Effects of n-3 PUFA on insulin resistance after an oral fat load

The aim of this study was to evaluate the effects of ω-3 PUFA (n-3 PUFA) on lipid profile and insulin resistance biomarkers. Patients were assigned to receive placebo or n-3 PUFA 1g three times a day, during the meals, for 6 months. We evaluated: body mass index (BMI), body weight, fasting plasma glucose (FPG), fasting plasma insulin (FPI), homeostasis model assessment insulin resistance index (HOMA-IR), blood pressure, lipid profile, resistin (r), retinol binding protein-4 (RBP-4), adiponectin (ADN), visfatin, and vaspin. Furthermore patients underwent an oral fat load (OFL) and an euglycemic hyperinsulinemic clamp to evaluate M value, and total glucose requirement (TGR). Triglycerides value obtained with n-3 PUFA was lower, while HDL-C, and ADN values were higher compared to placebo. After the OFL, and comparing the OFL performed at the baseline and at the end of the study, there was a decrease of triglycerides (Tg), resistin (r), and RBP-4 values, and an increase of ADN value with n-3 PUFA, but not with placebo. We conclude that the treatment with n-3 PUFA resulted in a greater improvement of lipid profile and ADN compared to placebo in a baseline condition, and an improvement of all insulin resistance parameters after an OFL. Practical applications: The inverse association between dietary intake of n-3 PUFA and cardiovascular disease morbidity/mortality was primarily established following the observation that the Greenland Inuits had low mortality from coronary heart disease despite a fat-rich diet. Our group has already shown that n-3 PUFA improved the lipid profile and the coagulation, fibrinolytic, and inflammatory parameters compared to placebo. We also observed that highly purified n-3 PUFA supplementation significantly reduced the blood pressure, pulse pressure, and basal heart rate in hypertriglyceridemic patients with normal-high blood pressure. The current study showed that treatment with n-3 PUFA not only improved lipid profile in a baseline situation, but it also improved all insulin resistance parameters in a post-prandial situation simulated with an OFL. This is another important action of the n-3 PUFA which can increase their utility in the clinical practice. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.