2017-07-31 16:57:15 UTC

What We Know About Diet and the Gut Microbiome

Aug. 1, 2017

Understanding mechanisms is important to develop personalized interventions for maintaining health or treating disease.

By Ece Mutlu, MD, MS, MBA, AGAF, scientific advisory board member, AGA Center for Gut Microbiome Research and Education

The gut microbiome is considered to be a second genome that can rapidly respond and integrate environmental signals with those within the host. One such important environmental factor is diet. Studies in the last few years have linked dietary patterns to microbiome composition. For example, it has been determined that extreme interventions such as switching from an animal-based diet to a plant-based diet, or switching from a Western type diet to a traditional African diet for a period as short as a few weeks can cause significant changes in the function of the gut microbiome in healthy individuals and at risk groups for colorectal cancer. Studies published to date also lend support to mechanisms linking food to microbial metabolites to diseases: in cardiovascular disease, high choline-containing foods have associated with increased cardiovascular disease risk through bacterial metabolites called TMAOs. In cancer, cruciferous vegetables (such as kale and broccoli) have been associated with decreases in cancer risk through metabolism of glucosinolates by intestinal bacteria.

Today, the science in this field is moving toward understanding mechanisms behind how food and dietary supplements exert their effects through the microbiome, and whether food can be used as a therapeutic intervention. A vast amount of data is emerging on the effects of diet-dependent changes in the microbiota on weight and metabolism, immune function and even cognitive ability; and these characterize the effects of diet-microbiota interactions beginning in the in-utero environment extending through infancy, adulthood and aging, and in the maintenance of overall health.

Of interest to gastroenterologists, diet-microbiome interactions have been implicated in various digestive diseases such as colorectal cancer and polyps, inflammatory bowel disease, gastrointestinal infections, malnutrition and obesity. There have also been links to disorders outside of the GI tract, such as diabetes and allergic, autoimmune, neuropsychiatric, kidney and bone diseases.

We are also beginning to realize that there are profound individual variations as to how a person and their microbiome responds to dietary interventions. Some of this could be due to the presence or absence of various components within the microbiota that can utilize dietary items. All of this research is expected to lead the way to personalized dietary interventions such as individualized diets, designer prebiotics, synbiotics and more.

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This article is part of the AGA Microbiome Update, delivered via email to AGA members on Tuesday, Aug. 1.

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