The promise seems incredible: Millions of microscopic bacteria that improve the health of your digestive tract, all alive and ready to flourish in one little pill.
Probiotics are one supplement that many doctors and health advocates say actually has science to help back up the claims.
Tamar Lieb, a naturopathic doctor who practices at London Health Center in Ferndale, says many of her patients are already taking a probiotic supplement when they come see her for their first appointment. And while studies have shown proven benefits to taking probiotics, she says not everyone needs the expensive supplements. For many healthy people, adding natural sources of probiotics in your diet might be easier and cheaper.
What are probiotics?
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In a healthy intestinal tract, the gut can have as many as 10 trillion bacteria that help digest carbohydrates, absorb nutrients and keep harmful microbes, such as yeast, from proliferating. Probiotics are one way to add more beneficial bacteria to your system, Lieb says.
Lieb says that although the intestinal track contains hundreds of types of bacteria, probiotic supplements usually focus on a few that have been identified as “good” bacteria, including lactobacillus and bifidobacterium, which are often added to commercial yogurt. Both have been shown in studies to help reduce diarrhea and to decrease incidents of yeast infections.
Scientists are studying the impact the bacteria have on the immune system, cancer and other health issues, such as inflammation, which has been linked to heart disease. At this point, many scientists say people understand just a fraction of how the bacteria work, how to keep a balance of “friendly” versus “unfriendly” bacteria and how many ways that bacteria influence the immune system and other body processes.
Probiotics as health treatment
One of the first people in Western medicine to address probiotics was Russian Nobel Prize-winner Ilya Metchnikoff, according to information from the National Institutes of Health. In the early 1900s, he studied the lifespan of people in Eastern Europe who lived on fermented milk and proposed that microbes in the milk could slow the aging process.
While there hasn’t been proof that probiotics can keep you young, other fermented foods in diets throughout the world were studied for health benefits. Certain strains of beneficial bacteria have been isolated and are now sold in supplement form.
Lieb says, in general, she prefers that healthy people start adding probiotics to their diet through naturally fermented foods. Sources include yogurt, kefir, sauerkraut, Korean kimchi, miso soup and certain cheeses, including Gouda.
Lieb suggests that people who would like to get probiotics from natural sources can even start fermenting their own foods. Books such as “Wild Fermentation” by Sandor Katz can help home fermenters.
Lieb also says keeping a good balance of bacteria in your intestinal tract is as much about what you don’t eat as what you do eat. Diets high in sugar and low in fiber can provide an environment for “unfriendly” bacteria to grow more rapidly and thus crowd out “friendly” bacteria, she says.
Supplements sometimes recommended
Lieb does recommend supplements if people have certain health issues, particularly people who are vulnerable to yeast infections or have short-term intestinal issues, such as traveler’s diarrhea. People with chronic intestinal problems, such as irritable bowel syndrome, might see a benefit, but should discuss adding a supplement with their doctor. Studies have also shown a benefit of probiotics after a round of antibiotics, which can kill beneficial bacteria as well as the infection.
Lieb says high-quality probiotics are expensive, so while there are few side effects from using a probiotic supplement, you might not need the added expense if you are otherwise healthy.
She also says that as people take in the good bacteria, either through supplements or food, it’s good to nourish them with foods known as “prebiotics.” Those include sources of indigestible fiber, including psyllium and inulin found in such vegetables as Jerusalem artichokes and in unrefined wheat and such foods as onions, shallots, garlic, honey and bananas.
Not all supplements the same
Lieb offers her patients some probiotic supplements that she has determined are quality products.
But several studies have shown some probiotic supplements don’t deliver what they promise in each capsule. The independent organization Consumer Lab, which tests commercial supplements, found that some probiotics contained only a fraction of the “colony-forming units” advertised on the bottle.
When buying probiotics, consumers should make sure they look at instructions on the bottle. If they contain active, live cultures, they typically must be refrigerated, or else your live cultures could literally die before you swallow them. Some freeze-dried probiotics remain stable on a shelf, but most probiotics can be damaged by exposure to high heat at the store or at home.
Lieb encourages consumers to research probiotic brands or obtain recommendations from a health care provider. There are also prescription-grade probiotics available.
“Generally, I try to encourage patients not to pick out probiotics randomly at the store,” she says. “You need to be aware of the specific strains of probiotics you are getting and the quality of the product.”