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Tag: gut microbiome

Published on Leave a comment on Certain Gut Bacteria Are Associated With Lower Cholesterol Levels
Intestines Credit:Wikipedia

New discoveries about our gut microbiome (the community of viruses, bacteria, fungi) keep occurring. There is growing evidence that certain bacterial species in the gut are associated with cholesterol levels and heart disease.

Adding to the evidence, a recent study found that people with higher levels of several species of Oscillibacter bacteria had lower cholesterol levels than people without or diminished levels of these bacteria. The researchers than  found (in the lab) that these species of Oscillibacter bacteria actually take up and metabolize artery-clogging cholesterol, which could explain the lower cholesterol levels.

By the way, other species (e.g., Eubacterium coprostanoligenes)  were also associated with lower cholesterol levels in the study. The same people with higher levels of beneficial bacteria also had greater diversity of gut bacteria, which is considered a sign of gut health.

Species of Oscillibacter bacteria are not available in any supplements at this time. You'll just have to eat a diet that feeds and nurtures beneficial gut microbes.

And what is a health-promoting diet? A recent study found that a diet rich in fruits, vegetables, whole grains, nuts, seeds, legumes, and olive oil promotes healthy bacteria in the gut, which are associated with good health. This also is a diet high in fiber. Think along the lines of a Mediterranean diet.

From Science Daily: Scientists link certain gut bacteria to lower heart disease risk

Changes in the gut microbiome have been implicated in a range of diseases including type 2 diabetes, obesity, and inflammatory bowel disease. Now, a team of researchers at the Broad Institute of MIT and Harvard along with Massachusetts General Hospital has found that microbes in the gut may affect cardiovascular disease as well. In a study published in Cell, the team has identified specific species of bacteria that consume cholesterol in the gut and may help lower cholesterol and heart disease risk in people. ...continue reading "Certain Gut Bacteria Are Associated With Lower Cholesterol Levels"

Published on Leave a comment on Artificial Sweeteners Alter the Gut Microbiome
Small intestine Credit: Wikipedia

It turns out that artificial sweeteners alter the gut microbiome, specifically the duodenum (the first part of the small intestine after the stomach). And not in a good way.

The gut microbiome is the community of microbes (bacteria, fungi, viruses) that lives in the small intestine - and it looks different in persons who use artificial sweeteners compared to persons who don't.

Researchers found that artificial sweeteners lowered microbial diversity (not good), and increased numbers of harmful bacteria in the duodenum. They also alter inflammation markers that circulate in the blood in a negative way. The use of non-aspartame artificial sweeteners (sucralose, saccharin, stevia) had slightly different effects than aspartame, but both overall had negative effects (when compared to gut microbiomes of persons not ingesting artificial sweeteners in their diet).

From Medical Xpress: Could artificial sweeteners alter your microbiome?

You may think that artificial sweeteners can help you lose some weight, but a new study finds they are no good for your gut's microbiome. ...continue reading "Artificial Sweeteners Alter the Gut Microbiome"

Published on Leave a comment on Kidney Stones and the Gut Microbiome
Kidney stones Credit: Wikipedia

What causes a person to develop kidney stones has long been debated. A recent study found that in persons who develop kidney stones, there are alterations in the gut, salivary, and urinary microbiomes. In other words, the community of fungi, viruses, and bacteria at each of these sites are out of whack or imbalanced.

In the study, not only were the 3 microbiomes imbalanced in the persons with kidney stones (when compared to healthy people without kidney stones), but they also had less diversity (fewer species) in their microbiomes. For example, persons with kidney stones had significantly fewer gut health associated bacteria F. prausnitzii, and significantly more inflammation associated E. lenta.

Those with kidney stones also had a history of having taken more antibiotics (antimicrobials).

The researchers conclusion: To avoid kidney stones a healthy diet is essential (for a healthy gut microbiome). One should also avoid taking antibiotics unless necessary. [BTW, the bacteria F. prausnitzii has long been viewed as a keystone microbe in a healthy gut microbiome. It can be increased by increasing fiber in the diet - e.g., fruits, vegetables, seeds, nuts, whole grains, legumes.]

