep habits in emotionally vulnerable children.
https://www.sciencedaily.com/releases/2020/07/200707113243.htm
Bedtime media use linked to less sleep in children who struggle to self-regulate behavior
June 23, 2020
Science Daily/Arizona State University
Researchers followed 547 children for a week and measured their media use and sleep patterns. For children who generally struggle to self-regulate their behavior, screen time in the hour before bed was associated with less sleep. Media use in children who scored high on measures of effortful control was not related to less sleep.
According to a study from the Arizona State University Department of Psychology, media use in the hour preceding bedtime impacts how kids sleep, especially children who struggle to self-regulate their behavior. Frequent media use before bed in these children predicted later bedtimes and less sleep. The work is now available online in Psychological Science.
"Among kids who used the same amount of media in the hour before bed, we found differences that were explained by a personality characteristic called effortful control," said Leah Doane, associate professor of psychology at ASU and senior author on the paper. "Kids who score low on measures of effortful control are the ones who struggle to wait to unwrap a present or are easily distracted. We found a strong association between media use in the hour before bed and when these kids went to sleep and how long they slept. Media use before bed was not associated with the sleep of kids who scored high on measures of effortful control."
The research team spent a week following 547 children, aged 7-9 years. The participant group was socioeconomically diverse and lived in rural and urban areas. The parents kept daily diaries that tracked the children's media use and sleep patterns. They also completed a survey that asked about their children's temperament, including their ability to self-regulate behavior.
For the entire week, the children wore specialized wrist watches called actigraphs that tracked their movement and also ambient light. The actigraph data gave the research team detailed information about when and how long the children slept.
The children slept an average of 8 hours a night and used media before bed for an average of 5 nights during the study week. Children who did not use media before bed during the study week slept 23 minutes more and went to bed 34 minutes earlier than children who used media most nights during the study week.
"Media use was generally associated with a shorter sleep duration, but this effect was most pronounced in children with low effortful control," said Sierra Clifford, a research scientist at ASU and first author on the paper. "The impact of media on sleep was also an average affect, meaning that it reflects habitual media use rather than occasionally staying up late to watch a movie."
The children who scored low on measures of effortful control slept the least amount of time when they consistently used media in the hour before bed during the study week. These children slept approximately 40 minutes less per night. Media use before bed did not affect the sleep of children who scored high on effortful control, which was approximately 35 percent of the study participants.
"Media exposure mattered for the children who measured lowest in effortful control," Clifford said.
Children with low effortful control might struggle with switching their attention from watching media before bed to calming down and falling asleep. But because effortful control is a personality characteristic, it is more difficult to change.
"Instead of parents wondering how to help their child better regulate their behavior, they can try to focus on creating more consistent sleep and media use schedules," Doane said.
https://www.sciencedaily.com/releases/2020/06/200623145328.htm
Higher parental stress linked to low screen-time enforcement
June 15, 2020
Science Daily/University of Guelph
When parents are under stress, household rules about screen time often get abandoned, new University of Guelph research finds.
A first of its kind in Canada, the study found parents of young children reporting high levels of life or parenting stress were less likely to monitor and limit their kids' screen use and more likely to use their own devices in front of their children.
Published in the Journal of Children and Media, the research comes at a time when many Canadian families are experiencing more stress than usual because of upheaval caused by COVID-19 pandemic.
The study surveyed 64 parents from 39 families of children 18 months to five years of age taking part in the Guelph Family Health Study. The parents were asked about their stress as well as whether they monitored and limited their children's screen use, and whether they used screens in front of their children.
Lead author Lisa Tang, a PhD student in the Department of Family Relations and Applied Nutrition, said previous U of G research has shown that parenting practices influence how much time children spend on screens.
"With this study, we wanted to understand the implications of parental stress on media parenting practices. We found parenting stress does indeed affect how parents manage screen time but influenced mothers and fathers differently," she said.
For example, when mothers reported a high level of general life stress, they were more likely to report they used devices in front of their children and less likely to monitor or limit their kids' screen use.
That may be because mothers anticipate conflicts with their children if they attempt to impose limits so decide it is either too hard or not worth the fight during times of stress, said Tang.
But fathers, who reported high general life stress, were more likely to limit their kids' screen use.
