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Published on Leave a comment on Gut Microbe Differences Between Active and Sedentary Women

A new study found differences in gut microbes between active women (they exercised at least the recommended amount) and those that are sedentary. When the gut bacteria were analyzed with modern tests (genetic sequencing) the active women had more of the health promoting beneficial bacteria such as Faecalibacterium prausnitzii, Roseburia hominis, and Akkermansia muciniphila than the sedentary women. The sedentary women also had some bacterial species not seen in the active women. The researchers said that exercise "modifies the composition of gut microbiota" (the gut microbes) in a way beneficial for health.

And what is the recommended minimal amount of exercise? The World Health Organization recommends at least 3 days of exercise per week for 30 minutes at a moderate intensity. Note that exercise can mean doing exercises, but it can also include walking briskly, intense housework (scrubbing, vacuuming with lots of bending, etc.), gardening (digging, raking, etc), or shoveling snow, etc. In this study the group of active women had at least 3 hours of physical exercise per week. Note that a sedentary lifestyle is associated with a high incidence of chronic diseases such as cardiovascular disease, cancer and diabetes, while physical exercise or activity has metabolic and immune health benefits (prevents disease).

But...reading the full study, the research also showed that the active group ate more fruits and vegetables - which we know has an effect on the gut microbiome and feeds beneficial bacteria. Although the diets of the 2 groups of women were similar in total carbohydrates, protein and fat content eaten, the active women ate more fruits, vegetables, and fiber, and the sedentary group ate more processed meat. So it looks like both exercise and a good amount of fruits and vegetables may be important for nurturing beneficial bacteria. By the way, the 3 species of beneficial bacteria mentioned currently are not found in any probiotic supplements on the market. (Earlier posts on the beneficial F. prausnitzii and Akkermansia muciniphila). From C. Bressa et al research article in PLoS ONE:

Differences in gut microbiota profile between women with active lifestyle and sedentary women

Physical exercise is a tool to prevent and treat some of the chronic diseases affecting the world’s population. A mechanism through which exercise could exert beneficial effects in the body is by provoking alterations to the gut microbiota, an environmental factor that in recent years has been associated with numerous chronic diseases. Here we show that physical exercise performed by women to at least the degree recommended by the World Health Organization can modify the composition of gut microbiota. Using high-throughput sequencing of the 16s rRNA gene, eleven genera were found to be significantly different between active and sedentary women. Quantitative PCR analysis revealed higher abundance of health-promoting bacterial species in active women, including Faecalibacterium prausnitzii, Roseburia hominis and Akkermansia muciniphila. Moreover, body fat percentage, muscular mass and physical activity significantly correlated with several bacterial populations. In summary, we provide the first demonstration of interdependence between some bacterial genera and sedentary behavior parameters, and show that not only does the dose and type of exercise influence the composition of gut microbiota, but also the breaking of sedentary behavior. ...continue reading "Gut Microbe Differences Between Active and Sedentary Women"

Published on Leave a comment on Gut Bacteria Associated With Strokes

After writing about Lactobacillus sakei in the sinuses for several years (present in healthy sinuses, absent or less in those with chronic sinusitis, and also a treatment for chronic sinusitis), I wondered whether L. sakei is found anywhere else in the body. Today I read a study (conducted in Japan) about gut microbes and strokes and there it was - the presence of L. sakei in the gut.

Specifically, a study found that people who have ischemic strokes tend to have lower amounts ("depletion") of L. sakei in the gut than healthy people, even though it was detected in 80% of both groups.

The study found that in people with ischemic strokes there was evidence for the gut microbes being out of whack (dysbiosis), as well as more inflammation, and more of certain bacteria species (Atopobium cluster and Lactobacillus ruminis), and depletion of L. sakei bacteria.

The researchers took samples of stool (fecal samples) from each person of both groups (ischemic stroke group and healthy group) and analyzed the stool with modern tests (genetic sequencing) to see whether 22 groups of bacteria were in it. (Note that there are normally hundreds of species of bacteria living in a healthy person's gut, as well as viruses, fungi, etc.).

So once again it looks like L. sakei may be beneficial bacteria, even in the gut. The researchers were careful to point out that they couldn't say that certain bacteria caused the strokes - just that there was an association.

And what diet is associated with lower levels of inflammation in the body? Once again - a diet with lots of fruits, vegetables, whole grains, nuts, seeds, and legumes (think Mediterranean style diet). You want to feed the beneficial bacteria in the gut.

