But if there is a disturbance in that balance—brought on by infectious illnesses, certain diets, or the prolonged use of antibiotics or other bacteria-destroying medications—dysbiosis occurs, stopping these normal interactions.

As a result, the body may become more susceptible to disease. Microbiota stimulate the immune system , break down potentially toxic food compounds, and synthesize certain vitamins and amino acids, [2] including the B vitamins and vitamin K.

For example, the key enzymes needed to form vitamin B12 are only found in bacteria, not in plants and animals. Sugars like table sugar and lactose milk sugar are quickly absorbed in the upper part of the small intestine, but more complex carbohydrates like starches and fibers are not as easily digested and may travel lower to the large intestine.

There, the microbiota help to break down these compounds with their digestive enzymes. The fermentation of indigestible fibers causes the production of short chain fatty acids SCFA that can be used by the body as a nutrient source but also play an important role in muscle function and possibly the prevention of chronic diseases, including certain cancers and bowel disorders.

The microbiota of a healthy person will also provide protection from pathogenic organisms that enter the body such as through drinking or eating contaminated water or food. Large families of bacteria found in the human gut include Prevotella , Ruminococcus , Bacteroides , and Firmicutes.

If microbiota are so vital to our health, how can we ensure that we have enough or the right types? You may be familiar with probiotics or perhaps already using them.

These are either foods that naturally contain microbiota, or supplement pills that contain live active bacteria—advertised to promote digestive health. Whether you believe the health claims or think they are yet another snake oil scam, they make up a multi-billion dollar industry that is evolving in tandem with quickly emerging research.

Allan Walker, Professor of Nutrition at the Harvard Chan School of Public Health and Harvard Medical School, believes that although published research is conflicting, there are specific situations where probiotic supplements may be helpful. Because probiotics fall under the category of supplements and not food, they are not regulated by the Food and Drug Administration in the U.

This means that unless the supplement company voluntarily discloses information on quality, such as carrying the USP U. Pharmacopeial Convention seal that provides standards for quality and purity, a probiotic pill may not contain the amounts listed on the label or even guarantee that the bacteria are alive and active at the time of use.

In addition to family genes, environment, and medication use, diet plays a large role in determining what kinds of microbiota live in the colon. A high-fiber diet in particular affects the type and amount of microbiota in the intestines.

Dietary fiber can only be broken down and fermented by enzymes from microbiota living in the colon. Short chain fatty acids SCFA are released as a result of fermentation.

This lowers the pH of the colon, which in turn determines the type of microbiota present that would survive in this acidic environment. The lower pH limits the growth of some harmful bacteria like Clostridium difficile.

Growing research on SCFA explores their wide-ranging effects on health, including stimulating immune cell activity and maintaining normal blood levels of glucose and cholesterol.

Foods that support increased levels of SCFA are indigestible carbohydrates and fibers such as inulin, resistant starches , gums, pectins, and fructooligosaccharides. These fibers are sometimes called prebiotics because they feed our beneficial microbiota.

Although there are supplements containing prebiotic fibers, there are many healthful foods naturally containing prebiotics. The highest amounts are found in raw versions of the following: garlic, onions, leeks, asparagus, Jerusalem artichokes, dandelion greens, bananas, and seaweed.

In general, fruits , vegetables , beans , and whole grains like wheat, oats, and barley are all good sources of prebiotic fibers. Be aware that a high intake of prebiotic foods, especially if introduced suddenly, can increase gas production flatulence and bloating.

Individuals with gastrointestinal sensitivities such as irritable bowel syndrome should introduce these foods in small amounts to first assess tolerance.

With continued use, tolerance may improve with fewer side effects. If one does not have food sensitivities, it is important to gradually implement a high-fiber diet because a low-fiber diet may not only reduce the amount of beneficial microbiota, but increase the growth of pathogenic bacteria that thrive in a lower acidic environment.

These include fermented foods like kefir, yogurt with live active cultures, pickled vegetables, tempeh, kombucha tea, kimchi, miso, and sauerkraut.

The microbiome is a living dynamic environment where the relative abundance of species may fluctuate daily, weekly, and monthly depending on diet, medication, exercise, and a host of other environmental exposures. The contents of this website are for educational purposes and are not intended to offer personal medical advice.

You should seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.

