A group of researchers from the US recently recovered unpublished documents and raw data from the Minnesota Coronary Experiment (MCE), conducted 45 years ago. This was a double blind randomized controlled trial investigating 9423 men and women from one nursing home and six mental hospitals. In the experimental group, saturated fats (animal fats, common margarines, shortening) was replaced with unsaturated fats (form corn oil and corn oil polyunsaturated margarine). Because patients had all their meals prepared by the facility, their diets could controlled to a level unmatched in other studies.
Common wisdom today is that unsaturated fats lower cholesterol and lower cholesterol is linked to a recued risk of coronary heart disease. Although this re-analysis of MCE data showed the experimental group had lower cholesterol, the experimental group also had a higher mortality rate. The authors conclude that these findings “add to growing evidence that incomplete publication has contributed to overestimation of the benefits of replacing saturated fat with vegetable oils rich in linoleic acid.”