Excerpts from a research article by Yamashiro et al in PLoS One: Gut dysbiosis is associated with metabolism and systemic inflammation in patients with ischemic stroke

The role of metabolic diseases in ischemic stroke has become a primary concern in both research and clinical practice. Increasing evidence suggests that dysbiosis is associated with metabolic diseases. The aim of this study was to investigate whether the gut microbiota, as well as concentrations of organic acids, the major products of dietary fiber fermentation by the gut microbiota, are altered in patients with ischemic stroke, and to examine the association between these changes and host metabolism and inflammation.

We analyzed the composition of the fecal gut microbiota and the concentrations of fecal organic acids in 41 ischemic stroke patients and 40 control subjects via 16S and 23S rRNA-targeted quantitative reverse transcription (qRT)-PCR and high-performance liquid chromatography analyses..... Although only the bacterial counts of Lactobacillus ruminis were significantly higher in stroke patients compared to controls, multivariable analysis showed that ischemic stroke was independently associated with increased bacterial counts of Atopobium cluster and Lactobacillus ruminis, and decreased numbers of Lactobacillus sakei subgroup, independent of age, hypertension, and type 2 diabetes....Together, our findings suggest that gut dysbiosis in patients with ischemic stroke is associated with host metabolism and inflammation.   ...continue reading "Gut Bacteria Associated With Strokes"

Published on Leave a comment on Should Pregnant Women Be Warned To Avoid Licorice?

Avoid eating licorice during pregnancy? That licorice is a food to avoid during pregnancy (or only eat in tiny amounts) will be news to many. Most people think of licorice (or liquorice) as a candy, but it can also be used as a herbal medicine that can have negative health effects, especially in large doses (e.g, high blood pressure, loss of potassium). The licorice flavor comes from the root of the plant (licorice root). Licorice contains glycyrrhizin, which is in black licorice candy, and in some chewing gums, ice creams, syrups, soft drinks, supplements, herbal teas, and other products.

In 2016, the government of Finland warned against consuming licorice (including black licorice and salty licorice) during pregnancy. In the United States, the FDA does not warn pregnant women about eating licorice or licorice root. The National Institutes of Health (NIH) recommends that pregnant women avoid consuming large amounts of licorice root in food or taking it as a supplement. But how about small amounts of licorice? And what are possible effects during pregnancy?

A recent study in Finland compared children (average age of 12 1/2 years) whose mothers had either consumed little to no licorice during pregnancy or had consumed large amounts of licorice (high glycyrrhizin levels were calculated as more than 500 milligrams per week). Note that 500 mg glycyrrhizin is equal to 250 grams or 8.8 oz licorice. The researchers found that children whose mothers ate large amounts of licorice during pregnancy  were about 7 points lower on IQ tests, had poorer memory, and had higher rates of attention deficit/hyperactivity disorder problems than those whose mothers had eaten little or no licorice during pregnancy. High-consumption group girls had earlier and more advanced puberty, and were taller and heavier than those in the low-licorice group.

The researchers wrote that glycyrrhizin results in "glucocorticoid overexposure", which may affect the developing fetus, and the effects persist into early adolescence. The study researchers concluded that pregnant women should be informed that consumption of licorice and other food products containing glycyrrhizin may be associated with harm to their developing baby. A little licorice candy here and there during pregnancy seems to be OK (so don't panic!), but licorice or licorice root is not something that should be eaten or drunk (e.g.,in a tea) regularly. From Science Daily:

Pregnant women should avoid liquorice

A new Finnish study supports food recommendations for families with children in that women should avoid consuming large amounts of liquorice during pregnancy. The limit for safe consumption is not known. In the study, youths that were exposed to large amounts of liquorice in the womb performed less well than others in cognitive reasoning tests carried out by a psychologist. The difference was equivalent to approximately seven IQ points. Those exposed to liquorice also performed less well in tasks measuring memory capacity, and according to parental estimates, they had more ADHD-type problems than others. With girls, puberty had started earlier and advanced further.

The Glaku study carried out by the University of Helsinki, the National Institute for Health and Welfare and the Helsinki and Uusimaa hospital districts compared 378 youths of about 13 years whose mothers had consumed "large amounts" or "little/no" liquorice during pregnancy. In this study a large amount was defined as over 500 mg and little/no as less than 249 mg glycyrrhizin per week. These cutoffs are not based on health effects. 500 mg glycyrrhizin corresponds on average to 250 g liquorice.

