Posted on May 18, 2012, 6 a.m.
Eating pistachios may positively impact bacterial profile of the digestive tract.
The gut microbiota, or the microbial environment in the gastrointestinal tract, provides important functions for the human body. A number of studies have suggested that modifying microbiota to favor a beneficial composition may help to support intestinal health, as well as overall health. Foods with prebiotic properties may enhance the growth of beneficial bacteria in the digestive tract. Pistachio nuts appear to have prebiotic characteristics; they contain non-digestible food components such as dietary fiber, which remain in the gut and serve as food for naturally occurring bacteria. They also contain phytochemicals that have the potential to modify microbiota composition. Volker Mai, from the University of Florida's Institute of Food and Agricultural Sciences (Florida, USA), and colleagues enrolled 16 healthy individuals, randomly assigning each to eat an American-style, pre-planned diet that included either 0 ounces, 1.5 ounces or 3 ounces of pistachios or almonds per day. Each participant's diet was calorie-controlled to ensure they neither gained nor lost weight during the intervention. Multiple stool samples were collected throughout the study and analyzed for bacterial community composition. The researchers also quantified the amounts of Lactic Acid Bacteria and Bifidobacteria in the stool, two groups of live microorganisms that reside in the digestive tract and help break down food substances. After controlling for age, dietary factors and other relevant variables, the researchers observed that after 19 days, people who ate up to 3 ounces of pistachios (about 147 nuts or 2 servings) per day had increased changes in levels of various gut bacteria. As well, the subjects who ate pistachios showed an increase in potentially beneficial butyrate-producing bacteria. Butyrate has been shown to be a preferred energy source for colonic epithelial cells and is thought to play an important role in maintaining colonic health in humans. Commenting that: "Fibers and incompletely digested foods, including nuts, that reach the proximal colon provide compounds required for maintaining a diverse microbiota” the study’s lead author submits that: “this study is a promising sign that increasing consumption of nuts, specifically pistachios, provides a novel means to modify the number of the gut's 'healthy' microbiota, with potential health benefits."
B. Langkamp-Henken, C. Nieves, Jr., S-A. Girard, C. Hughes, M.C. Christman, W.J. Dahl, V. Mai, et al. “Whole-grain foods and gastrointestinal and immune health in adolescents: a randomized intervention” [Abstract 115.4]. Presented at 2012 Experimental Biology Conference, 22 April 2012.