Probiotics: Benefits vs. Drawbacks

They appear to combat “tummy troubles,” but there is scant evidence to support other widely circulated probiotics benefits.

probiotics benefits

Look for probiotic-rich yogurts and kefir in the dairy aisle.

Probiotics are live micro­organisms—bacteria and yeasts—that are commonly referred to as “good” bacteria. Probiotic benefits, experts believe, extend to our digestive health by increasing the population of good bacteria in the intestines, which prevents “bad” bacteria (for example, Clostridium difficile and Escherichia coli) from causing illness.

Yogurt and kefir (a drink made from cow’s or goat’s milk) contain probiotics, which are a natural product of the fermentation process. Other fermented foods that contain probiotics include sauerkraut, kimchi (a Korean cabbage dish), and miso (soybean paste), but these foods are very high in sodium.


A recent study published in Frontiers in Aging Neuroscience (Nov. 10, 2016) suggests that probiotics may improve thinking and memory in people with Alzheimer’s disease (AD). Probiotics are live bacteria that are present in some yogurts, and also available in supplement form. They are typically recommended to relieve conditions like irritable bowel syndrome, but research suggests they also may benefit the brain.

The 60 study participants, who had advanced AD, were divided into two groups: 30 were given probiotic-rich milk each day for 12 weeks, and the other group received plain milk. After the study period, brain function test scores improved in the probiotic group compared with the placebo group.

Research Says…

Some studies suggest that taking probiotics can help lessen the duration and/or severity of diarrhea associated with antibiotic use, and that they may help alleviate the symptoms of irritable bowel syndrome. And, researchers who published a study in 2016 found that overweight and obese women who consumed probiotic yogurt daily for 12 weeks had healthier levels of total cholesterol, LDL (“bad”) cholesterol, blood glucose, and insulin levels than women who ate low-fat yogurt that contained no probiotics.

More recently, research has suggested that probiotics might benefit brain health (see sidebar, “Probiotics Linked to Brain Health”). However, clinical trials overall have yielded mixed results, and health experts have differing opinions on the beneficial effects of probiotics. On the other hand, few side effects are reported among healthy people who take probiotics.

If you’re considering adding probiotics to your diet, talk to your doctor about potential interactions with other supplements or medications you take. If your doctor prescribes an antibiotic, ask if diarrhea is a common side effect, and if your doctor can recommend any specific strain(s) or brand of supplement that might help.

If you have a weakened immune system or any type of intestinal disorder, do not take probiotics without discussing their possible effects with your doctor.

Selecting Supplements

There are many varieties of probiotic supplement available. Align, Culturelle, and Florastor are brands commonly recommended by gastroenterologists because they are produced by large manufacturing companies and have undergone rigorous clinical studies. You can find these brands in most pharmacies.

If you’re getting your probiotics from a health food store, here are some guidelines to help you choose:

  • If you want to take probiotics to support your general health, choose options with multiple strains of bacteria. The most common groups of probiotic bacteria include Lactobacillus and Bifidobacterium, and a common probiotic yeast strain is Saccharomyces boulardii (see “Sources of Probiotics” chart for examples).
  • Select products that contain at least 1 billion colony-forming units (CFUs) per dose—this information is provided on the label. Also check the label for the expiration date.
  • Since probiotics are live organisms, they can be destroyed by unfavorable environmental conditions. Store supplements in a cool, dry place, out of sunlight. Some probiotics require refrigeration.

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Originally published in 2017, this post is regularly updated.

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Dawn Bialy

Dawn Bialy has been executive editor of Weill Cornell Medicine’s Women’s Health Advisor newsletter since 2007. Bialy also has served as managing editor for a variety of special health reports, … Read More

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