A study reevaluating “the traditional diet-heart hypothesis” concludes that replacing dietary saturated fat with vegetable oils lowers serum cholesterol but does not reduce the risk of death from coronary heart disease or other causes. Christopher Ramsden, et al., “Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73),” BMJ, April 2016.

Using previously unpublished data from the Minnesota Coronary Experiment (MCE)—“a double blind randomized controlled trial designed to test whether replacement of saturated fat with vegetable oil rich in linoleic acid reduces coronary heart disease and death by lowering serum cholesterol”—researchers examined data on diet, serum cholesterol and health outcomes for 9,423 women and men ages 20 to 97 years. Their results evidently showed that substituting saturated fat with linoleic acid showed no benefits for coronary atherosclerosis or myocardial infarcts, even though participants in the dietary intervention group exhibited a significant reduction in serum cholesterol compared with controls.

“The pooled results of the MCE and four similar trials failed to find any reduction in mortality from coronary heart disease,” notes a concurrent BMJ editorial. “In the past decade, old certainties regarding dietary fats have been questioned, and some have been abandoned… With these new findings, the recommendation to consume less than 10% of calories per day from saturated fats will be under increased scrutiny.”