Atherosclerosis is the process of deposition of cholesterol in the walls of blood vessels that results in coronary occlusion and heart attack. Controversy exists on the optimal diet to prevent atherosclerosis and heart attack. Publishing in this month's American Journal of Clinical Nutrition, Mozaffarian and colleagues at the Harvard School of Public Health report on a 3 year study of progression of coronary disease in 235 postmenopausal women in whom their outcome was related to typical baseline dietary habits.

The subjects were predominantly white and overweight; half were obese, one-quarter diabetic, and two-thirds hypertensive. Contrasting angiography measurements of coronary blood vessels at baseline and 3 years later, the authors found the least progression of coronary narrowing, an index of atherosclerosis, in women with the highest daily intakes of saturated fat. Further diet evaluation showed that the greatest vessel narrowing after 3 years was associated with the greatest dietary intakes of carbohydrate.

These unexpected findings contrast with many prior studies that correlated coronary disease risk with high dietary saturated fat intake. In an accompanying editorial, Knopp and Retzlaff point out that prior studies of dietary risk factors for coronary disease were focused mainly on men, and, perhaps more importantly, that the current study population of postmenopausal women had many of the characteristics of the metabolic syndrome, with high incidences of obesity, diabetes, and hypertension.

Thus, while restriction of saturated fat may be most important in prevention of atherosclerosis for all, restricting refined carbohydrates assumes greater importance in the growing population of Americans at risk for the metabolic syndrome of hypertension and glucose intolerance or outright diabetes in the settings of overweight and obesity.

Mozaffarian D, Rimm EB, Herrington DM. Dietary fats, carbohydrate, and progression of coronary atherosclerosis in postmenopausal women. Am J Clin Nutr 2004;80:117584. Knopp RH, Retzlaff BM. Saturated fat prevents coronary artery disease? An American paradox. Am J Clin Nutr 2004;80:1102