EDMONTON, CANADA. Diabetics are at significantly increased risk for cardiovascular disease and any dietary intervention that could decrease this risk would be of great importance. Studies have shown that taking fish oil supplements lowers triglycerides, very low density lipoprotein (VLDL) levels, and blood pressure in non-diabetic individuals and thereby diminishes their risk of heart disease. Unfortunately, some early experiments with type II diabetics taking fish oil supplements reported adverse effects on glycemic control and cholesterol levels. So is there any relationship between fish oil and diabetes, and is it positive or negative?
Researchers at the University of Alberta have just released the results of a new study aimed at evaluating the overall effects of fish oil supplementation in type II diabetics. Eleven subjects with non-insulin- requiring type II diabetes took part in the randomized, double-blind, crossover study. All participants underwent a 3-month run-in period during which they supplemented with olive oil capsules (placebo). They were then randomized into two groups with one group taking fish oil supplements (about 2.0 grams/day) and the other group supplementing with flax seed oil capsules. After 3 months the participants underwent a crossover to the alternative oil for a final 3 months of supplementation.
All study participants had acceptable blood levels of total cholesterol, triglycerides, high density lipoproteins, low density lipoproteins, and low density triglycerides prior to initiating supplementation with fish oil or flax seed oil. Supplementation did not change these levels except in the case of triglycerides which were markedly reduced after fish oil supplementation. Glycemic control was not adversely affected by supplementation with either oil and there was a trend towards decreased insulin sensitivity in the group taking fish oils. The researchers conclude that taking fish oil supplements is safe in type II diabetics and can help ameliorate cardiovascular disease risk factors such as high triglyceride levels. They also conclude that flax seed oil supplementation, while having no adverse effects, is not of significant benefit in type II diabetes. Therefore, not only is NOTE: This study was partially funded by the Canadian Dairy Bureau.
McManus, Ruth M., et al. A comparison of the effects of n-3 fatty acids from linseed oil and fish oil in well-controlled type II diabetes. Diabetes Care, Vol. 19, May 1996, pp. 463-67.