By Matt Knight, RDN, LDN
Highlights from the AGA’s Newly Released Clinical Guidelines
Earlier this year, the American Gastroenterological Association (AGA) released new clinical guidelines for the use of probiotics in managing gastrointestinal (GI) disorders.1,2 The AGA is a professional organization representing gastroenterologists and other clinicians who specialize in digestive health.
These new guidelines represent the first clinical guidance focusing on single-strain or multistrain formulations of probiotics and their efficacy for specific digestive conditions. The AGA’s findings run counter to conventional thinking and may require dietitians and other health professionals to rethink their position on the therapeutic use of probiotic supplements.
Here’s a quick refresher on probiotics for RDs who may not counsel clients regularly on their use.
What Are Probiotics?
Probiotics are defined as “live microorganisms, which when administered in adequate amounts, confer a health benefit on the host.”3 Because they’re not considered drugs, probiotic supplements aren’t regulated in the same way as pharmaceutical medications in the United States or Europe.
Unfortunately, this lack of regulation has allowed manufacturers to make health claims for their probiotic products without sufficient evidence from clinical trials.
These health claims have fueled the perception that probiotics offer several health benefits when taken regularly. An estimated 3.9 million American adults used probiotics in 2015, and total sales of probiotic supplements are forecast to continue growing every year.4
These individuals are our clients, patients, and family members. Based on the latest guidance, unless one is taking a specific probiotic strain or combination of strains backed by clinical evidence, the AGA now recommends patients consider stopping their use outside of participating in a supervised research trial.
Summary of the AGA Findings
After a thorough literature review of all the available research as of December 2018, the AGA found sufficient evidence to support the use of probiotics for three health conditions: the prevention of necrotizing enterocolitis in preterm, low–birth weight infants; the prevention of Clostridiodes difficile (C diff) infection in high-risk adults and children taking antibiotics; and the management of pouchitis, a complication of ulcerative colitis treatment.
Probiotics for Preterm Infants
Preterm infants born before the gestational age of 37 weeks weighing less than 2,500 g (5.5 lbs) may benefit from specific probiotic supplements. There’s moderate high-quality evidence showing a reduction in infant mortality and reduced incidence of necrotizing enterocolitis when probiotics are given to preterm infants. Evidence also supports the use of probiotics to help reduce the number of days until infants can begin full feeds and decrease the total time spent in the hospital. These findings were given the highest level of confidence for all conditions mentioned in the AGA report.
Prevention of C diff Infection While Taking Antibiotics
There’s low-quality evidence supporting the use of probiotics for adults and children who are at high risk of developing C diff infection while taking antibiotics. It’s important to note that the benefit was seen only in high-risk individuals; those at low or moderate risk of infection saw no benefit from probiotic supplementation.
Probiotics for Prevention or Treatment of Pouchitis
There’s low-quality evidence supporting the use of probiotics for the prevention or treatment of pouchitis, a postsurgical complication associated with the treatment of ulcerative colitis.
Other Digestive Health Conditions
For children with acute infectious gastroenteritis, the guidelines don’t recommend the use of probiotics. Much of the data for this population come from studies conducted outside of North America. There’s concern the findings may not be applicable to children in the Unites States. A review of studies conducted on children in the United States and Canada found no benefit associated with probiotic use.
Outside of clinical trials, the AGA currently doesn’t recommend probiotics as a treatment option for active C diff infection, Crohn’s disease, ulcerative colitis, or irritable bowel syndrome. In each condition, the AGA found a knowledge gap due to a lack of consistency across patient populations and the probiotic treatment provided.
Takeaways for Dietitians
A significant challenge the AGA identifies in its literature review is heterogeneity in the research data. Much of the existing literature investigates the efficacy of “probiotics” as a broadly defined term. Differences in patient populations, probiotic strains, dosage, and length of use made it difficult to compare results.
The AGA was careful to point out that its report wasn’t intended to discourage further study of probiotics. Many small trials have documented beneficial effects of probiotics across a wide range of conditions. Both RDs and consumers often read and hear of these results. The AGA’s call to action is for more consistent studies designed to assess the clinical efficacy of specific probiotic strains in ways that can be replicated across multiple study sites.
The probiotic industry is largely unregulated, and marketing often is directed at consumers without direct and consistent proof of evidence. Probiotic supplements can be costly, and according to the AGA clinicians should suggest the use of probiotics to their patients only if there’s clear benefit.
— Matt Knight, RDN, LDN, is a dietitian and blogger based in Naperville, Illinois. He emphasizes eating real, local foods and translates the science of nutrition into easy-to-understand, simple, and actionable steps on his blog. More information on his latest work is available on Twitter and Facebook.
References
1. Su GL, Ko CW, Bercik P, et al. AGA clinical practice guidelines on the role of probiotics in the management of gastrointestinal disorders. Gastroenterology. 2020;159(2):697-705.
2. Preidis GA, Weizman AV, Kashyap PC, Morgan RL. AGA technical review on the role of probiotics in the management of gastrointestinal disorders. Gastroenterology. 2020;159(2):708-738.e4.
3. Food and Agriculture Organization. Probiotics and food: health and nutritional properties and guidelines for evaluation. http://www.fao.org/3/a-a0512e.pdf. Published 2006.
4. Parker EA, Roy T, D’Adamo CR, Wieland LS. Probiotics and gastrointestinal conditions: an overview of evidence from the Cochrane Collaboration. Nutrition. 2018;45:125-134.e11.
