Long-term effects of n-3 fatty acids on serum lipids and glycaemic control

Abstract

Eritsland J, Seljeflot I, Abdelnoor M, Arnesen H, Torjesen PA. Long-term effects of n-3 fatty acids on serum lipids and glycaemic control. Scan J Clin Lab Invest 1994; 54: 273-80.

The long-term influence of n-3 polyunsaturated fatty acids (n-3 PUFAs) on serum lipids and glucose homeostasis was studied in a group of non-diabetic, moderately hypertriglyceridaemic patients undergoing coronary artery bypass grafting. They were investigated according to the same procedure before and 6 months after the operation. Following randomization postoperatively, 28 patients received 3.4g eicosapentaenoic and docosahexaenoic acid per day, whereas 29 patients comprised the control group. The decline in serum triglycerides after 6 months was significantly greater in the n-3 PUFA group than in the control group (median decline, -33.2% vs. -11.1%, p = 0.002), while no group difference was noted in serum total, HDL, or LDL cholesterol levels. Fasting plasma glucose levels decreased less in the n-3 PUFA group compared with the control group (median change, -0.2mmoll⁻¹ vs. -0.5mmoll⁻¹, p = 0.054). The corresponding changes in fasting insulin levels were -2mIUml⁻¹ in the n-3 PUFA group and no change in the control group (p = 0.039). In both groups combined, the recorded changes in serum triglyceride and serum insulin levels were negatively correlated with the change in serum phospholipid n-3 fatty acids (r = -0.35, p = 0.008 and r = -0.32, p = 0.016, respectively). An oral glucose tolerance test revealed no significant group differences after 6 months, neither in the peak levels, nor in the areas under the curves between 0 and 3h after the glucose load for glucose, insulin, and C-peptide. The long-term effects on glucose homeostasis by moderate-dose n-3 PUFA supplementation are probably of little clinical significance in this patient group.

Key Words:

• coronary disease
• fatty acids, omega-3
• glucose tolerance test
• hyper-triglyceridaemia
• insulin