This could mean that stressed dads are more likely to enforce rules, said Tang. Or it could suggest that when children already have screen limits, fathers are more likely to report high general life stress because children who can't use devices might increase their demands on their parents, she added.
Mothers who reported they found parenting itself stressful were more likely to say they used devices in front of their children and were less likely to monitor or limit their children's screen use. Fathers experiencing similar stress reported no change.
"Parents do seem to say they use their screens more when they say they are under stress, perhaps as an escape," said Tang. "This is an important finding because research has shown that when parents use screens in front of their preschool-aged children, it is associated with those children having greater levels of screen time."
Prof. Jess Haines said this research is not about making parents feel guilty about screen use.
"There's nothing wrong with using screens now and again. We are all doing the best we can, especially now, and parents of children under five need to allow themselves a break. This is really about excess screen time. It's about making parents conscious of their practices and balancing active play with screen time, and modelling that behaviour," she said.
Study co-author Valerie Hruska, a doctoral candidate in U of G's Department of Human Health and Nutritional Sciences, said the study's findings are important given the potential health consequences for young children.
"Previous research has shown that high screen use is linked to health issues in children, including lower activity levels, obesity and even language delays in younger children because they engage in less back-and-forth conversation," she said.
One surprising finding involved a slightly different kind of stress called household chaos, which assesses commotion and noise in a home. The researchers expected high household chaos would be linked to high screen use but found the opposite: chaos was linked with more screen-time monitoring by both mothers and fathers.
The researchers theorize that when children put away their devices and get involved in other activities in the house, it leads to more chaos compared to quieter screen time.
"So perhaps a little chaos in the home isn't a bad thing if it means kids take a break from screens," said Hruska, adding the next goal is to help find ways for parents to limit screen times without increasing household chaos.
https://www.sciencedaily.com/releases/2020/06/200615140823.htm
Early high school start times adversely affect attendance
April 27, 2020
Science Daily/North Carolina State University
A new study finds that earlier high school start times can have significant adverse consequences for students, including increased rates of tardiness and absenteeism.
"The American Academy of Pediatrics recommends that high schools begin class after 8:30 a.m., but we know that most schools start much earlier," says Melinda Morrill, an associate professor of economics at North Carolina State University and corresponding author of a paper on the work. "We were able to look at five high schools that moved start times from 8:05 a.m. to 7:25 a.m. in order to examine the effect that the change had on students."
The researchers looked at data on seven cohorts of students, with graduation years ranging from 2013 to 2019. Specifically, researchers looked at data from the freshman, sophomore and junior years of each cohort. The change in start times was implemented in the 2012-13 school year. As an additional control group, the researchers also looked at data from 14 other high schools in the same school district that had already adopted a 7:25 a.m. start time.
"There's a growing body of research that suggests earlier start times can hurt test scores," Morrill says. "We looked at that, but the numbers weren't statistically significant one way or the other."
"However, the move to the earlier start times caused a small increase in the number of students who did not advance to 12th grade on time," says John Westall, a Ph.D. candidate at NC State and co-author of the paper. "Specifically, the move from 8:05 to 7:25 was associated with students being 8% more likely not to advance to 12th grade on schedule."
"We also wanted to look beyond testing to see if there were effects on other measures of academic engagement," Morrill says. "And we found a significant increase in both absences and tardiness."
"The change to an earlier start time led to an increase of about one additional absence per year and just over three additional tardy arrivals per year for students," Westall says. "So students were definitely missing more school."
"Looking at all 19 of the schools, we found that historically, the five schools that started at 8:05 had significantly lower rates of absenteeism and tardiness than the 14 schools that started at 7:25," Morrill says. "But once those five schools moved their start time to 7:25, those advantages disappeared.
"The take-home message here is that we need to look at more than just test scores if we want to understand all of the ways that early start times can affect high school students," Morrill says. "We know that school districts have to consider a wide range of issues, such as transportation logistics, student safety, extracurricular activities and school finances. But the more we look, the more the findings suggest that there are significant consequences of early start times for students."
https://www.sciencedaily.com/releases/2020/04/200427125128.htm
Nutrients in microalgae: An environmentally friendly alternative to fish
July 7, 2020
Science Daily/Martin-Luther-Universität Halle-Wittenberg
Microalgae could provide an alternative source of healthy omega-3 fatty acids for humans while also being more environmentally friendly to produce than popular fish species. This is the result of a new study by scientists from Martin Luther University Halle-Wittenberg (MLU). The study was recently published in the Journal of Applied Phycology and offers an initial indication of the environmental effects of producing microalgae in Germany.
