Diet as a source of phospholipid esterified 9,11-octadecadienoic acid in humans.
1. Diene-conjugated fatty acids are one of the products of free-radical attack upon lipids and therefore have been used as markers of such attack. The major diene-conjugated fatty acid in human tissue and serum is an isomer of linoleic acid (9,12-octadecadienoic acid), namely 9,11-octadecadienoic acid. Diet may be another source of this isomer, raising questions as to its value as a free-radical marker. The aim of this study was to determine the importance of diet as a source of 9,11-octadecadienoic acid in phospholipid esterified fatty acids in human serum. 2. Foodstuffs rich in 9,11-octadecadienoic acid were identified. Fourteen subjects volunteered to alter their diets, either increasing ('high diet') or decreasing ('low diet') their intake of these foodstuffs for 3 weeks. Where subjects undertook both diets, a washout period of at least 3 weeks was allowed between phases. 3. Seven-day diet histories were kept and scored with respect to their content of 9,11-octadecadienoic acid. The concentrations of 9,11-octadecadienoic acid and linoleic acid in serum phospholipids were measured by h.p.l.c. with u.v. detection. 4. The percentage molar ratio of 9,11-octadecadienoic acid to linoleic acid was calculated. The percentage molar ratio rose significantly on the 'high diet' [1.3(0.4) versus 1.9(0.7), P = 0.01, mean (SD)] and fell significantly on the 'low diet' [1.6(0.4) versus 1.1(0.4), P = 0.004, means (SD)]. There was a significant correlation between the change in dietary intake of 9,11-octadecadienoic acid and the change in the percentage molar ratio (r = 0.829, P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Britton
M
M
Academic Unit of Diabetes and Endocrinology, Whittington Hospital, London, U.K.
Fong
C
C
Wickens
D
D
Yudkin
J
J
D000328:Adult; D004032:Diet; D005231:Fatty Acids, Unsaturated / Q000737:chemistry; D005260:Female; D005609:Free Radicals / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000008:administration & dosage* / Q000097:blood / Q000378:metabolism; D044243:Linoleic Acids, Conjugated; D008297:Male; D010743:Phospholipids / Q000097:blood / Q000378:metabolism*
D005231:Fatty Acids, Unsaturated; D005609:Free Radicals; D008041:Linoleic Acids; D044243:Linoleic Acids, Conjugated; D010743:Phospholipids; C046938:9,11-linoleic acid; D019787:Linoleic Acid