Response to CBS News Report: Do Probiotics Actually Do Anything?

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They got a lot right, but we have a few (cited) details to add to the conversation

By Mike Grochocki, RD, LDN

On June 28^th, 2020 the CBS News show 60 MINUTES aired a segment on probiotics, which have become wildly popular in both professional and retail nutritional supplement markets. The main question CBS News wanted to answer was: “do probiotics actually do anything”.

60 MINUTES interviewed doctors and researchers from the United States and Israel who provided their stance on clinical uses and their understanding of the research involving probiotics. As expected, opinions varied. Some messages seemed to be in conflict, and overall left the viewer possibly more confused about and skeptical of probiotic supplements. We would like to offer some insight and clarifications.

What did 60 MINUTES report?

Some of the doctors they interviewed were in strong support of existing clinical research showing probiotic benefits. Jeff Gordon, MD, said that our gut microbiome helps us process the food we consume, it produces vitamins^[1] and essential amino acids^[2] for us, and it supports the human immune system^[3] in various ways.

Dan Merenstein, MD, a professor of family medicine at Georgetown University, stated “I think the data is there,” but also noted that more research is needed. He’s not wrong.

Patricia Hibberd, MD, PhD, had a different take on the subject. She stated, “there’s not enough high-quality research to recommend off-the-shelf probiotics for the medical problems for which they’re commonly used.” One of her main points is that taking probiotics ‘may’ help, but we don’t know how to do it.

When asked if there is convincing evidence that commercially available probiotics have been found to be beneficial for reducing antibiotic-associated diarrhea (AAD), treating Irritable Bowel Syndrome (IBS), or decreasing allergies, Dr. Hibberd responded emphatically “no.” There are many healthcare practitioners, researchers, and nutritional supplement experts who disagree.

Within one minute, Frank Greer, MD, professor emeritus of pediatrics at the University of Wisconsin, said “we don’t really know how probiotics work,” and that there’s no evidence that adding probiotics to infant formula is good for babies who consume it, and then “there’s no evidence that says they’re harmful, and finally, “there are no long term [laugh] studies.”

Confused yet?

What are probiotics?

Probiotics are broadly defined as live microorganisms which, when administered in adequate amounts, confer a health benefit to the host.

Probiotics are broadly defined as live microorganisms which, when administered in adequate amounts, confer a health benefit to the host. For a microorganism to be considered a viable probiotic by any reputable manufacturer or probiotic lab, the following criteria must be met: 1) it should benefit the host, 2) it should be non-pathogenic, 3) enough of it should be able to survive transit through the gastrointestinal tract to its target location, and 4) a large number of viable CFUs must be able to survive extended periods of storage.^[4]

In this 60 MINUTES segment, Eran Elinav, MD, PhD, and Eran Segal, PhD, professors at Israel’s Weizmann Institute of Science, said they looked at whether probiotics populated the gut. In their study, they stated that for half of the test subjects, probiotics did not stick around. They didn’t mention whether the species or strains of bacteria tested have been shown in other studies to populate the gut. This is important because we know that some strains do not stick around but will provide benefits as they transit through the gastrointestinal tract.

They cited another of their studies in which some subjects who were given probiotics after a round of antibiotics, experienced a delay in the return of their normal GI microbiome compared to subjects who did not take probiotics. They didn’t mention how they confirmed the quality of the probiotics they used in their studies, and whether they were tested for purity and potency. The only thing they said in this regard, was that the probiotics “are out there in your supermarket.”

Statements made during this news segment, and in general, about how nutritional supplements sold in the U.S. are unregulated is preposterous and wholly inaccurate.

Statements made during this news segment, and in general, about how nutritional supplements sold in the U.S. are unregulated is preposterous and wholly inaccurate. The Food and Drug Administration (FDA) strictly enforces regulations regarding the intended use of nutritional supplement ingredients, and monitors for abuses and medical claims based on the Dietary Supplement Health and Education Act^[5] (DSHEA).

Dr. Greer’s statement that the Generally Recognized as Safe (GRAS)^[6] status of probiotics is substandard, in an infant formula containing food ingredients regulated by the same standard, fails to provide clarity for consumers. Outside of the U.S., countries including Canada, Australia, Japan, South Korea, and Brazil have their own regulatory bodies which require manufacturers to conform with Good Manufacturing Practices (GMP)^[7] which equal the United States’ requirements, as well as provide safety data and analyses for microbiological, heavy metal, and/or chemical contaminants.

