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Category: brain

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Several recent studies have found that constant exposure to high levels of air pollution has negative effects on the brain. The last post described negative effects on the gray matter in brains (resulting in smaller brain volumes) of elderly women from air pollution, but this study found negative effects (lower grade point averages) in young children from high air pollution. From Environmental Health News:

Bad air means lower grade point averages in Texas

Fourth and fifth graders in El Paso, Texas, are more likely to have lower grade point averages if heavily exposed to contaminated air at home, according to a new study.It bolsters a growing body of evidence that air pollution can impair success in school.

They found that for all types of air pollution sources, more exposure corresponded with lower grade point averages. Only one type of pollution—point sources such as factories—was not significantly linked to lower grade point averages.University of Texas at El Paso researchers analyzed the grade point averages of 1,895 children and, using their home location, estimated their exposure to air toxics—such as benzene, arsenic, lead, mercury, hydrochloric acid, toluene, vinyl bromide, xylenes, and diesel particulate matter—using federal data.

“Effects appear to be insidious, since they are mild, unlikely to be perceived, and, hence, unlikely to be addressed in any way … seemingly trivial effects on children’s development may translate into substantial impacts throughout the life course in terms of physical and mental health and personal success,” the authors wrote.The researchers did control for some other things that can affect children’s grades such as poverty, mother’s age, education and ability to speak English, and the child’s race and sex.

Still, the study doesn’t prove that dirty air makes kids do worse in school. It does, however, suggest children’s developing bodies are more susceptible to air pollution, which can harm their respiratory systems and brain.Air pollution might hamper kids’ grades via two primary ways: Illnesses, mostly respiratory, that would make them miss school, and developmental problems resulting from long-term exposure, said Sara Grineski, an associate professor of sociology at The University of Texas at El Paso and co-author of the new study.

Others have found similar links between air pollution and academic performance. Three months ago Columbia University's Perera and colleagues reported that New York City children born to mothers in poverty and exposed to certain air toxics during pregnancy had lower IQs.  Perera, tracking the mothers and children since before birth, said the pollution exposure prior to birth is more strongly linked to learning and behavioral problems. 

In the current study it’s unclear if the children were exposed in their mothers’ womb—an exposure window that is critical to brain development, Perera said....Other studies support this—in February Calderón-Garcidueñas and colleagues reported Mexico City smog was linked to impaired short-term memory and IQ in children.

The city is more than 80 percent Hispanic....Previous studies have shown that El Paso’s minorities are disproportionately impacted by toxics, Grineski said. The city of 675,000 is one of the worst when it comes to particulate matter—a mix of substances emitted by combustion sources, including cars, trucks, industrial plants and wood burning—especially coarse particulates, PM10, those between 2.5 and 10 micrometers (from about 25 to 100 times thinner than a human hair, according to the EPA). El Paso’s 24-hour PM10 average is about 233 micrograms per cubic meter of air, according to the latest EPA data from 2013, which was eighth highest among more than 500 U.S. cities. El Paso, along with Laredo, has the highest carbon monoxide levels in Texas.

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Several recent studies found that air pollution has a negative effect on the brain. This study of elderly women in North Carolina found that long-term exposure to higher levels of air pollution (specifically fine particulate matter smaller than 2.5 micrometers (called PM2.5) resulted in smaller brain volumes (especially the brain's white matter). They studied elderly women (aged 71 to 89), but the findings should be of concern to everyone exposed to high levels of air pollution.  White matter connects brain regions (with nerve fibers that pass signals throughout the brain) and determines how information is processed in the brain. The researchers pointed out that other recent studies reported that high air pollution is linked to cognitive decline and accelerated brain aging. From Futurity:

AIR POLLUTION MAY SHRINK BRAIN’S WHITE MATTER

Exposure to air pollution may have a negative impact on how the brain’s white matter ages. Older women who lived in geographic locations with higher levels of fine particulate matter in ambient air had significantly smaller white matter volumes across a wide range of brain areas, new research shows.

Fine particulate matter is smaller than 2.5 micrometers and is known as PM2.5, a form of pollution that easily enters the lungs and possibly the bloodstream. White matter connects brain regions and determines how information is processed in the brain....“Our study provides convincing evidence that several parts of the aging brain, especially the white matter, are an important target of neurotoxic effects induced by long-term exposure to fine particles in the air.”

