DALLAS, TEXAS. High cholesterol and triglyceride levels are common among diabetics and are major contributors to their increased risk of cardiovascular disease. Researchers at the Texas Woman's University and the University of Texas Medical Center now report that fish oil supplementation can markedly decrease cholesterol and triglyceride levels without adversely affecting glycemic control.
Their study involved 40 patients with non-insulin-dependent diabetes mellitus (NIDDM) who had abnormally high blood plasma levels of one or more of the following lipids: total cholesterol (greater than 5.17 mmol/L), LDL cholesterol (greater than 3.36 mmol/L), or triglycerides (greater than 6.47 mmol/L). After a four-week baseline phase during which cholesterol levels, weight, blood pressure, and diabetes control were assessed every two weeks the participants were randomly assigned to one of four groups - daily dose of 9 grams of corn oil (57% linoleic acid), 18 grams of corn oil, 9 grams of fish oil (29% EPA and 27% DHA), and 18 grams of fish oil. All participants were assessed every two weeks during the 12-week supplementation period.
A significant reduction in the levels of very-low-density lipoproteins, triglycerides and very-low-density triglycerides was observed among the participants supplementing with fish oils at both the 6-week and 12-week mark. There were no significant differences in the effect of 9 grams/day versus 18 grams/day supplementation. The level of LDL cholesterol increased temporarily at the 6-week mark, but this effect was no longer present at the 12-week examination. Neither fish oil nor corn oil supplementation produced any significant changes (over baseline values) in total cholesterol levels, HDL cholesterol levels, fasting plasma glucose, weight or blood pressure. A small increase in VLDL cholesterol was noted in the corn oil group at the end of the experiment.
The researchers conclude that fish oil supplementation is useful in lowering triglycerides in diabetics with excessive levels and has no deleterious effect on glycemic control.
Morgan, Wanda A., et al. A comparison of fish oil or corn oil supplements in hyperlipidemic subjects with NIDDM. Diabetes Care, Vol. 18, January 1995, pp. 83-86