Studies show that it's a must to add tree nuts to your diet if you haven’t already. Considered a “superfood,” they're chock-full of fiber, omega-3 fatty acids, and antioxidants—and one of the top choices, walnuts, may also help to shift your gut bacteria to higher levels of the more beneficial populations.

A new study from the Louisiana State University Health Sciences Center has found that increased walnut consumption may be able to bump up levels of “good” bacteria like Lactobacillus and Ruminococcaceae. It also can drop the amount of harmful bacteria like Bacteriodetes and Anaerotruncus—these “bad” guys may contribute to metabolic disease and other dysfunction in bodily systems.

"We found that walnuts in the diet increased the diversity of bacteria in the gut, and other non-related studies have associated less bacterial diversity with obesity and other diseases like inflammatory bowel disease," said Lauri Byerley, Ph.D., R.D., a research associate professor of physiology at LSU Health New Orleans School of Medicine. The study, the authors said, also showed that walnuts increased bacteria populations that are usually linked to probiotics, or food that helps increase levels of beneficial bacteria, suggesting walnuts may be a potent prebiotic.

Gut health is an emerging research area, and researchers are finding that greater bacterial diversity may be associated with better health outcomes,” said Byerley. Be sure to add nuts to your training plan—go for about an ounce a day, which equals 28g or around 25 individual nuts. Choose almonds, walnuts, pistachios, and cashews to get the most out of your new, nutty meals.