Fat modification in the diabetes diet.

The modification of dietary fat in the diet of diabetic patients is of interest with respect to metabolic and other consequences of this modification. To begin with the data are reviewed for the use of monounsaturated fatty acids (MUFA) in the diabetes diet. Compared to a carbohydrate-rich diet, glucose concentrations are lower. Blood pressure was also found to be lower. There were no major differences with respect to lipid concentrations. HDL-cholesterol levels tended to be higher after a MUFA-rich diet. In type-1 diabetic patients, the number of circulating big VLDL particles was greater after a MUFA diet than after a carbohydrate-rich diet. Comparisons were also made between diets enriched with MUFA and with polyunsaturated fatty acids (PUFA). With respect to lipid concentrations, different groups observed different effects. While one group saw no differences in fasting lipids, they measured a higher remnant-like particle cholesterol after a diet enriched with MUFA. Another group found higher total and LDL-cholesterol levels after a PUFA-rich diet than after a MUFA-diet. In their study, fasting glucose, insulin and fasting chylomicrons and postprandial chylomicrons and VLDL were higher following the PUFA diet. A MUFA-rich diet increased endothelium-dependent flow-mediated dilatation in the superficial femoral artery. Alpha-linolenic acid appears to be a precursor of eicospentaenoic and docosahexaenoic fatty acids. As a diet rich in n-6 PUFA reduces this conversion, a n-6/n-3 PUFA ratio not exceeding 4 - 6 should be observed. No prospective data are available for alpha-linolenic acid in diabetic patients. The review summarizes the results of the Lyon Diet Heart Study and the Nurses' Health Study. Both studies saw a reduced cardiovascular risk associated with a higher intake of alpha-linolenic acid. Finally, data on the effects of fish oil are given. The latter has a clearly expressed triglyceride-lowering effect. Data with respect to glucose control are heterogeneous. Major studies did not find any influence in glucose concentrations. Hepatic glucose production and peripheral insulin sensitivity remained constant. Evidently, nerve function can be improved by fish oil. Data have been compiled comparing the effects of fish oil with those of olive oil, linseed oil and sunflower oil.