Among the saturated fatty acids (SFA), myristic acid is known to be one of the most atherogenic when consumed at high levels. Our purpose was to compare the effects of two moderate intakes of myristic acid on plasma lipids in an interventional study. Twenty-five male monks without dyslipidemia were given two isocaloric diets for 5 weeks each. In diet 1, 30% of the calories came from fat (8% SFA, 0.6% myristic acid) and provided 200 mg cholesterol/day. Calories of diet 2 were 34% fat (11% SFA, 1.2% myristic acid) with the same levels of oleate, linoleate, alpha-linolenate and cholesterol. A baseline diet was provided before each diet. In comparison with baseline, diets 1 and 2 induced a decrease in total cholesterol, LDL-cholesterol and triglycerides (P<.001); HDL-cholesterol was not modified and the apo A-I/apo B ratio increased (P<.001). Plasma triglycerides were lower after diet 2 than after diet 1 whereas HDL-cholesterol was higher (P<.05). In phospholipids, myristic acid, oleic acid, linoleic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased after diet 2 vs. baseline (P<.01) and diet 1 (P<.05). Both diets were associated with an increase in alpha-linolenate of cholesteryl esters (P<.05), but only diet 2 was associated with an increase in DHA of cholesteryl esters (P<.05). In diet 2, myristic acid intake was positively correlated with myristic acid of phospholipids, and alpha-linolenic acid intake was correlated with alpha-linolenic acid of cholesteryl esters. Moderate intake (1.2% of total calories) of myristic acid has beneficial lipidic effects and enhances DHA of cholesteryl esters.