From Medical Xpress: New study sheds light on the connection between the microbiome and kidney stones

A new study from Lawson Health Research Institute and Western University published in the journal Microbiome has found changes in the microbiome in multiple locations in the body are linked to the formation of kidney stones. ...continue reading "Kidney Stones and the Gut Microbiome"

Published on Leave a comment on Lupus Involves Changes In Gut Microbes

Recent research found that flare-ups of the disease lupus involves microbial changes in the gut microbiome. The gut microbiome is the community of microbes (fungi, bacteria, viruses) living in the small intestine.

NYU School of Medicine researchers found in a study that about half of the individuals having flare-ups of lupus (Systemic lupus erythematosus) had an overgrowth (or "bloom") of the bacteria Ruminococcus blautia gnavus. They also found that during flare-ups the gut microbiome was out-of-whack, with an increase in some harmful (pathogenic) species.

Lupus is an autoimmune disease that occurs when the body's immune system attacks its own tissues and organs, especially kidneys, joints, skin, blood vessels, brain, heart, and lungs. A tell-tale sign of lupus that many people get is a butterfly shaped rash across the nose and cheeks.

These research results raise the possibility that future treatments for lupus may involve somehow altering gut microbes. Maybe dietary changes or certain probiotics?

From Science Daily: Lupus flare-ups strongly linked to specific bacterial growth in gut

Recurrent bouts of systemic lupus erythematosus, marked by the body's immune system attack of its own tissues, closely tracked with measureable upticks in growth in the gut of a certain species of bacteria. ...continue reading "Lupus Involves Changes In Gut Microbes"

Published on Leave a comment on Certain Foods Are Great For Gut Health

Another recent study confirmed that what you eat determines the microbes living in your gut (small intestines). This is the gut microbiome or microbiota (the community of bacteria, fungi, viruses). The microbes living in a person's gut can be determined by analyzing a sample of a person's poop.

The researchers found that persons eating more fruits, vegetables, and foods high in fiber (e.g., whole grains, fruits, vegetables, nuts, seeds) have gut microbes associated with health. They also have more diversity of species in the gut (this is a sign of health). But eat a diet rich in highly processed foods and low in fiber, and you'll have microbes associated with health problems (e.g., heart disease, cancer, diabetes).

The researchers point out that following the recommendations of the Dietary Guidelines for Americans (DGA) supports a healthy gut microbiome. Especially important for a healthy gut microbiome were vegetables, whole grains, legumes, and dairy. Yes, dairy foods have oodles of microbes (your cheese is alive!), whole fat dairy is beneficial, but skim milk or 0% is not. Eating a variety of high fiber foods is important because then you'll be eating a variety of fibers.

Bottom line: you are what you eat.

Excerpts from Medical Xpress: How diet quality affects the gut microbiota to promote health

We know that eating a healthy diet affects body weight, cholesterol levels, and heart health. A new study from the University of Illinois focuses on another component: the role of diet in supporting a healthy gastrointestinal microbiota. The researchers conclude that following the Dietary Guidelines for Americans (DGA) promotes a gut microbiota composition that may support overall health. ...continue reading "Certain Foods Are Great For Gut Health"

Published on Leave a comment on Fermented Foods Are Good For Your Gut Microbiome

It has been known for a while that eating fermented foods and high fiber foods is healthy for us. A recent study confirms this view. Researchers at the Stanford Univ. of Medicine found that eating fermented foods actually reduces inflammation and increases the diversity of gut microbes (gut microbiome).

Researchers randomly assigned volunteers to one of 2 groups for 10 weeks: the fermentation foods group, and the high fiber group. Surprisingly, the group eating the high fiber diet for 10 weeks did not have changes in microbial diversity or changes in the 19 inflammatory markers studied. Instead, the researchers reported that the high-fiber diet "changes microbiome function and elicits personalized immune responses".

