1. Electrical ‘switch’ in brain’s capillary network monitors activity and controls blood flow

    March 29, 2017 by Ashley

    From the Larner College of Medicine at the University of Vermont press release:

    All it takes is the flip of a protein “switch” within the tiny wire-like capillaries of the brain to increase the blood flow that ensures optimal brain function. New research has uncovered that capillaries have the capacity to both sense brain activity and generate an electrical vasodilatory signal to evoke blood flow and direct nutrients to nourish hard-working neurons.

    These findings were reported online in Nature Neuroscience.

    When there is an increase in brain activity, there is an increase in blood flow, says Thomas Longden, Ph.D., assistant professor of pharmacology at the Larner College of Medicine at the University of Vermont and first author of the study. “The area of the brain covered by the capillaries — the smallest blood vessels in the body — vastly surpasses the area covered by arterioles. This ideally positions them for monitoring neuronal activity and controlling blood flow.”

    Understanding the mechanisms that precisely direct cerebrovascular blood flow to satisfy the brain’s ever-changing energy needs has, to date, eluded scientists. Neurons consume an enormous amount of the body’s energy supplies — about 20 percent — yet lack their own reserves, so are reliant on blood to deliver nutrients. Previously, capillaries were thought to be passive tubes and the arterioles were thought to be the source of action. Now, Longden and colleagues have discovered that capillaries actively control blood flow by acting like a series of wires, transmitting electrical signals to direct blood to the areas that need it most.

    To achieve this feat, the capillary sensory network relies on a protein (an ion channel) that detects increases in potassium during neuronal activity. Increased activity of this channel facilitates the flow of ions across the capillary membrane, thereby creating a small electrical current that generates a negative charge — a rapidly transmitted signal — that communicates the need for additional blood flow to the upstream arterioles, which then results in increased blood flow to the capillaries.

    The team’s study also determined that if the potassium level is too high, this mechanism can be disabled, which may contribute to blood flow disturbances in a broad range of brain disorders.

    “These findings open new avenues in the way we can investigate cerebral diseases with a vascular component,” says co-first author Fabrice Dabertrand, Ph.D., an assistant professor of pharmacology at the University of Vermont’s Larner College of Medicine. Cerebrovascular illnesses like Alzheimer’s disease, CADASIL, and other conditions that cause cognitive decline can, in part, be a consequence of neurons not receiving enough blood flow and therefore not getting sufficient nutrients.

    “If you’re hungry, you’re not able to do your best work; it may be the same for neurons,” says Dabertrand, who adds that the group’s next phase of research will focus on exploring potential pathological factors involved in disabling the capillary potassium-sensing mechanism.

    An image from the Vermont team’s research will be featured on the cover of the May 2017 issue of Nature Neuroscience.


  2. Blueberry concentrate improves brain function in older people

    March 20, 2017 by Ashley

    From the University of Exeter press release:

    Blueberries

    Drinking concentrated blueberry juice improves brain function in older people, according to research by the University of Exeter.

    In the study, healthy people aged 65-77 who drank concentrated blueberry juice every day showed improvements in cognitive function, blood flow to the brain and activation of the brain while carrying out cognitive tests.

    There was also evidence suggesting improvement in working memory.

    Blueberries are rich in flavonoids, which possess antioxidant and anti-inflammatory properties.

    Dr Joanna Bowtell, head of Sport and Health Sciences at the University of Exeter, said: “Our cognitive function tends to decline as we get older, but previous research has shown that cognitive function is better preserved in healthy older adults with a diet rich in plant-based foods.

    “In this study we have shown that with just 12 weeks of consuming 30ml of concentrated blueberry juice every day, brain blood flow, brain activation and some aspects of working memory were improved in this group of healthy older adults.”

    Of the 26 healthy adults in the study, 12 were given concentrated blueberry juice — providing the equivalent of 230g of blueberries — once a day, while 14 received a placebo.

    Before and after the 12-week period, participants took a range of cognitive tests while an MRI scanner monitored their brain function and resting brain blood flow was measured.

    Compared to the placebo group, those who took the blueberry supplement showed significant increases in brain activity in brain areas related to the tests.

    The study excluded anyone who said they consumed more than five portions of fruit and vegetables per day, and all participants were told to stick to their normal diet throughout.

    Previous research has shown that risk of dementia is reduced by higher fruit and vegetable intake, and cognitive function is better preserved in healthy older adults with a diet rich in plant-based foods.