Researchers suggest that pregnant women and women planning pregnancy should be informed of the harmful effects that products containing glycyrrhizin -- such as liquorice and salty liquorice -- may have on the fetus. In Finland, this is already reality. In January 2016, the National Institute for Health and Welfare published food recommendations for families with children, in which liquorice was placed in the 'not recommended' category for pregnant women. According to the recommendations, occasional consumption of small amounts such as a portion of liquorice ice cream or a few liquorice sweets is not dangerous.

As a result of animal experiments, the biological mechanism of the effects of liquorice is well known. Glycyrrhizin intensifies the effects of stress hormone cortisol by inhibiting the enzyme that inactivates cortisol. While cortisol is essential to the development of a fetus, it is detrimental in large amounts. It has long been known that glycyrrhizin causes higher blood pressure and shorter pregnancies in humans, but such long-lasting effects on the fetus have not been proven before. [Original study.]

Published on Leave a comment on Gut Bacteria Linked to Hypertension?

Interesting idea - that perhaps our community of gut microbes being out of whack (dysbiosis) leads to hypertension. This study was done in both humans and mice - with an analysis of bacteria in both hypertensive individuals and pre-hypertensives, and also healthy individuals (the controls). Then the microbes from 2 hypertensive individuals were transplanted into mice (fecal microbiota transplants). And lo and behold - the mice became hypertensive with an alteration of their gut microbes. This is amazing!

The study showed that transplanting microbes from hypertensives to non-hypertensives caused an elevation in blood pressure in the formerly healthy group. This shows the direct influence of gut microbes on blood pressure. The bacteria found in both the pre-hypertensives and hypertensives (especially an overgrowth of Prevotella and Klebsiella bacteria) are those linked to inflammation. And what kind of diet is linked to that bacteria? A high fat diet. Yes, the Western diet with lots of fat and highly processed foods.

The researchers talked about other research also showing Prevotella being associated not only with hypertension, but also other diseases (e.g., periodontal diseases and rheumatoid arthritis). On the other hand, Faecalibacterium, Oscillibacter, Roseburia, Bifidobacterium, Coprococcus, and Butyrivibrio, which were "enriched" in healthy controls, were lower in pre-hypertensive and hypertensive persons. In the past I have posted about a "special" bacteria that is even called  a "keystone" gut bacteria - Faecalibacterium prausnitzii - that is linked to health and is low or absent in the gut in a number of diseases ((here and here). It is not available in a supplement at this time (because it dies within a few minutes upon exposure to oxygen), but diet influences it. A high animal meat, high animal fat, high sugar, highly processed foods, and low fiber diet (the typical Western diet) lowers F. prausnitzii numbers, while a high-fiber, low meat diet increases F. prausnitzii numbers.

What you can do: Feed the beneficial gut microbes by increasing the amount of fruits, vegetables, whole grains, seeds, nuts that you eat. And cut back on the greasy, high fat processed and fast foods.

The following excerpt is misleading - for example, it ignores the first part of the actual study which looked at the gut bacteria of pre-hypertensives, hypertensive, and healthy people. Then gut bacteria from hypertensive people were transplanted into healthy mice, and gut bacteria from healthy people were transplanted into hypertensive mice. Also, it wasn't rats, but mice used in the study. It goes to show why it's important to look at original studies - not just believe articles out there blindly. [See original study.] From Science Daily: Unhealthy gut microbes a cause of hypertension, researchers find

Researchers have found that the microorganisms residing in the intestines (microbiota) play a role in the development of high blood pressure in rats mice....Scientists studied two sets of rats mice, one group with high blood pressure ("hypertensive") and one with normal blood pressure ("normal").... All animals were then given antibiotics for 10 days to reduce their natural microbiota. After the course of antibiotics, the researchers transplanted hypertensive microbiota to normal blood pressure rats mice and normal microbiota to the hypertensive group. 

The researchers found that the group treated with hypertensive microbiota developed elevated blood pressure. A more surprising result is that the rats mice treated with normal microbiota did not have a significant drop in blood pressure, although readings did decrease slightly. This finding is "further evidence for the continued study of the microbiota in the development of hypertension in humans and supports a potential role for probiotics as treatment for hypertension," wrote the researchers. "Studies showing that supplementing the diet with probiotics (beneficial microorganisms found in the gut) can have modest effects on blood pressure, especially in hypertensive models."

NOTE that the actual study said in its CONCLUSIONS:  "Taken together, we have described clearly the disordered profiles of gut microbiota and microbial products in human patients with pre-hypertension and hypertension, established the relationship between gut dysbiosis and hypertension, and provided important evidence for the novel role of gut microbiota dysbiosis as a key factor for blood pressure changes. Our findings point towards a new strategy aimed at preventing the development of hypertension and reducing cardiovascular risks through restoring the homeostasis of gut microbiota, by improving diet and lifestyle or early intervening with drugs or probiotics."

