Overview of the Leon Diet Heart Study

The podcast discusses the Leon Diet Heart Study, a landmark trial that explored the effects of a dietary intervention on heart disease in high-risk individuals. The study took place between 1992 and 1996 and focused on secondary prevention, specifically targeting participants under 70 years of age who had survived a myocardial infarction. The intervention group followed a Mediterranean-style diet, although with some modifications like using rapeseed oil instead of olive oil. The study employed various methodological strategies to control bias and ensure rigorous design, such as blinding physicians and maintaining participant blinding regarding the comparative trial. The results showed a significant reduction in the risk of subsequent cardiovascular events in the intervention group, with hazard ratios indicating a 73% lower risk in the 1994 interim analysis. The final analysis in 1999 confirmed and maintained the magnitude of the effect. Overall, the Leon Diet Heart Study is seen as a pioneering whole-of-diet intervention that provided strong evidence for the role of dietary changes, particularly in fatty acid composition, in improving cardiovascular health.