Microalgae have been the focus of several decades of research -- initially as a raw material for alternative fuels, but more recently as a source of nutrients in the human diet. They are mainly produced in open ponds in Asia; however, these ponds are at risk of potential contamination. Also, some species of algae are easier to cultivate in closed systems, so-called photobioreactors. "We wanted to figure out whether microalgae produced in photobioreactors in Germany could provide a more environmentally friendly source of essential nutrients than fish," says Susann Schade from the Institute of Agricultural and Nutritional Sciences at MLU. Up to now, photobioreactors had usually only been compared to pond cultivation and they often scored worse due to their higher environmental impacts. "However, little research has been done on the precise extent of the environmental impacts of algae produced for human consumption, especially under climatic conditions such as those found in Germany," adds Schade.
For their study, the researchers developed a model to determine location-specific environmental impacts. "One of the things we did was to compare the carbon footprint of nutrients from microalgae and fish. We also analysed how much both food sources increase the acidification and eutrophication in water bodies," explains Dr Toni Meier, head of the Innovation Office nutriCARD at MLU. The researchers were able to show that microalgae farming has a similar impact on the environment as fish production. "However, if we compare the environmental effects in relation to the amount of omega-3 fatty acids produced, fish from aquaculture comes off far worse," says Schade. One advantage of algae cultivation is its low land consumption; even infertile soils can be used. In contrast, both open ponds and the cultivation of feed for aquaculture require very large areas of land. In particular, fish species that are popular in Germany, such as salmon and pangasius, are primarily produced through aquaculture and therefore put the environment under a considerable amount of pressure. However, even fishing wild Alaska pollack had poorer values than microalgae for all environmental indicators.
"Microalgae should not and cannot completely replace fish as a food source. But if microalgae could be established as a common food, it would be another excellent environmentally friendly source of long-chain omega-3 fatty acids," explains Meier. Several algae are already used as a food supplement in powder or tablet form and as an additive to foods such as pasta or cereals. It would be a way to reduce the current gap in the global supply of omega-3 fatty acids. At the same time, it would provide considerable relief to the world's oceans.
https://www.sciencedaily.com/releases/2020/07/200707084008.htm
Probiotics alone or combined with prebiotics may help ease depression
July 6, 2020
Science Daily/BMJ
Probiotics either taken by themselves or when combined with prebiotics, may help to ease depression, suggests a review of the available evidence, published in BMJ Nutrition Prevention & Health.
But as to whether they might help to lessen anxiety isn't yet clear, say the researchers.
Foods that broaden the profile of helpful bacteria in the gut are collectively known as probiotics, while prebiotics are compounds that help these bacteria to flourish.
In the UK in 2016-17, 1.4 million people were referred with mental health issues, over half of them (53%) had anxiety or stress related disorders, while a third (33%) had depression.
A two-way relationship exists between the brain and digestive tract, known as the gut-brain axis. And the possibility that the microbiome -- the range and number of bacteria resident in the gut -- might help treat mental ill health has become a focus of interest in recent years.
To explore this further, the researchers searched for relevant studies published in English between 2003 and 2019, which looked at the potential therapeutic contribution of pre-and probiotics in adults with depression and/or anxiety disorders.
Out of an initial haul of 71 studies, just 7 met all the criteria for inclusion. All 7 investigated at least 1 probiotic strain; 4 looked at the effect of combinations of multiple strains.
In all, 12 probiotic strains featured in the selected studies, primarily Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidium. One study looked at combined pre-probiotic treatment, while one looked at prebiotic therapy by itself.
The studies varied considerably in their design, methods used, and clinical considerations, but all of them concluded that probiotic supplements either alone or in combination with prebiotics may be linked to measurable reductions in depression.
And every study showed a significant fall or improvement in anxiety symptoms and/or clinically relevant changes in biochemical measures of anxiety and/or depression with probiotic or combined pre-probiotic use.
