Explainer: What is the gut microbiome?

Our microbiomes take the phrase “trust your gut” to a whole new level.

The gut microbiome is a rich population of bacteria, fungi, viruses and other microorganisms that work together to power digestion and fuel our immune system. These helpful microbes inhabit the complex system of organs that comprise the gastrointestinal tract, including the stomach, small and large intestines, and colon.

In recent years, research has underscored the gut microbiome as a critical player in health and illness. Research in this area continues to gain steam, helping to form a clearer picture of how the microbiome changes over time and the implications this may have for our bodies.

What role does the gut microbiome play in disease?

Research suggests that imbalances and other problems in the gut microbiome can create conditions that impair health and may give rise to disease.

A 2021 study co-authored by Van Andel Institute scientists and collaborators found changes in the microbiome of people with Parkinson’s that favored production of toxic bile acids. In the study’s healthy control group, this change was not seen — a critical difference that suggests bile acids may be a viable biomarker for diagnosing Parkinson’s early and tracking its progression. The team reached its findings after examining the appendix, an oft-maligned bit of tissue that actually plays an important role in regulating gut microbes. Previous research by VAI scientists and colleagues linked removal of the appendix early in life to a reduced risk for Parkinson’s, although evidence does not support removing the appendix as a way to prevent the disease.

VAI scientists and collaborators also are undertaking research to further understand how the gut microbiome is influenced by diet and supports immune function. Though the gut microbiome is understood to support immune function, its precise role in the process has been unclear.

What factors affect the gut microbiome?

The makeup of the gut microbiome varies from person to person, and is influenced by factors such as genetics, diet and even environment [1].

Medications like antibiotics also can affect the composition of the gut microbiome, which is why their possible side effects include indigestion and diarrhea. Probiotics, such as those found in dietary supplements and foods like yogurt, may promote healthy gut functions by introducing beneficial bacteria to the gut microbiome. Researchers are still determining just how helpful probiotics are in supporting a healthy gut, though studies suggest they may help with conditions like irritable bowel syndrome [2].

[1] https://www.hsph.harvard.edu/nutritionsource/microbiome/

[2] https://my.clevelandclinic.org/health/articles/14598-probiotics