The study found that older women ages 71 to 89 who had lived in places with greater PM2.5 exposures had significantly smaller volumes of white matter and that this could not be explained by the geographic region where they lived, their race or ethnic background, socioeconomic status, lifestyle, or medical conditions that may also influence brain volumes.

The researchers performed brain magnetic resonance imaging scans of 1,403 women who are part of the Women’s Health Initiative Memory Study (WHIMS), a nationwide report based at Wake Forest Baptist Medical Center in Winston-Salem, NC. The researchers also used residential histories and air monitoring data to estimate the participants’ exposure to air pollution in the previous six to seven years.

White matter contains nerve fibers and connects brain regions with each other by traveling deep within and passing nerve signals throughout the brain. Gray matter is primarily composed of neuronal cell bodies, dendrites, glial cells, and capillaries. The study did not find impacts from exposure to air pollution in participants’ gray matter.

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People fear dementia and Alzheimer's disease, because they are progressive diseases that nothing treats successfully. However, in the past year there have been some studies showing improvements with lifestyle changes (not cures, but for some the progression was slowed or showing some improvements).

The latest studies found that exercise (especially aerobic execise) had some beneficial effects on those with mild cognitive impairment (MCI), Alzheimer's disease, and vascular cognitive  impairment (VCI): neuropsychiatric improvements, improvements in biomarkers for the disease, and improved blood flow to the brain. From Medscape:

Physical Activity May Help Treat Dementia

New research shows that being physically active not only reduces cognitive decline and improves neuropsychiatric symptoms in patients with dementia but may actually reduce Alzheimer's disease (AD) biomarkers, including amyloid and tau protein in the brain. Exercise could also benefit patients with types of dementia other than AD, another study suggests.Some of this promising new research on exercise was presented at the Alzheimer's Association International Conference (AAIC) 2015. 

Danish researchers had already presented cognition-related results of the multicenter ADEX study ...The intervention consisted of 1 hour of aerobic exercise three times a week for 16 weeks. The control group received usual care..... The analysis found that these [neuropsychiatric] symptoms improved in the 66 patients in the "high exercise"group... The NI is a 12-item questionnaire that rates, among other things, depression, apathy, agitation, hallucinations, irritability, weight loss, and sleep."We saw that the control group got worse; there was a small decline in this group, which you would expect because this is progressive disease," said Steen Hasselbalch, MD, Danish Dementia Research Centre, Copenhagen, Denmark. "But the intervention group remained at the same level and even got a little better, so at end of the intervention there was a significant difference."

The question arises of whether exercise could not just delay worsening of symptoms but actually change brain pathology.The answer, suggests other research, is yes. In a separate study presented at the AAIC 2015, researchers found decreased phosphorylated tau (P tau) in older, previously sedentary persons completing a 6-month regimen of moderate- to high-intensity aerobic exercise.

The study enrolled 70 patients aged 55 to 89 years with prediabetes as well as amnestic mild cognitive impairment (MCI)....We think they are at high, high risk for developing dementia of the Alzheimer's type." These patients were randomly assigned to the aerobic exercise group or to the stretching group. Those in the aerobic group started slowly — 10 minutes of exercise a week — and gradually built the time and intensity up over 6 weeks to the point where they were exercising 45 minutes a day, 4 days a week, at 75% to 85% of their maximum heart rate...."This group had a choice of exercises: treadmill, stationary cycling, elliptical trainer, or preapproved group classes.

The stretching group, whose members could do balance exercises, gentle yoga, and other approved classes in addition to stretching, maintained a maximum heart rate of below 35%. All exercises were adapted to the needs and limitations of individual patients and were done at a local YMCA.

The researchers looked at biomarkers in cerebrospinal fluid (CSF), including P tau protein and amyloid β 42....Most intervention trials don't show such changes in P tau. "But we saw it with exercise and no medications," said Dr. Baker. "Exercise was enough to move a biomarker that indicates the severity of the disease."  It wasn't surprising, she added, that this was true only for older patients. "It may be that before age 70, you have a lot of compensatory mechanisms that help to maintain brain health, and after 70, those start breaking down."

