The lack of clarity hasn’t stopped consumers from using probiotics. According to a survey by the Council for Responsible Nutrition, 14 percent of people ages 55 and older use them. The new study, published in June 2019 in the Journal of General Internal Medicine, found that only about one-third of the probiotics purchased were associated with clinical evidence that suggests they’re effective. It’s challenging for consumers to know which probiotic they should buy, says the senior investigator, Dan Merenstein, MD, a professor of family medicine and the director of research programs for the Department of Family Medicine at Georgetown University in Washington, DC. “People have to educate themselves through research or by talking to their physician or nutritionist, so that when they go to buy a probiotic, they know what to look for on the product label,” says Dr. Merenstein. That’s the only way to make sure it has evidence behind it, he adds.
What Are Probiotics and What Are Their Touted Health Benefits?
Probiotics are “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host,” according to the International Scientific Association for Probiotics and Prebiotics, in an expert consensus document published June 2014 in Nature Reviews Gastroenterology and Hepatology. The National Center for Complementary and Integrative Health defines probiotics as “good” bacteria that may help the digestive system and boost the immune system. Probiotics may play a role in preventing cancer, lowering cholesterol, and protecting against allergies, among other touted benefits, notes a review published in ISRN Nutrition. For example, another review, this one published in September 2017 in Clinics and Practice, notes that probiotics may also help reduce symptoms of mental health disorders including depression and anxiety. Probiotics are naturally found in foods like yogurt, sauerkraut, tempeh, and kombucha, or you can take them in supplement form, according to the National Institutes of Health (NIH). There is evidence that several strains of probiotic work as intended, but some studies show that other strains don’t perform any better than placebo in clinical trials, according to the study. The Food and Drug Administration (FDA) classifies most probiotics as supplements, which means it is left up to the manufacturer to ensure the probiotic is safe and labeled truthfully. The FDA does not regulate supplements with the same level of scrutiny as medications. RELATED: What Are the Pros and Cons of Probiotics?
Can You Judge a Probiotic Supplement by Its Label?
After hearing many naysayers point to the lack of evidence backing probiotics, Merenstein and his colleagues set out to determine if it was possible to identify and purchase evidence-based probiotics. They bought 93 different bottles of probiotics from four national probiotic retailers in the Washington, DC, area and examined the labels to see if they included recommended use; dosage/serving size; colony-forming unit (CFU), which is an estimate of the number of viable bacteria in a sample; storage information; genus/species/strain of probiotic; and expiration date. Then researchers used that information to see if clinical evidence supported the product claims. The probiotic needed to meet three requirements:
The strain designation was on the labelThe strain amount was at the level of an efficacious doseThe dose and strain were subjects of at least one controlled clinical study listed on PubMed, a web-based search engine for biomedicine and health studies run by the National Institutes of Health
Researchers found that only 33 bottles, or 35 percent of the number they purchased, could be linked to medical efficacy. Although some of the products may have the components and clinical evidence needed to meet the criteria, if the labeling didn’t contain enough information for researchers to track down the information, it wasn’t included in the group that had evidence-based efficacy. The labeling of probiotics is lacking, agrees Emeran A. Mayer, MD, a gastroenterologist at UCLA Medical Center and the author of the book The Mind-Gut Connection. Dr. Mayer did not take part in this research. Rather than considering the number of evidence-backed probiotics low, Mayer says he was surprised that it was as high as 35 percent. “If you used the same rigorous criteria for evidence that would be used in pharmaceutical trials, I don’t think this number would be so high,” says Mayer. This isn’t necessarily because of unsuccessful probiotic trials or because probiotics don’t work, but rather because large-scale placebo-controlled probiotic trials on humans are almost never performed, says Mayer. Unlike pharmaceutical drugs, probiotics don’t have to go through a series of trials to be approved for sale on the market. If companies already have a probiotic that is doing well on the market, they often decide that the risk and cost of performing a big clinical trial isn’t worth it, says Mayer. RELATED: Should You Start Drinking Kombucha?
What to Look for on the Label When You’re Buying a Probiotic
There are some key things to look for to make sure the probiotic you are buying will be safe and effective, says Merenstein. Fortunately for consumers, a higher price tag isn’t one of them, he says. “It might be counterintuitive, but we found that products with fewer strains and lower cost were more likely to be supported by evidence we could trace,” says Merenstein.
1. Pay Attention to the Dosage
It’s important to look for a dosage, as some products don’t list it on the label, he says. “Make sure it says that the dose [applies] until the end of shelf-life. It doesn’t matter what the dose is when it leaves the manufacturing facility, because that might change,” says Merenstein. Probiotics contain living bacteria, and the CFUs can vary over time.
2. Look for the Phrase ‘Recommended Use’
The label should say what you should be using the probiotic for, says Merenstein.
3. Make Sure These 3 Key Terms Are on the Label
It’s important that the probiotic has three names, because that indicates the company knows what they are putting in the supplement, says Merenstein. “It should list the genus, the species, and the strain. A lot of the probiotics we purchased had only two names, which means you couldn’t tell exactly what their product was,” says Merenstein. The above criteria are good guidelines if you’re looking for a new product, says Merenstein. “I would try to pick one that has been studied more and has more evidence,” he says. On the other hand, if you’ve been taking a probiotic that’s been helping you but doesn’t have all the information or evidence, don’t automatically switch to something else, says Merenstein. RELATED: The Connection Between the Gut Microbiome and Type 2 Diabetes
What Might the Probiotic Marketplace Look Like in the Future?
Currently, there aren’t any independent third parties that evaluate probiotics for consumers. “There’s been some talk about that happening, and I think that would be great; it would be a game changer in helping consumers navigate the probiotic market,” says Merenstein. Don’t expect the FDA to begin adding new regulations or guidelines for probiotics anytime soon, says Merenstein. Although labeling may be lacking or unclear, what’s in the bottle has been safe, he says. “The FDA directs more of their attention to areas where there are clear risks for the consumer, like dietary supplements that contain anabolic steroids or things that are more dangerous,” says Merenstein. The FDA has limited resources, so it makes more sense for them to prioritize safety, he adds. “The good news is that as far as we know, most of these probiotic strains that have been studied for a long time are very safe in the short term,” says Merenstein. Long term, there’s not a lot of data available, but that’s true for many supplements and approved pharmaceuticals as well, he says. These findings shouldn’t worry consumers of probiotics; there’s nothing in this paper that says these companies weren’t following the rules or that they were selling dangerous products, says Merenstein. “It’s more that the companies either aren’t sharing all the information they have about the probiotic or they don’t have the appropriate information to share,” he says.
