The Washington Post published an article September 19, 2016 titled If probiotics work for a friend, why won’t they work for you, too?
I had a hard time reading this article, as it was full of incorrect assertions and misleading insinuations. Let’s take a look at what passes as science in this newspaper and my attempt to right the wrongs.
WP: Skeptics say “…many probiotics disappear after entering the digestive system.”
MES: Yes they do. A permanently colonizing probiotic has yet to be isolated. However, this does not mean that they can’t impact human health as they transit the body. Colonization is not a requirement for efficacy.
WP: Skeptics say “They (probiotics) affect different people in different ways.”
MES: Of course they do. So do all drugs. Have you ever had your physician say, “Let’s try this statin and if it doesn’t work, we can try a different one”? People are different. They have different genetics, different diets and different colonizing microbiota. It would be unreasonable to expect one probiotic to impact all people in the same way. [Also see quote later in the article “Many people swear by them (probiotics), but it doesn’t mean they work all the time for every ailment.”]
WP: “They (skeptics) note that research about the products hasn’t been done…”
MES: This IS true for some products, but not all. If you search PubMed for all studies done on probiotics that are classified as ‘human clinical trials,’ 1,590 citations show up. Some of these studies are grade 1 highest level of evidence and have resulted in some probiotics becoming the standard of care for certain conditions.
WP: Research “…might not be reliable because it was paid for or conducted by the manufacturers themselves.”
MES: There are many reasons for possible bias or fraudulent research: plagiarism, fabricated data, overextension of results to make the outcomes seem more important than they really are (to consumers, to tenure committees, etc.), incorrect interpretation of results to make the study more interesting to journal editors or potential funders, suppression of results that do not support the hoped-for outcome, or compromising blinding. Academic and industry researchers alike can perpetuate such fraud. Clearly industry research is a potential source of bias but that is all it is potential. The goal of research is to uncover the truth in the relationship between the tested intervention and the outcome. There are many ways bias can be introduced into a study, and it is incumbent upon researchers to do their best to minimize it. One valuable means to minimize bias is for researchers to register a human trial prior to subject recruitment. The study dismissed in the WP article was in fact registered prior to recruitment at UMIN Clinical Trials Registry (http://www.umin.ac.jp/ctr/) as UMIN000011926. If industry funding were a fatal flaw for research, there would be almost no drugs on the market today.
WP: Regarding probiotic effectiveness, “…for healthy people seeking to stay that way, forget it.”
MES: Probiotics have been shown to have effects in healthy people. A Cochrane review by Hao et al. 2015 concluded, “Probiotics were better than placebo in reducing the number of participants experiencing episodes of acute URTI, the mean duration of an episode of acute URTI, antibiotic use and cold-related school absence. This indicates that probiotics may be more beneficial than placebo for preventing acute URTIs. However, the quality of the evidence was low or very low.” Granted this is not the most enthusiastic endorsement but the conclusion found benefit for probiotics in healthy subjects.
WP: Regarding probiotic impact on gut microbiology, “Only one of the seven trials showed any difference in the bacteria in the gut, as measured in the study participants’ waste…This came as a surprise to us that there is no scientific evidence that probiotics do have an impact on the gut microbiology. The problem is many people think there is a benefit.”
MES: These results may have come as a surprise to this expert, but they didn’t come as a surprise to those who follow probiotic research. These trials had all been published, and as individual studies they were clear in reporting that the probiotic being evaluated conferred no significant changes to overall microbiota populations based on the methods used. But these comments reported by the WP conflate probiotic impact on gut microbiology and the ability of probiotics to impact health. There are many ways probiotics may impart health benefits that don’t require macro changes in fecal microbiota. See here.
WP: Regarding consistency of results, “…some clinical trials show a modest effect on clinical outcomes, while others do not.”
MES: As do studies for basically all researched substances. If all studies are positive, you should be suspicious. Studies for mammograms, aspirin, diabetes drugs, etc. all have had mixed results.
WP: “…the field of probiotics needs more research before manufacturers (sic) claims can be proved.”
MES: Numerous reviews of the totality of evidence have concluded that probiotic can be beneficial for a variety of endpoints including preventing antibiotic associated diarrhea, helping manage symptoms of irritable bowel syndrome, reducing crying time in colicky babies, preventing atopic dermatitis in at-risk infants, treating acute pediatric diarrhea and preventing necrotizing enterocolitis in preterm infants. Of course these benefits cannot be extrapolated to all probiotic products on the market. But the few that have been studied deserve to be acknowledged.
One thing this article got right – there doesn’t appear to be research showing that the strain in Karma Culture’s product impacts stress, metabolism or weight control. Marketers of this product should not imply that it does.