The microbiome might sound like something from a science fiction film, and in a way it is: trillions of microorganisms, mostly bacteria but also yeasts and other microbes, live on and in your body. The largest community lives in your large intestine. These microbes help digest food, train the immune system and protect the gut lining, and the gut-associated lymphoid tissue represents almost 70% of the entire immune system. Keeping that community healthy does not take anything exotic. Here are three keys that the research supports.
Key 1: Eat a wide variety of plants
Diversity is one of the best markers of a healthy gut microbiome, and diversity on your plate seems to feed diversity in your gut. In the American Gut Project, which analyzed samples from more than 10,000 citizen scientists, the number of different plants people ate was linked to the diversity of their gut microbes: people eating more than 30 types of plants a week had more diverse microbiomes than those eating fewer than 10.
Thirty sounds like a lot, but everything counts: vegetables, fruit, beans and lentils, whole grains, nuts, seeds, herbs and spices. Many of these foods also contain prebiotic fibers, which resist digestion and reach the colon, where gut bacteria ferment them. A greens powder can help fill gaps on busy days; Easy Being Green contains 20+ organic greens plus prebiotics.
Key 2: Add fermented foods, and consider a probiotic
Fermented foods are a direct way to bring live microbes into your diet. In a 17-week randomized study, a diet high in fermented foods steadily increased microbiome diversity and decreased inflammatory markers, more than a high-fiber diet did over the same period. Try yogurt or kefir, unpasteurized sauerkraut and kimchi, miso, tempeh or kombucha.
A probiotic supplement can complement those foods with specific, studied strains at a known dose. Trust Your Gut Probiotic + Prebiotic Daily Essential provides 16 billion CFU from 6 acid-resistant Lactobacillus and Bifidobacterium strains, plus organic prebiotics. See How & When to Take Your Probiotic for tips.
Key 3: Protect the balance you have
A healthy microbiome is not about wiping out every "bad" organism. Yeasts such as Candida are normal residents of the gut, and the immune system works to keep these commensal fungi from becoming harmful. Problems tend to arise when the community is thrown out of balance. A few common disruptors:
- Antibiotics you do not need. Even a short course can have lasting effects: in one study, nine common gut species were still undetectable in most people six months after a four-day antibiotic course. Take antibiotics when they are prescribed for a bacterial infection, and not otherwise. Our guide covers how to support your gut after antibiotics.
- Diets high in added sugar and ultra-processed food. In mice, high-sugar and high-fat diets shifted the gut microbiome within weeks. These foods also tend to replace the fiber-rich plants your gut bacteria depend on.
- Chronic stress. Students had lower levels of fecal lactic acid bacteria during exam week than at the start of term. Read more in Chronic Stress & Gut Health.
Where to start
Pick one change this week: add a new vegetable or bean to your rotation, try a fermented food you have never had, or take a walk after dinner instead of scrolling. Small, consistent habits add up for your microbiome, just as they do for the rest of your health. If you have ongoing digestive symptoms, see a doctor rather than self-diagnosing an "overgrowth."
