Factors that appear to be associated with the increasing prevalence of type 2 diabetes in the United States include obesity, decreased physical activity, and a “western” diet. Recent studies of food consumption patterns analyzed relationships between diet and health. These studies focused on the effects of macronutrient and fiber intake on glucose metabolism, but an examination of nutrients, additives, contaminants, unknown compounds, the physical properties of foods, and nutrient interactions may also prove helpful. Van Dam and associates looked at the association between major dietary patterns and type 2 diabetes risk among men enrolled in the Health Professionals Follow-up Study, a large prospective study of American men that was begun in 1986.

This study enrolled 51,529 health professionals who were 40 to 75 years of age in 1986 and who were predominately white. Participants completed regular questionnaires on medical history, diet, and other potential risk factors for major diseases. Exclusion criteria included men who had inadequate information about daily energy intake and participants who had serious medical problems at the time of enrollment. After exclusions, 42,504 men were followed for at least 12 years for incidence of type 2 diabetes or other major diseases.

Questionnaires were completed every two years, and the follow-up rate for nonfatal events was about 97 percent. Dietary intake recording was done every four years. Dietary patterns were identified by (1) combining food items with similar nutrient profiles and culinary use (e.g., spinach and lettuce were combined into “green leafy vegetables”); (2) classifying a food individually if its composition was substantially different from other foods (e.g., eggs or pizza) or if it represented a particular dietary habit (e.g., wine or French fries); (3) identifying a prudent diet pattern characterized by higher consumption of vegetables, legumes, fruit, whole grains, fish, and poultry, and a western diet pattern characterized by higher consumption of red meat, processed meat, refined grains, French fries, high-fat dairy products, sweets and desserts, high-sugar drinks, and eggs; and (4) scoring each participant's diet according to the degree of conformity with each dietary pattern.

Men with higher prudent-pattern diet scores were older, more physically active, less likely to smoke, and more likely to have hypercholesterolemia. Participants with higher western-pattern diet scores were generally younger, had a higher body mass index, were more likely to smoke, and were less physically active. During follow-up, 1,321 cases of type 2 diabetes were identified.

The prudent-pattern diet was associated with a modestly decreased risk for type 2 diabetes, while the western-pattern diet was associated with a substantially increased risk. These associations did not change when adjusted for physical activity, smoking, alcohol consumption, hypercholesterolemia, hypertension, ancestry, and family history of diabetes. Obesity increased the positive risk associated with the western-pattern diet. Whole-grain intake had the strongest negative effect on diabetes risk, while all the individual foods associated with the western-pattern diet were associated with increased diabetes risk.

The authors conclude that dietary patterns can predict risk for diabetes mellitus in men. This risk is compounded by concomitant obesity. Weight reduction and avoidance of a western-pattern diet can potentially reduce the risk for type 2 diabetes in men.