Ensuring and protecting the human microbiome has long been understood as an integral aspect of maintaining good health. The intestines contain more than 100 trillion bacterial cells with each individual person harboring their own ecosystem of microbiota species.
Typically, the relationship between bacterial flora and host is symbiotic. These beneficial bacteria aid the body in many different ways ranging from digestion support to playing a role in the appropriate functioning of our adaptive immune system. However, fluctuations in this ecosystem can lead to a host of symptoms and conditions. C. Diff. infection, for example, is one such bacterial overgrowth where the disruption of this ecosystem can lead to a serious and potentially life-threatening situation if not prevented or treated. In cases like these, supplements are often used to restore gut health — and understanding the common supplements and how they function is essential to helping patients maintain this delicate balance.
To be clear, research examining the use of supplements for the maintenance of intestinal health is sparse, and more research needs to be done to evaluate the role that these bacteria play in our daily lives. That said, the most common supplements for the maintenance of gut health are probiotics. Their use is common throughout the world for a whole host of conditions, but due to a lack of disease-specific clinical trials, the American Gastroenterological Association currently only recommends specific strains for the prevention of C. difficile infections in patients taking antibiotics. Additionally, recommendations for patients with active intestinal conditions such as C. difficile, ulcerative colitis, and Crohn’s disease are at this time limited to the setting of a clinical trial. While the AGA brings to light the need for species, strain, and disease state-specific clinical trials, it also acknowledges that probiotics hold the promise of an effective way to alter the microbiome for our benefit.
A less commonly talked about tool in the maintenance of the gut microbiome is the prebiotic supplement. Prebiotics are a subset of dietary fibers. They are nondigestible by the gut and are used essentially as a food source for gut bacteria. One of the most common prebiotic non-digestible fibers is inulin. A common dietary food additive and supplement, inulin is a heterogeneous blend of fructose polymers. Its consumption does not lead to a rise in serum glucose or a spike in insulin secretion. Inulin is typically synthesized from glucose or extracted from chicory root.
The World Gastroenterology Organization’s global guidelines for probiotics and prebiotics outline the mechanism of action of prebiotics as working to increase the population of beneficial anaerobic microorganisms. Bolstering the population of our own “good” bacteria helps to prevent “bad bacteria” from growing through antagonism and competition with potential pathogens.
There is a subset of intestinal supplements that contain both a probiotic (bacterial strain) and a prebiotic (non-digestible fiber). This product is considered a synbiotic. Synbiotics function through two mechanisms. Combining a prebiotic with a probiotic encourages the survival of the probiotic strain being administered. This greater survival can lead to a more efficacious result from the probiotic strain. Additionally, the presence of the prebiotic may work independently of the probiotic. Probiotic effects are largely seen in the small intestine while prebiotic action can more readily be seen in the large intestine. It may be that through these independent mechanisms of action, the combination supplement may have a synergistic effect on the gut.
Despite the popularity of their use in the community, there is currently a lack of reliable evidence with respect to human clinical trials evaluating the efficacy of probiotics, prebiotics, and synbiotics with decreasing study availability respectively. One animal study in rats has shown that b. coagulans (probiotic) administered in combination with inulin (prebiotic) had greater survivability in fecal material than did rats receiving a control diet or a diet that just contained the probiotic.
When selecting a probiotic, prebiotic, or synbiotic product, it is important to consider some key factors. To date, no probiotic product has been approved by the FDA to treat, lessen, cure, or prevent any disease. Because of this, most products are sold over the counter with less oversight assuring quality and purity. When choosing a product to carry at your pharmacy, here are a few things to keep in mind:
- When possible, use products made by long established companies, companies that have their products verified by an independent lab, or companies that have voluntarily registered their products with the FDA. One such example is ProbiChew, a prescription-only synbiotic (full disclosure: ProbiChew is an Amplicare partner).
- Look for labels and packaging that include strain information, storage recommendations, number of colony-forming units, and use by date.
Ultimately, probiotics, prebiotics, and synbiotics perform similar functions when it comes to restoring and/or maintaining good gut health. With limited studies making it difficult to make a discrete determination on use cases, choosing the "right" supplement may result in trialing more than one product. This is why having a working knowledge of the options available as well as the tools to determine a quality manufacturer is required to confer the greatest benefit to your patients.
Alex Yampolsky, Pharm D, is a pediatric clinical pharmacist and healthcare tech consultant.
