Improvement of diabetic control by continuous subcutaneous insulin infusion therapy changes fatty acid composition of serum lipids and erythrocytes in type 1 (insulin-dependent) diabetes.

The influence of improved diabetic control on the fatty composition of serum lipids, erythrocytes and platelets was investigated in 24 patients with Type 1 (insulin-dependent) diabetes treated for 6 months with either continuous subcutaneous insulin infusion (n = 14) or conventional insulin therapy (n = 10). The groups were matched for age, sex, body mass index, serum lipids, duration of diabetes, glycosylated haemoglobin and insulin dose. Glycaemic control improved, and the contents of dihomogammalinolenic acid and arachidonic acid but not linoleic acid rose significantly (p less than 0.05), in serum lipids of patients treated with continuous infusion. No changes were observed in the group treated with insulin injections. Both in serum and erythrocytes the n-6 polyunsaturated fatty acid ratios rose consistently in the patients, with improvement of control regardless of the mode of treatment. Furthermore, the change of HbA1 was negatively correlated with that of arachidonic acid in erythrocytes. No changes were found in the platelet fatty acid compositions. The findings suggest that improved diabetic control enhances the conversion of linoleic acid to arachidonic acid, probably by activating enzymes needed for chain elongation and desaturation.