How Does My Microbiome Affect My Health?

You may be surprised to learn that your microbiome impacts nearly every aspect of your physical and mental health.  Medical research is showing that the impact of your microbiome on your health extends to areas far beyond your gastrointestinal system.  Your metabolism, immune response and even your moods and psychological health are impacted by the health of your microbiome.  Scroll down the page to learn more about each of the following topics.

    • Metabolism, Nutrient Absorption, and Gastrointestinal Health
    • Autoimmune Conditions 
    • Diabetes, Obesity and Metabolic Disorders
    • Cancers
    • Psychological Health
    • Many More...

Metabolism, Nutrient Absorption, and Gastrointestinal Health

Perhaps the most studied and intuitively obvious impact of your gut microbiome is on your ability to process and absorb nutrients and vitamins from your food.  This can affect your weight and how you feel after a meal.

Most of us are aware that the bacteria in our gut play an important role in digestion. When the stomach and small intestine are unable to digest certain foods we eat, gut microbes jump in to offer a helping hand, ensuring we get the nutrients we need.

In addition, gut bacteria are known to aid the production of certain vitamins - such as vitamins B and K - and play a major role in immune function.

The gut microbiome: How does it affect our health?   Honor Whiteman (2015) Medical News Today

The details of the role played by the various microbes that inhabit your gut was not well understood until recently due to the difficulty associated with culturing and identifying the many species that are found in each of us.  Recent advances in DNA sequencing technology have now made it possible to detect these microbes without culturing.  This has led to a rapid advance in understanding the complexity and importance of the microbiome.  Now researchers are working to understand how microbes, particularly the ones that are unique to us individually, influence our health and risk of disease.  One example is how the microbiome influences body weight.  Quoting again from Medical News Today:

What is more, introducing these bacteria to the guts of mice caused the animals to gain less weight, indicating the bacteria may reduce or prevent obesity.

"Our findings show that specific groups of microbes living in our gut could be protective against obesity - and that their abundance is influenced by our genes," said study author Prof. Tim Spector of King's College London. "The human microbiome represents an exciting new target for dietary changes and treatments aimed at combating obesity."

Several other conditions show clear correlations to the health of the gut flora: chronic diarrhea, inflammatory bowel diseases such as Crohn’s Disease and Ulcerative Colitis, gastric ulcers and malnutrition related to poor vitamin absorption.  Studies have shown that these conditions to be aggravated by disruptions of the microbiome resulting from antibiotic use and other issues.

Autoimmune Conditions

The microbiome has been shown to have profound influences on the immune system through the interaction of the microbes and the response your body has to them.

Autoimmune diseases can also be caused by changes in the gut microbiome, the population of bacteria that reside within the gastrointestinal tract. In the study, the team led by Yuying Liu and J. Marc Rhoads at The University of Texas Health Science Center at Houston McGovern Medical School find that mice carrying a mutant version of the Foxp3 gene show changes in their gut microbiome at around the same time that they develop autoimmune symptoms. In particular, the mice have lower levels of bacteria from the genus Lactobacillus. The researchers discovered that by feeding the mice with Lactobacillus reuteri, they could "reset" the gut bacterial community and reduce the levels of inflammation, significantly extending the animals' survival.

Gut bacteria may hold key to treating autoimmune disease,  Science Daily, 19 Dec 2016

The studies have shown that your body reacts to many of the metabolic products that microbes produce as they live in and on your bodies.  Your autoimmune system is just one facet of that response, but one that has consequences throughout your life. Various conditions such as allergies, lupus, and rheumatoid arthritis are known to be associated with problems with the immune system.  Studies have shown in turn that your T-cell responses are influenced by the presence or absences of microbes in your gut - specifically the genus Lactobacillus.  In turn the relative abundance of such microbes can be influenced by your diet and other factors.

Diabetes Obesity and metabolic disorders

It has been known for decades that gut bacteria synthesize essential vitamins and amino acids and help degrade toxins. During the past decade, it has become clear that the influence of the microbiome on health may be even more profound.

The Microbiome and Risk for Obesity and Diabetes, Anthony L. Komaroff (2017)  Journal of the American Medical Association,

Studies on both mice and human subjects have indicated that the relative abundance of certain types of microbes in the gut have strong correlations to conditions such as obesity and Type 2 Diabetes.  Studies are ongoing to determine the mechanisms of how our systems react to the presence of these various microbes and how our diet and behaviors may influence them.


Of all of the potential impacts of the microbiome on our health, cancer is perhaps the most frightening.  It is also one of the more difficult to detect or assign direct impacts.  But there are signs that microbes play a role.  Studies indicate that the metabolic products of the microbes in our gut and the body’s responses to them may impact our ability to react to cancer cells or the tendency for those cells to appear in the first place.

“Microbial pathogens drive tumorigenesis in 15% to 20% of cancer cases. Even larger numbers of malignancies are associated with an altered composition of commensal microbiota (dysbiosis) based on microbiome studies using metagenomic sequencing. Although association studies cannot distinguish whether changes in microbiota are causes or effects of cancer, a causative role is supported by rigorously controlled preclinical studies using gnotobiotic mouse models colonized with one or more specific bacteria.”

The role of the microbiome in cancer development and therapy. Bhatt, et. al. (2017), A Cancer Journal for Clinicians

Psychological Health

“A research team at McMaster University in Ontario led by microbiologist Premsyl Bercik and gastroenterologist Stephen Collins discovered that if they colonized the intestines of one strain of germ-free mice with bacteria taken from the intestines of another mouse strain, the recipient animals would take on aspects of the donor's personality. Naturally timid mice would become more exploratory, whereas more daring mice would become apprehensive and shy. These tendencies suggested that microbial interactions with the brain could induce anxiety and mood disorders.

Mental Health May Depend on Creatures in the Gut, Charles Schmidt Scientific American, March 1, 2015

From studies such as these, researchers have begun to piece together possible mechanisms by which microbes in our gut may influence the most complex part of our health – Our personalities.  Experiments have shown that certain microbes may induce anxiety, hyperactivity and risk-taking behaviors. The mechanisms to drive such behaviors are thought to stem from compounds produced that are psychobiotic in nature and interact with the nerves tied closely into our gastrointestinal system.  Studies have also shown that the abundances of certain microbes have strong correlations to behaviors on the autism spectrum of disorders.

“Demonstrations in both animal and human studies have shown that the administration of beneficial microbes can reduce both inflammation and anxiety or behavioral signs of distress. These agents work on the same system but in a different location as chemical antidepressants, suggesting possibilities for a new “psychobiotic” class of low-side effect anti-inflammatory, anti-anxiety, and antidepressant.”

Microbiome and Mental Health in the Modern Environment.  Deans E. (2017) Journal of Physiological Anthropology

And Many More....

For more information about these and other health conditions influenced by the microbiome, see the website hosted by the University of Utah School of Medicine.

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