The Nutrition Source does not recommend or endorse any products. Skip to content The Nutrition Source. The Nutrition Source Menu. A study indicated that supplements with collagen may benefit the gut microbiome in mice, though further research is needed.

To help your body make collagen, try eating more:. Each of these elements varies in different people, influencing their gut microbiomes in different ways. This variation results in individuals having unique gut microbiomes.

According to one small study of 16 people, fasting was linked to lower levels of a bacteria that promotes colorectal cancer. Research in animals also shows the benefits of fasting. A study in fruit flies found that intermittent fasting appeared to improve gut health and increase lifespan.

Another study in mice indicated that fasting promoted the growth of beneficial gut bacteria and reduced inflammation in the intestines. Some studies have found no impact of probiotics on the gut microbiome. Still, other research suggests that probiotics may significantly affect the makeup of the gut microbiome and positively impact other areas of health, like immunity.

You can improve your gut health by taking steps to improve your overall health. This can include eating more fiber-rich foods, eating fewer ultra-processed foods, getting enough sleep, and managing your stress levels. Some signs of unbalanced gut bacteria can include upset stomach, unintentional weight changes, and fatigue.

The human gut is complex. While research is ongoing, it seems clear that the gut microbiome impacts whole-body health. A healthy gut contributes to:. Lifestyle and dietary changes may positively affect not only your gut health but your overall health.

Our experts continually monitor the health and wellness space, and we update our articles when new information becomes available.

VIEW ALL HISTORY. MindBodyGreen provides third-party-tested supplements made with high quality ingredients. Our testers and dietitians discuss whether MindBodyGreen…. Vitamins are for athletes to stay healthy.

You may get all you need from the food you eat. Some athletes may benefits from vitamin supplements. Docosahexaenoic acid, or DHA, is a type of omega-3 fat that may improve many aspects of your health, from your brain to your heart.

Here are 12…. Vitamins are what your body needs to function and stay healthy. It's possible to get all the vitamins you need from the food you eat, but supplements…. Vitamin K is an essential nutrient that helps with blood clotting and healthy bones.

It can be found in leafy greens, vegetable oils, and broccoli. L-citrulline is an amino acid made naturally in your body. It may also be taken as a supplement to help boost exercise performance, lower blood….

Who needs to take vitamin C supplements, and how much is enough? The answer may depend on your age and overall health. Dietary supplements are products such as vitamins, herbs, and minerals that may help provide nutrients and health benefits.

They may have risks and…. A Quiz for Teens Are You a Workaholic? How Well Do You Sleep? Health Conditions Discover Plan Connect. Signs of an Unhealthy Gut and What to Do About It. Medically reviewed by Cynthia Taylor Chavoustie, MPAS, PA-C — By Megan Dix, RN, BSN and Erika Klein — Updated on January 29, Gut microbiome Effect on health Signs of an unhealthy gut What to do Foods for gut health FAQ Takeaway Poor gut health may manifest as fatigue, upset stomach, skin conditions, and autoimmune challenges.

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Our Testers and Dietitians Explain. By Kelsey Kunik, RDN. Are Vitamins Good for Athletes? READ MORE. What Are Vitamins and Can They Help Your Health? It's possible to get all the vitamins you need from the food you eat, but supplements… READ MORE.

Vitamin K: Everything You May Need to Know Vitamin K is an essential nutrient that helps with blood clotting and healthy bones. L-citrulline: Benefits, Side Effects and More L-citrulline is an amino acid made naturally in your body.

Omega-3 fatty acids are polyunsaturated fatty acids that reduce inflammation throughout the body. The recommended fiber intake for adult females and males ranges between grams g per day according to the Dietary Guidelines for Americans.

Many cereals and fiber bars have prebiotic ingredients. Fruits, vegetables, legumes, nuts and teas are common sources. Include a variety of these foods in the diet. Fish is a major source of Omega-3s. We can also get small amounts from foods like nuts, seeds and oils.

Fermented foods are made with live cultures. Common strains listed on labels are lactobacillus and bifdobacteria. Skip to main content. Find Doctors Services Locations. Medical Professionals. Research Community. Medical Learners.

Job Seekers. Quick Links Make An Appointment Our Services UH MyChart Price Estimate Price Transparency Pay Your Bill Patient Experience Locations About UH Give to UH Careers at UH. The study subjects provided blood, urine, and fecal samples throughout the study.

