THE EFFECTS ON SERUM-LIPOPROTEIN LEVELS OF 2 MONOUNSATURATED FAT RICHDIETS DIFFERING IN THEIR LINOLEIC AND ALPHA-LINOLENIC ACID CONTENTS

The effects of alpha-linolenic acid (C18:3, n-3) on serum lipoprotein levels were investigated. Apparently healthy, 29 +/- 9 year old males and females (n = 40) participated in this study. Two test diets high i n monounsaturated fatty acids, a low-erucic-acid rapeseed oil diet (RO ) containg 5.9 g of C18:3 and 16.2 g of linoleic acid (C18:2, n-6) per day and TRI-SUN(R)-sunflower oil diet (TSO) containing 0.8 g of C18:3 and 21.1 g C18:2 per day were fed for 6 weeks each, with a wash-out p eriod of 6 weeks between periods, in a blind cross-over design. The pr oportions of energy from saturated (approximate to 11.5% of total ener gy, En%), monounsaturated (approximate to 17.5En%) and polyunsaturated fatty acids (approximate to 8.5En%) were kept similar in both test di ets. Both experimental diets reduced serum total cholesterol (p < 0.00 1) LDL cholesterol (p < 0.001), total triglycerides (p < 0.001), LDL t riglycerides (p < 0.01), apolipoprotein B (p < 0.01 for RO, and p < 0. 05 for TSO diet), as well as phospholipids (p < 0.001). Serum HDL chol esterol, HDL triglyceride, as well as apolipoprotein A-1 levels were u naffected, but HDL(2) cholesterol was reduced (p < 0.001), HDL(3) chol esterol increased (p < 0.001) by both test diets. VLDL cholesterol and triglyceride values did not change significantly In conclusion, the a lpha-linolenic acid does not seem to have an effect on serum lipoprote in levels different from that of linoleic acid under dietary condition s where there are considerable amounts of linoleic acid available.