How Microbes Partner Up to Digest Fiber-Rich Foods

By Nicholas Weiler

For animals to digest lignans, a common chemical in fiber-rich foods such as grains, nuts, seeds, and vegetables – and even in drinks such as coffee, tea and wine – multiple gut bacteria must work together in a biochemical version of the “telephone” game, according to research in mice by the UC San Francisco lab of Peter Turnbaugh, PhD.

In a study published Nov. 4, 2019, in Nature Microbiology, Turnbaugh lab researchers mapped out the multistage biochemical pathway by which different strains of bacteria in the mouse gut contribute to digesting inert and otherwise indigestible lignans into useful nutrients as well as biologically active compounds such as phytoestrogens, which have been studied both for their health benefits and for their potential to produce hormonal imbalances when at elevated levels. 

The research, led by former postdoctoral researcher Elizabeth Bess, PhD, now an assistant professor of chemistry at UC Irvine, also revealed that slight genetic differences between closely related strains of bacteria in animals’ guts could have profound impacts on how dietary lignans are digested.

“To develop a personalized science of nutrition, we need to understand how complex communities of microbial partners living in the gut help digest the foods we eat to produce important nutrients,” said Turnbaugh, an associate professor of microbiology and immunology and member of the UCSF Benioff Center for Microbiome Medicine. “While the complexity of these relationships may seem daunting, our ability to work out such pathways gives me hope that we may soon be able to understand individual differences in nutrition and digestion at a mechanistic level.”