Effects of n-3 pufas on fasting plasma glucose and insulin resistance in patients with impaired fasting glucose or impaired glucose tolerance

Aim: to evaluate if a supplementation with n-3 PUFAs at high doses could give a regression of the condition of impaired glycemia. Methods: we enrolled 281 overweight/obese patients with impaired fasting glucose (IFG) or impaired glucose tolerance (IGT); 138 subjects were randomized to n-3 PUFAs group, 1 g three times a day, and 143 to placebo for 18 months. We assessed at baseline, and after 9, and 18 months: circumferences, body mass index (BMI), fasting plasma glucose (FPG), fasting plasma insulin (FPI), HOMA-index, lipid profile. At baseline and at the end of the study, all patients underwent an oral glucose tolerance test (OGTT). Results: we observed a decrease of glycemia and HOMA-IR with n-3 PUFAs, compared to baseline, and to placebo. Fasting plasma insulin decreased with n-3 PUFAs and increased with placebo. HDL-cholesterol increased after 18 months of n-3 PUFAs, while triglycerides decreased compared to baseline and to placebo. After OGTT performed at the end of the study, more patients returned to a condition of euglycemia with n-3 PUFAs compared to placebo. Conclusions: n-3 PUFAs were effective in reducing glycemia in patients affected by IFG or IGT and seem to be helpful to slow the development of type 2 diabetes mellitus.