Divergent lipoprotein responses to fish oils with various ratios of eicosapentaenoic acid and docosahexaenoic acid.

To determine if the ratio of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in fish oil had an effect on plasma lipid responses, we randomly fed eight normolipidemic men three 36%-fat diets containing primarily butter, EPA-rich pollock oil, or DHA-rich tuna or salmon-blend oils. Plasma EPA and DHA reflected the amounts in the diets. Compared with values for the butter diet, very-low-density lipoprotein (VLDL) triglycerides decreased equally (71-78%) with all diets; low-density lipoprotein (LDL) cholesterol (LDL-C) and apolipoprotein B decreased 26% and 13%, respectively, on the tuna and salmon-blend oil but did not change (-1%) and increased 19% with the pollock diet; high-density lipoprotein cholesterol (HDL-C) and lipoproteins A-I and A-II decreased with all diets but more with the pollock diet than with the tuna and salmon diets. The 23-31% decrease in total cholesterol on the tuna and salmon diets resulted mostly from decreased LDL-C whereas the 16% decrease on pollock oil resulted mostly from a decrease in HDL-C.