Lipid, glycemic, and insulin responses to meals rich in saturated, cis-monounsaturated, and polyunsaturated (n-3 and n-6) fatty acids in subjects with type 2 diabetes

OBJECTIVE - The recommendations for dietary fats in patients with type 2 diabetes are based largely on the impact of fatty acids on fasting serum lipid and glucose concentrations. How fatty acids affect postprandial insulin, glucose, and triglyceride concentrations, however, remains unclear. The objective of this study was to study the effect of fatty acids on postprandial insulin, glucose, and triglyceride responses. RESEARCH DESIGN AND METHODS - Test meals rich in palmitic acid, linoleic acid, oleic acid, and eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) and containing 1,000 kcal each were administered in a randomized crossover design to 11 type 2 diabetic subjects. Serum insulin, glucose, and triglyceride concentrations were measured for 360 min. All subjects received an isoenergetic diet of constant composition throughout the study. RESULTS - According to repeated-measures ANOVA, the insulin (P = 0.0002) but not glucose (P = 0.10) response was significantly different between meals. The insulin response was lower to meals rich in oleic acid or EPA and DHA than to meals rich in palmitic acid or linoleic acid (P < 0.01). The triglyceride response did not reach statistical significance (P = 0.06) but tended to be lower with EPA and DHA than with the other fatty acids. Similar trends were seen for area under the curve (AUC) and incremental AUC for serum insulin and triglycerides, but the differences were not significant. CONCLUSIONS - In comparison with palmitic acid and linoleic acid, oleic acid or EPA and DHA may modestly lower insulin response in patients with type 2 diabetes without deteriorating the glucose response. EPA and DHA may also reduce the triglyceride response.