The idea of the use of probiotics has a history going back more than a century when Russian scientist, Elie Metchnikoff, theorized that lactic acid bacteria may offer health benefits as well as promote longevity. In the early 1900s, intestinal disorders were frequently treated with nonpathogenic bacteria to replace gut microbes.
Today, the market is flooded with products from foods to prescription medications containing probiotics that extol their health benefits. It has been estimated that the global market for probiotics is more than $32 billion dollars annually and is expected to increase 8% per year.
Dr. Linda Girgis
As family doctors, patients come to us with many questions about the use of probiotics. Look online or on store shelves — there are so many types, doses, and brands of probiotics it is hard to decipher which are worth using. We older doctors never received much education about them.
Earlier this year, the World Gastroenterology Organization (WGO) developed recommendations around the use of probiotics and defined them as “live microbes that have been shown in controlled human studies to impart a health benefit.” Their recommendation is to use the strains that have been shown to be beneficial for the condition they claim to help and have been shown to do so in controlled studies. The dosage advised should be that shown to be useful in studies.
While this is an easy statement to make, it is much less so in clinical practice. The guidelines do a good job breaking down the conditions they help and the strains that have shown to be beneficial for specific conditions.
There have been claims that probiotics have been shown to be beneficial in colorectal cancer. While there have been some studies to show that they can improve markers associated with colorectal cancer, there are no data that probiotics actually do much in terms of prevention. Eating a healthy diet is more helpful here.
One area where probiotics have been shown to be beneficial is in the prevention of antibiotic-associated diarrhea. This makes sense since we know that antibiotics can kill the “good bacteria” lining the gut wall and probiotics work to replace them. Other conditions where these agents have been shown to be beneficial include radiation-induced diarrhea, acute diarrhea, irritable bowel syndrome, and colic in breast-fed infants.
The guideline contains good evidence of where and which types of probiotics are useful and it is good to look at the charts in the paper to see the specific strains recommended. It also contains an extensive reference section, and as primary care physicians, it is imperative that we educate ourselves on these agents.
While probiotics are typically sold as supplements, we should not dismiss them summarily. It is easy to do that when supplemental products are marketed and sold unethically with no clinical evidence of benefit. We need to remember that just because something is a supplement doesn’t necessarily mean that it was not studied.
Family physicians need to be able to educate their patients and answer their questions. When we don’t have the answers, we need to find them. Any time our patient doesn’t get good information from us, they will probably go to the Internet and get bad advice from someone else.
There is much ongoing research about the gut microbiome and the bacteria that can be found in the gut. Researchers are looking into the “gut-brain” axis but there is not much good evidence of this link yet. There is no evidence that probiotics can cure Alzheimer’s disease or Parkinsonism. The future may reveal different stories, but for now, we need to follow the evidence we have available.
There are many outlandish claims about what the gut microbiome is responsible for and can do for health. It is easy to have a knee-jerk reaction when anyone brings it up in conversation. We need to arm ourselves with the evidence. We are stewards of the health and safety of our patients.
Dr. Girgis practices family medicine in South River, N.J., and is a clinical assistant professor of family medicine at Robert Wood Johnson Medical School, New Brunswick, N.J. She was paid by Pfizer as a consultant on Paxlovid and is the editor in chief of Physician’s Weekly.