The study also showed that the aerobic activity increased blood flow to the brain...The researchers demonstrated that the increased blood flow was in regions characteristically affected by aging and AD (ie, memory and processing). Cognitive benefits were particularly noteworthy for executive function..."Our brain imaging results are just fantastic; they show some really nice increases in blood flow in the areas of brain that support executive function and areas of the brain that normally show decreased flow for people with MCI, so it's reversing the blood flow detriment in MCI."

AD may not be the only dementia potentially treatable through exercise. Another study discussed at the meeting showed that this intervention may help those with vascular cognitive impairment (VCI). It's the first intervention trial to suggest that exercise can improve cognition in patients with confirmed VCI, said Teresa Liu- Ambrose, PhD, Canada Research Chair, University of British Columbia, Vancouver, Canada, who reported the results.The 6-month study included 71 patients aged 56 to 96 years with mild VCI of varying physical capacities. They were assigned to usual care that included a nutrition component or to an intervention of moderate-intensity walking, 3 times a week for an hour....In a subset of patients who had neuroimaging, there was "evidence of efficiency" in the brain of those who exercised, Dr Liu-Ambrose told Medscape Medical News.

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Recently I've seen a number of published studies that found benefits to someone being bilingual or benefits in learning a new language. Some benefits recently found in bilinguals (or the "billngual advantage"): more gray matter in the executive control area of the brain, 4 to 5 year delay in onset of Alzheimer's symptoms, processing of information more efficiently and more easily, and young bilingual children are more likely to think that everything is learned (while monolinguals more likely to think things are innate). From Science Daily:

Bilinguals of two spoken languages have more gray matter than monolinguals

A new study published in the journal Cerebral Cortex suggests people who speak two languages have more gray matter in the executive control region of the brain...Early on, bilingualism was thought to be a disadvantage because the presence of two vocabularies would lead to delayed language development in children. However, it has since been demonstrated that bilingual individuals perform better, compared with monolinguals, on tasks that require attention, inhibition and short-term memory, collectively termed "executive control."

This "bilingual advantage" is believed to come about because of bilinguals' long-term use and management of two spoken languages. But skepticism still remains about whether these advantages are present, as they are not observed in all studies...."Given this concern, we took a different approach and instead compared gray matter volume between adult bilinguals and monolinguals. We reasoned that the experience with two languages and the increased need for cognitive control to use them appropriately would result in brain changes in Spanish-English bilinguals when compared with English-speaking monolinguals. And in fact greater gray matter for bilinguals was observed in frontal and parietal brain regions that are involved in executive control."

Gray matter of the brain has been shown to differ in volume as a function of people's experiences. A prominent finding of this type was a report that London taxi drivers have more gray matter in brain areas involved in spatial navigation.

What about being bilingual leads to these advantages?....The researchers compared gray matter in bilinguals of American Sign Language (ASL) and spoken English with monolingual users of English...."Unlike the findings for the Spanish-English bilinguals, we found no evidence for greater gray matter in the ASL-English bilinguals," Olulade says. "Thus we conclude that the management of two spoken languages in the same modality, rather than simply a larger vocabulary, leads to the differences we observed in the Spanish-English bilinguals."

Science Daily: Bilingualism delays Alzheimer's manifestation by more than four years

The symptoms of Alzheimer disease (AD) manifest themselves about four to five years later in bilinguals as opposed to monolinguals. In bilinguals, the disease onset was estimated at the age of 77, while in monolinguals, this was at the age of 73.

From Science Daily:  Bilingual brains better equipped to process information

Speaking more than one language is good for the brain, according to new research that indicates bilingual speakers process information more efficiently and more easily than those who know a single language. The benefits occur because the bilingual brain is constantly activating both languages and choosing which language to use and which to ignore, said a researcher.

From Science daily:  Bilingualism changes children's beliefs

Most young children are essentialists: They believe that human and animal characteristics are innate. That kind of reasoning can lead them to think that traits like native language and clothing preference are intrinsic rather than acquired. But a new study suggests that certain bilingual kids are more likely to understand that it's what one learns, rather than what one is born with, that makes up a person's psychological attributes.