Of the 12 different probiotics investigated, 11 were potentially useful, the findings showed.
The researchers highlight several caveats to their review: none of the included studies lasted very long; and the number of participants in each was small.
This makes it difficult to draw any firm conclusions about the overall effects, whether they are long lasting, and whether there might be any unwanted side effects associated with prolonged use, they say.
Nevertheless on the basis of the preliminary evidence to date, pre- and probiotic therapy warrant further investigation, they suggest.
Probiotics may help reduce the production of inflammatory chemicals, such as cytokines, as is the case in inflammatory bowel disease, suggest the researchers. Or they may help direct the action of tryptophan, a chemical thought to be important in the gut-brain axis in psychiatric disorders.
As anxiety disorders and depression affect people very differently, they require treatment approaches that take account of these complexities, they say. "In this way, with a better understanding of the mechanisms, probiotics may prove to be a useful tool across a wide range of conditions," they write.
People with depression and/or anxiety disorders also often have other underlying conditions, such as impaired insulin production and irritable bowel syndrome, they point out.
"As such, the effect that probiotics have on patients with [common mental disorders] may be twofold: they may directly improve depression in line with the observed findings of this review, and/or they might beneficially impact a patient's experience of their [common mental disorder] by alleviating additional comorbidities," they write.
"Purely from the information gathered for this review, it is valid to suggest that, for patients with clinically recognised depression: isolate, or adjuvant prebiotic therapy is unlikely to affect an individual's experience of their condition in a quantitatively evident way; and that isolate or adjuvant, probiotic/combined prebiotic-probiotic therapy may offer a quantitatively measurable improvement in parameters relating to depression," they conclude.
"However, there are inadequate data to suggest anything meaningful to support or refute the use of either pre/probiotic agents (or a combination of both) in patients with clinically recognised anxiety disorders; this would be a useful area to investigate further."
https://www.sciencedaily.com/releases/2020/07/200706203820.htm
Universal gut microbiome-derived signature predicts cirrhosis
June 30, 2020
Science Daily/University of California - San Diego
Researchers report that stool microbiomes of NAFLD patients are distinct enough to potentially be used to accurately predict which persons with NAFLD are at greatest risk for having cirrhosis.
Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide, affecting an estimated one-quarter of the global population. It is a progressive condition that, in worst cases, can lead to cirrhosis, liver cancer, liver failure and death.
In a new paper published online June 30, 2020 in Cell Metabolism, a team of scientists, led by researchers at University of California San Diego School of Medicine, report that stool microbiomes -- the collection of microorganisms found in fecal matter and in the gastrointestinal tract -- of NAFLD patients are distinct enough to potentially be used to accurately predict which persons with NAFLD are at greatest risk for having cirrhosis -- the late-stage, irreversible scarring of the liver that often requires eventual organ transplantation.
"The findings represent the possibility of creating an accurate, stool microbiome-based, non-invasive test to identify patients at greatest risk for cirrhosis," said senior author Rohit Loomba, MD, professor of medicine in the Division of Gastroenterology at UC San Diego School of Medicine and director of its NAFLD Research Center. "Such a diagnostic tool is urgently needed."
Loomba said a novel aspect of the study is the external validation of gut microbiome signatures of cirrhosis in participant cohorts from China and Italy. "This is one of the first studies to show such a robust external validation of a gut microbiome-based signature across ethnicities and geographically distinct cohorts.
The work builds upon previous published research in 2017 and 2019 by Loomba and colleagues.
A link between NAFLD and the gut microbiome is well-documented, but specifics were scant and it has not been clear that discrete metagenomics and metabolomics signatures might be used to detect and predict cirrhosis. In the latest study, researchers compared the stool microbiomes of 163 participants encompassing patients with NAFLD-cirrhosis, their first-degree relatives and control-patients without NAFLD.
Combining metagenomics signatures with participants' ages and serum albumin (an abundant blood protein produced in the liver) levels, the scientists were able to accurately distinguish cirrhosis in participants differing by cause of disease and geography.
The next step, said Loomba, is to establish causality of these gut microbial species or their metabolites in causing cirrhosis, and whether this test can be used and scaled up for clinical use.
https://www.sciencedaily.com/releases/2020/06/200630125126.htm