    Flavonoids, which are abundant in plants, are likely to be an important component in causing these effects.


  3. Mediterranean diet may have lasting effects on brain health

    January 13, 2017 by Ashley

    From the American Academy of Neurology (AAN) media release:

    healthy, vital seniorA new study shows that older people who followed a Mediterranean diet retained more brain volume over a three-year period than those who did not follow the diet as closely.

    The study is published in the January 4, 2017, online issue of Neurlogy®, the medical journal of the American Academy of Neurology. But contrary to earlier studies, eating more fish and less meat was not related to changes in the brain.

    The Mediterranean diet includes large amounts of fruits, vegetables, olive oil, beans and cereal grains such as wheat and rice, moderate amounts of fish, dairy and wine, and limited red meat and poultry.

    As we age, the brain shrinks and we lose brain cells which can affect learning and memory,” said study author Michelle Luciano, PhD, of the University of Edinburgh in Scotland. “This study adds to the body of evidence that suggests the Mediterranean diet has a positive impact on brain health.”

    Researchers gathered information on the eating habits of 967 Scottish people around age 70 who did not have dementia. Of those people, 562 had an MRI brain scan around age 73 to measure overall brain volume, gray matter volume and thickness of the cortex, which is the outer layer of the brain. From that group, 401 people then returned for a second MRI at age 76. These measurements were compared to how closely participants followed the Mediterranean diet.

    The participants varied in how closely their dietary habits followed the Mediterranean diet principles. People who didn’t follow as closely to the Mediterranean diet were more likely to have a higher loss of total brain volume over the three years than people who followed the diet more closely. The difference in diet explained 0.5 percent of the variation in total brain volume, an effect that was half the size of that due to normal aging.

    The results were the same when researchers adjusted for other factors that could affect brain volume, such as age, education and having diabetes or high blood pressure [hypertension].

    There was no relationship between grey matter volume or cortical thickness and the Mediterranean diet.

    The researchers also found that fish and meat consumption were not related to brain changes, which is contrary to earlier studies.

    It’s possible that other components of the Mediterranean diet are responsible for this relationship, or that it’s due to all of the components in combination,” Luciano said.

    Luciano noted that earlier studies looked at brain measurements at one point in time, whereas the current study followed people over time.

    “In our study, eating habits were measured before brain volume was, which suggests that the diet may be able to provide long-term protection to the brain,” said Luciano. “Still, larger studies are needed to confirm these results.”

     


  4. Increased reaction to stress linked to gastrointestinal issues in children with autism

    January 6, 2017 by Ashley

    From the University of Missouri-Columbia media release:

    One in 45 American children lives with autism spectrum disorder, according to the Centers for Disease Control and Prevention.

    Many of these children also have significant gastrointestinal issues, but the cause of these symptoms is unknown. Now, researchers from the University of Missouri School of Medicine suggest that the gastrointestinal issues in these individuals with autism may be related to an increased reaction to stress. It’s a finding the researchers hope could lead to better treatment options for these patients.

    “We know that it is common for individuals with autism to have a more intense reaction to stress, and some of these patients seem to experience frequent constipation, abdominal pain or other gastrointestinal issues,” said David Beversdorf, M.D., associate professor in the departments of radiology, neurology and psychological sciences at MU and the MU Thompson Center for Autism and Neurodevelopmental Disorders. “To better understand why, we looked for a relationship between gastrointestinal symptoms and the immune markers responsible for stress response. We found a relationship between increased cortisol response to stress and these symptoms.”

    Cortisol is a hormone released by the body in times of stress, and one of its functions is to prevent the release of substances in the body that cause inflammation. These inflammatory substances — known as cytokines — have been associated with autism, gastrointestinal issues and stress. The researchers studied 120 individuals with autism who were treated at MU and Vanderbilt University. The individuals’ parents completed a questionnaire to assess their children’s gastrointestinal symptoms, resulting in 51 patients with symptoms and 69 without gastrointestinal symptoms.

    To elicit a stress response, individuals took a 30-second stress test. Cortisol samples were gathered through participants’ saliva before and after the test. The researchers found that the individuals with gastrointestinal symptoms had greater cortisol in response to the stress than the participants without gastrointestinal symptoms.

    When treating a patient with autism who has constipation and other lower gastrointestinal issues, physicians may give them a laxative to address these issues,” Beversdorf said. “Our findings suggest there may be a subset of patients for which there may be other contributing factors. More research is needed, but anxiety and stress reactivity may be an important factor when treating these patients.”

