We’ve written about walnuts before.
A new July 2017 study (on animals) by Louisiana State University suggests that, “walnut consumption may be beneficial for digestive health by increasing the amount of good probiotic-type bacteria in the gut. Walnuts do this by acting as a prebiotic to help nourish and grow the bacteria that keeps the digestive system healthy.”
Source: EurekAlert!, the online, global news service operated by AAAS, the science society.