Probiotics are all the rage, thanks to a wealth of new research suggesting that consuming "good" bacteria can aid digestion, keep you regular and boost your immune system. But probiotic foods are nothing newthey've been around for thousands of years and are a staple of traditional cuisines around the world.
And it's well worth branching out from yogurt. "Different species of bacteria flourish in different fermented foods, and they offer a spectrum of benefits," explains Justin Sonnenburg, PhD, associate professor of microbiology and immunology at Stanford University and author of The Good Gut. "So it's smart to eat a variety of fermented foods." Check out this sampling of ancient probiotic powerhouses.
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A Central American cousin of sauerkraut, this fermented salsa from El Salvador usually consists of cabbage, onions and chilies, among other vegetables. It's traditionally served with pupusas (thick, handmade corn tortillas), but curtido also makes a tasty taco filling and topping for grilled chicken, fish, and rice and beans. Or you can simply give a bowl of chips a probiotic kick with fermented salsas sold by brands like Wildbrine.
Native to Russia, this fermented grain drink is traditionally made by adding yeast to brown bread that's been soaked in water. The kvass at your local health-food store is likely made from beets or carrots instead of bread. So in addition to probiotics, kvass has all the vitamins in fresh-pressed beet or carrot juice but with a fraction of the sugar, owing to its carb-hungry microbes. (For example, Zukay Beet Kvass contains just 4 grams of sugar per 6-ounce serving, while commercial beet-juice blends typically have more than twice that.) Can't handle drinking it straight? Try adding small amounts to salad dressing or using it in no-cook recipes (cooking kills the good bugs) in place of vinegar.
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One more reason to love Roquefort and Gruyère: "The same bacteria and fungi that give aged cheeses incredible flavor profiles can add great microbial diversity to your diet," Sonnenburg says. Just use caution with aged cheeses made from raw milk; while harmful bacteria may be reduced in the aging process, pregnant women and the immunocompromised should still steer clear.
In its simplest form, sauerkraut is shredded cabbage fermented in salted water. The tart condiment is packed with Lactobacillus plantarum, a powerful probiotic, which may help fight cancer and lower cholesterol. Look for raw (not pasteurized) varieties in the refrigerated section of your supermarket.
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This fermented milk beverage (originally developed in the Caucasus Mountain region of Eurasia) tastes like liquidy yogurt but contains a more diverse range of bugstypically at least 10 species (compared with yogurt's usual two to four). It's made using kefir "grains," a starter culture that often includes a type of yeast that may protect against gastrointestinal distress, as well as a bacteria thought to ease constipation and another that can help alleviate inflammatory gut disorders. If you're lactose intolerant, you might find kefir easier to digest than milk because its probiotics consume much of the problematic sugar before you drink it.
This trendy, fizzy fermented tea originated in China around 220 BC as a health elixir. Today it's the subject of many claims (detoxifying! Boosts energy!) that are hard to prove. But it may have some healing powers: An animal study published in Pharmaceutical Biology in April found that kombucha lowered LDL cholesterol and improved liver and kidney function. "Make sure the label says ‘raw' and that the formula contains little or no added sugar," suggests Jayson Calton, PhD, co-author of The Micronutrient Miracle, who prefers the brand LIVE Kombucha Soda.
Because it's made from a variety of veggies and seasonings (including napa cabbage, garlic, chilies, ginger and fish sauce) and ferments for a long time, this spicy and pungent Korean staple contains a very diverse assortment of bugs. "Of all probiotic foods, kimchi probably ranks number one," says Raphael Kellman, MD, a New York City integrative physician and author of The Microbiome Diet.
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They can be loaded with probiotics, but choose carefully. Many are pasteurized and jarred in white vinegar, which gives them a piquant taste but no friendly microbes. Instead, you want pickles that have been fermented in brine the way they were made in ancient Mesopotamia. One study on Lactobacillus brevis, a bacteria from fermented pickles, found that regular intake significantly reduced incidence of the flu. You'll find traditional pickles in the refrigerated section of the grocery or health-food store. The label should say "naturally fermented," "nonpasteurized" or "contains live cultures," advises Michelle Schoffro Cook, PhD, author of The Probiotic Promise. Look for fermented green beans, cauliflower and beets, tooeach packs a wide array of vitamins, minerals and probiotics.
A seasoning paste made from fermented soybeans, miso might deserve some credit for the famous longevity of the Japanese. Animal research suggests it may protect against cancers of the breast, colon, liver and lungs. The longer soybeans are left to ferment (sometimes with rice, barley or other ingredients), the more potent their health perks. (Red and brown varieties are typically fermented longer than white.) Try stirring miso into rice, dressings and sauces. Sadly, miso soup isn't a good source of probiotics, because it's cooked. Sensitive to soy? A company called South River offers varieties made with chickpeas instead.
Food is by far the best way to build up healthy gut microbes. But if you're not consuming lots of kimchi and kefir on a regular basis, consider taking a probiotic supplement. Tips for choosing a quality product:
Look for diversity of microbes For general gut health, the more kinds, the better.
Check the colony-forming units (CFUs) The recommended daily dose varies but tends to be in the range of 1 to 10 billion CFUs per day. Most importantly, the label should specify that this number applies at the time of expirationnot the time of manufacture. Reliable brands will promise live cultures through the expiration date. A "USP Verified" seal is another sign of a good buy.
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Feed the friendly microbes
Your gut bacteria like to eat some of the same things you do, particularly plant-based whole foods like fruits, veggies, nuts, legumes and whole grains. Many of these foodscalled prebioticscontain types of fiber that your body doesn't readily digest; when the fiber reaches your large intestine, your microbes make a meal of it. Variety is key, says Justin Sonnenburg, PhD: "The healthy bacteria in your gut prefer different prebiotic fibers. Eating a range of prebiotics encourages microbial diversity."