The Nutrition Diva's Quick and Dirty Tips for Eating Well and Feeling Fabulous

When do probiotic supplements make sense?

Episode Summary

US consumers are spending 3 billion dollars a year on probiotic supplements. Are they getting a good return on investment?

Episode Notes

US consumers are spending 3 billion dollars a year on probiotic supplements. Are they getting a good return on investment?

Nutrition Diva is hosted by Monica Reinagel. A transcript is available at Simplecast.

Have a question you want answered on the podcast? Send an email to or leave a voicemail at 443-961-6206.

Find Nutrition Diva on Facebook and Twitter, or subscribe to the newsletter for more diet and nutrition tips.

Nutrition Diva is a part of Quick and Dirty Tips.

Resources and selected research:
Fiber content of common foods
Impact of probiotics on colonizing microbiota of the gut
Are probiotics and prebiotics effective in the prevention of travellers' diarrhea: A systematic review and meta-analysis
Choosing an appropriate probiotic product for your patient: An evidence-based practical guide


Episode Transcription

Hello and welcome to the Nutrition Diva podcast. I’m your host, Monica Reinagel and today we’re talking about probiotic supplements and when it makes sense to take them. 

Long time listener Mahin sent a great question recently: 

“I started taking probiotic supplements after having a few rounds of antibiotics (and the negative digestive effects they come with). I feel like they have been very beneficial for me over the past month. Should I continue taking them? Or should my gut be repopulated by now and able to sustain itself?”

Probiotic supplements, of course, contain various strains of bacteria and other microbes that are thought to be beneficial to our health. We also talk a lot about the intestinal microbiome–the bacteria that live in our gut–and the effects they have on our health. And I think there are some widespread misunderstandings about the relationship between the two. 

People tend to think about probiotic supplements the way we think of stocking a trout pond.  We’re ingesting specific strains of bacteria in the hopes that they will set up housekeeping in our guts. 

But that’s not really how probiotic supplements work. Most of the bacteria that we ingest in probiotic foods and supplements do not actually colonize the gut in any permanent way. They are transient. 

Our particular microbiome–our bacterial signature, if you will–is established early in life. The microbiome can be temporarily disrupted by things like infection or antibiotics. And probiotics can also have a short-term impact. But they are unlikely to displace or significantly alter those resident populations. 

As Professor Maria Marco of the University of California, Davis, explains

“The resident gut microbiota that develops during infancy tends to remain relatively stable throughout adulthood. Even with perturbations caused by antibiotics or foodborne illness, the gut microbiome tends to be resilient to the long-term establishment of exogenous bacterial strains.”  

(Exogenous meaning: Introduced from the outside).

So: When we take probiotics, we’re not colonizing our guts with the bacteria in the probiotic itself. We’re not actually stocking the pond. 

But even if these bugs don’t persist in the gut, that's not to say they don't provide some benefits as they move through your system. For example, they can help to suppress the growth of pathogenic or undesirable organisms, which gives the resident good guys a leg up. They may produce compounds that encourage the growth of beneficial bacteria that do stick around. 

And there are some specific situations where certain probiotic supplements have been demonstrated to be helpful. 

One is in the prevention of traveler’s diarrhea, caused by pathogenic bacteria in the food or water. While locals may have developed immunity to those pathogens, a traveler’s immune system is caught off-guard, with unpleasant results. Traveler’s diarrhea is usually not serious but it can really take the fun out of a vacation. And this is one place where probiotic supplementation can help. 

But all probiotics are not equally useful for this. The strain with the best record against traveler’s diarrhea is Saccharomyces boulardii CNCM I-745. It’s sold in North America under the brand-name Florastor–and it’s actually a yeast, not a bacteria.You can take this (or another probiotic) as a preventive measure when traveling, but there’s no need to continue once you get home. 

Florastor is also available in a lower dose for kids–who also frequently suffer from diarrhea. (Apparently, for your first few years on the planet, you’re essentially a traveler everywhere you go!) Check with your pediatrician before dosing your kids, though.

