Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: May 11, 1997
Publication Date: N/A
Technical Abstract: Six male subjects were fed either a high arachidonic acid (AA) diet (HIAA) containing 1.8 g/d or a low AA diet (LOAA) containing 0.3 g/d of arachidonic acid for 50 days. Each subject was fed about 5g of 18:2n-6[d2] as the triglyceride at 8 am, 12 N, and 5 pm. The total amount of 18:2n-6[d2] fed (14g) was about equal to the daily intake of 18:2n-6 in a typical U.S. diet. Nine blood samples were drawn over a 96 hr period. Methyl esters of plasma total lipid (TL), triglyceride (TG), phospholipid (PL), and cholesterol ester (CE) were analyzed by GC-MS. Results indicate that dietary AA supplementation did not affect the enrichments and concentrations of 18:2n 6[d2] in plasma lipid TL, TG, PL and CE. The percentage of major 18:2n-6[d2] desaturation and elongation products (as a % of the total deuterated fatty acids in plasma total lipid) were 1.35% and 1.34% 18:3n-6[d2]; 0.53% and 0.50% 20:2n-6[d2]; 1.80% and 0.93% 20:3n-6[d2] and 2.9% and 1.5% 20:4n-6[d2] for the LOAA and HIAA diet groups, respectively. Only trace amounts (<0.1%) of the 22:4n-6[d2] and 22:5n-6[d2] metabolites were present. Concentrations for both 20:3n-6[d2] and 20:4n-6[d2] were 48% lower in plasma total lipids from the HIAA diet group than from the LOAA group. The results suggest that about 435 mg (2.9%) of the 18:2n-6 in a typical U.S. diet is converted to AA over a 4-day period.