The fermented foods group ate a diet rich in yogurt, kefir, fermented cottage cheese, kimchi and other fermented vegetables (e.g. sauerkraut, traditional dill pickles), vegetable brine drinks, and kombucha tea. Each day they ate 6 servings (1/2 cup = 1 serving generally). The high fiber diet was rich in legumes, seeds, whole grains, nuts, vegetables, and fruits (increased their fiber intake from about 22 grams per day to 45 grams).

The fermented foods group ate six servings daily (e.g. 1/2 cup yogurt, kefir, fermented cottage cheese, kimchi, sauerkraut, traditional dill pickles, and kombucha tea). The high fiber group increased their fiber intake from about 22 grams per day to 45 grams, by eating a diet rich in legumes, seeds, whole grains, nuts, vegetables, and fruits.

High-fiber diets are associated with numerous health benefits such as lower rates of numerous chronic diseases and mortality. The consumption of fermented foods can help with weight maintenance and may decrease the risk of diabetes, cancer, and cardiovascular disease.

From Futurity: Fermented Food Diet Boosts Microbiome and Cuts Inflammation

In a clinical trial, 36 healthy adults were randomly assigned to a 10-week diet that included either fermented or high-fiber foods. The two diets resulted in different effects on the gut microbiome and the immune system. 
...continue reading "Fermented Foods Are Good For Your Gut Microbiome"

Published on Leave a comment on Glyphosate May Be Having a Harmful Effect On Our Gut Microbiome

Uh oh... Glyphosate is the most widely used herbicide (plant-killer) in the world, and its pervasive use may be harming our gut microbiomes. Glyphosate (which is in Roundup) is used not only as a weed-killer, but also applied to glyphosate resistant genetically engineered (GE) crops such as soy, canola, corn, and also right before harvest (preharvest) on many grain crops. Thus we find glyphosate and glyphosate residues all around us, including in the foods we eat.

Researchers at the University of Turku  in Finland developed a bioinformatics tool to examine glyphosate effects on gut bacteria. They found that glyphosate kills many bacterial species found in the human gut, including such important keystone bacteria as Faecalibacterium prausnitzii. Their words: "54% of species in the core gut microbiome are sensitive to glyphosate". (A nice way of saying it kills them.) They summarize:

"A large proportion of bacteria in the gut microbiome (Qin et al., 2010) are susceptible to glyphosate (class I); thus, the intake of glyphosate may severely affect the composition of the human gut microbiome. "

Glyphosate has already been linked to a number of health problems (e.g. cancer, endocrine disruption). The gut microbiome or microbiota is the millions of microbes living in our intestines, and they are very important to our health. Imbalance or disruptions to our gut microbiome result in inflammation, chronic conditions, and diseases.

What to do? Try to eat as many organic foods, especially grains, soy, and corn, as possible. Organic farmers are not allowed to use glyphosate. Try to avoid using glyphosate-based herbicides on your property.  Unfortunately, our government agencies are not protecting us with regards to glyphosate, and the US allows higher glyphosate residues in food than in the European Union.

From Science Daily: Glyphosate may affect human gut microbiota

Glyphosate is the most commonly used broad-spectrum herbicide. Researchers from the University of Turku in Finland have developed a new bioinformatics tool to predict if a microbe, e.g. a human gut bacterium, is sensitive to glyphosate.  ...continue reading "Glyphosate May Be Having a Harmful Effect On Our Gut Microbiome"

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Published on 6 Comments on Daily Use of Probiotics Can Hurt Gut Health

Researchers are starting to raise concerns about routine daily intake of probiotics for "gut health". Much is still unknown, but problems are starting to appear. A healthy gut contains hundreds of species (bacteria, fungi, viruses), and taking megadoses of a few species (a probiotic supplement) can overwhelm the normal gut microbial community. A healthy gut is one with a greater diversity of species, not just some species.