     


  5. Vitamin D supplements may benefit children with autism spectrum disorder

    December 13, 2016 by Ashley

    From the Wiley media release:

    vitaminsVitamin D supplementation improved symptoms of autism in a recent trial.

    Studies have shown an association between the risk of autism spectrum disorder and vitamin D insufficiency. In this latest study, 109 children with autism spectrum disorder were randomized to receive four months of vitamin D3 supplementation or a placebo.

    Autism symptoms — such as hyperactivity, social withdrawal, and others — improved significantly following vitamin D3 supplementation but not after receiving placebo,” said Dr. Khaled Saad, lead author of the Journal of Child Psychology and Psychiatry study.

     


  6. Vitamin D status in newborns and risk of MS in later life

    December 9, 2016 by Ashley

    From the American Academy of Neurology (AAN) media release:

    pregnancy measurementBabies born with low levels of vitamin D may be more likely to develop multiple sclerosis (MS) later in life than babies with higher levels of vitamin D, according to a study published in the November 30, 2016, online issue of Neurology®, the medical journal of the American Academy of Neurology.

    “More research is needed to confirm these results, but our results may provide important information to the ongoing debate about vitamin D for pregnant women,” said study author Nete Munk Nielsen, MD, MSc, PhD, of the State Serum Institute in Copenhagen, Denmark.

    In Denmark, dried blood spots samples from newborn screening tests are stored in the Danish National Biobank. Researchers identified everyone in Denmark who was born since April 30, 1981, had onset of MS by 2012 and whose dried blood spots samples were included in the biobank. The blood from those 521 people was then compared to that of 972 people of the same sex and birthday who did not have MS. In this study, newborns with levels of vitamin D less than 30 nanomoles per liter (nmol/L) were considered born with deficient levels. Levels of 30 to less than 50 nmol/L were considered insufficient and levels higher than or equal to 50 nmol/L were considered sufficient.

    The study participants were divided into five groups based on vitamin D level, with the bottom group having levels of less than 21 nmol/L and the top group with levels higher than or equal to 49 nmol/L. There were 136 people with MS and 193 people without MS in the bottom group. In the top group, there were 89 people with MS and 198 people without the disease. Those in the top group appeared to be 47 percent less likely to develop MS later in life than those in the bottom group.

    Nielsen emphasizes that the study does not prove that increasing vitamin D levels reduces the risk of MS.

    The study has several limitations. Dried blood spots samples were only available for vitamin D analysis for 67 percent of people with MS born during the time period. Vitamin D levels were based on one measurement. Study participants were 30 years old or younger, so the study does not include people who developed MS at an older age. In addition, the Danish population is predominantly white, so the results may not be generalizable to other populations. Furthermore, it cannot be excluded that this apparent beneficial effect could be mediated through other factors in later life such as vitamin D levels, in which case a possible maternal vitamin D supplementation would not reduce the MS risk in the offspring.

    Sources of vitamin D are diet, supplementsn and the sun. Dietary vitamin D is primarily found in fatty fish such as salmon or mackerel. Levels of vitamin D should be within the recommended levels, neither too low nor too high.

     


  7. Common probiotics can reduce stress levels, lessen anxiety

    November 28, 2016 by Ashley

    From the University of Missouri media release:

    probiotics gut floraProbiotics, or beneficial live bacteria that are introduced into the body, have become increasingly popular as a way to improve health and well-being.

    Previous studies have shown a direct correlation between gut microbes and the central nervous system. Now, researchers at the University of Missouri, using a zebrafish model, determined that a common probiotic sold in supplements and yogurt can decrease stress-related behavior and anxiety. Studying how gut bacteria affect behavior in zebrafish could lead to a better understanding of how probiotics may affect the central nervous system in humans. Their results recently were published in Scientific Reports a journal of Nature.

    “Zebrafish are an emerging model species for neurobehavioral studies and their use is well-established in drug-screening,” said Aaron Ericsson, director of the MU Metagenomics Center and a research assistant professor in the Department of Veterinary Pathobiology. “Our study has shown that simple probiotics that we normally use to keep our digestive tract in sync, could be beneficial to reducing our stress levels as well.”

    In a series of studies, researchers tested how zebrafish behaved after doses of Lactobacillus plantarum, a common bacteria found in yogurt and probiotic supplements. In the first study, scientists added the bacteria to certain tanks housing zebrafish; other tanks of zebrafish received no probiotics. Then, the researchers introduced environmental stressors to both groups, such as draining small amounts of water from the tank and overcrowding.

