In addition to providing ample protein, vitamin B6 and thiamin, new research conducted at the Human Nutrition Research Center in Beltsville, Md., found that people who ate 3 ounces—a couple handfuls—of pistachios daily for 19 days had elevated levels of probiotics (good bugs) in their digestive tracts.

Specifically, pistachios promoted butyrate-producing flora—microbes believed to maintain colon health and even reduce colon cancer risk. Scientists think pistachios' abundant dietary fiber and phytochemicals may be the reasons behind these benefits.