Probiotic supplements have also been demonstrated to help prevent the diarrhea associated with antibiotic use, which is how Mahin was using them. 

Antibiotics are used to treat sinus infections, pneumonia, skin infections, ulcers, and other problems caused by bacteria. While they're taking out the bad guys, however, antibiotic drugs can also do a number on the good guys–the beneficial bacteria in your digestive tract. That's why people commonly experience diarrhea and other gastrointestinal issues when taking antibiotics. 

In the past, many believed that taking probiotics at the same time as you are taking antibiotics was a waste of time and money, reasoning that the antibiotics would simply kill off the beneficial bacteria as fast as you could take them in. 

However, research has now established that taking probiotics during antibiotic therapy significantly reduces the number of side effects. The two strains with the best record are our friend S. boulardi (Florastor) and a strain of bacteria called Lactobacillus rhamnosus GG (or LGG for short). LGG is sold under the brand name Culturelle.

Only about 1 in 3 people experience side effects with antibiotics so you don't necessarily need a probiotic supplement—especially if you're only taking antibiotics for a week or so. Digestive effects are more common with extended or repeated courses of antibiotics.

You may also want to ask your doctor about probiotics if you're taking antibiotics to treat a stomach ulcer. Most stomach ulcers are caused by a bacteria called h. pylori, which is most effectively treated by antibiotics. With this particular bacteria, probiotics actually increase the effectiveness of antibiotic therapy. 

Probiotics have also been found to have some efficacy in the treatment of digestive diseases such as Ulcerative Colitis and Irritable Bowel Syndrome. But, here, I urge you to work with your physician to identify whether or not a probiotic makes sense for your particular symptoms and, if so, which one, how much, and how often.

But what about taking an all-purpose probiotic just to bolster your general gut health?  Personally, I don’t recommend taking a daily probiotic supplement the way you might take a vitamin supplement.  

I get the desire to foster a healthy microbiome. But, as I said earlier, probiotics are unlikely to actually colonize the gut. Instead of trying to stock the pond, I suggest you approach this the way you might go about attracting songbirds to your backyard.  

You don’t release a bunch of birds into your yard and hope they stick around. Rather, you put out the kind of food and feeders that are likely to attract the birds you’d like to see more of. 

In the case of your microbiome, this means eating foods that provide the substrates (or nutrients) that desirable bacteria need to thrive. I can also say that in a much less fancy way: eat more plant fiber.  

Fiber, especially soluble fiber, is indigestible by the human digestive system. But it provides a veritable buffet for the beneficial bacteria that live in our guts. Providing more food will result in a more robust, balanced, and stable population. 

If your goal is to promote a healthy microbiome, the best way to do that is not not to take probiotic supplements but to eat a greater abundance and variety of fiber-containing foods, such as vegetables, legumes, nuts, and whole grains. 

In the show notes for today, I’ll include links to a cheatsheet with good sources of fiber, as well as citations for some of the research I reviewed. 

Nutrition Diva is a Quick and Dirty Tips podcast. It's audio-engineered by Nathan Semmes with script editing by Adam Cecil. Our Podcast and Advertising Operations Specialist is Morgan Christianson. Our Digital Operations Specialist is Holly Hutchings. Our marketing and publicity assistant is Davina Tomlin, and our intern is Brendan Picha.

If you have a question you'd like me to answer, you can email me at You can also leave me a message at 443-961-6206

That's all for this episode. Thanks for listening! I'll see you next week.

Selected Research

Sanders ME. Impact of probiotics on colonizing microbiota of the gut. J Clin Gastroenterol. 2011 Nov;45 Suppl:S115-9. Link

McFarland LV, Goh S. Are probiotics and prebiotics effective in the prevention of travellers' diarrhea: A systematic review and meta-analysis. Travel Med Infect Dis. 2019 Jan-Feb;27:11-19. Link 

Sniffen JC, McFarland LV, Choosing an appropriate probiotic product: An evidence-based practical guide. PLoS One. 2018;13(12):e0209205. Published 2018 Dec 26.  Link