    “Each day we introduced a different stressor — tests that are validated by other researchers and cause higher anxiety among zebrafish,” said Elizabeth Bryda, professor of veterinary pathobiology in the MU College of Veterinary Medicine. “These are common environmental stress patterns, such as isolation stress and temperature change, so it made the tests relevant to humans as well.”

    By analyzing the gene pathways of both groups of fish, the research team found that zebrafish that were given the supplements showed a reduction in the metabolic pathways associated with stress.

    “By measuring the genes associated with stress and anxiety, our tests were able to predict how this common probiotic is able to benefit behavioral responses in these fish,” said Daniel Davis, assistant director of the MU Animal Modeling Core. “Essentially, bacteria in the gut altered the gene expression associated with stress- and anxiety-related pathways in the fish allowing for increased signaling of particular neurotransmitters.”

    To test their theory further, the researchers measured the movements of fish in their tanks using sophisticated computer measuring and imaging tools. Previous studies of fish behavior have found that fish that are stressed tend to spend more time at the bottom of their tanks. Once the fish were administered probiotics, they tended to spend more time toward the top of the tanks — the change in behavior indicating they were less stressed or less anxious.

    “Using zebrafish, we’ve developed a relatively inexpensive platform for testing of other species of bacteria and probiotics and their potential benefit on different systems of the body,” Ericsson said.

     


  8. The healthiest eaters are the most culturally fit

    November 7, 2016 by Ashley

    From the Society for Personality and Social Psychology media release:

    comfort food curryHow to be a healthy eater depends on culture. A recent study shows that in the U.S. and Japan, people who fit better with their culture have healthier eating habits. The results appear in Personality and Social Psychology Bulletin.

    “Our results suggest that if you want to help people to eat healthier — or if you want to promote any type of healthy behavior — you want to understand what meaning that behavior has in that culture, and what motivates people to be healthy in that culture,” says lead author Cynthia Levine.

    Healthy eating can help reduce one’s risk for a number of different diseases down the line, including heart disease, type 2 diabetes, and certain types of cancer.

    “In the U.S., having choice and control and being independent are very important,” says Levine. “Giving people lots of healthy choices or allowing people to feel that they have control over whether they eat healthy options is likely to foster healthier eating.”

    In Japan where the culture places more emphasis on interdependence and maintaining relationships, a focus on choice and control is less likely to be the key to more healthy eating, write the authors.

    “Instead,” says Levine, “in Japan, promoting healthy eating is likely to be most effective when it builds on and strengthens social bonds.”

    Research

    In a series of studies, the international team of researchers from the U.S., Japan, and Chile analyzed samples of eating habits of middle-aged adults in the United States and Japan. The researcher’s utilized data that included how often people eat certain items each week, including fish, vegetables, or sugary beverages, as well as some information on cholesterol and how participants relate to food when under stress.To understand how well people in each country fit in with the predominant culture, participants responded to a series of statements such as “I act in the same way no matter who I am with” (a statement reflecting independence) or “My happiness depends on the happiness of those around me” (a statement reflecting interdependence). Participants with high scores on independence have the best cultural fit in the U.S. Participants with high scores on interdependence have the best cultural fit in Japan.

    Healthy Habits

    In the U.S., which favors independence, being independent predicted eating a healthy diet including higher amounts of fish, protein, fruit, vegetables, and fewer sugary beverages. The research also showed the more independent adults were less likely to use food as a way to cope with stress.While the overall diets in Japan were healthier than U.S. participants, those in Japan who rated themselves as more interdependent showed healthier eating habits then their Japanese peers who did not.

    This research is consistent with other work showing that fitting into one’s culture shapes the healthiness of one’s food consumption.

    Levine is interested in utilizing these results for future studies that further reveal the role of culture in everyday behaviors.

    We would like to explore how these cultural differences in the meanings of common behaviors can be utilized to encourage healthy eating or healthy behaviors,” says Levine.

     


  9. Early supplementation may help offset early-life stress on the adult brain

    October 28, 2016 by Ashley

    From the Federation of American Societies for Experimental Biology media release:

    babies_cryingEarly-life stress has been shown to impair learning and memory in later life, but new research, published online in The FASEB Journal, suggests that improved nutrition may help offset the negative effects of this stress.