Published on Leave a comment on Eating An Egg A Day May Be Beneficial?

Remember all the dietary advice that for years told us to avoid or limit consumption of eggs - that since they were high in cholesterol, they were bad for us and would increase our risk for heart disease? And the nonsense that we should only eat the egg whites while throwing out the yolks? Hah...That advice was wrong, which another recent study confirms.

Eggs are an amazingly nutritious food. They’re loaded with high quality protein, healthy fats, vitamins, minerals, high in choline (a brain nutrient), biotin, antioxidants, lutein, and zeaxanthin. One review of studies (involving millions of people) looked at whole egg consumption  and found that high egg consumption (up to one egg per day) is not associated with increased risk of coronary heart disease or stroke, and in fact there was a reduced risk of hemorrhagic stroke. Only among diabetics was there an elevated risk of coronary heart disease with high egg consumption (up to 1 egg per day). Another study found a lower risk of type 2 diabetes in middle-aged men (see post).

A recent study from Finland found that neither cholesterol nor egg intake (eating one egg per day) was associated with an increased risk of dementia or Alzheimer's disease in Finnish men who were followed for 22 years. Instead, eating eggs was associated with better cognitive performance in certain areas such as executive function, which includes memory, problem solving, and planning (they were given neuropsychological tests). From Science Daily:

High cholesterol intake and eggs do not increase risk of memory disorders

A new study from the University of Eastern Finland shows that a relatively high intake of dietary cholesterol, or eating one egg every day, are not associated with an elevated risk of dementia or Alzheimer's disease. Furthermore, no association was found in persons carrying the APOE4 gene variant that affects cholesterol metabolism and increases the risk of memory disorders. APOE4 is common in Finland.

The dietary habits of 2,497 men aged between 42 and 60 years and with no baseline diagnosis of a memory disorder were assessed at the onset the Kuopio Ischaemic Heart Disease Risk Factor Study, KIHD, in 1984-1989 at the University of Eastern Finland. During a follow-up of 22 years, 337 men were diagnosed with a memory disorder, 266 of them with Alzheimer's disease. 32.5 per cent of the study participants were carriers of APOE4.

The study found that a high intake of dietary cholesterol was not associated with the risk of dementia or Alzheimer's disease -- not in the entire study population nor in the carriers of APOE4. Moreover, the consumption of eggs, which are a significant source of dietary cholesterol, was not associated with the risk of dementia or Alzheimer's disease. On the contrary, the consumption of eggs was associated with better results in certain tests measuring cognitive performance. 

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Published on 1 Comment on A Lot of Fast Food Packaging Contains Harmful Chemicals

Another study is adding to the evidence that food packaging  is frequently coated  with harmful chemicals - called perfluorinated chemicals or PFCs. The chemicals are used because they resist grease and stains, but unfortunately they then leach into the food, and when people eat the food - it gets into them. The evidence is also growing that these chemicals have all sorts of harmful health effects, including endocrine disruption (they are hormone disruptors) - even in low doses. They are linked to kidney and testicular cancer, high blood cholesterol levels, thyroid problems, development and immune system problems, low birth weights, and decreased sperm quality. (See earlier post) The list keeps growing each year.

Researchers tested about 400 pieces of food packaging from 27 fast food chains,  including McDonald’s, Burger King, Taco Bell, Chick-Fil-A, Quiznos, Starbucks, and Dunkin’ Donuts (see how they scored). Overall, about 33 percent of the packages contained fluorine (a chemical not found in paper, but is an indicator of perfluorinated chemicals present to make the packaging grease and stain resistant). What is even more disturbing is that when the researchers more closely examined 20 samples to find out exactly what fluorinated compounds they contained - they found that 6 of the more rigorously tested packages contained PFOA (which was used in Teflon). PFOA was phased out for use in the USA years ago due to it being so long-lasting in the environment and its serious health effects, but other countries still produce it. Unfortunately, even the replacement chemicals  seem to be similarly harmful (not surprising because of the chemical similarities), and they also persist in the environment.

It should be pointed out that perfluorinated chemicals are also used in products such as stain and water resistant coatings on clothing, upholstery, carpeting and floor waxes. They are in non-stick coatings in pots and pans. The chemicals leach or migrate out of products and degrade very slowly — thus showing up in air, household dust, water, dirt, wildlife, and people. Yes, studies show that almost everyone in the U.S. has these chemicals in their blood, and unfortunately some of them can stay in the body for years. PFCs pass from mothers to their babies during pregnancy, and in breast milk after birth. Exposure to perfluorinated chemicals from fast food packaging is of big concern for children, because one-third of U.S. children consume fast food daily, and children may be especially susceptible to the adverse health effects.

