linoleic-acid and pentadecanoic-acid

Erythrocytes, compared with plasma, are considered more robust markers of n-3 (ω-3) polyunsaturated fatty acid (PUFA) intake, because dietary-induced change in fatty acid (FA) composition takes longer to complete. The extent to which this applies to intakes of saturated fatty acid (SFA) or n-6 PUFA is unclear. We compared the pattern of change over time in the fatty acid composition of plasma, erythrocyte, buccal cell, and adipose tissue lipids when changing between diets high in SFA or n-6 PUFA. Twenty-four (n = 7 male) healthy participants were instructed to consume either an SFA-rich (18% energy) or n-6 PUFA-rich (10% energy) diet for 8 wk before crossing over, without washout, to the alternate diet. The FA composition of plasma triacylglycerol (TG), nonesterified FAs, cholesterol ester, total phospholipids, erythrocyte total phospholipids, erythrocyte phosphatidylcholine, and buccal cell total phospholipids was measured every 2 wk and adipose tissue TG every 4 wk during the 16-wk intervention. Linoleic acid composition of plasma, erythrocyte, and buccal cell lipids increased (P < 0.01) during the first 2 wk of the n-6 PUFA diet and remained unchanged during the remaining 6 wk. During the 8-wk SFA diet, the same pattern of change over time occurred for the pentadecanoic acid composition of plasma and erythrocyte lipids; however, the pentadecanoic acid composition of buccal cell lipids did not differ between the diet periods. There were no differences in linoleic or pentadecanoic acid composition of adipose tissue TG. These results suggest plasma and erythrocyte FAs reflect intakes of SFA and n-6 PUFA over a similar period of time.

Topics: Adipose Tissue; Adult; Biomarkers; Cholesterol Esters; Cross-Over Studies; Diet; Dietary Fats; Energy Intake; Erythrocytes; Fatty Acids; Fatty Acids, Omega-6; Female; Humans; Linoleic Acid; Male; Middle Aged; Phosphatidylcholines; Time Factors; Triglycerides

This study has determined oil, fatty acid (FA) and phytosterols content during the ripening of the Tunisian Onopordum acanthium L. seeds. In total, nine FAs and six phytosterols were identified. The main FAs were linoleic acid (0.18-8.06 mg/g of seed) followed by oleic acid (0.051-2.45 mg/g of seed), palmitic acid and stearic acid. Pentadecanoic acid was detected, for the first time, in unripe fruits and the two last stages of development were characterised by a relative abundance of erucic acid. Overall, β-sitosterol (34.5-77.79% of total sterols) was the major 4-desmethylsterols during maturation. The first episodes of growth were characterised by the best amounts of stigmasterol and campesterol, while stigmastanol and Δ7 sitosterol had quoted the semi-ripe and fully ripe fruits; however, cholesterol was absent. These findings are useful in understanding a potential new source of important natural compounds (Phytosterols and USFA) found in this fruit and when harvest should be undertaken to optimise desired FA and phytosterols content.

Topics: Cholesterol; Fatty Acids; Fruit; Linoleic Acid; Oleic Acid; Onopordum; Phytosterols; Plant Oils; Seeds; Sitosterols; Stigmasterol; Tunisia