BMJ won’t retract controversial dietary guidelines article; issues lengthy correction
The BMJ has released a detailed correction to a much-debated article critiquing the expert report underlying the U.S. dietary guidelines.
After the article was published in 2015, the Center for Science in the Public Interest (CSPI) organized a letter signed by more than 100 researchers, urging the publication to retract the article. Today, the journal said it found “no grounds” to do so.
However, in a press release accompanying the announcement of the correction, the BMJ notes that some aspects of the CSPI’s criticisms were merited.
Editor in chief Fiona Godlee said in a statement:
We stand by [author Nina Teicholz’s] article with its important critique of the advisory committee’s processes for reviewing the evidence, and we echo her conclusion: ‘Given the ever increasing toll of obesity, diabetes, and heart disease, and the failure of existing strategies to make inroads in fighting these diseases, there is an urgent need to provide nutritional advice based on sound science.’
Teicholz — who already announced the article wouldn’t be retracted — said in a statement that she appreciates the journal’s support:
I am very grateful to The BMJ editors for their profound commitment to verifying the facts of my article and for their professionalism and integrity throughout this process. I am also grateful that they are providing a space for rigorous scientific debate, especially on a subject so important to public health. I hope the original intention of that article can now be fulfilled—to help improve nutritional advice, so that it is based on rigorous science. This will help us to better combat nutrition-related diseases that have caused so much human suffering around the world.
Bonnie Liebman, CSPI’s Director of Nutrition, told us she was not pleased with the decision:
The BMJ has stained its reputation by circling the wagons around Nina Teicholz’s discredited and opinionated attack on the science underpinning the Dietary Guidelines for Americans. The BMJ corrected or “clarified” 7 of the 11 errors cited by the letter from more than 180 scientists requesting a retraction, and failed to respond to the remaining four. (The clarifications are thinly veiled corrections.) It’s startling that despite this long list of corrections and clarifications—including several that undergirded the article’s attack on the Dietary Guidelines Advisory Committee report–the journal nevertheless stands by the article’s conclusions.
Liebman added:
As one reviewer noted, the article never should have been published as an “investigation by the BMJ” when it is “ better described as an opinion piece, editorial, or even an example of lobbying literature than an independent investigation.”
“The scientific report guiding the US dietary guidelines: is it scientific?” criticized several aspects of the expert report, noting it used “weak scientific methods,” according to today’s statement; it has already received a “clarification” (issued soon after it was published), and a previous correction, which addressed the research behind the analysis about saturated fats. The 2015 article has been cited six times, according to Clarivate Analytics’ Web of Science, formerly part of Thomson Reuters.
After receiving heavy criticism, the journal asked two independent experts — Lisa Bero at the University of Sydney, and Mark Helfand at the Oregon Health & Science University — to review the article. As the BMJ statement notes:
Both reviewers found that the authors of the CSPI letter were correct in their contention that the [Dietary Guidelines Advisory Committee] report described methods for identifying, selecting, and evaluating evidence for its report.
But they also noted problems with the committee’s methods and rejected the letter’s contention that the article should be retracted.
Professor Bero concluded: “Teicholz’s criticisms of the methods used by DGAC are within the realm of scientific debate” and Professor Helfand said that “it is clear that further investigation of the composition of the committee, as well as its conflict of interest policies and work group structure, are warranted.”
The review culminated in a lengthy correction notice, published today:
This article (BMJ 2015;351:h4962, doi:10.1136/bmj.h4962) stated that the 2015 US Dietary Guidelines Advisory Committee (DGAC) “conducted an [ad] hoc examination of the scientific literature without well defined systematic criteria for how studies or outside review papers were identified, selected, or evaluated.” The article also stated that the committee “conducted ad hoc reviews of the literature, without defining criteria for identifying or evaluating studies.” These statements are incorrect. The DGAC defined the methods it used for identifying, selecting, and evaluating such evidence in its advisory report1 in Part C: Methodology and Appendix E2.2 However, it should be noted that the DGAC also used non-systematic approaches in its evidence selection.
The article also stated that the DGAC’s recommendations on saturated fats were based, in part, on “the 2015 committee’s ad hoc selection of seven review papers,” and that “papers on saturated fats published since 2010 were covered by the committee’s ad hoc review, which did not use a systematic method to select or evaluate studies.” These statements are incorrect. Appendix E2.43 of the DGAC report defines the search strategy and inclusion criteria for the committee’s selection of papers for this topic and gives the DGAC’s quality rating (using AMSTAR, the methods of which were also described in Part C: Methodology of the report).
The article’s data supplement Table D includes the phrases “DGAC ad hoc selection” and “DGAC ad hoc review” of the literature, under the sections “dietary patterns and heart disease” and “dietary patterns and obesity,” respectively, and notes that “no systematic methodology is given for the selection of these studies.” This is incorrect. The prespecified search strategy and inclusion criteria are described in Appendices E2.26 and E2.27, respectively.
The article also stated, in reference to evidence regarding DGAC’s recommended diets and heart disease: “The committee reviewed other, more recent studies but not using any systematic or predefined methods.” This is incorrect. The DGAC defined its methods in Appendix E2.26, including search strategy, inclusion criteria, and quality rating (using AMSTAR, the methods of which were also described in Part C: Methodology of the report).
Included with the correction is a three-paragraph-long “Clarification,” which states:
The article stated that the committee did not systematically review certain studies on saturated fats from the 1960s and 1970s. This statement was insufficiently clear. It should have stated that the committee did not “directly” review these studies. The committee did consider two systematic reviews45 that themselves included five678910 of the six trials mentioned in the article.67891011
The article also stated, “There have been at a minimum, three National Institutes of Health funded trials on some 50 000 people showing that a diet low in fat and saturated fat is ineffective for fighting heart disease, obesity, diabetes, or cancer. Two of these trials are omitted from the NEL review.” This statement was insufficiently clear. The two trials referred to1213 were indeed omitted from the NEL’s 2010 review, as stated in the article, but it should be noted that they were evaluated in a Cochrane review,4 and that this review was considered by the committee in its 2015 advisory report.1 In addition, the two trials evaluated the effects of diet modification on serum lipids as a proxy for heart disease.1213
The article also stated, regarding the Nutrition Evidence Library (NEL), that “a systematic review on health and red meat has not been done. Although several analyses look at ‘animal protein products,’ these reviews include eggs, fish, and dairy and therefore do not isolate the health effects of red meat, or meat of any kind.” This statement requires clarification. Several of the NEL reviews used “meat” as a search term and presented and discussed results of individual studies of red meat and total meat.141516171819
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