Yes, we are surrounded by a sea of harmful chemicals that are tough to avoid, but we should at least try to minimize our exposure. Fast food restaurants should be encouraged to use nontoxic alternatives (e.g., aluminum foil or wax paper) - after all, the study showed that there is packaging out there without these chemicals.

What can we do to avoid PFCs? 1) Try to avoid or eat less fast food and food that comes in "grease-proof" containers. 2) Don't use non-stick pots and pans - use stainless steel instead. 3) Try to avoid clothing, upholstered furniture, and carpets with stain and water-resistant coatings. 4) Don't use microwave popcorn bags, and try to avoid microwaving foods in their packaging - use a glass dish instead. 5) Don't use dental floss such as Oral-B Glide dental floss (uses PFC), and use unwaxed or natural wax floss instead. 6) Avoid personal care products that contain ingredients that include the words “fluoro” or “perfluoro". *Please check out the Environmental Working Group site for more information (here and here).

From Science Daily: Extensive use of fluorinated chemicals in fast food wrappers: Chemicals can leach into food

Americans may be consuming fast food wrapped in paper treated with perfluorinated chemicals (PFCs) -- the same chemicals used in stain-resistant products, firefighting materials and nonstick cookware, according to a new study published in the journal Environmental Science & Technology.

Researchers tested more than 400 samples of packaging materials, including hamburger and sandwich wrappers, pastry bags, beverage cups and French fry containers, and found evidence of fluorinated compounds called per- and polyfluoroalkyl substances (PFASs). Of the materials tested, these chemicals were found in 56 percent of dessert and bread wrappers, 38 percent of sandwich and burger wrappers and 20 percent of paperboard.

Previous studies have shown that these PFASs can migrate, contaminating the food and, when consumed, accumulating in the body....Previous studies have linked PFASs to kidney and testicular cancers, thyroid disease, low birth weight and immunotoxicity in children, among other health issues. The chemicals have an especially long half-life and take many years before just 50 percent of the intake leaves the human body. The results are concerning when considering the role of fast food in the American diet. The National Center for Health Statistics reported one-third of U.S. children consume fast food daily.

Samples were collected from a total of 27 fast food restaurant chains including McDonald's, Burger King, Chipotle, Starbucks, Jimmy Johns, Panera and Chick-Fil-A, in and around Boston, San Francisco, Seattle, Washington, D.C., and Grand Rapids, Michigan. The study did not include takeout containers, such as Chinese food boxes or pizza boxes. [Original study]

Published on Leave a comment on Older Adults, Exercise, and the Brain

 Once again, research supports that you should get off your butt and exercise! Or do a moderate to vigorous physical activity at least several times a week, which can include housework, gardening, dancing, swimming, or walking briskly. Most important is to MOVE. And why is this so important? Not just for physical health and prevention of certain diseases, but also for the health of your brain, especially as it ages.

The research looked at both 31 young healthy adults (18 to 31 years old) and 26 older healthy adults (55 to 74 years old), assessed their cardiorespiratory (heart/lung) fitness on the treadmill, gave them a number of neurological tests, and also a memory task while their brain activity was observed during functional Magnetic Resonance Imaging (fMRI). They found that the older adults with higher heart/lung fitness had better performance on the memory task and greater brain activity in multiple regions than the older adults with low heart/lung fitness. The increased brain activity in those with higher levels of heart/lung fitness occurred in brain regions typically affected by age-related decline - in other words, higher fitness in older adults reduced some age-related differences.

The researchers thought these and other study results indicate that heart/lung fitness (cardiorespiratory fitness) may keep the brain younger (that is, it preserves neurological function and "neuroplasticity") as people age. They pointed out that some recent studies have revealed that lower cardiorespiratory (heart/lung) fitness was associated with accelerated cognitive decline and that older adults with lower heart/lung fitness had an increased risk for dementia.

From Health Day: Fitter Seniors May Have Healthier Brains

Good heart and lung fitness can benefit older adults' brains, researchers report.They assessed the heart/lung fitness of healthy young adults (aged 18 to 31) and older adults (aged 55 to 74), and compared their ability to learn and remember the names of strangers in photos. MRI scans recorded images of their brain activity as they learned the names.

