Comparison of effects of N-3 to N-6 fatty acids on serum level of lipoprotein(a) in patients with coronary artery disease

The influence of dietary supplementation with n-3 versus n-6 fatty acids on plasma lipoprotein(a) (Lp[a]) levels was studied. Thirty-five male hospitalized patients with coronary artery disease were treated for 4 weeks with 12 g/day of fish oil (≈8.5 g of n-3 fatty acids) in combination with a 5, 000 kilojoule, 30% fat diet and moderate exercise. Eighteen control patients given the same dietary and training program were treated with 12 g/day of rapeseed oil. Plasma Lp(a), in addition to several lipids and lipoproteins, blood clotting factors, and platelet reactivity, were measured before and at the end of therapy. Results can be summarized as follows: total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B levels decreased significantly in both the rapeseed oil (−14.4%, −20.3%, −15.2%, respectively) and fish oil (−12.2%, −16.0%, and −14.2%, respectively) groups. Triglycerides decreased (−20.3%) and high-density lipoprotein cholesterol increased (+8.3%) significantly only in patients treated with fish oil. Plasma Lp(a) levels were reduced by 14% in the fish oil group, but unaffected in the rapeseed oil group. Patients treated with fish oil could be categorized into 2 subgroups: “responders”, with a reduction in Lp(a) by 24% and “nonresponders”, with a small nonsignificant increase in serum Lp(a). Responders and nonresponders exhibited a marked reduction in cholesterol, low-density lipoprotein cholesterol, apolipoprotein B, and triglycerides, and an increase in high-density lipoprotein3 cholesterol. There was a large reduction in tissue plasminogen activator in the fish oil group, which correlated significantly with reduction in Lp(a). Platelet number and aggregation behavior were not significantly changed in either group. No physiologic differences were seen between responders and nonresponders.