Next time you open the fridge, remember that you’re not eating for just one. You’re also feeding the 100 trillion bacteria that call your digestive system home -- and help control your weight, heart health, blood sugar, immune system and even your moods.
Your goal: Nurture the good gut bugs and keep the detrimental types in check. Probiotic supplements can help, but a growing stack of research proves that what you eat has enormous power over your inner world. Here’s the latest on what the good gut bugs like for dinner, and what they hate:
Beans, tofu and quinoa: A pot of three-bean chili, curried tofu and a veggie stir-fry over protein-rich quinoa are great alternatives to meat, and your gut bugs will say “thank you!” In a 2014 study, people who substituted fiber-rich plant foods for red meat and fried foods doubled their amount of bacteria that produce inflammation-cooling butyrate in just two weeks.
Dark chocolate: Have a 1 ounce square for dessert, paired with your favorite fruit. Gut bugs love munching on the fiber and polyphenols in dark cocoa, say Louisiana State University scientists. “The good microbes, such as bifidobacterium and lactic acid bacteria, feast on chocolate,” one of the researchers says. “When you eat dark chocolate, they ferment it, producing compounds that are anti-inflammatory. When these compounds are absorbed by the body, they lessen inflammation of cardiovascular tissue, reducing the long-term risk of stroke.”
Chewy produce: The cellulose in the chewy stuff like carrot skin, broccoli stems and asparagus ends is an insoluble fiber that good gut bacteria thrive on. Get more by scrubbing carrots instead of peeling them and by grating tough veggie stalks for use in salads or coleslaw. Crunch on cruciferous goodies like broccoli, kale, cabbage and cauliflower several times weekly; they contain glucosinolates that gut bugs convert into cancer-fighting compounds.
Onions, asparagus, raspberries and more: These plant foods are great sources of a “prebiotic” fiber called fructans (your good-for-you gut bacteria ferment the fructans and then dine on that). Other fructan-packed foods include artichokes (Jerusalem and regular) and leeks. You’ll also get some in pears, bananas, watermelon and nectarines.
Yogurt and fermented foods: Yogurt with live active cultures is a great way to introduce more good bacteria into your digestive system. So is kefir, a fermented dairy drink.
Emulsifiers: Processed-food ingredients with tongue-twisting names like carboxymethylcellulose and polysorbate 80 keep ice cream smooth and prevent mayonnaise from separating. But research suggests that these emulsifiers may affect gut bugs in ways that boost inflammation and raise your risk for weight gain, heart disease and diabetes.
Refined and processed grains: Skipping white-flour foods — one of the Five Food Felons — could help you nurture good gut bacteria. Some experts say coarse whole grains are best, a good reason to enjoy brown rice, barley or oatmeal daily. Or try polenta, the high-fiber, Italian cornmeal that’s a foodie fave.
Saturated fats: That’s the fat in meats, full-fat milk, cheese, butter and ice cream. A large and well-constructed lab study from Sweden’s University of Gothenburg shows that whether it’s the fat or just the stuff with the fat — carnitine in red meat, for example — foods with saturated fat encourage the growth of detrimental bacteria called Bilophila, Turicibacter and Bacteroides. And that leads to weight gain and messed-up blood sugar.
Fast food: In an informal study that made headlines around the world, a 23-year-old U.K. college student working on a dissertation project ate fast food for breakfast, lunch and dinner for 10 days — and his gut bacteria took a big hit. A steady diet of burgers, fries, sodas and chicken nuggets wiped out one-third of the diversity in his gut-bug community (a problem, because a good mix of different bacteria is important for balance and health). Levels of inflammation-cooling bifidobacteria fell 50 percent, and a type of gut bug linked with obesity, bacteroidetes, increased, according to a Kings College London researcher (father of the young man).
Mehmet Oz, M.D. is host of “The Dr. Oz Show,” and Mike Roizen, M.D. is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. To live your healthiest, tune into “The Dr. Oz Show” or visit www.sharecare.com.