For example, one study found that daily probiotic ingestion can result in overgrowth of some bacterial species in the intestines, resulting in such symptoms as brain fogginess, bloating, and gas. Successful treatment was antibiotics and stopping the use of probiotics.   Another recent study found that after using antibiotics, those who took probiotics (thinking it would help microbial recolonization of the gut microbes) actually had slower recovery of the gut microbiome (microbial community).  The best recovery was in those who took nothing, no supplements at all, or those who received a fecal microbial transplant (where an entire microbial community is transplanted).

The evidence is showing that for gut microbial health, the best thing to do is eat a variety of real whole foods (and not highly processed foods) that have lots of fiber, such as whole grains, fruits, vegetables, seeds, nuts, and legumes (beans). In other words, feed the beneficial bacteria. A Mediterranean style diet is good.

A recent article in Medscape (the medical site) highlights these same concerns. [See below.] A study that looked at the gut microbiome of people who were about to undergo treatment for melanoma found that those who were taking probiotics actually had worse gut microbial diversity. [Remember, gut microbial diversity is considered an indicator of gut health.] And the cancer treatment (immunotherapy) did not work as well on them.

Bottom line: The evidence is showing that for gut microbial health, the best thing to do is eat a variety of real whole foods (and not highly processed foods) that have lots of fiber, such as whole grains, fruits, vegetables, seeds, nuts, and legumes (beans). In other words, feed the beneficial bacteria. A Mediterranean style diet is good. Don't take routine daily supplements or probiotics for  "gut health" - they won't help. Instead, if you want - only take probiotics for a short while for a specific symptom or problem.

Dr. Lorenzo Cohen wrote a piece for the Wall Street Journal laying out those same points. Excerpts from: Those Probiotics May Actually Be Hurting Your ‘Gut Health’  ...continue reading "Daily Use of Probiotics Can Hurt Gut Health"

Published on Leave a comment on Eat More Fiber to Improve Your Gut Microbiome

Another article commenting that increasing the amount of dietary fiber eaten by people eating a typical Western diet (which is low in fiber) will improve their gut microbiome (community of microbes). Research is finding that the added dietary fiber is food (nutrition) for microbes in the gut, and eating additional fiber daily will help restore or increase bacterial diversity, which then should lead to health benefits. Note: Easy ways to increase dietary fiber are increasing intake of whole grains, legumes, nuts, seeds, fruits, and vegetables. Think of food writer Michael Pollan's advice: "Eat food. Not too much. Mostly plants."

Researchers feel that fiber intake needs to be increased to more than current dietary guidelines, and that beneficial effects to the microbiome starts to occur rapidly (within 2 weeks) of changing to a higher fiber diet. This post from January 21, 2016 discussed the Sonnenburg research on gut microbe depletion (from a low fiber diet), and this April 28, 2015 post discussed the O'Keefe research (changing the diet has big effect on colon cancer risk) - both studies are mentioned below. See the page Feeding Your Gut Microbes for more information. From Science Daily:

Can more fiber restore microbiome diversity?

Scientists are pushing to restore human health in Western countries by changing our diet to restore the microbial species lost over the evolution of Western diet. Researchers advocate for strategically increasing dietary fiber intake as one path forward in regaining microbial biodiversity.

Insufficient nutrients for our gut microbes have been linked to a loss of certain beneficial bacterial species in industrialized societies and are likely impacting our immunological and metabolic health, although more data is needed. For example, most Westerners consume half of the amount of dietary fiber recommended by dietary guidelines, which nutritionists refer to as the "fiber gap," which is a problem because dietary fiber is the primary source of nutrition (e.g., carbohydrates) accessible to gut bacteria in humans.

"The idea to boost fiber levels is not new," says Jens Walter of the University of Alberta, Canada. "However, depletion of the microbiome adds a new perspective to this low-fiber Western diet that we are currently eating." Earlier this year, Stanford University's Justin Sonnenburg found that mice fed a typical Western diet (high in fat and carbohydrates and low in fiber) transferred a lower diversity of beneficial microbial species to future generations. The re-introduction of the microbes' preferred fiber at that stage did not result in a return of some (good) species, indicating that extinctions had occurred in only a few generations.

