Your gut bacteria are doing more than just helping you digest food. They are creating small molecules that play a big role in your overall health, according to a new study from ETH Zurich and Stanford University.
These molecules, called fermentation products, are made when gut bacteria break down food. They include acetate, propionate and butyrate, which can help regulate the immune system, support intestinal healing and even influence behavior. While scientists have long known about their benefits, this study, published in Cell, is the first to calculate how much of these molecules the body actually receives each day.
Researchers combined data on diet, stool production and bacterial regeneration to measure the daily exchange of these compounds between gut microbes and the human body. They found that diet has a major influence on how many of these molecules are produced.
For example, people eating a modern Western diet get only about 2 to 5% of their daily energy from these bacterial byproducts. In comparison, people following a more traditional diet, such as the Hadza hunter-gatherers of Tanzania, get up to 10%.
The researchers say this type of measurement offers a foundation for future studies on how these molecules affect conditions such as colon cancer or chronic inflammatory bowel disease. It also shows that changing what you eat can have a bigger impact on these health-supporting compounds than simply changing the mix of bacteria in your gut.
This research was supported by the Swiss National Science Foundation (including the NCCR Microbiomes program), Innosuisse, the Botnar Research Centre for Child Health, the U.S. National Institutes of Health, a Stanford Bio-X Seeding Grant and the Center for Pediatric IBD and Celiac Disease.