ABSTRACT
BACKGROUND: Dietary advice, including modification of dietary fat quality, is the basis of treatment of diabetes, but there is some uncertainty about the optimal amount of polyunsaturated fatty acids of the n-6 (omega-6) and n-3 (omega-3) series. OBJECTIVE: The objective was to compare the effects of diets rich in n-3 or n-6 fatty acids on glucose and lipoprotein metabolism in type 2 diabetes. DESIGN: In a crossover study during 2 consecutive 3.5-wk periods, the participants were provided diets with identical nutrient compositions containing either a high proportion of n-3 (n-3 diet) or n-6 (n-6 diet) fatty acids through the inclusion of fatty fish or lean fish and fat containing linoleic acid, respectively. RESULTS: Blood glucose concentrations at fasting and during the day were lower with the n-6 than with the n-3 diet (P = 0.009 and P = 0.029, respectively), and the area under the insulin curve during the day was significantly higher (P = 0.03) with the n-6 diet. Both diets showed similar effects on insulin sensitivity and plasminogen activator inhibitor 1 concentrations. The reductions in VLDLs and serum apolipoprotein B concentrations were more pronounced after the n-3 diet. CONCLUSIONS: The risk related to the moderately higher blood glucose concentrations with the n-3-enriched diet may be counteracted by positive effects with regard to lipoprotein concentrations. An increase in long-chain n-3 fatty acids from fatty fish, and of n-6 fatty acids from linoleic acid, may be recommended for patients with type 2 diabetes.