    Specifically, using mice, scientists focused on essential micronutrients, including methionine, vitamin B6 and vitamin B12, and folic acid, none of which are made by the body and need to be ingested through diet. They found that early-life stress reduces the levels of these nutrients in mouse pups, but supplementation prevented the reduction of methionine levels and even prevented some of the lasting negative effects of early-life stress on later learning and memory in adult offspring.

    “Today’s children are tomorrow’s future,” said Aniko Korosi, Ph.D., a researcher involved in the work from the Swammerdam Institute for Life Sciences and the Center for Neuroscience at the University of Amsterdam in Amsterdam, The Netherlands. “We hope that this study can contribute to novel nutritional strategies that help prevent lasting consequences of a stressful childhood on later mental health.”

    To make their discovery, Korosi and colleagues mimicked a stressful early-life environment during the first week after birth (postnatal days 2-9) for newborn mice and their mothers. Control mice and their mothers were housed in a normal environment. During the stress period, half of the mouse mothers (control and early-life stress) received a standard rodent diet, the other half received a diet that was supplemented with essential micronutrients. The lactating mouse mothers ate the diet and thereby developed elevated micronutrient levels in maternal milk and subsequently in the blood and the brains of their pups. After the initial stress period, all mice received a standard diet and environment. Once the mice became 4 months old, their learning and memory skills were tested in various cognitive/behavioral tasks. Mice that were previously exposed to early-life stress performed worse than control animals and demonstrated poor learning and memory skills. However, stress-exposed mice from mothers that received the supplemented diet performed equally well as the control mice did.

    “The field of postnatal nutrition has sometimes taken a back seat to research on the maternal-fetal axis, but of course we cannot ever ignore either,” said Thoru Pederson, Ph.D., Editor-in-Chief of The FASEB Journal. “Here we see strikingly beneficial cognitive effects of a sound postnatal diet. The nutrients tested were familiar ones, but the results speak for themselves.”

     


  10. Older adults gain weight when spouse is stressed out

    October 20, 2016 by Ashley

    From the University of Michigan media release:

    marriageStress isn’t good for your waist line. For older married couples, the added pounds may be caused by a spouse’s long-term stress levels.

    A new University of Michigan study looked at how the negative quality of marriage can be detrimental for weight gain — possibly leading to obesity — when couples 50 and older are stressed. The results varied by gender.

    The study specifically focused on chronic stress, which is an ongoing circumstance occurring for more than a year and threatens to overwhelm an individual’s resources, such as financial problems, difficulties at work or long-term caregiving.

    Participants came from the nationally longitudinal Health and Retirement Study at the U-M Institute for Social Research. The sample included 2,042 married individuals who completed questions about their waist circumference, negative marriage quality, stress levels and other factors in 2006 and 2010. Couples were married for an average of 34 years.

    Greater negative quality ties as reported by husbands exacerbated the effects of partner stress on both husbands’ and wives’ waist circumference.

    Interestingly, lower negative quality ties reported by wives exacerbated the effect of wife stress on husbands’ waist circumference, said Kira Birditt, a research associate professor at ISR’s Survey Research Center.

    For the increased risk of obesity, 59 percent of the husbands and 64 percent of the wives were at higher risk of disease in the study’s first assessment, whereas 66 percent of husbands and 70 percent of wives were at increased risk at the study’s conclusion.

    About 9 percent of the participants showed a 10 percent increase in waist circumference, which represented an average increase of four inches of more over four years, the study indicated.

    “Marriage has powerful influences on health,” said Birditt, the study’s lead author. “The stress experienced by partners, and not the individual’s stress, was associated with increased waist circumference. This effect of stress was even stronger in particular spousal relationships.”

    Husbands, she said, usually experience lower negative marital quality and thus greater negative feelings may be less expected and more harmful. Because women tend to report greater negative marital quality, low levels of negative marital quality among wives may be an indicator of a lack of investment in the marriage.

    Researchers said the study does not address what to do to lessen stress. However, other findings indicate that it’s important for couples to cope with stress together, and that goals created by a couple can be more effective than goals created individually.

    Birditt said the findings are applicable to younger couples. Previous research has shown that stress has strong effects on marital quality among this group, too.

    “We can only assume that this may translate into health effects, although they are probably not as strong on younger, often healthier, samples,” she said.

    The study’s other authors were Nicky Newton, assistant professor at Wilfrid Laurier University in Canada, and U-M researchers Jim Cranford and Noah Webster.

    The findings appear in the Journals of Gerontology: Social Sciences.