In the second half of the 20th century, conventional wisdom in the medical community held that overconsumption of saturated fats — the kind found in milk, cheese, meats and butter — was dangerous. And so, between 1968 and 1973, a well-planned, well-executed study involving more than 9,000 patients was performed to test this widely accepted relationship between diet and heart disease.
The results of the Minnesota Coronary Experiment were notable for two reasons. First, the findings contradicted much of what was believed at the time: The study demonstrated that people who ate a diet rich in saturated fats did not go on to have more heart disease than those who ate a diet rich in polyunsaturated fat from vegetable oil.
Second, and perhaps more important, these iconoclastic findings went unpublished until 1989 and then saw the light of day only in an obscure medical journal with few readers. One of the principal investigators told a science journalist that he sat on the results for 16 years and didn’t publish because “we were just so disappointed in the way they turned out.”
The long-forgotten study was revisited with a recent analysis of the original data and published this month by the National Institutes of Health in the prestigious, and well-read, British Medical Journal.