White and gray matter of the human brain. Credit: Medline Plus, US National Library of Medicine

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Huh - all that talk and research for years about the first born being the smartest and most responsible. Yes...but according to this large study comparing 377,00 high school students from different families, the differences are so small as to be meaningless (1 IQ point!). Researchers looking within-families (studying siblings within families) say that the effects are larger. Depends on who you want to believe. And this study did not look at the siblings later in life - at achievements, etc. From Medical Xpress:

Birth order has no meaningful effect on personality or IQ, massive study reports

For those who believe that birth order influences traits like personality and intelligence, a study of 377,000 high school students offers some good news: Yes, the study found, first-borns do have higher IQs and consistently different personality traits than those born later in the family chronology. However, researchers say, the differences between first-borns and "later-borns" are so small that they have no practical relevance to people's lives. The analysis found - as a previous large-scale study did - that first-borns enjoy a one-IQ-point advantage over later-borns, Damian said. The difference is statistically significant but meaningless, she said.

The analysis also revealed consistent differences in personality traits between first-borns and later-borns - first-borns tended to be more extroverted, agreeable and conscientious, and had less anxiety than later-borns, for example - but those differences were "infinitesimally small," amounting to a correlation of 0.02, Roberts said. "But in terms of personality traits and how you rate them, a 0.02 correlation doesn't get you anything of note. You are not going to be able to see it with the naked eye. You're not going to be able to sit two people down next to each other and see the differences between them.."

The study controlled for potentially confounding factors - such as a family's economic status, the number of children and the relative age of the siblings at the time of the analysis - that might skew the results, Damian said. For example, wealthier families tend to have fewer children than other families, and so have a higher proportion of first-borns who also have access to more resources that may influence their IQ or personality, she said.

Many previous studies of birth order suffered from small sample sizes, Damian said. Many compared children with their siblings - a "within-family" design that some assert is better than comparing children from different families, as the new analysis did.

The team also evaluated a subset of the children in the study - those with exactly two siblings and living with two parents. This allowed the researchers to look for specific differences between first- and second-borns, or second- and third-borns. The findings confirmed those seen in the larger study, with specific differences between the oldest and a second child, and between second and third children. But the magnitude of the differences was, again, "minuscule," Roberts said.

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The following article excerpts are from the talk "Food and Brain" about the best foods for the brain, at the annual 2015 meeting of the American Psychiatric Association (APA). This is in the new emerging field of food psychiatry, or how certain foods and diet influence the brain. The data is emerging that we can positively influence mental health through dietary interventions. For ex.: recent work reported that adults who followed the Mediterranean dietary pattern the closest over 4.4 years had a significantly reduced risk of developing depression (by 40% to 60%).

One key comment was: "Perhaps diet is the closest we've come to prevention in psychiatry." Some foods that are especially beneficial for the brain: seafood, greens, nuts, legumes (beans) and occasional dark chocolate. Use smaller amounts of meat (more as flavorings rather than just eating huge chunks of it) on top of a plant based diet. Also mentioned were the benefits of turmeric (because of the curcumin in it) and rosemary. And focus on improving the whole dietary pattern rather than just eating or not eating certain foods.

Note that BDNF is Brain-derived neurotrophic factor. This is a protein that acts on the brain, the nervous system, and it is very important for learning, memory, and higher thinking. So increasing BDNF levels is good. And remember, what's good for the brain is also good for the body and microbes - it's all intertwined. From Medscape:

Beans, Greens, and the Best Foods For the Brain

Dr Ramsey, in collaboration with the new International Society for Nutritional Psychiatry, is in the process of developing a standardized "brain food diet." "Food is a very effective and underutilized intervention in mental health," he started off. "We want to help our patients have more resilient brains by using whole foods...by helping get patients off of processed foods, off of white carbohydrates, and off of certain vegetable oils."

