Plant Foods Are Good for Our Gut Bugs

Our bodies host a huge population of microorganisms, dubbed the human microbiome. In recent years, the makeup of critters in our guts has been linked to a plethora of conditions, including depression, heart disease and obesity. And now bug-friendly scientists at the University of California, San Diego School of Medicine have presented initial findings from the American Gut Project, a crowdsourced initiative that analyzes people’s survey responses and fecal samples to better understand how things like diet, lifestyle and disease affect the human microbiome.

Using data from 11,336 citizens across 45 countries, the researchers discovered that plant-based foods appear to be good news for our gut microbiome. People who ate more than 30 types of plant foods per week had a greater diversity of bugs than those who consumed 10 or fewer types of plant foods weekly. The makeup of plant foods, including fiber, is likely what spurs a more robust and diverse population of microbes.

The project leaders still don’t know what, if any, impact this uptick in microbiota diversity could have on long-term health, but in the meantime it’s not a bad idea to work more plant-based foods into our daily menus. A good place to start is with walnuts: A study in the Journal of Nutrition found that people who ate 42 grams of walnuts (about one-third of a cup) daily for 3 weeks had more beneficial bacteria—including Faecalibacterium—in their digestive tracts than they did after a 3-week period when they did not eat walnuts. It appears the bacteria hunger for the fats and fiber found in walnuts.