Susceptibility of LDL to oxidative modification in healthy volunteers supplemented with low doses of n-3 polyunsaturated fatty acids

The objective of the present study was to evaluate the oxidative susceptibi lity of LDL in human volunteers following supplementation with various low doses (<1 g/d) of n-3 polyunsaturated fatty acids (PUFA). Sixty-two healthy volunteers (thirty-seven males and twenty-five females, aged 19-63 years) were recruited to take part in a randomised placebo-controlled trial. Volun teers were required to take 0.9, 0.6 or 0.3 g n-3 PUFA as fish oil or place bo capsules daily for 16 weeks. Susceptibility of LDL to oxidative modifica tion was assessed by measuring the production of conjugated dienes and thio barbituric acid-reactive substances in LDL oxidised by Cu2+ (15 <mu>M) or 2 ,2'-azobis(2-amidinopropane) dihydrochloride (1 mM) for 5 h. Plasma fatty a cid and LDL-fatty acid composition, cholesterol levels and antioxidant conc entrations were also measured. While post-treatment n-3 PUFA compositions o f plasma and LDL reflected the capsule contents, no meaningful differences in antioxidant concentrations or cholesterol levels were observed between t he groups. Supplementation with low doses of n-3 PUFA as fish oil did not i nfluence the oxidative susceptibility of LDL. The results of the present st udy suggest that moderate dietary intakes of n-3 PUFA do not significantly influence the susceptibility of LDL to oxidative modification in vitro.