Scientists found that the avocado eaters developed a greater abundance of gut microbes that break down fiber and produce beneficial SCFAs.

They also developed a more diverse array of healthful gut microbes compared to people who did not eat the avocado meals. And while the avocado group consumed slightly more calories, they had more fat in their stool, which means they absorbed less fat from their digestive tracts into their bloodstreams.

Researchers say this is the first study to evaluate the effects of avocado consumption on human gut microbiota in the absence of a caloric restriction, which eliminates calorie change as a factor in the changes observed. Some foods have been shown to negatively impact the health of the gut and its microbiota.

Limit or avoid these foods to optimize gut health. Research shows that an amino acid called L-carnitine from red meat is metabolized by gut microbes into a compound called trimethylamine-N-oxide TMAO , which is linked to artery hardening and increased heart disease risk factors.

Processed red meat consumption bacon, sausage, pepperoni may also increase levels of microbes in the gut that increase inflammation and up the risk of colorectal cancer. Ultra-processed foods are defined as industrially manufactured ready-to-eat or ready-to-heat formulations containing food additives and little or no whole foods.

Examples include soft drinks, fast food, chicken nuggets, hot dogs, and sweets. A high consumption of these foods is associated with an increased risk of heart disease and obesity.

A research review concluded that ultra-processed foods reduce the type and variety of beneficial gut microbes compared to diets rich in minimally processed plant foods. This shift promotes inflammation in the gut and increases gut permeability. Studies show that chronic alcohol consumption significantly alters the gut microbial community.

Alcohol causes a decrease in beneficial microbes, an increase in harmful, pro-inflammatory microbes, and an increased gut permeability, which can allow pathogenic bacteria to be absorbed into the bloodstream. While artificial sweeteners are sugar-free and calorie-free, their use has been linked to an increased risk of obesity and type 2 diabetes, and the effects may start in the gut.

In experiments where gut microbiota taken from hosts who consumed low calorie sweeteners were transferred into healthy mice, the animals developed impaired glucose tolerance.

Other studies shows that sugar substitutes may shift the makeup of microbes in the gut, reduce the production of beneficial SCFAs, and increase inflammation. Gut-supporting foods increase the type and number of beneficial gut microbes, reduce the growth of harmful bacteria, increase the production of anti-inflammatory compounds, like SCFAs, support immune function, and strengthen the integrity of the gut wall to keep harmful compounds out of the bloodstream.

Some foods counter these positive effects within the gut, which may lead to weakened immune function, digestive illnesses, and even increased chronic disease risk. Wiertsema SP, Van Bergenhenegouwen J, Garssen J, Knippels LMJ.

The interplay between the gut microbiome and the immune system in the context of infectious diseases throughout life and the role of nutrition in optimizing treatment strategies. Published online Mar 9. doi: National Human Genome Research Institute. Appleton J. The gut-brain axis: Influence of microbiota on mood and mental health.

Integr Med Encinitas. Bander ZA, Nitert MD, Mousa A, Naderpoor N. The gut microbiota and inflammation: An overview. Int J Environ Res Public Health. Published online Oct St John H, Doucet E, Power KA. Dietary pulses as a means to improve the gut microbiome, inflammation, and appetite control in obesity.

Obes Rev. Epub Jul 3. Kim SK, Guevarra RB, Kim YT, Kwon J, et al. Role of Probiotics in Human Gut Microbiome-Associated Diseases. J Microbiol Biotechnol.

Wastyk HC, Fragiadakis GK, Perelman D, Dahan D, et al. Gut-microbiota-targeted diets modulate human immune status. Green M, Arora K, Prakash S. Microbial medicine: Prebiotic and probiotic functional foods to target obesity and metabolic syndrome. Int J Mol Sci. Holscher HD.

Dietary fiber and prebiotics and the gastrointestinal microbiota. Gut Microbes. Published online Feb 6. Fraga CG, Croft KD, Kennedy DO, Tomás-Barberán FA. The effects of polyphenols and other bioactives on human health. Food Funct. Rana A, Samtiya M, Dhewa T, Mishra V, et al.

Health benefits of polyphenols: A concise review. J Food Biochem. Epub Jun Pérez-Burillo S, Navajas-Porras B, López-Maldonado A, Hinojosa-Nogueira D, et al. Green Tea and Its Relation to Human Gut Microbiome.

