You know they’re there—those zillions of microorganisms that have set up shop in your GI system. It’s hard to fathom, but some researchers believe there are as many bacteria cells in your body as human cells, or perhaps more. And science suggests these tiny guests do a mind-boggling amount of good beyond breaking down food molecules into nutrients. Studies have found that gut bacteria play a role in , metabolism, and even mood. Researchers are just beginning to explore the wild world of your , but one thing is clear: A healthy intestinal ecosystem is a balanced one, in which beneficial types of bacteria keep the harmful species in check. You can help foster that equilibrium by feeding the “good” bacteria, so they flourish and thrive. Here’s how to show those friendly bugs some love.
The microbiome diet
When it comes to cultivating robust and resilient , there isn’t one magic ingredient or regimen. But it certainly can’t hurt to eat like the Greeks, experts say.
The Mediterranean diet is famously good for the heart and the brain—and now new (albeit early) research suggests it may benefit your digestive tract, too. For a study published last spring in the journal Frontiers in Nutrition, researchers fed one group of monkeys a Westernstyle diet (including lard, beef tallow, eggs, and high-fructose corn syrup) and a second group a Mediterranean-style diet (including fish oil, butter, eggs, and fruit puree). After 30 months, the researchers found that the Mediterranean group had a higher amount of “good” bacteria in their intestines than the Western group.
The Mediterranean diet supports your gut in more ways than one, says Joseph Murray, MD, a gastroenterologist at the Mayo Clinic in Rochester, Minnesota. Plenty of fruits and vegetables supply prebiotics—a type of dietary fiber that fuels the helpful bacteria. Olive oil contains monounsaturated fat, which “gets the bowel moving.” And fatty fish, like tuna and sardines, are known to lower inflammation. “The more Mediterranean elements you work into your diet, the greater the effect,” Dr. Murray says.
It can’t hurt to copy the Scandinavians either, he adds. The Nordic diet, like the Mediterranean diet, is high in produce, whole grains, and fatty fish—but also includes probiotic-rich fermented foods, such as pickled herring and skyr (Icelandic yogurt).
Whatever eating plan you choose to follow, be adventurous, suggests nutritionist Jill Weisenberger, RDN. “Seek out a variety of exciting plant foods, and keep challenging yourself to try new things,” she says— from dandelion greens to jicama to kimchi. Varying what’s on your plate can cultivate a more diverse mix of organisms in your gut— and the more types you have, the healthier you’re likely to be.
Picking your probiotic
Considering all the amazing things beneficial bacteria can do, what could be better than bugs-in-abottle, right? Well, here’s a hard pill to swallow: “The data on probiotic supplements is weak and contradictory,” says Dr. Murray.
The effectiveness of any tablet or capsule depends on the dose and strains it contains, and your own unique internal ecosystem, says Dr. Murray. “Everyone’s different,” he points out, which means there’s no single perfect pill. (For example, it’s possible the encapsuled microorganisms you dutifully swallow every morning may never grow inside your body.)
To make things even more complicated, most probiotic supplements aren’t subject to FDA approval—so a company’s marketing claims may be totally bogus.
Experts agree it’s better to nurture a diverse microbial community through your diet: “Your gut bacteria are much more about what you’re eating than what supplements you’re taking” Dr. Murray says. But if you feel your “good” bugs need reinforcements, here are some guidelines to help you choose a pill.
Pick studied bugs
Science is only starting to scratch the surface of the human microbiome. In the years ahead, researchers will be investigating hundreds of species to learn how they impact our bodies. So far, most of the work has centered on two types of bacteria: Lactobacillus and Bifidobacterium, which are common in products geared toward digestive health. On labels, look for them abbreviated as the first letter of the genus (L. or B.) followed by a species name, such as L. acidophilus or B. lactis.
Size up the units
There are few hard and fast rules about dosing with probiotics, but in general, you want a supplement that provides at least 1 billion CFUs (colonyforming units), according to ConsumerLab.com, an independent evaluator of health and nutrition products.
Consider the packaging
Probiotic supplements are living organisms sensitive to heat, light, and moisture. That’s why they must be stored carefully—for example, in blister packs and opaque boxes or bottles. Most tablets and capsules these days contain freeze-dried microbes that can survive at room temperature, but some brands do need to be refrigerated. If you notice the label says to refrigerate and the bottle is parked on a shelf, skip it.
Check the calendar
Make sure the expiration date printed on the bottle or box hasn’t passed. It’s also a good idea to mark the day you start a new supplement: “If you take it for a month and don’t notice any positive changes, it’s time to quit,” says Dr. Murray.
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