The moral of this story is that probiotics are regulated in all these cases.

But what about safety and efficacy?

Nutritional supplements are regulated by the FDA, and by NSF International^[8] which provides GMP certification and monitoring for nutritional supplement manufacturers to ensure they are following GMP guidelines regardless of whether they are certified. In addition, organisms with GRAS status include lactobacillus, lactococcus, bifidobacterium, and yeast. Together, these guidelines when followed closely, ensure that nutritional supplements are pure and safe. Safety of probiotics has been further demonstrated in numerous studies and meta-analyses, from infant to adult ages.^[9],^[10],^[11]

What the guidelines do not ensure is that products are effective, because the FDA does not approve nutritional supplements to diagnose, treat, cure, or prevent any disease.^[12]

As long as there’s no claim of curcuminoid content listed on a turmeric supplement label, there’s no current regulation that states that the product must contain any curcuminoids at all.

Therein lies the rub. If nutritional supplement companies cannot make any claims about efficacy, then there is potential for products on the market to contain little if any of the active compounds shown in research to be effective. Consider curcuminoids, the primary active compounds found in turmeric (Curcuma longa), which are well researched for their health benefits.^{[13],[14],[15]} As long as there’s no claim of curcuminoid content listed on a turmeric supplement label, there’s no current regulation that states that the product must contain any curcuminoids at all. It’s up to 1) individual companies to provide turmeric supplements with a standardized curcuminoid content and label it as such, and 2) for consumers to recognize that this is what they want when shopping for a turmeric supplement. The same goes for probiotics, which may list the potency of the species found in the product, along with a disclaimer stating, “viable cell count at the time of manufacture.” This provides no assurance that the product contains the potency claimed on the bottle by the time the consumer brings it home.

What Drs. Hibberd, Elinav, and Greer didn’t mention when they were explaining that there isn’t enough evidence of exactly what probiotic supplements are doing, is that numerous pharmaceuticals approved by the FDA and prescribed to patients, have unknown mechanisms of action as described in their monographs.^[16] So this lack of complete understanding is acceptable for drugs, but not for nutritional supplements which are considered foods according to the FDA?

These, along with a multitude of other confounding factors can contribute to misconceptions that probiotics are ineffective in all cases, when really it’s more complicated than that.

What does the research say?

In this 60 MINUTES segment, Dr. Hibberd seemed convinced that probiotics have not been shown to benefit AAD, IBS, or allergies.

Meta-analyses published over the course of 10 years have shown that probiotics can reduce the incidence of AAD anywhere from 42% to 50%.^[17],^[18],^[19],^[20] One particular meta-analysis published in the Journal of the American Medical Association in 2012 included 63 randomized, double-blind, placebo-controlled trials (RDPCT) comprising 11,181 participants. Probiotic species included: Lactobacillus rhamnosus, L. casei, L. acidophilus, L. reuteri, L. plantarum, L. casei, Bifidobacterium lactis, B. infantis, B. longum, Saccharomyces boulardii, and Bacillus coagulans. Probiotic potency in these studies varied between 100 million to 50 billion CFUs per day. The combined evidence showed a 42% reduction in the incidence of AAD.²⁰

We would be remiss if we didn’t give a shout out specifically to Saccharomyces boulardii, a probiotic yeast used often in supplements and documented in hundreds of peer-reviewed studies. Dr Lynne McFarland at the University of Washington describes one such study conducted in 2008, which showed no benefit of S. boulardii in the setting of AAD.^[21],^[22] This study was underpowered, not run for long enough to observe delayed-onset AAD, and did not confirm the strain of S. boulardii used for the intervention group.

We would be remiss if we didn’t give a shout out specifically to Saccharomyces boulardii, a probiotic yeast used often in supplements and documented in hundreds of peer-reviewed studies.

Of course, not every nutritional supplement study will show significant benefits, but that is the nature of research in general. With pharmaceuticals, we typically find greater amounts of publications with positive findings due to what is known as publication bias – researchers tend to only publish if the data or outcome is that which they seek.

