Objectives: The effect of a fish oil preparation, K-85, in which the omega-3 fatty acid content was concentrated to 92% of total fat, on serum lipid and lipoprotein concentrations was investigated in patients with primary hypertriglyceridaemia.
Design: The study was a randomized, double-blind, placebo-controlled study.
Setting: Seven centres participated in the study, five secondary referral centres and two general practices.
Subjects: Men and women aged 18-70 years with fasting serum triglyceride concentrations between 2 and 10 mmol/l and fasting serum cholesterol concentrations > 5.2 mmol/l were studied. Patients with diabetes mellitus, hypothyroidism, serious illness in the previous 3 months or severe concurrent illness were excluded from the study, as were drug or alcohol abusers and pregnant and lactating women. Ninety-five subjects entered the study, 79 completed the study.
Interventions: Patients were randomized to receive K-85 2 g twice daily or corn oil 2 g twice daily for 14 weeks.
Main outcome measurements: The serum concentrations of triglycerides and cholesterol, very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), high-density lipoprotein (HDL) and lipoprotein (a). Fasting blood glucose and blood pressure.
Results: Serum triglycerides and VLDL-cholesterol were significantly lower in the group treated with K-85 than in the placebo group after 6, 10 and 14 weeks (all P < 0.01) and there was a decrease in the serum triglyceride concentration from 3.99 (2.94-9.47) to 2.87 (1.2-9.93) mmol/l (P < 0.001) and in VLDL-cholesterol from 1.47 (0.77-3.63) to 1.12 (0.21-3.67) mmol/l (P < 0.01) in patients receiving K-85. Serum HDL-cholesterol increased from 0.98 (0.95-1.01) to 1.11 (1.07-1.15) mmol/l (P < 0.01) in the patients with type IV hyperlipoproteinaemia but did not change in those with type IIb. Serum LDL-cholesterol, lipoprotein (a) and fasting blood glucose were unaffected by K-85. Diastolic blood pressure decreased from 86 +/- 11 to 80 +/- 12 mmHg (P < 0.02) and was also lower than in the placebo group (P < 0.05). The corn oil placebo did not affect any of the parameters.
Conclusion: K-85 is effective in lowering serum triglycerides and VLDL in patients with primary hypertriglyceridaemia and may have utility as a triglyceride-lowering agent.