Though the field is in its infancy, food psychiatry is increasingly being embraced by clinicians and researchers, as a paper published earlier this year in the Lancet Psychiatry attests. "Although the determinants of mental health are complex," the authors wrote, "the emerging and compelling evidence for nutrition as a crucial factor in the high prevalence and incidence of mental disorders suggests that diet is as important to psychiatry as it is to cardiology, endocrinology, and gastroenterology." ..."The data are very promising that we can positively influence mental health through dietary interventions," commented Dr Ramsey.

"Hominid diets have changed drastically through millions of years of evolution.,,,But only in the past 100 years has our diet drastically switched from a whole foods diet to one that is more processed and high in refined carbohydrates; that includes more vegetable fats rather than meat fats; and preservatives, emulsifiers, and other additives, which appear to have contributed to a decline in our collective health.

Early humans evolved in the African Rift Valley, which is near a seacoast. It's possible that whatever evolutionary spark occurred that made us human occurred here, in part due to reliable access to seafood—oysters in particular—which glutted our brains with omega-3 fatty acids and cholesterol (our brains are composed of 60% fat). Oysters and other mollusks are also very high in nutrients, including B12, which is commonly deficient in people consuming vegan or vegetarian diets and is necessary for myelin and neurotransmitter function. 

A number of studies have linked the Mediterranean diet (high in fish oils, nuts, and grains and including maybe a little red wine) with advantageous effects on neurologic and mental health. Dr Deans cited recent work reporting that adults who followed the Mediterranean dietary pattern the closest over 4.4 years had a significantly reduced risk of developing depression (40%-60%)....When taken together, most of these dietary pattern studies, which have been conducted all over the world, consistently show that traditional, pre-processed diets are the healthiest, including for the brain. ..."Eat the rainbow," he says, given that bold, bright colors in nature tend to signify valuable vitamins and phytonutrients (the reds, purples, and greens in particular).

Seafood: Seafood is packed with brain-healthy omega-3 fatty acids. These healthy fats are also abundant in plants like chia and flax, but plant-based sources aren't as efficiently converted to docosahexaenoic acid (DHA), an important structural component of neuronal membranes. DHA also influences the expression of brain-derived neurotrophic factor (BDNF), which can benefit people who have mood and anxiety disorders. Bivalves like mussels, oysters, and clams are the top source of vitamin B12 as well as zinc: Six oysters (only about 10 calories each) provide 240% of our recommended daily B12 intake and 500% of our recommended zinc intake! Seafood is also a leading dietary source of vitamin D (we don't get it all from the sun) as well as iodine and chromium. Although many people worry about mercury in fish, Dr Ramsey provided an easy way around the concern: Eat small fish like sardines, anchovies, and herring, which typically don't accumulate toxic levels.

Leafy greens: A great base for a brain-food diet, leafy greens are a good source of fiber, folate (derived from the wordfoliage), magnesium, and vitamin K. Perhaps surprising, kale, mustard greens, and bok choy provide the most absorbable form of calcium on the planet, more so than milk. Greens also provide flavanols and carotenoids that have beneficial epigenetic influences (eg, including upping hepatic toxin processing). 

Nuts:... Nuts are packed with healthy monounsaturated fats. They help keep us full and also aid in absorbing fat-soluble nutrients. Nuts also provide fiber as well as minerals like manganese and selenium. A serving of 22 almonds (just 162 calories) contains 33% of our recommended vitamin E, plenty of protein, and minerals, including iron. One study from 2013 found that the Mediterranean diet augmented with nuts is associated with significantly higher BDNF levels in patients with depression.

Legumes: Dr Ramsey is pro-meat, but he acknowledges that many people are eating far too much and the wrong types of meat, and that nuts and legumes are a great alternative source of protein and nutrients...Some data suggest that vegan and vegetarian diets are associated with improved mood. But as previously mentioned, these dietary patterns can result in B12 deficiency, which has been associated with brain atrophy and developmental delay. Hence, supplementation is important in this population. Vegetarianism has also been linked with depression, anxiety, and eating disorders, as well as increased healthcare utilization and worse quality of life. These negative associations also could be due to the fact that it's harder to absorb nutrients like zinc, iron, and certain omega-3s from plants.