Published online Jun Cardona F, Andrés-Lacueva C, Tulipani S, Tinahones FJ, et al. Benefits of polyphenols on gut microbiota and implications in human health. J Nutr Biochem. Williamson G. Your intestinal lining acts as a barrier between your gut and bloodstream to prevent potentially harmful substances from entering your body 1 , 2.

Nutrient and water absorption mostly occurs in your intestines. Your intestines have tight junctions, or small gaps, that allow nutrients and water to pass into your bloodstream.

Certain health conditions cause these tight junctions to loosen, potentially allowing harmful substances like bacteria, toxins, and undigested food particles to enter your bloodstream. Alternative health practitioners claim that leaky gut triggers widespread inflammation and stimulates an immune reaction, causing various health problems that are collectively known as leaky gut syndrome 3.

They believe leaky gut leads to various conditions, including autoimmune diseases, migraines, autism, food sensitivities, skin conditions, brain fog, and chronic fatigue.

Yet, there is little evidence to prove that leaky gut syndrome exists. As a result, mainstream physicians do not recognize it as a medical diagnosis. Leaky gut, or increased intestinal permeability, occurs when the tight junctions of your intestinal walls loosen.

This may allow harmful substances, such as bacteria, toxins, and undigested food particles, to pass into your bloodstream. However, increased intestinal permeability is well known and occurs alongside several chronic diseases, including celiac disease and type 1 diabetes 5.

Zonulin is a protein that regulates tight junctions. Research has shown that higher levels of this protein may loosen tight junctions and increase intestinal permeability 6 , 7. Two factors are known to stimulate higher zonulin levels in certain individuals — bacteria and gluten 8.

There is consistent evidence that gluten increases intestinal permeability in people with celiac disease 9 , However, research in healthy adults and those with non-celiac gluten sensitivity shows mixed results. While test-tube studies have found that gluten can increase intestinal permeability, human-based studies have not observed the same effect 10 , 11 , Research shows that higher levels of inflammatory mediators, such as tumor necrosis factor TNF and interleukin 13 IL , or the long-term use of nonsteroidal anti-inflammatory drugs NSAIDs , such as aspirin and ibuprofen, may increase intestinal permeability 13 , 14 , 15 , Furthermore, low levels of healthy gut bacteria may have the same effect.

This is called gut dysbiosis The exact cause of leaky gut remains a mystery, but certain proteins like zonulin and markers of inflammation provide some clues. Other potential causes include long-term NSAID use and an imbalance of gut bacteria known as gut dysbiosis.

One is to eat a diet rich in foods that aid the growth of beneficial gut bacteria. An unhealthy collection of gut bacteria has been linked to poor health outcomes, including chronic inflammation, cancers, heart disease, and type 2 diabetes A diet that promotes digestive health should focus on fibrous vegetables, fruits, fermented vegetables, cultured dairy products, healthy fats, and lean, unprocessed meats.

Some foods have been shown to cause inflammation in your body, which may promote the growth of unhealthy gut bacteria that are linked to many chronic diseases The following list contains foods that may harm healthy gut bacteria , as well as some that are believed to trigger digestive symptoms, such as bloating, constipation, and diarrhea:.

Avoiding processed junk foods, alcohol, sugary beverages, refined oils, and artificial sweeteners may aid the growth of healthy gut bacteria. Cutting out foods containing gluten or common stimulants of digestive symptoms may also help.

It focuses on incorporating foods that promote the growth of healthy gut bacteria while removing foods that are notorious for causing uncomfortable digestive symptoms.

Some menu items contain sauerkraut , a type of fermented cabbage that is easy, simple, and inexpensive to prepare. A healthy gut menu should be rich in fruits, vegetables, and lean protein.

Some people also find that diets like the Gut and Psychology Syndrome GAPS diet may ease leaky gut symptoms. However, this diet is incredibly restrictive, and no scientific studies support its health claims. Aside from diet, try taking a probiotic supplement, reducing your stress levels, sleeping more, avoiding smoking, and limiting alcohol intake to improve your gut health.

However, mainstream physicians do not recognize leaky gut syndrome as a medical diagnosis, as there is currently little evidence that increased intestinal permeability is a serious health problem in and of itself.