Probiotics 101: What You Need to Know

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The next time you're in the dairy aisle of the grocery store, pick up a carton of yogurt and look for the words "contains live and active cultures." The label might even include a list of active yogurt cultures such as  Lactobacillus acidophilus and  Bifidobacterium lactis, which are the most common. Those cultures are also known as probiotics.

But what are probiotics? An international group of experts met in 2001 and agreed on this definition for probiotics: "live microorganisms which when administered in adequate amount confer a health benefit on the host." Or, in simpler terms, probiotics are microorganisms that help maintain a healthy balance of "good" bacteria in your gut and can aid in digestion. Sometimes you might hear them called "friendly bacteria," too.

Here's what you need to know about probiotics:

Probiotics may offer several health benefits.

Depending on which probiotics you're consuming, you may experience various health benefits. Probiotics are reported to help strengthen your intestines against infections, reduce gas production, boost your immune system, and restore or maintain the "good bacteria" in your gut.

The easiest place to find probiotics is your supermarket.

Yogurt is the food that most of us associate with probiotics. Be sure to read the label to be certain, though, because not all yogurt contains probiotics. Read further down the label to see if any specific bacteria are listed, too. You could also try the fermented dairy product called kefir and certain aged cheeses that contain live cultures. Not a dairy fan? Other products containing probiotics to check out include tempeh and miso, both of which are made from fermented soybeans, and fermented cabbage like sauerkraut or kimchi. Again, be sure to read the labels.

Keep them cool.

Store your yogurt and kefir in the fridge so they stay cool. Watch out for the expiration dates, too. Also, keep in mind that cooking certain items like the cheese or cabbage can decrease or eliminate the probiotic cultures.

Probiotics are often linked with prebiotics.

Prebiotics are non-digestible carbohydrates that provide the nutrients for the probiotic bacteria—they're essentially the food that helps probiotics survive and thrive. Bananas, legumes and artichokes are some foods that are good sources of prebiotics.

Few side effects are associated with probiotics.

Generally speaking, probiotics seem to be safe and have few side effects. However, the National Center for Complementary and Alternative Medicine warns that there's not a lot of long-term data on safety yet. People with underlying health conditions may be at the greatest risk for any side effects.

Probiotics seem to help people suffering from diarrhea.

About a quarter of people who take antibiotics find themselves coping with the gut-wrenching effects of diarrhea as a result of the antibiotics disturbing the usual balance of bacteria in their gastrointestinal tract. But they could probably lower their risk of experiencing that particular side effect by taking probiotics. Studies also show consuming probiotics may be able to help people with a nasty GI bug like acute infectious diarrhea.

Skip the probiotic supplement.

There are plenty of dietary supplements that contain probiotics on the supermarket and drugstore shelves, but you really don't need to take any of them. In fact, some experts suggest that you avoid these capsules, tablets and powders because supplements aren't regulated by the Food and Drug Administration (FDA) in the same way that drugs are regulated. That means that the supplement makers can make all sorts of health claims about their products even though the FDA hasn't given approval for those particular therapeutic uses.

Stay tuned.

There may be other benefits still to be determined. Research about the benefits of probiotics—or the lack thereof—continues, so we may learn more. For example, earlier this year, a study was published in the Journal of Food Science that purported that probiotics from peanuts may help prevent some foodborne illnesses. Research is also ongoing to determine if probiotics are an effective and safe tool for fighting off complications like diarrhea associated with  Clostridium difficile, or C. diff., and for treating stomach ulcer symptoms.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2019 Jun 20

  1. Marcason W. Probiotics: Where Do We Stand? Journal of the Academy of Nutrition and Dietetics, Vol. 2013; 113(10): 1424.

  2. Heller KJ. Probiotic bacteria in fermented foods: product characteristics and starter organisms. American Journal of Clinical Nutrition. 2001; 73(2): 374s-379s.

  3. Ishibashi N and Yamazaki S. Probiotics and Safety. American Journal of Clinical Nutrition. 2001;73(2): 465s-470s.

  4. Isolauri E. Probiotics in human disease. American Journal of Clinical Nutrition. 2001; 73(6): 1142S-1146S.

  5. Hempel S, et al. Probiotics for the Prevention and Treatment of Antibiotic-Associated DiarrheaA Systematic Review and Meta-analysis. JAMA. 2012; 307(18):1959-1969.

  6. Hoffman DE, et al. Probiotics: Finding the Right Regulatory Balance. Science, 2013; 342 (6156): 314.

  7. Healthy Eating Tip of the Month: The Pros and Cons of Probiotics. University of Michigan. August 2014.

  8. Probiotics handout. University of North Carolina School of Medicine.

  9. Probiotics: In Depth. National Center for Complementary and Integrative Health (NCCIH).

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