"The notion that the vegan diet is the healthiest diet on the planet is probably incorrect," said Dr Ramsey, before explaining that he just feels that we should approach meat in our diets differently....We want to help patients use beef and seafood more as flavorings on top of a plant-based diet." A modest amount of meat in the diet has its benefits, including nutrient availability: Hemoglobin-derived iron is up to 40% more absorbable than plant-based iron. Unlike most plants, meat provides all of the amino acids necessary for protein synthesis. Dr Ramsey emphasized the importance of seeking out leaner, grass-fed meats if one has the means.

The understanding of how microbiota contribute to our mental and medical well-being is rapidly advancing....One of the most powerful interventions to alter our microbiome is diet. Research shows that stressed mice experienced changes in the gastrointestinal microbiota, reflecting the gut-brain relationship. There are 260 million neurons connecting the gut and the brain; furthermore, many commensal gut bacteria make neurotransmitters and communicate with the brain via the vagus nerve....Although the science of probiotic therapies is relatively young, it's clear that these commensal organisms co-evolved with us and are adapted to our diet.

Finally, to close out the session, Dr Ramsey returned to the stage and asked, "So, can you eat to build a better brain? We think that you can if you focus on dietary patterns and not a single food here or there." He also reminded the audience to help their patients identify and increase their consumption of nutrient-dense foods and to "eat the rainbow,"..."I don't know of anything else that can potentially decrease the risk of depression in a population by 40%," he concluded. "Perhaps diet is the closest we've come to prevention in psychiatry."

...Evidence suggests that curcumin, an ingredient in turmeric, increases BDNF. Other research has found that populations that eat more curry have a decreased risk for dementia, while rosemary extract may help prevent cognitive impairment. "Many spices seem to have healing properties," Dr Ramsey commented.

Although the "Food and the Brain" session at the American Psychiatric Association annual meeting focused on what to eat in the interest of brain health, intermittent fasting might also be beneficial for the brain. In addition to helping maintain a healthy weight, fasting induces ketosis. Ketone metabolism has been shown to be beneficial for the brain and improve cognition in patients with mild cognitive impairment or Alzheimer disease. Keep in mind that fasting can come with risks for some people, particularly diabetics, and should be discussed with a healthcare provider.

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The wonders of nature! A small study found that taking a 90 minute walk in "natural" (wild) environments boost mental well-being by reducing rumination  (obsessive, negative thoughts focused on yourself). It is thought that rumination is associated with increased risk for depression and other mental illnesses. Rumination actually shows up in MRIs scans as increased activity in a brain region called the subgenual prefrontal cortex, an area of the brain that regulates negative emotions. The researchers suggest that these findings support the need for natural areas (parks) in urban areas.There have been a number of other studies finding that nature reduces stress and improves well being. Bottom line: take a walk in nature to feel better. From Medical Xpress:

Walking in nature found to reduce rumination

A team of researchers working at Stanford University has found that people walking in a "natural" environment tend to engage in less rumination...Biomedical researchers believe that some instances of both anxiety and/or depression come about due to what they call rumination—constantly flogging oneself with criticism of past mistakes and some studies have suggested that living in an urban environment might contribute to an increase in rumination. In this new effort, the researchers sought to learn if it might be possible for people to lessen the degree of rumination they engage in by simply going for a walk in a natural setting.

To find out, the team enlisted the assistance of 38 reasonably healthy adult male and female individuals—they were asked to participate in a study that consisted of taking questionnaires and undergoing fMRI scans before and after going for an hour and a half walk. The volunteers were split into two groups, one got to walk in a grassy area near the Stanford campus that was lined with lots of trees—the other group found themselves marching around in a strictly urban setting. The questionnaires were designed to illuminate rumination, while the fMRI scans focused on the subgenual prefrontal cortex—prior research showed it tended to light up during periods of rumination.

Afterwards, the researchers analyzed and crunched the data from the questionnaires and brain scans and came up with a rumination score which they then used to compare people in the two groups. They found that rumination remained level for the urban walkers but fell on average from 35.4 to 33.1 for the nature walkers. This the team claims, shows that taking a walk in a natural environment setting can reduce rumination, and possibly reduce symptoms of anxiety and depression, though they acknowledge that their sample size was small and suggest more research will need to be done to confirm their findings.