The older adults had more difficulty with the memory test than the young adults. But older adults with high levels of heart/lung fitness did better on the test and showed more brain activity when learning new names than those of their peers with lower levels of heart/lung fitness. The increased brain activity in those with higher levels of heart/lung fitness occurred in regions typically affected by age-related decline. The findings suggest that heart/lung fitness may also help keep the brain healthy as people get older, according to the researchers. But the study did not prove a cause-and-effect link.

"Importantly, [heart/lung fitness] is a modifiable health factor that can be improved through regular engagement in moderate to vigorous sustained physical activity such as walking, jogging, swimming or dancing," said study corresponding author Scott Hayes....The researchers said high levels of fitness will not prevent brain decline, but may slow it.

An excerpt from the original study, from Cortex: FMRI activity during associative encoding is correlated with cardiorespiratory fitness and source memory performance in older adults

For brain regions in which older adults showed reduced activation relative to young adults, including left inferior frontal gyrus, medial frontal gyrus, bilateral thalamus, and fusiform gyrus, we observed a step-wise pattern, with the greatest activation in young adults, followed by high CRF [cardiorespiratory fitness] older adults and then low CRF older adults, indicating that higher fitness in older adults reduced age-related differences. These findings suggest that CRF supports successful brain maintenance in aging, in that it promotes the preservation of neural function seen in young adults (Nyberg, Lovden et al., 2012). 

Published on Leave a comment on Air Pollution, the Aging Brain, and Dementia

Another study finding a link between air pollution and negative health effects - this time a higher incidence of decline in cognitive functioning  and dementia in older women (65 and older) exposed to fine particles (PM2.5 ). These extremely small particles from vehicle emissions are a major source of urban air pollution throughout the world. These results match other studies finding a link with urban air pollution, especially vehicle traffic, to negative effects on the brain (dementia, cognitive decline, shrinking of the brain, etc.). The researchers also exposed mice to this air pollution for 15 weeks and then studied their brains for evidence of degenerative effects in their brains - and yes, they did find them.

The researchers found that the adverse effects of fine particulate air pollution was stronger in both women and mice who had the APOE4 gene, a genetic variation that increases the risk for Alzheimer's disease. They said that while the air pollution has negative effects in general, that having the APOE4 gene interacted with the air pollution. The researchers also wrote that the mice studies they did showed that "...exposure to urban airborne particulates can intensify amyloid accumulation and neurodegeneration". Medical Xpress:

Air pollution may lead to dementia in older women

Tiny air pollution particles—the type that mainly comes from power plants and automobiles—may greatly increase the chance of dementia, including Alzheimer's disease, according to USC-led research. Scientists and engineers found that older women who live in places with fine particulate matter exceeding the U.S. Environmental Protection Agency's standard are 81 percent more at risk for global cognitive decline and 92 percent more likely to develop dementia, including Alzheimer's.

If their findings hold up in the general population, air pollution could be responsible for about 21 percent of dementia cases, according to the study. "Microscopic particles generated by fossil fuels get into our body directly through the nose into the brain," said University Professor Caleb Finch at the USC Leonard Davis School of Gerontology and co-senior author of the study. "Cells in the brain treat these particles as invaders and react with inflammatory responses, which over the course of time, appear to exacerbate and promote Alzheimer's disease.

The adverse effects were stronger in women who had the APOE4 gene, a genetic variation that increases the risk for Alzheimer's. "Our study .....provides the inaugural scientific evidence of a critical Alzheimer's risk gene possibly interacting with air particles to accelerate brain aging," said Jiu-Chiuan Chen, co-senior author of the study....[Their study] adds to an emerging body of research from around the world that links air pollution to dementia. The offending pollutants—known as PM2.5—are fine, inhalable particles with diameters 2.5 micrometers or smaller. A human hair is about 70 micrometers in diameter, making it 30 times larger than the largest PM2.5. The researchers analyzed data of 3,647 65- to 79-year-old women from the Women's Health Initiative Memory Study (WHIMS). These women lived across 48 states and did not have dementia when they enrolled.

USC scientists chronically exposed female mice carrying the APOE4 gene to nano-sized air pollution for 15 weeks. Compared to the control group, mice predisposed to Alzheimer's disease accumulated as much as 60 percent more amyloid plaque, the toxic clusters of protein fragments that further the progression of Alzheimer's.

