It’s a Gut Reaction

Most of us think of bacteria as the bad guys, something to scrub away and protect ourselves from. But some types of bacteria are good for us, which is reassuring considering that we are crawling with the stuff. On any given day, trillions of microbes including bacteria reside on our skin, in our gut and in other parts of our body. Genetics, diet, medication and other factors can influence the makeup of this living, microscopic population and create imbalances that raise the risk of disease, so it’s a good idea to properly feed and care for it.

Scientists are still learning about the links between overall health and the microbiome, which refers to the personal collection of bacteria and other microorganisms that each of us has, but since a large percentage of bacteria exists in the gut, it makes sense that what we eat plays a particularly vital role in maintaining a healthy microbiome.

Many fermented foods, which in recent times have experienced a surge in popularity, can help because they are rich in probiotics, which boost beneficial bacteria. During fermentation, yeast and bacteria break down sugars, helping to preserve food and lending a distinctive taste. It’s a process that occurs naturally over time in some food, such as sourdough, but it can also be achieved by adding probiotics to food. Common fermented foods include yogurt, kefir, kombucha, sauerkraut, miso, tempeh, kimchi, and some cheeses and pickles.

Before you load up on fermented products, though, a few caveats: Some people find the taste of certain fermented foods, such as kimchi, off-putting, says LeeAnne Mather, A.P.R.N., R.D., of Core Gastroenterology in Exeter, and some fermented foods often come with added sugar. Also, some people — especially those with digestive disorders such as irritable bowel syndrome — find that they don’t tolerate fermented foods well, Mather says. “Start with small amounts,” she advises, and see how you feel.

If fermented foods are not for you, be sure to incorporate food that contains prebiotics in your diet. In general, good sources of prebiotics include high-fiber foods such as fruit, vegetables and beans. Mather likens eating high-fiber food to spreading fertilizer on a lawn; when you eat apples, onions or chickpeas, for example, you feed your current store of beneficial bacteria, helping it to grow and flourish. If you are not accustomed to eating high-fiber foods, introduce them gradually to your diet to lessen the chance of bloating or other abdominal discomfort.

Regardless of which route you choose — taking in prebiotics, probiotics or both — evidence suggests that regular consumption of foods and drinks that support the microbiome can lead not only to better gastronomical health but can also benefit the cardiovascular and immune systems and lower the risk of diabetes and obesity, at least in part because maintaining sufficient numbers and diversity among beneficial bacteria in the gut decreases inflammation, “one of the roots of all evil in the body,” says Hannah K. Brilling, R.D.N., a clinical dietitian and member of a culinary medicine team at Dartmouth-Hitchcock’s Weight and Wellness Center. Inflammation has been linked to a host of health problems, from heart disease to cancer, diabetes, Alzheimer’s disease and more.

But don’t just swig some kombucha or occasionally sprinkle legumes on a salad and stop there. “We have to continue to support the microorganisms once they enter our bodies,” Brilling says, through healthy behaviors like consuming adequate fiber and minimizing sugar, artificial sweeteners, processed foods and packaged foods in general.

Admittedly, the typical American diet does not include a lot of fermented foods and drinks, and many of us still choose processed products over high-fiber food, but foods that foster a healthy microbiome are a staple in other cultures, Mather notes. The Mediterranean diet, for example, leans heavily on plant-based foods that are microbiome-friendly, and residents of some countries “use yogurt at every meal to help with digestion,” Mather says.

Regularly eating food that supports a healthy microbiome “is like adding an extra layer of nutrition,” Brilling says, and can be especially helpful for individuals who have an inflammatory condition such as arthritis, heart disease or gout.

Indeed, benefits of a healthy gut microbiome extend beyond the digestive tract to affect metabolism, blood sugar and even mood. “The bacteria of the gut is a living organism,” Mather says, and many health experts consider the microbiome to be one of the body’s organs. How you care for it should reflect the significant influence it has on your health.

Help your body’s flora to flourish

Trends come and go but some, such as the fermentation craze, are worth paying attention to. Not too long ago, many Americans had never heard of kefir, kimchi or kombucha, but today all are hot sellers in supermarkets, specialty shops and cafés. If you don’t already regularly consume them, you might want to give them a try, as fermented foods appear to benefit health by supporting the microbiome, or collection of microorganisms that lives on and inside each of us.

Not feeling adventurous enough to try kefir, kimchi or kombucha? Yogurt and some cheeses and pickles are also fermented, as are sauerkraut, miso and tempeh. Look for labels that identify the product as fermented or as containing probiotics or active cultures, and when possible, avoid cooking fermented foods because high heat kills beneficial bacteria.