Walter and co-author Edward Deehan, his PhD student, are concerned that a dramatic shift away from a diet similar to the one under which the human-microbiome symbiosis evolved is a key factor in the rise of non-communicable disorders like obesity. "There is a lot of epidemiological evidence that fiber is beneficial, and food products containing dietary fiber have FDA-approved health claims for both colon cancer and coronary heart disease. There is also quite a bit of clinical evidence (although it is less consistent)," Walter says. "The most pressing issue at the moment that neither consumption of fiber in society nor the doses used in clinical research are high enough."

People living in non-industrialized societies have an average intake of fiber that is much higher than the low norms of Western societies. The authors note the recent work from the Stephen J.D. O'Keefe lab in Nature Communications in which modern African-Americans were given a traditional South-African diet that contained 55 grams of daily dietary fiber and had improved markers for colon cancer within two weeks.

Published on Leave a comment on Our Gut Microbes Need Dietary Diversity

A thought-provoking article by Heiman and Greenway was just published in the journal Molecular Metabolism making the case that changes in farming practices over the last 50 years have resulted in decreased agricultural diversity which, in turn, has resulted in decreased dietary diversity, and that the reduction in dietary diversity has changed and decreased the richness of the human gut microbiota (microbes living in the gut). And meanwhile, during the past 50 years, the rates of obesity, type 2 diabetes, and inflammatory bowel diseases sharply increased - and in each of these conditions there is a reduction of the gut microbial diversity. Similar views have also been stated by others in the field of microbiology.

The thinking is that the more diverse the diet, the more diverse the gut microbiome (and healthier), and the more it can adapt to disturbances. Heiman and Greenway state: "Unfortunately, dietary diversity has been lost during the past 50 years because of economic pressures for greater food production to support a growing world population.... Of the 250,000 to 300,000 known edible plant species, humans use only 150 to 200...Today, 75 percent of the world's food is generated from only 12 plants and five animal species."

Also, agricultural practices of using antibiotics as growth promoters for poultry, swine, and cattle further harm the human gut microbiome when the meat is ingested by humans, and pesticide residues on crops ingested by humans may have gut microbiome effects. Even emulsifiers, used in processed foods, reduce microbial richness. Every time a person goes on a certain diet (vegan, Paleo, etc) or makes dietary choices in which some foods are eliminated, it makes it easier for some microbial species, and gives them a competitive advantage over other gut microbes. From Science Daily:

Reduction in dietary diversity impacts richness of human gut microbiota

Changes in farming practices over the last 50 years have resulted in decreased agro-diversity which, in turn, has resulted in decreased dietary diversity. The significant impact of this change in dietary richness on human health is an emerging topic for discussion

Heiman and Greenway describe how the reduction in dietary diversity has changed the richness of human gut microbiota, the community of microorganisms living in the gut. The researchers point out that healthy individuals have diverse gut microbiota and many of the common pathologies of the 21st century, including type 2 diabetes, obesity and inflammatory bowel disease, are associated with reduced microbiotic richness.

Gut microbiota function as an endocrine organ, metabolizing specific nutrients from the diet and producing specific substances that act as metabolic signals in the host. It follows then that highly specialized diets will change the landscape of the gut microbiome over time. In fact, it takes only a few days of changing diet to alter the microbiotic makeup of the human gut. And if the dietary change involves elimination of one or more macronutrients (think Atkins or Paleo or vegan), humans are essentially selecting for some microbiotic species over others.

The importance of microbiota diversity cannot be overstated. They produce an abundance of important molecules for the host and with increased variation comes increased adaptability and an increased range of physiological responses. "The greater the repertoire of signals, the more likely is the ability to maintain homeostasis when dietary intake is perturbed," explain Heiman and Greenway. "Furthermore, because each particular macronutrient has the potential to be metabolized by microbiota into unique metabolic signals, the greater the variety in signals, the greater the variety of responses possible."