PARIS, FRANCE. People suffering from type II diabetes often have high blood levels of triglycerides and are therefore prone to coronary heart disease. Fish oils are known to be effective in lowering triglyceride levels, but concern has been expressed that they may also increase low-density lipoprotein (LDL) levels and be deleterious to glucose control.
Medical researchers at the Hotel-Dieu hospital now report the results of a study designed to investigate these concerns. The study involved 10 men with type II diabetes (average age of 54 years). The men were randomized into two groups in the double-blind crossover study. Group 1 supplemented with 6 grams/day of fish oils (containing 320 mg of eicosapentaenoic acid [EPA] and 215 mg of docosahexaenoic acid [DHA]) for two months while group 2 supplemented with 6 grams/day of sunflower oil (containing 65% linoleic acid). At the end of the two months all participants went through a 2-month wash-out period and group 1 was then assigned to supplement with sunflower oil while group 2 was given fish oil supplements. All participants maintained their regular diet (55% carbohydrates, 15% protein, and 30% fat) and continued with their medications throughout the study except for cholesterol-lowering drugs which were discontinued 2 months before the start of the trial.
The researchers noted a considerable increase in both EPA and DHA content in blood plasma phospholipids and in red blood cell membranes after two months on the fish oil supplements. Triglyceride levels and the level of plasma lipoprotein(a) were both significantly lowered following fish oil supplementation. No adverse effects on glucose control were observed; there was a small increase in the LDL level, but this was compensated for by a similar increase in the HDL (high-density lipoprotein) level so that the important LDL/HDL ratio remained unchanged. The researchers conclude that fish oil supplementation is effective in lowering triglyceride levels in type II diabetics and has not adverse effects on glycemic control or overall cholesterol levels.
Luo, Jing, et al. Moderate intake of n-3 fatty acids for 2 months has no detrimental effect on glucose metabolism and could ameliorate the lipid profile in type 2 diabetic men. Diabetes Care, Vol. 21, May 1998, pp. 717-24.
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