Montana Public Radio

Do Gut Bacteria Tell Us What To Eat?

Jan 17, 2015

Scientists at Pacific Northwest National Laboratory are developing a model of the microbial environment inside the human gut. (CC BY-NC 2.0)
Credit Courtesy of Pacific Northwest National Laboratory

Greg and Jon continue their discussion of Ari LeVaux's online column, "Irony Alert: Artificial Sweeteners Make You Fat" with information from a second article cited by LeVaux: "Do Gut Bacteria Rule Our Minds?" by Jeffrey Norris, UC San Francisco -  itself summarizing research review findings that were new in 2014.

"In an article published in August 2014 in the journal BioEssays, researchers from UC San Francisco, Arizona State University and University of New Mexico concluded from a review of the recent scientific literature that microbes influence human eating behavior and dietary choices to favor consumption of the particular nutrients they grow best on, rather than simply passively living off whatever nutrients we choose to send their way."

In other words: yes, they do. Our gut microbiomes send chemical signals to our brains via the vagus nerve, manipulating our taste receptors into releasing toxins that make us feel bad and chemical rewards that make us feel good. The situation is complicated not only by the diversity of gut bacteria, but by all the connections between the gut and the immune, nervous and endocrine systems. One result is clear: gut bacteria sometimes lead us to eat foods that are good for them, but bad for us.

"Bacterial species vary in the nutrients they need. Some prefer fat, and others sugar, for instance. But they not only vie with each other for food and to retain a niche within their ecosystem — our digestive tracts — they also often have different aims than we do when it comes to our own actions...As Dr. Carlo Maley, director of the UCSF Center for Evolution and Cancer, explained, “There is a diversity of interests represented in the microbiome, some aligned with our own dietary goals, and others not.”"

(Broadcast: "The Food Guys," 1/18/15 and 3/18/18. Listen weekly on the radio at 11:50 a.m. Sundays, or via podcast.)