Probiotics have become increasingly popular in recent years. Much of the buzz surrounding probiotics can be attributed to growing interest in the role of gut bacteria on overall health, our evolving understanding of the human microbiome, and finally, good marketing strategies. After all, probiotics directly translates to “for life,” which is an alluring name for consumers seeking to find the cure to what ails them.
Despite their popularity, however, there is insufficient evidence to support the use of probiotics for most medical conditions they have been purported to help. If you have wondered what impact probiotics can have on your own health or that of your child, you may have found that the evidence is not so clear.
Right now, we are still learning which bacteria could provide health benefits, which medical conditions they can treat, and what their optimal dosing would be. On top of this, we still are not even completely confident that the probiotics we eat actually colonize our gastrointestinal tract. In a study published in Cell in September 2018, researchers found that probiotics more readily colonize the gut of some people than others, meaning that some people will get little to no effect from the probiotics they consume.
What types of probiotics are available?
Whether you meant to or not, you have likely consumed plenty of foods containing probiotics in your lifetime. In general, foods that undergo a fermentation process such as yogurt, soft cheeses, kimchi, and kombucha contain living microorganisms, and some of these bacteria may confer the health benefits that earn them the title of “probiotic.” Probiotics are also sold as capsules.
Which conditions can probiotics potentially treat?
Currently, the strongest early evidence we have for using probiotics is for the prevention and treatment of diarrhea.
- Antibiotic-associated diarrhea: Antibiotics can wipe out our body’s store of “good” bacteria. This can make it easier for “bad” bacteria to take over and cause you to have diarrhea. Taking probiotics while on antibiotics might help maintain your body’s delicate bacterial ecosystem and prevent you from the unpleasant side effect of diarrhea. The strongest evidence we have for preventing antibiotic-associated diarrhea is with the following bacteria: L. rhamnosus, L. casei, and S. boulardii.
- Infectious diarrhea or “stomach flu”: Probiotics can shorten the duration of symptoms for some infectious causes of diarrhea. Several different bacteria have been shown to reduce the duration of infectious diarrhea in children, including L. reuteri, L. rhamnosus GG, L. casei, and S. boulardii. There is also promising research suggesting adults may also benefit from taking probiotics when they have traveler’s diarrhea.
In both of these cases, it is important to remember that each of us has a unique gut microbiome and the effects of different bacteria on our bodies is highly variable. Other areas where the use of probiotics is being studied include inflammatory bowel disease, allergic disorders, infant colic, liver disease, and the common cold, to name a few. We do not have conclusive evidence supporting the treatment of any of these conditions with probiotics, so if you are suffering from any of these conditions and are considering trying probiotics as a treatment, consult with your doctor first and find out what available treatment options exist.
What are the risks of consuming probiotics?
Probiotics pose a risk for causing infections in people with underlying medical conditions — especially in those with weakened immune systems or who are critically ill.
Another consideration with probiotics is that the Food & Drug Administration (FDA) does not regulate them, which means that if you purchase probiotic pills, for example, it is impossible to know how much probiotic the pill contains or if it contains any probiotics at all.
The Bottom Line on Probiotics
We still have a lot to learn about this topic, and at this time, there is not enough evidence to support the use of probiotics as a medical treatment. Even in cases where the use of probiotics is promising — such as in the cases of the stomach flu or for treating antibiotic-associated diarrhea — it is important to recognize that the products we have on the market now may not contain the correct strains or quantities of bacteria to provide you any benefit. Hopefully in the years to come we will develop a better understanding of how to use probiotics to alter our gut microbiomes in a beneficial way, possibly even by designing probiotic concoctions that are personalized for your unique gut microbiome. In the meantime, if you are thinking of starting probiotics, talk with your doctor about your medical condition to find out what other treatments are available.