RESUMEN
BACKGROUND: The degree of fatty acid (FA) unsaturation as a determinant of lipid peroxidation has been inadequately studied. METHODS: We examined associations of plasma free F2α-isoprostanes (F2-IsoPs), an indicator of in-vivo lipid peroxidation, with the levels/intake of FAs, adjusted for the risk factors of cardiovascular disease (CVD) in 1211 Finnish men and women, of whom 50% were hypertensive, aged 59.3 ± 8.3 years, mean ± SD. RESULTS: Elevated age- and sex-adjusted plasma free levels of omega-6 and omega-3 polyunsaturated Fas (PUFAs), saturated FAs (SFAs), and the PUFA/SFA and the omega-6/omega-3 PUFA ratios were all associated with decreased F2-IsoPs. High dietary SFA intake was associated with elevated F2-IsoP concentrations. In a multivariable regression (with clinical, nutritional, and behavioral CVD risk factors), female gender, body mass index (BMI), serum apolipoprotein A1, and NT-proBNP (natriuretic peptide) were positively associated with the F2-IsoPs, whereas the dietary PUFA/SFA ratio, plasma ß-carotene, the omega-6/omega-3 PUFA ratio, and protein intake showed inverse associations. CONCLUSIONS: We propose that elevated lipid peroxidation is associated with several risk factors of CVD, such as a low PUFA/SFA ratio, whereas the FA precursors of lipid peroxidation, i.e. omega-3 and omega-6 PUFAs are associated with attenuated F2-IsoP levels. These findings provide mechanistic support for earlier observations linking PUFA to improved cardiovascular health.