Effects of fish oil concentrate on lipoproteins and apolipoproteins in familial combined hyperlipidemia.

The effects of two moderate doses of long-chain n-3 fatty acids (3.0 and 4.5 g EPA+DHA per day for 4 weeks each) on serum lipids and lipoproteins of patients with familial combined hyperlipidemia (FCH) were studied in a double-blind, placebo-controlled clinical trial. In nine patients with FCH n-3 fatty acids led to a statistically significant, dose-dependent fall in very low density lipoprotein (VLDL) triglycerides (3 g/day: -42%, 4.5 g/day: -55%) VLDL cholesterol (3 g/day: -41%, 4.5 g/day: -47%), and VLDL apolipoprotein (apo) B-100 (3 g/day: -40%, 4.5 g/day: -56%). No overall change in low-density lipoprotein (LDL) cholesterol was found, as confirmed statistically. However, when analyzing the data of single patients LDL cholesterol and LDL apo B did not change in five patients but increased dose dependently (from pretreatment 4.80 +/- 0.93 mmol/l to 5.70 +/- 0.93 mmol/l LDL cholesterol after 4.5 g/day) in four. LDL and VLDL composition as indicated by cholesterol/apo B-100 and triglyceride/apo B-100 ratios did not change significantly. High-density lipoprotein (HDL) cholesterol was unchanged; the HDL cholesterol/apo A-I+apo A-II ratio increased by 19% (P < 0.05) during fish oil treatment. We conclude that in FCH moderate doses of long-chain n-3 fatty acids are highly effective in lowering pathological VLDL triglycerides, VLDL cholesterol, and VLDL apo B. LDL cholesterol must, however, be monitored during treatment as it may rise substantially in some although not in all patients with this disease.