Elsewhere, a meta-analysis including 31 randomized, placebo-controlled treatment arms in 27 trials encompassing 5,029 participants found S. boulardii to be significantly effective for prevention of AAD (P<0.001). Randomized trials have also shown benefits of S. boulardii in the setting of traveler’s diarrhea, Helicobacter pylori overgrowth, and it shows promise in the setting of Clostridium difficile recurrences, treatment of IBS, acute adult diarrhea, Crohn’s disease, giardiasis, and HIV-related diarrhea, although more supporting evidence is warranted in these settings.^[23] It is important to note that S. boulardii is contraindicated in immunocompromised patients at risk for intestinal translocation or who have a central venous line.^[24]

There is also significant clinical data and meta analyses showing efficacy of probiotics in the setting of IBS.^{[25],[26],[27],[28]} The most common positive results include improvements in abdominal pain, bloating and flatulence. A meta-analysis published in the American Journal of Gastroenterology in 2014 included 35 RDBPCTs and comprised 3,452 IBS patients as participants,^[26] which found that probiotics provided benefits for global IBS, abdominal pain, bloating, and flatulence scores.^[26]

Multiple high-quality studies have supported the hypothesis that supplementation of specific probiotic strains can help mitigate allergic reactions to foods.

The ability of probiotics to improve symptoms of food allergies was documented over 20 years ago.^[29],^[30],^[31] More recently, multiple high-quality studies have supported the hypothesis that supplementation of specific probiotic strains can help mitigate allergic reactions to foods. A study involving infants with atopic eczema and cow’s milk allergy found that a blend of whey protein enhanced with Lactobacillus rhamnosus GG was shown to significantly improve signs and symptoms of intestinal inflammation.^[32]

A double-blind, placebo-controlled crossover study involving children with atopic dermatitis aged one to 13 years found that a blend of lyophilized Lactobacillus rhamnosus 19070-2 and Lactobacillus reuteri DSM 122460 improved skin health in 56% of participants in the treatment group, while only 15% in the placebo group improved. The treatment response was also more pronounced in patients who tested positive for allergic response and elevated IgE.^[33] One 12 month study of involving children with allergic asthma and/or rhinitis found that the group given probiotic-fermented milk had significantly fewer rhinitis episodes and a trend towards longer time periods between asthma episodes and rhinitis, compared with the group given unfermented milk.^[34]

Dr. Gordon stated early in this news segment that they are testing whether the microbiome of a slender person can be transferred to an overweight person in order to help them lose weight. A study published in March 2020 tested if manipulation of the microbiome would support weight loss in 220 overweight or obese participants aged 30 to 65, over the course of six months. The test looked at multiple outcomes related to health and considered a probiotic blend shown to reduce weight gain in mice. The results showed that supplementation with the probiotic product resulted in significant reductions in body weight and improvements in small dense low-density lipoprotein-cholesterol (sdLDL-C) profiles, quality of life scores, and a reduction in the incidence of upper respiratory tract infections.^[35]

Final Thoughts

Overall, this 60 MINUTES segment offered a variety of professional viewpoints regarding probiotics, and it wasn’t all wrong. Everyone they interviewed either confirmed or discussed the great potential of probiotics to benefit health. But it’s the conflicting message that really sticks in the mind.

Most everyone affirmed that there is no reason to believe that short- or long-term use of probiotics is harmful (except for severely immune-compromised people), but that there are no long-term studies to confirm that. In fact, the International Probiotics Association (IPA) reminded us in a recent press release of a clinical study using probiotics with pregnant and lactating mothers, and children from birth to six months of age. They followed these participants for 11 years or more.^[36] The IPA also pointed to a specific clinical study involving cancer patients given probiotics and followed for over 21 years.^[37] Neither of these studies found safety concerns related to the use of probiotics.

With years of clinical data supporting the benefits of probiotics, including in the setting of specific health dysfunction, and a relative lack of documented health detriments, our question is: what’s the problem?

It’s important to ask questions, especially when it relates to health. And it’s important to be skeptical of clinical research, because it’s not always as clear or generalizable as the authors might intend. But it’s also important to not discount a vast body of evidence that does exist, and to unnecessarily increase consumer confusion about the very complicated and dynamic subject of human nutrition.

About the author

Mike Grochocki is a Product Specialist, and manages the Technical Services Department at Allergy Research Group®. Mike graduated with a Dietetics degree from Arizona State University, interned at a Veterans Administration hospital, and worked as a Clinical Dietitian for a Chicagoland area hospital group before transitioning into the nutritional supplement industry and functional nutrition.

Mike is a self-professed foodie, and has a Culinary Arts degree from Le Cordon Bleu in Scottsdale, Arizona. He is a life-long learner, and enjoys traveling and experiencing languages and cuisine from around the world.

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