Type 2 diabetes (T2D) is a major chronic disease and a leading cause of morbidity and mortality worldwide. Dietary factors are thought to play a significant role in the prevention or development of T2D. Among dietary factors, omega-6 polyunsaturated fatty acids (PUFA) may have the potential to prevent T2D because of research suggesting they increase insulin sensitivity. To examine this hypothesis, Finnish researchers evaluated the relationship between diabetes risk and serum n–6 PUFA and the activities of enzymes involved in the metabolism of PUFA. The study included 2,189 men from the prospective Kuopio Ischaemic Heart Disease Risk Factor Study, aged 42–60 y who were free of diabetes at baseline. Diabetes was assessed by self-administered questionnaires, fasting and 2-h oral-glucose-tolerance test blood glucose measurement at years 4, 11, and 20 y after enrollment. Diabetes medication use was also considered. During the average follow-up of 19.3 y, 417 men developed diabetes. Men with higher concentrations of linoleic acid (hazard ratio: 0.52; 95% CI: 0.39, 0.70; P-trend, 0.001) and arachidonic acid (hazard ratio: 0.62; 95% CI: 0.46, 0.85; P-trend = 0.007) were statistically significantly less likely to develop T2D. Those with higher delta-5-desaturase activity, the enzyme which converts dihomo-gamma-linolenic acid into arachidonic acid were also less likely to develop diabetes. Conversely, those with higher levels of gamma-linolenic acid (18:3 n–6) and dihomo-gamma- linolenic acid (20:3 n–6) were more likely to develop diabetes.
Yary T, Voutilainen S, Tuomainen TP, Ruusunen A, Nurmi T, and Virtanen JK. Serum n-6 polyunsaturated fatty acids, Delta5- and Delta6-desaturase activities, and risk of incident type 2 diabetes in men: the Kuopio Ischaemic Heart Disease Risk Factor Study. Am J Clin Nutr 2016.