We know that pistachios contain heart-healthy fat, and overall, have a very good nutritional profile - one ounce (about 47 nuts) provides more fiber than a half cup of spinach. They’re also good sources of vitamin B-6, thiamin, copper, phosphorus, and magnesium. Now, new findings suggest that pistachios have prebiotic characteristics as well, and can help support higher levels of potentially beneficial bacteria in the digestive tract. Researchers at the U.S. Department of Agriculture’s Beltsville Human Nutrition Research Center in Maryland recruited 16 healthy volunteers to consume a calorie-controlled diet that included daily servings of 1.5 ounces of pistachios or almonds, three ounces of the nuts or no nuts. The researchers collected and analyzed stool samples during the study, and after 19 days found that the volunteers who ate up to 3 ounces of pistachios had indications of increased activity of beneficial bacteria in the gut. While the results are considered preliminary, they suggest that eating pistachios regularly may help develop and maintain normal, healthy levels of flora in the digestive tract.