In other studies, Chen and his colleagues linked long-term exposure to high PM2.5 levels to smaller gray and white matter volumes in important areas such as the frontal lobe, which carries out thinking, decision-making and planning. For every 3.5 micrograms of PM2.5 per cubic meter of air, white matter (insulated nerve fibers that connect different brain regions) decreased by 6 cubic centimeters, according to one earlier study. [see post]

Published on Leave a comment on Environmental Pollutants and Gut Microbes

What things in our environment have an effect on the microbes living within us? We now know that gut microbes are important for our health in many ways, and that thousands of species of bacteria, as well as viruses, fungi, and other microbes normally live in a healthy person's gut. We refer to these microbes as the human microbiota or human microbiome. When the community of gut microbes is thrown out of whack (dysbiosis) there can be a number of negative health effects, including diseases. Researchers are just learning about all the microbes within us and their importance in health and disease. [See all posts on the human microbiome.]

Past posts have discussed such things as antibiotics, emulsifiers, different foods and diets, heartburn drugs, etc. having an effect on the human microbiome, but what else? A recent study from China reviewed some environmental pollutants and their effects on gut microbiota - as shown in both human and animal studies. They reviewed studies on antibiotics, heavy metals (arsenic, cadmium, lead), persistant organic pollutants or POPs (organochlorine pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers, and polycyclic aromatic hydrocarbons or PAHs), pesticides (permethrin, chlorpyrifos, pentachlorophenol, epoxiconazole and carbendazim, imazalil), emulsifiers, nanoparticles (e.g., silver nanoparticles), and artificial sweeteners. They found that all these environmental pollutants had effects on gut microbes - with some effects lasting for years. Their conclusion: gut microbes are very sensitive to drugs, diet, and environmental pollutants. By the way, notice that popular food ingredients such as emulsifiers and artificial sweeteners were considered "environmental pollutants" by the researchers.

Excerpts from Environmental Pollution: Effects of environmental pollutants on gut microbiota

Environmental pollutants have become an increasingly common health hazard in the last several decades. Recently, a number of studies have demonstrated the profound relationship between gut microbiota and our health. Gut microbiota are very sensitive to drugs, diet, and even environmental pollutants. In this review, we discuss the possible effects of environmental pollutants including antibiotics, heavy metals, persistent organic pollutants, pesticides, nanomaterials, and food additives on gut microbiota and their subsequent effects on health. We emphasize that gut microbiota are also essential for the toxicity evaluation of environmental pollution. In the future, more studies should focus on the relationship between environmental pollution, gut microbiota, and human health.

Thousands of species are found in the gut microbiome, and the majority of these species belong to six bacterial phyla: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, Fusobacteria, and Verrucomicrobia (Eckburg et al., 2005). Gut microbiota are highly dynamic and have substantial interindividual and intraindividual variation....The gut microbiota are very essential for host health. They participate in the regulation of many physiological functions. The gut microbiota reside in our intestinal mucus layer and even participate in shaping the mucus layer (Jakobsson et al., 2015). They help us to digest food (such as fiber); synthesize vitamins and amino acids (Spanogiannopoulos et al., 2016); play very important roles in energy metabolism and storage, immune system modulation, growth, and neurodevelopment; and can even regulate our behavior.... The occurrence of many diseases is correlated with altered gut microbiome composition (Lange et al., 2016). Gut microbiota dysbiosis is considered to be a potential cause of obesity (Cani et al., 2007; Fei and Zhao, 2013). However, gut microbiota are very sensitive to drugs, diet, and environmental pollutants.

Although most environmental pollutants do not directly target gut microbiota, some pollutants can enter the body and interact with the gut microbiota through different pathways. A number of previous studies have shown that exposure to environmental pollutants can alter the composition of the gut microbiome, leading to disorders of energy metabolism, nutrient absorption, and immune system function or the production of other toxic symptoms (Jin et al., 2015c; Zhang et al., 2015b). In the present review, we conclude that different kinds of environmental pollutants can induce gut microbiota dysbiosis and have multiple potential adverse effects on animal health. 

Heavy metals in the environment have become a severe health risk in recent years (Liu et al., 2016a). As a common form of environmental pollution, heavy metals are associated with a wide range of toxic effects, including carcinogenesis, oxidative stress, and DNA damage, and effects on the immune system..... Recently, several studies have stated that heavy metal exposure could also lead to gut microbiota dysbiosis, indicating that study of gut microbiota provides a new approach to analyze the mechanisms of heavy metal toxicity

Immune system function is tightly coupled to our gut microbiome. Gut microbiota and their metabolites can interact with both the innate immune system and the adaptive immune system (Honda and Littman, 2016; Thaiss et al., 2016).... Alterations in the gut microbiome can disrupt the balance between the host immune system and gut microbiota, induce immune responses, and even trigger some immunological diseases. Furthermore, immune system imbalance may influence the microbiota metabolites. For example, trimethylamine, which is absorbed from food by gut microbiota, can induce atherosclerosis (Chistiakov et al., 2015).

