2006 Ancel Keys Memorial Lecture—Diet and Heart Disease: The Seven Countries and Beyond
Studies of different populations worldwide and of migrants from low- to high-risk regions indicate that coronary heart disease (CHD) is potentially almost entirely preventable. Mechanistic studies during the past decade have indicated that many biological pathways can lead to CHD, and the opportunities for prevention have thus been expanded. Smoking accounts for about one third of myocardial infarctions in Western countries, and overweight and obesity contribute similarly. Reducing intake of total fat as a percent of calories is not an effective means for prevention, but multiple lines of evidence indicate that the type of dietary fat has a major impact on risk of CHD. Intake of trans fat from partially hydrogenated vegetable oils most strongly increases the risk, saturated fat is weakly associated with greater risk, monounsaturated fats moderately decrease risk, and polyunsaturated fats strongly decrease risk. Both N-6 and N-3 polyunsaturated fatty acids contribute to lower risk. The form of dietary carbohydrate also appears to influence risk of CHD importantly: Highly refined starches are related to increased risk, but consumption of whole-grain, high-fiber cereal products consistently have been associated with lower risks. Higher consumption of fruits and vegetables contributes to lower risk, probably by multiple mechanisms. Many issues remain to be settled, including the optimal mix of mono- and polyunsaturated fatty acids, the optimal amounts of N-3 and N-6 fatty acids, the amount and source of protein, and the effects of antioxidants, other phytochemicals and minerals. From our long-term studies, we have calculated that modest dietary changes, together with avoidance of smoking, regular physical activity, and maintenance of a healthy body weight, can reduce rates of CHD by more than 80%. Failure to take advantage of dietary and lifestyle means of preventing these diseases represents a tremendous lost opportunity for improved health and well-being.