Dr. Geoffrey Preidis leads the AGA technical review on the use of probiotics for specific gastrointestinal conditions

American Gastroenterological Association (AGA), a leading society of medical professionals, has published the first-ever clinical guidelines for the use of probiotics in the prevention and treatment of common gastrointestinal (GI) conditions. These guidelines are a culmination of a comprehensive two-year technical review conducted by a team of researchers and gastroenterologists. The review team, led by Dr. Geoffrey Preidis, pediatric gastroenterologist at Texas Children’s Hospital and assistant professor at Baylor College of Medicine, performed a rigorous analysis of published clinical trials to find evidence supporting the use of probiotics in preventing and treating specific GI disorders. The technical review and guidelines were published in Gastroenterology, the official journal of AGA.

“Most technical reviews and the guidelines they support focus on a specific disease and evaluate different treatment options available for a given condition. We flipped this model and examined evidence that addressed the efficacy of a single therapeutic modality - probiotics - in preventing and treating various GI conditions. With this initiative, our goal was to create a comprehensive resource and evidence-based guidance for clinicians regarding prescription of probiotics for GI disorders,” Dr. Preidis said.

Probiotics are live microbes which when consumed in adequate amounts confer a health benefit on the host, and are available in various forms such as fermented foods, yogurts, kefirs, drinks, sachets, and pills. The probiotics industry is growing rapidly, with sales in the United States alone expected to exceed $6 billion this year. 

Probiotics and the gut microbiome are areas of growing interest among researchers and the general public. While there is mounting anecdotal evidence that shows beneficial effects of probiotics for various GI disorders, until now, general practitioners and gastroenterologists have had minimal guidance on how and when to recommend probiotics for treating, mitigating or preventing GI disorders.

Since probiotics are generally classified as dietary supplements, their manufacturing process is not as strictly regulated as pharmaceutical drugs. Moreover, few rigorously designed multi-center clinical trials have been conducted to study the efficacy of probiotics in treating or preventing serious GI conditions. Finally, while probiotics are generally safe for most people, rare adverse effects have been reported in patients with serious underlying health problems.

“The most important take-home message from our review is that not all probiotics are created equally and that clinicians and researchers need to consider the distinct biological effects of individual species and strains of microorganisms that make up a probiotic formulation. Different strains of the same bacterial species can have very different biological effects and clinical outcomes, both in laboratory and in human studies – suggesting that we cannot lump all probiotics together into a single group of therapeutics. Just like we use different antibiotics to target specific bacterial species or strains, we have to employ precisely selected strains of probiotics for different clinical scenarios and purposes,” Preidis explained.

The review covered studies that involved otherwise healthy patients and excluded studies on medically fragile patients such as those undergoing chemotherapy or organ transplantation, or those with compromised immune systems. The team examined eight clinical scenarios, and identified four key areas in which enough evidence exists to form the basis of a recommendation.  Based on their technical review, the panel developed guidelines for the following conditions -

1. The most compelling evidence supporting the use of probiotics is to reduce the risk of devastating outcomes in preterm, low birthweight newborns. The team found moderate to strong evidence supporting the beneficial effect of probiotics in reducing the risk of complications like necrotizing enterocolitis, sepsis and mortality by 50% in premature babies. In addition, they found a few bacterial strains or strain combinations that offered the best outcomes. Therefore, AGA makes a conditional recommendation (based on moderate/high quality evidence) for the oral use of probiotics in preterm, low birthweight newborns.
    
2. On the other hand, the team found that probiotics should not be prescribed to children presenting to the emergency room with acute viral gastroenteritis - which contrasts with current practices in many children’s hospitals. The reason for this reversal was that previous meta-analyses have focused on data from mostly small studies that showed beneficial effects of probiotics These trials were not conducted in North America - many were based in Europe, Asia, or the Middle East, where the types of pathogens encountered by the children as well as host genetics and dietary traditions are very different – and the majority of these studies revealed significant concerns regarding risk of bias.. The technical review team found two large multi-center trials conducted in North America using either a single strain of probiotic bacteria or a combination of two strains; neither study reported a significant benefit. Given that probiotics have associated costs with unclear benefits in this population, the AGA recommends (based on moderate quality evidence) that North American physicians not use probiotics for children with acute gastroenteritis.
    
3. They also found some evidence to suggest probiotics can reduce the risk of antibiotic-associated diarrhea and C. difficile infections among patients taking antibiotics, especially in elderly or hospitalized patients. Probiotics seem to have the greatest benefit for those at highest risk of developing C. difficile infection. AGA offers a conditional recommendation (based on low quality evidence) for the use probiotics in this context on a case-by-case basis.
    
4. The team found a specific combination of eight strains of probiotics may benefit patients with pouchitis, an inflammation that occurs in the lining of the pouch that is created after a surgery to treat ulcerative colitis and so, they offer a conditional recommendation (based on very low quality evidence) for this clinical scenario.

For further details, see this video by Dr. Geoffrey Preidis.