Can Diabetes Be Prevented by Vegetable Fat?

The prevention of type 2 diabetes has become an important clinical and health policy issue around the globe because of the increasing rates of diabetes in developed as well as in developing countries. Evidence of successful programs concerning the primary prevention of diabetes has only very recently been provided. The Finnish Diabetes Prevention Study (1) was the largest randomized intervention study, which included 522 middle-aged overweight subjects with impaired glucose tolerance. The intervention consisted of individual counseling on reducing body weight, total fat intake, and intake of saturated fatty acids (SFAs) and increasing fiber intake and physical activity. After 4 years, the cumulative diabetes incidence was 11 vs. 23% in the control group (P < 0.001). The reduction in diabetes was highest in the group with the largest changes in lifestyle.

An important feature of this study is that it resulted in a substantial decrease in diabetes risk despite an only modest difference in body weight (3 kg), which shows that other parts of the intervention played a role as well.

In this light, it is worthwhile to pay close attention to the role of dietary composition in diabetes etiology. In this issue of Diabetes Care, Meyer et al. (2) report on the impact of various dietary fatty acids on the risk of type 2 diabetes in the Iowa Women’s Health Study. They studied 35,988 women, aged 55–69 years, free of diabetes, and followed them for 11 years, resulting in 1,890 new cases of type 2 diabetes. Intake of fat and fatty acids was assessed from a validated food-frequency questionnaire. After adjustments for main risk factors, including BMI, waist-to-hip ratio, physical activity, dietary fiber, magnesium, and other dietary fat subtypes, substituting polyunsaturated fatty acid (PUFA) intake for SFA was inversely associated with diabetes risk, with a 16% reduction in …