The effect of various intakes of omega 3 fatty acids on the blood lipid composition in healthy human subjects.

In a study with 52 healthy volunteers, the effect of different amounts of omega 3 fatty acids on the blood lipid composition was investigated. Doses of 1.4, 2.3, 4.1, and 8.2 g of omega 3 fatty acids were administered to these subjects daily over a period of 4 wk. Total cholesterol, high-density lipoprotein cholesterol, total triglycerides, and glucose were determined in blood serum and hemoglobin in whole blood in all individuals before, during, and after the intake of omega 3 fatty acids. In pooled serum samples, the lipoprotein composition and the fatty acid composition of blood lipids were determined. All dosages caused a shift in the fatty acid composition of blood serum lipids in a favor of omega 3 fatty acids and at the expense of omega 6 and/or omega 9 acids. In the sterol esters, only the percentage of C20:5 omega 3 increased. Maximum shifts depended on the amount of omega 3 acids ingested and were evident within 1 to 2 wk. Two wk after the last ingestion of omega 3 acids, the fatty acid composition of blood serum lipids had returned to the original state. In the groups receiving 8.2 of omega 3 fatty acids, there was a significant decrease in serum triglyceride and very low-density lipoprotein levels, which is in accord with earlier observations. In the other parameters, including cholesterol and high-density lipoprotein cholesterol, no decrease or increase was observed.