Published on Leave a comment on Study Finds Fecal Transplants Improve Autism and Gut Symptoms in Children

For years it has been known that most children with autism spectrum disorder (ASD) have all sorts of gastrointestinal (GI) problems (e.g., constipation, diarrhea, stomach pain, food intolerance), and the more severe the autism, the more severe the GI problems. Recent studies suggested that a major factor in this are abnormal gut bacteria, with the gut microbial community out of whack (dysbiosis). Previous studies looking at the gut microbiome of children with autism have shown lower diversity and lower amounts (abundances) of certain bacteria in children with autism compared to neurologically normal (neurotypical) children.

A recent study of children with autism spectrum disorder found that giving the children a fecal microbiota transplant (FMT) led to significant and lasting improvements in both gastrointestinal (GI) symptoms and autism-related behaviors and symptoms. A fecal microbiota transplant (FMT) is a transplant of fecal matter from a healthy donor to the recipient. A fecal microbial transplant contains approximately a thousand bacterial species that live in a healthy gut, as well as other microbes such as viruses and fungi. FMTs have so far been an amazingly successful treatment for recurrent Clostridium difficile infections, and are now being looked at as promising treatments of chronic inflammatory diseases such as inflammatory bowel disease.

The researchers were surprised to see an 80% improvement in gastrointestinal symptoms, especially abdominal pain, indigestion, diarrhea, and constipation. They also saw about a 25% improvement in autism related behaviors and symptoms which persisted for 8 weeks after treatment stopped, which is when the study ended. One measurement of adaptive behaviors (such as communication, daily living skills, and socialization) found that the average developmental age increased by 1.4 years after treatment. The researchers also found that there was a "rebalancing" of the gut microbes following treatment. They found evidence of "successful partial engraftment of donor microbiota and beneficial changes in the gut environment" - meaning they could see that donor microbes were living in the gut. Also, overall bacterial diversity increased (which is good) and the abundance of certain bacteria increased (including Bifidobacterium, Prevotella, and Desulfovibrio), and these changes persisted until the end of the study.

The researchers caution that this was a small trial, that there could be placebo effects, and so the results should be "cautiously interpreted and viewed as preliminary." But nonetheless, the results are exciting. Really exciting. From Science Daily:

Autism symptoms improve after fecal transplant, small study finds

Children with autism may benefit from fecal transplants -- a method of introducing donated healthy microbes into people with gastrointestinal disease to rebalance the gut, a new study has found. Behavioral symptoms of autism and gastrointestinal distress often go hand-in-hand, and both improved when a small group of children with the disorder underwent fecal transplant and subsequent treatment. In the study of 18 children with autism and moderate to severe gastrointestinal problems, parents and doctors said they saw positive changes that lasted at least eight weeks after the treatment. Children without autism were included for comparison of bacterial and viral gut composition prior to the study.

Previous research has established that children with autism typically have fewer types of some important bacteria in their guts and less bacterial diversity overall -- a difference that held true in this study. That could be because many of them are prescribed a lot of antibiotics in the first three years of life, the research team wrote in the study.

Parents of the children not only reported a decrease in gut woes including diarrhea and stomach pain in the eight weeks following the end of treatment: They also said they saw significant changes for the better when it came to behavioral autism symptoms in their sons and daughters, who ranged from 7 to 16 years old....One of those tools showed the average developmental age increased by 1.4 years after treatment. 

Researchers also were able to document a rebalancing of the gut following treatment. At the end of the study, the bacterial diversity in the children with autism was indistinguishable from their healthy peers. The study also included a unique viral analysis by Ohio State scientists, made possible because of previous work in the world's oceans. Gregory, who is particularly interested in the interplay between viruses and bacteria, used genetic testing to examine the viral diversity in the guts of the treated children. It rebounded quickly, and became more similar to the donor's microbiome. "Those donor viruses seemed to help," she said.

Fecal transplantation is done by processing donor feces and screening it for disease-causing viruses and bacteria before introducing it into another person's gastrointestinal tract. In this study, the researchers used a method called microbiota transfer therapy, which started with the children receiving a two-week course of antibiotics to wipe out much of their existing gut flora. Then, doctors gave them an initial high-dose fecal transplant in liquid form. In the seven to eight weeks that followed, the children drank smoothies blended with a lower-dose powder. [Original study.]