As initially reported by Retraction Watch, on March 20, 2018 the journal PLoS One retracted a June 2017 paper touting the Gut Makeover diet, a four-week program sold as a way to positively manipulate gut microbes through food. The article had gone through peer review, meaning experts uninvolved in the research had vetted the article to help ensure its validity and integrity. The article was written by U.K.–based nutritional therapist, Jeannette Hyde, who also created the diet, and Kate Lawrence, PhD, a psychology professor at St. Mary’s University, Twickenham, London. Hyde, whose LinkedIn profile shows she has a bachelor’s degree in nutritional therapy at the University of Westminster in London, authored the book upon which the diet is based, called The Gut Makeover: 4 Weeks to Nourish Your Gut, Revolutionise Your Health and Lose Weight. The diet calls for eating gut-friendly, prebiotic, fiber-rich veggies and grains, such as raw oats and soybeans, and doing a 12-hour fast between dinner and breakfast, among other steps. The article on the diet is one of thousands of papers on the gut microbiome, which is defined as a collection of good bacteria and other microbes in the gut that may influence immunity and risk for diseases such as obesity, diabetes, rheumatoid arthritis, and some types of cancer, as highlighted by a review published in January 2015 in Current Opinion in Gastroenterology. At the time this Everyday Health story was published, a search of “gut microbiome” on the federal government’s PubMed, a database of research, turned up nearly 9,700 results. RELATED: How Your Gut Microbiome May Affect Diabetes
What the Retracted Article Claimed About the Gut Makeover Diet
The retracted article by Hyde and Lawrence claimed the Gut Makeover diet could result in weight loss, as well as improved digestion, cognitive function, and mood. Furthermore, Hyde and Lawrence wrote in the article, the diet “has the potential for improving physical and emotional wellbeing in the general population and for being used as part of a treatment protocol for conditions as diverse as (irritable bowel syndrome), anxiety, depression, and Alzheimer’s disease.” Using data based on 21 people (only one of whom was male) — a sample size considered relatively small — who were undergoing the Gut Makeover protocol, the article detailed an author-led study that relied on self-reported data provided by participants in a questionnaire. In the months following its publication, the article drew backlash from scientists and the public alike.
Public Outcry Led to the Article’s Retraction in the Journal
In its retraction, PLoS One cited the lack of a control group of non-dieters and the fact that participants weren’t blind to the treatment. Controlled, blinded studies can help eliminate the potential for bias and add credibility to a study’s findings. Research published in the July–December 2012 issue of the Indian Journal of Sexually Transmitted Diseases and AIDS points out that randomized, controlled, double-blind studies are considered the gold standard in such research. The retraction also stated that “the conclusions of this study are not supported by the data presented.” The aforementioned deficiencies were among the reasons that a volunteer editor for the journal, Duane Mellor, PhD, nutrition professor at Coventry University in the U.K., resigned from his post as an academic editor for the journal. “Sorry @PLOSONE when you publish uncontrolled diet book #nutribabble like http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0179017 … now you have 1 less Academic Editor. Bye!” Mellor tweeted on June 16, 2017. In an interview with Everyday Health, Mellor calls the study that the article detailed “an audit of people trying the [Gut Makeover] book” rather than a clinical trial. As the article originally described, and which Mellor notes, because participants were given a description of the Gut Makeover diet and were not blinded to what was being studied, they may have experienced a placebo effect. Mellor also points out that despite using the term “microbiome” in the title and abstract of the article, the authors never measured the effect the diet had on bacteria. “That’s a key shortcoming” that prevented the authors from drawing conclusive results, he says. In its retraction, PLoS One also cites this discrepancy. Article coauthor Lawrence, on the other hand, stands by the publication of the article, arguing the retraction was a misunderstanding of what she and Hyde had sought out to analyze. “Some people seem to be under the misapprehension that this was a clinical trial. It was not. It was a retrospective assessment of nutritional therapy group work,” Lawrence says. She calls PLoS One’s decision to retract the article “both disappointing and baffling.” PLoS One spokesman David Knutson says the journal decided to retract the article after receiving multiple complaints via email and social media, which prompted the journal to reassess the article, effectively repeating its initial peer review process. “We cannot reveal details as to the issues raised during review; the content of reviews is confidential as part of the peer review process,” says Knutson, adding that the journal would be “enhancing our internal editorial scrutiny of manuscripts involving health-related interventions.
Shortcomings in the Peer Review Process May Have Led to Initial Publication
Adam Marcus, cofounder of Retraction Watch, a blog that reports on retractions of studies published in scientific journals, says the retraction of the Gut Makeover diet article highlights how the peer-review process established by medical journals isn’t fail-proof. “We want to believe that when a study is published in a peer-reviewed journal, that means it’s been vetted not only by the editors, who are scientists, but also by some number of independent-thinking, outside experts in the relevant field who give their stamp of approval to the scientific quality of the article,” Marcus says. “It’s a quality-control step that is really important to generating trust in scientific publishing. Does it always work? No, and in this case I think it’s pretty clear that the peer review process regarding this particular paper failed miserably.” RELATED: The Gut-Brain Connection: How Gut Bacteria May Treat Depression His blog sees roughly 1,000 retractions in scientific journals each year, but the current article stands out because the fundamental model upon which the article was written fell short of the journal’s typical standards for publication. “Usually it’s a retraction because there are findings that couldn’t be reproduced or there are findings of plagiarism, or data manipulation or fabrication, but it’s unusual to see a journal retract a paper for this reason,” Marcus says. PLoS One identifies itself as the world’s first multidisciplinary open-access journal that accepts all submissions that meet its ethical standards, regardless of the results drawn. In 2017, Retraction Watch published an interview with PLoS One Editor-in-Chief Joerg Heber that noted a decline in submissions and several high-profile retractions in 2016. Heber added in the interview that the publication was addressing its peer review process and striving to reduce its rate of corrections.
Buzz Over Gut Microbiome Likely Encouraged Article Publication, Some Say
In the case of Hyde and Lawrence’s article, Marcus speculated that the subject matter of the current article may have prompted the journal to preemptively publish it. “I think everything with the word microbiome in it is really hot, and journals often fall for the latest fad and the sexiest key words. Maybe that’s what happened here,” Marcus says. Neurologist David Perlmutter, MD, author of Brain Maker: The Power of Gut Microbes to Protect and Heal Your Brain — For Life, acknowledges the hype around gut microbiome research but emphasizes that research is still limited, supporting an argument made by the authors of a review published in January 2015 in Nutrients, which concluded “there are still many gaps in our understanding of the interactions between diet, lifestyle, gut microbes, and health.” “We do understand the broad strokes in terms of what makes for good dietary choices for the health of the microbiome,” Dr. Perlmutter says. “Where we run into difficulty is making much more refined and specific recommendations that we hope might have broad-spectrum appeal to many people.” Among the factors that must be considered are genetic differences between individuals, how the microbiome interrelates with each person’s genetic makeup, his or her environment, and how the body reacts to various foods, he explains. “It’s really inappropriate to make a global statement that, ‘Here is the best microbiome for everybody’ — that ‘This specific diet is one that everyone should be on.’” Mellor similarly advises caution when assessing science and medical news. “I think part of the issue is how the general public — and the media — digest what we see in research journals as always being true, whereas it’s really just more of an observation. We need more than one observation to build a true picture of what a theory is.” The publisher of PLoS One made an announcement on Monday, March 26 that relates directly to the peer review process in its stable of journals. It has created the PLoS Reviewer Center, a new educational resource “to support reviewers working on manuscripts submitted to PLoS journals.”
