COMMENTARY

Guidelines Reveal Probiotics' Limited Value for GI Conditions

David A. Johnson, MD

Disclosures

July 14, 2020

This transcript has been edited for clarity.

Hello. I'm Dr David Johnson, professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia. Welcome back to another GI Common Concerns.

Today I want to talk to you about probiotics. I'm sure that any of us engaged in clinical care have had patients ask about probiotics or seen patients who are already taking them.

Probiotics have experienced a meteoric emergence over the past decade. It is estimated that probiotic use in the United States alone has quadrupled. Probiotics are not considered a drug by the US Food and Drug Administration. As a result, the various admixtures, indications, and different strains of probiotics in the products being advertised are largely unregulated. This has led people to question what the evidence is surrounding their use.

This question is nicely addressed in clinical guidelines from the American Gastroenterological Association (AGA) Institute and an accompanying technical review. I wanted to summarize their findings, which provide a solid overview of the current evidence that we can apply in 2020 and beyond.

When discussing probiotics, we should first define what they are. The Food and Agriculture Organization of the United States and the World Health Organization define probiotics as live microorganisms that, when ingested in an adequate amount, confer health benefit on the host. That's the backbone for what these agents are purported to do.

In their recommendations, the AGA Institute looked at specific gastrointestinal conditions purported to have the most evidence supportive of probiotic use: Clostridioides difficile, inflammatory bowel disease, irritable bowel syndrome, gastroenteritis, and necrotizing enterocolitis in infants. Let's look at what the evidence suggests in those conditions.

C difficile Infection

First, for patients with C difficile infections, the guidelines concluded that there was not enough evidence to support the use of probiotics outside of a clinical trial.

However, there was a conditional recommendation based on a low quality of evidence that certain forms of probiotics could be considered in patients at risk for C difficile, including Saccharomyces boulardii, a variety of admixtures with Lactobacillus and Bifidobacterium, and some Streptococcus salivarius species.

The guidelines are in line with a 2017 Cochrane review which reported that probiotics' benefits were driven by patients at high risk for C difficile rather than in those at low, indeterminate, or average risk.

There is evidence that probiotics should potentially be avoided in patients at higher risk for infection, such as those with indwelling lines, in the intensive care unit, or in immunocompromised states.

Therefore, using probiotics as a strategy for preventing C difficile should be viewed with some skepticism in patients who are not at high risk.

IBD and IBS

Regarding inflammatory bowel disease, the guidelines found no strong evidence to recommend probiotics for patients with ulcerative colitis or Crohn's disease, outside of a clinical trial.

The exception was in patients with pouchitis, where there was fairly weak evidence to offer a conditional recommendation supporting the use an eight-strain mixture of lactate-producing organisms, again combining Lactobacillus, Bifidobacterium, and a Streptococcus salivarius species. Given the relative weakness of the evidence, as well as the cost and availability of these probiotics, the authors noted that it is reasonable for patients with pouchitis to choose not to use them as well.

For irritable bowel syndrome, the authors noted that there were many studies into the use of probiotics but they were characterized by their tremendous heterogeneity. The recommendation was that there was nothing to support the proactive use of probiotics in these patients outside of a clinical trial.

Gastroenteritis and Necrotizing Enterocolitis

The guidelines regarding acute infectious gastroenteritis focused on pediatric populations and recommended against the use of probiotics. Data supporting the use of probiotics in this indication come from studies outside the United States and Canada, whereas two high-quality studies performed in those countries have shown no benefit.

Finally, the guidelines noted that there was moderate- to high-quality evidence in preterm (< 37 weeks) infants with a low birth weight. There is a conditional but evidence-based recommendation for the proactive use of certain probiotic combinations in these infants to prevent or minimize the risk of developing necrotizing enterocolitis.

In summary, these new guidelines indicate that based on the existing evidence, probiotics should likely not be recommended in the majority of patients with gastrointestinal disorders. Hopefully this gives you some guidance to steer your conversations with your patients, peers, and friends.

This is Dr David Johnson. I look forward to chatting with you again soon.

David A. Johnson, MD, a regular contributor to Medscape, is professor of medicine and chief of gastroenterology at Eastern Virginia Medical School in Norfolk, Virginia, and a past president of the American College of Gastroenterology. His primary focus is the clinical practice of gastroenterology. He has published extensively in the internal medicine/gastroenterology literature, with principal research interests in esophageal and colon disease, and more recently in sleep and microbiome effects on gastrointestinal health and disease.

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