What are the risks/benefits of taking probiotics, and for which indications? Is one probiotic better than another?

First, what is a probiotic?

Probiotics are live microorganisms that help maintain “good” bacteria in the gut. They are thought to help in many conditions involving the gut such as diarrhea from antibiotic use and ulcerative colitis, and even in some conditions not involving the gut. Different probiotics contain different microorganisms, so they can have different effects on the body. Many people use probiotics, but it is unclear whether or not they are truly helpful.

What are the benefits of taking probiotics?

Many probiotics being studied are classified as dietary supplements, so the FDA regulates them as food rather than drugs. As a result, there aren’t as many good clinical studies to show if they are helpful. For example, conditions such as Clostridium difficile infection or C. diff (an infection that causes inflammation of the colon and diarrhea, sometimes caused by antibiotics), Crohn’s disease, ulcerative colitis, and irritable bowel syndrome do not have enough strong research to show if probiotics are helpful in their treatment. Therefore, current guidelines only recommend that patients use probiotics in the context of a clinical trial. In C. diff prevention, certain probiotic formulations were shown to be beneficial in studies, but mostly in patients with high risk for C. diff. Studies have also shown that probiotic use can lower the risk of getting diarrhea from using antibiotics. However, once again, these are not good, quality studies, making it difficult to really know if probiotics are helpful.

What are the risks of taking probiotics?

Though many studies mentioned above involving probiotics reported no side effects from probiotic use, some reported mild-moderate GI symptoms such as gas and bloating. On rare occasions, probiotics have caused serious infections in severely ill patients and newborns.

Is one probiotic better than another?

As previously stated, different probiotics contain different microorganisms, so they can have different effects on the body. Therefore, there isn’t one probiotic that is overall better than another. Specific probiotics work better for specific conditions. Listed in the chart below are some of the probiotic formulations with microorganisms that were shown to have strong evidence of benefit for different conditions. When looking for probiotics, look for brand names with these microorganisms. The probiotics that have brand name products are listed in parenthesis.

Should I use probiotics?

There is a lot of interest in learning about probiotics, how they can help in different conditions, and which ones are the best. However, there is currently not enough research to have strong answers to these questions. Therefore, it is difficult to know if there is truly a benefit in taking different probiotics based on the information available. Although, there seems to be minimal side effects from probiotic use besides mild-moderate GI symptoms. While there are some cases of more serious infections from probiotic use, these events are rare and only seem to occur in seriously ill patients. As a result, seriously ill patients may want to avoid probiotics. While there is little risk with most patients trying probiotics, there may also be little benefit. Therefore, you may choose to avoid probiotics to also avoid unnecessary costs. However, it is extremely important that more quality research is done about probiotics so we have better information about using them.

Written by: Jamie Voss, PharmD Candidate 2023