“…when you consume walnuts it increases microbes that produce butyrate, a beneficial metabolite for colonic health”
Read more here.
Walnut Consumption Alters the Gastrointestinal Microbiota, Microbially Derived Secondary Bile Acids, and Health Markers in Healthy Adults: A Randomized Controlled Trial
https://doi.org/10.1093/jn/nxy004