This study reveals a pathway by which nature experience may improve mental well-being and suggests that accessible natural areas within urban contexts may be a critical resource for mental health in our rapidly urbanizing world.

 Views from the nature (A and B) and urban (C and D) walks the participants took (PNAS)

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Could this be true? Eating fermented foods linked to fewer social anxiety symptoms? Fifteen years ago before the world of bacteria could be explored with state of the art genetic tests, this would have sounded too woo-woo. And now we say - could be. Next the researchers will test an experimental version of this study to see if they find causation. Right now all we can say they are linked or that we see an association.

But note that exercise also reduced social anxiety (this was also a finding in other studies). From Science Daily:

Decreased social anxiety among young adults who eat fermented foods

A possible connection between fermented foods, which contain probiotics, and social anxiety symptoms, is the focus of recent study...The researchers found that young adults who eat more fermented foods have fewer social anxiety symptoms, with the effect being greatest among those at genetic risk for social anxiety disorder as measured by neuroticism. "It is likely that the probiotics in the fermented foods are favorably changing the environment in the gut, and changes in the gut in turn influence social anxiety," said Hilimire. "I think that it is absolutely fascinating that the microorganisms in your gut can influence your mind."

The researchers designed a questionnaire that was included in a mass testing tool administered in the university's Introduction to Psychology courses during the fall 2014 semester; about 700 students participated. The questionnaire asked students about the fermented foods over the previous 30 days; it also asked about exercise frequency and the average consumption of fruits and vegetables so that the researchers could control for healthy habits outside of fermented food intake, said Hilimire.

"The main finding was that individuals who had consumed more fermented foods had reduced social anxiety but that was qualified by an interaction by neuroticism. What that means is that that relationship was strongest amongst people that were high in neuroticism," Hilimire said.The secondary finding was that more exercise was related to reduced social anxiety. 

"However, if we rely on the animal models that have come before us and the human experimental work that has come before us in other anxiety and depression studies, it does seem that there is a causative mechanism," said Hilimire. "Assuming similar findings in the experimental follow-up, what it would suggest is that you could augment more traditional therapies (like medications, psychotherapy or a combination of the two) with fermented foods -- dietary changes -- and exercise, as well."

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Two studies showing detrimental effects on children from pyrethroids in 2 weeks! The June 3 post was about research linking household pyrethroid exposure to ADHD in children and young teens. The second study found that low level childhood exposures to pyrethroid insecticides was linked to lower scores on an IQ test (Wechsler Intelligence Scale for Children - verbal comprehension and working memory) in 6 year old children. The researchers viewed this as evidence that pyrethroid insecticides may "negatively affect neurocognitive development".

Bottom line: even though pyrethroid pesticides are considered safer than many other pesticides, they still can have undesirable effects on humans, especially developing children. To be safe, use least toxic pest control that uses non-toxic, safe "alternative" or "natural" methods rather than just "spraying a chemical". Another possibility is looking for "organic pest control" or"least-toxic Integrated Pest Management" (IPM) that looks to deal with pest problems with non-toxic methods (which may include sealing holes, heat, caulking, trapping, using sticky traps, and even vacuuming up insects). From Science Daily:

Impact of insecticides on the cognitive development of 6-year-old children

Researchers have provided new evidence of neurotoxicity in humans from pyrethroid insecticides, which are found in a wide variety of products and uses. An increase in the urinary levels of two pyrethroid metabolites (3-PBA and cis-DBCA) in children is associated with a significant decrease in their cognitive performances , particularly verbal comprehension and working memory. This study was carried out on nearly 300 mother and child pairs from the PELAGIE cohort (Brittany).

Pyrethroids constitute a family of insecticides widely used in a variety of sectors: agriculture (various crops), veterinary (antiparasitics) and domestic (lice shampoo, mosquito products). Their mode of action involves blocking neurotransmission in insects, leading to paralysis. Because of their efficacy and relative safety for humans and mammals, they have replaced older compounds (organochlorides, organophosphates, carbamate) considered more toxic.

Exposure of children to pyrethroids is common. It is different to adult exposure, due to the closer proximity of children to ground-level dust (which stores pollutants), more frequent hand-to-mouth contact, lice shampoos, etc. In children, pyrethroids are mainly absorbed via the digestive system, but are also absorbed through the skin. They are rapidly metabolised in the liver, and mainly eliminated in the urine as metabolites within 48 hours.

