WHO draft guidelines on dietary saturated and trans fatty acids: time for a new approach?

While revising this Analysis article (BMJ 2019;366:l4137, doi:10.1136/bmj.l4137) the authors mistakenly included a section on the reanalysis of the Minnesota Coronary Experiment. The authors had originally agreed among themselves not to include the section in the final manuscript for two reasons. First, the key message of the article is to move from recommendations of single nutrients into food based recommendations because saturated fat is a heterogeneous group of fatty acids with divergent health effects, and the effect is furthermore dependent on the food matrix they exist in. For that reason, the authors felt the section was redundant. Second, for a discussion of the health effects of polyunsaturated fat, the authors did not feel that the section provided a balanced and complete analysis of the issue.

Soon after publication the authors contacted The BMJ to notify the journal of the mistake and request correction of the article by removing the following paragraphs, which does not substantially change the message or argument of the Analysis:

“Reanalysis of the Minnesota Coronary Experiment (a double blind randomised controlled trial that tested whether replacing saturated fat with polyunsaturated fat reduced coronary heart disease and death) also supports the claim that serum cholesterol is not a valid surrogate biomarker for cardiovascular disease risk when making dietary changes.¹⁰ Despite the finding that the polyunsaturated fat diet produced a 13% greater reduction in serum cholesterol than the saturated fat diet, there was no reduction in cardiovascular disease endpoints.¹⁰

“The reanalysis found a 22% higher mortality for each 0.78 mmol/L reduction in serum cholesterol caused by the polyunsaturated diet.10 A meta-analysis found that cholesterol lowering using polyunsaturated fat diets did not show any evidence of benefit on mortality from coronary heart disease (1.13, 0.83 to 1.54) or all cause mortality (1.07, 0.90 to 1.27).¹⁰”

These paragraphs have been removed from the article online.