THE EFFECT OF DIETARY ARACHIDONIC-ACID ON PLASMA-LIPOPROTEIN DISTRIBUTIONS, APOPROTEINS, BLOOD LIPID-LEVELS, AND TISSUE FATTY-ACID COMPOSITION IN HUMANS

Normal healthy male volunteers (n = 10) were fed diets (high-AA) conta ining 1.7 g/d of arachidonic acid (AA) for 50 d. The control (low-AA) diet contained 210 mg/d of AA. Dietary AA had no statistically signifi cant effect on the blood cholesterol levels, lipoprotein distribution, or apoprotein levels. Adipose tissue fatty acid composition was not i nfluenced by AA feeding. The plasma total fatty acid composition was m arkedly enriched in AA after 50 d (P < 0.005). The fatty acid composit ion of plasma lipid fractions, cholesterol esters, triglycerides, free fatty acids, and phospholipid (PL) showed marked differences in the d egree of enrichment in AA. The PL plasma fraction from the subjects co nsuming the low-AA diet contained 10.3% AA while the subjects who cons umed the high-AA diet had plasma PL fractions containing 19.0% AA. The level of 22:4n-6 also was different (0.67 to 1.06%) in the plasma PL fraction after 50 d of AA feeding. After consuming the high-AA diet, t he total red blood cell fatty acid composition was significantly enric hed in AA which mainly replaced linoleic acid. These results indicate that dietary AA is incorporated into tissue lipids, but selectively in to different tissues and lipid classes. Perhaps more importantly, the results demonstrate that dietary AA does not alter blood lipids or lip oprotein levels or have obvious adverse health effects at this level a nd duration of feeding.