Pregnancy is also an important period of life for the future health of the child. For this reason, the researchers studied the PELAGIE mother-child cohort established between 2002 and 2006, which monitors 3,500 mother-child pairs. This cohort simultaneously considers exposure to pyrethroid insecticides during fetal life and childhood. A total of 287 women, randomly selected from the PELAGIE cohort and contacted successfully on their child's sixth birthday, agreed to participate in this study.

Two psychologists visited them at home. One assessed the child's neurocognitive performances using the WISC scale (verbal comprehension index, VCI, and working memory index, WMI). The other psychologist characterised the family environment and stimuli that might have had a role on the child's intellectual development, collected a urine sample from the child, and collected dust samples. Exposure to pyrethroid insecticides was estimated by measuring levels of five metabolites (3-PBA, 4-F-3-PBA, cis-DCCA, trans-DCCA and cis-DBCA) in urine from the mother (collected between the 6th and 19th weeks of pregnancy) and from the child (collected on his/her 6th birthday).

Results show that an increase in children's urinary levels of two metabolites (3 PBA and cis-DBCA) was associated with a significant decrease in cognitive performances, whereas no association was observed for the other three metabolites (4-F-3-PBA, cis-DCCA and trans-DCCA). With respect to metabolite concentrations during pregnancy, there was no demonstrable association with neurocognitive scores.

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Textbooks will have to be rewritten with the recent discovery of a system of lymphatic vessels that are a direct link from the immune system to the brain. Amazing that after centuries of studying people, that only now was this system detected (but they are very small and they follow a major blood vessel down into the sinuses). After extensive research,  the researchers determined that these vessels carry both fluid and immune cells from the cerobrospinal fluid, and that they exist in humans. The discovery reinforces findings that immune cells are present even within healthy brains, a notion that was doubted until recently.From Medical Daily:

Discovery Of 'Missing Link' Between Brain And Immune System Could Change How Disease Is Studied

The recent discovery of a "missing link" between the brain and the immune system may lead to a complete revision of biology textbooks. The link, vessels of the lymphatic system that run through the sinuses, were previously unidentified and thought not to exist. However, the true significance of the discovery lies in the potential effects this finding could have on both the study and treatment of neurological diseases such as Alzheimer’s disease and multiple sclerosis.  

The newly discovered "central nervous system lymphatic system vessels" follow a major blood vessel down into the sinuses, an area that has been traditionally difficult to obtain images of. Their presence is causing a stir in the medical world, as the researchers responsible believe the vessels may help to explain current medical mysteries, such as why patients with Alzheimer’s disease have accumulations of large protein plaques in the brain.

The fascinating discovery was made by researchers at the University of Virginia School of Medicine, and a study on the finding is currently available in the online journal Nature....Using a recently developed method, the team mounted the meninges, the membranes covering the brain, on a single slide so that they could be better observed. Only after doing this were they able to notice the brain’s elusive lymphatic vessels.   "It's so close to the blood vessel, you just miss it," Kipnis said. "If you don't know what you're after, you just miss it."

The team believes that the “missing link” between the brain and the immune system could explain why some diseases like Alzheimer’s can cause plaque buildup in the brain. Kipnis believes this plaque may be the result of the meningeal lymphatic vessels not efficiently removing buildup before it reaches the brain. Although scientists are currently not sure what causes cell death and tissue loss in the brains of those with Alzheimer’s, this plaque buildup is believed to play a role.

It’s not just the presence of plaque in the brain that the researchers hope this discovery can shed light on. According to Kipnis, this discovery could completely change the way we perceive the neuro-immune interaction.“We believe that for every neurological disease that has an immune component to it, these vessels may play a major role,” Kipnis said. “Hard to imagine that these vessels would not be involved in a [neurological] disease with an immune component.”The vessels also appear to look different with age, which has lead the researchers to suggest that they may play a role in the aging process.

 

Maps of the lymphatic system: old (left) and updated to reflect UVA's discovery.   Credit: University of Virginia Health System