n-3 fatty acids and blood glucose control in diabetes mellitus

Our knowledge of the effects of n-3 fatty acids on the glucose homeostasis in diabetes mellitus is at present incomplete. The results are in certain respects conflicting. Several studies have shown that addition of n-3 fatty acids, especially in type-2 diabetes, may increase blood glucose concentrations without a concomitant increase of insulin or C-peptide concentrations. The glucose/insulin ratio is increased in fasting as well as after meals. On the other hand, some data indicate that, in spite of increased or unchanged glucose concentrations, there may be an improved peripheral insulin sensitivity. The stimulated insulin response may be reduced after mixed meals, although there are no indications of significant impairments of the response to intravenous glucose. The reasons for the observed changes are still obscure. More controlled studies, during prolonged periods of time, are needed. At present it would seem important to closely follow diabetic patients with respect to glucose and lipid metabolism if treated with n-3 fatty acids. As for now, diabetic patients are recommended to increase their intake of fish in the diet. The use of pharmacological doses of n-3 fatty acids remains investigational.