Probiotics are good bacteria found in fermented foods, such as yogurt, sauerkraut, miso, kimchi, kombucha and kefir.
Popular theories claim extraordinary health benefits—such as better immunity and less stress—can come from eating probiotics
and fostering the good bacteria in your gut.
But the research to support all this is sparse.
Some benefits science has shown, to date: probiotics can help with certain respiratory infections, diarrhea and
irritable bowel syndrome.
And in high doses, specific strains of probiotics could protect against insulin resistance, obesity and high cholesterol.
It’s also still unclear whether fermented foods have any lasting effect on the gut microbiome, but Stanford microbiologist
Justin Sonnenburg, Ph.D., believes the resulting increase in the diversity of gut microbes is likely to be health-promoting.
And more promising studies are on the way, he says.
You don’t have to eat foods like yogurt or miso to get probiotics, either. You can also get probiotics in supplement form.
But only roughly 20 strains (compared to more than 1,000 in your gut) are available in supplements. And many of the strains
showing promise of health benefits in labs aren’t available to consumers.
Also, buyer beware: the FDA doesn’t regulate supplements, so you may not always be getting what you think. When
ConsumerLab.com analyzed 19 popular probiotic supplements, five brands fell far short of their claims.
How you store the capsules can also impact bacteria counts. Your best bet: store supplements in the fridge to keep the
bacteria alive longer.