Blog | Wednesday, January 22, 2014

The microbiome's profound effect on health

I am fascinated by the new research and information on the gut microbiome. These microorganisms (germs, bacteria, microbes) live harmoniously in every part of our body and especially in our gastrointestinal system. It wasn’t even really discovered until the late 1990s and we now know that these microbial communities affect our health in ways we never dreamed. The human microbiome may play a role in obesity, immune response, diabetes, irritable bowel syndrome, and maybe even anxiety, depression and autism.

Anything that is this new has many possibilities the science is just starting, but there is clearly something very important here. The Human Microbiome Project is a NIH initiative with the goal of identifying and characterizing the microorganisms which are found in association with both healthy and diseased humans. They intend to test how changes in the human microbiome are associated with human health or disease.

A study published in Nature showed that adaptation to the gut microbiome can change in a day. This is important because dietary changes can have a huge immediate effect on disease. The researchers showed how immediate changes occur, depending upon subjects eating a plant based or animal based diet. They fed the volunteers either plant (grains, legumes, fruits and veggies) or animal (meats, cheese, eggs) diets for 5 consecutive days. They tracked food in the digestive tract, how the subjects felt and bowel movements.

The researchers analyzed 16S ribosomal RNAs to identify microbiome components in fecal samples, which were collected for several days before the dietary changes and each day during the study.

The animal-based diet clearly had a greater effect on the microbiome than the plant-based diet. Even after 1 day, the microbiome of those eating the animal-based diet differed significantly from baseline analyses.

The researchers found fecal bile acid changes in the animal based diet that are associated with liver cancer and Irritable bowel disease. These bile acids change the bile tolerant bacterium that is associated with IBD.

There is no cause-effect found here and the study size was too small to know what is actually occurring. But the fact that changes could be found in the gut microbiome in such a short amount of time is compelling. It is simply another potential explanation why diet is so important to health, and how changing our diet can have an immediate effect on our health.

This post originally appeared at Everything Health. Toni Brayer, MD, FACP, is an ACP Internist editorial board member who blogs at EverythingHealth, designed to address the rapid changes in science, medicine, health and healing in the 21st Century.