Effect of Omega-3 Fatty Acids in Diet of Type I Diabetic Subjects on Lipid Values and Hemorheological Parameters

Twelve type I (insulin-dependent) diabetic subjects in stable metabolic control for at least 3 mo received a controlled diet containing 50% carbohydrate, 35% fat, and 15% protein. Calorie intake varied from 1800 to 2200 calories, depending on individual needs. Part of the polyunsaturated omega-6 fatty acids (ω6FAs) were isocalorically exchanged with ω3FAs (2.7 g/day provided by fish oil concentrates) for 10 wk. Subject selection was based on the fact that the atherogenic index (total cholesterol/high-density lipoprotein cholesterol [HDL-chol]) remained >5. Total cholesterol did not change, but HDL-chol (P < .05) increased significantly, and the mean ± SD atherogenic index decreased from 5.9 ± 1.1 to 5.1 ± 1.3. Plasma triglyceride levels also decreased (P < .05). There was a small (∼2%) but significant (P < .05) decrease of whole-blood viscosity at low shear rate because of a similarly small (∼2%) decrease (P < .05) of plasma viscosity. Erythrocyte viscosity values and the erythrocyte transit time, measured with the St. George's filtrometer, remained unchanged during fish oil intake. Four weeks after stopping the ω3FA administration, the triglyceride level was again increased (P < .05) and was even higher than the starting value (P < .05). Plasma and whole-blood viscosity also increased to the starting levels, demonstrating that lipid alterations are accompanied with blood viscosity changes in the presence of a stable metabolic control.