Diets to Prevent Coronary Heart Disease 1957-2013: What Have We Learned?
Our understanding of the potential cardioprotective properties of nutrition is relatively recent, with most relevant studies completed in the last several decades. During that time, there has been an evolution in the focus of nutritional intervention. Early trials emphasized reduction of dietary fat with the goal of preventing heart disease by reducing serum cholesterol. Results from trials focused exclusively on dietary fat reduction were disappointing, prompting subsequent studies incorporating a whole diet approach with a nuanced recommendation for fat intake. The Mediterranean-style diet, with a focus on vegetables, fruit, fish, whole grains, and olive oil, has proven to reduce cardiovascular events to a degree greater than low-fat diets and equal to or greater than the benefit observed in statin trials.
One of the earliest clues that coronary heart disease is influenced by nutrition was the observation of Ignatowski in 19081that high dietary intake of cholesterol promoted atherosclerosis in rabbits. Finking and Hanke2 reported on Anitschkow’s finding that a cholesterol-enriched diet led to fatty streaks and advanced atheromatous plaques in rabbits, similar to the lesions in patients with coronary atherosclerosis. Later, cholesterol was isolated from the atheromatous plaque of patients with coronary heart disease.3
In 1952, Kinsell4 reported that replacement of animal fats with vegetable oil resulted in a dramatic decrease of serum cholesterol in patients. Groen et al5 found that vegetarian diets were associated with reduction of cholesterol levels.
The Diet Heart Hypothesis
In 1957, Ancel Keys6 cited extensive epidemiologic evidence suggesting that indigenous diets have an important impact on the variability of coronary heart disease across populations. It was well established that patients with coronary heart disease tend to have higher serum cholesterol levels than their clinically healthy counterparts. Those observations were pivotal for the development of the cholesterol hypothesis: Dietary saturated fat increases serum cholesterol, which in turn leads to coronary atherosclerosis.6
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–James E. Dalen, MD, MPH, Stephen Devries, MD, FACC
This article originally appeared in the May 2014 issue of The American Journal of Medicine.
