The antioxidant status response to low-fat and walnut paste-enriched meat differs in volunteers at high cardiovascular Risk carrying different PON-1 polymorphisms.

BACKGROUND Cardiovascular risk largely depends on diet, antioxidant status, and gene polymorphisms. Low-fat meat (CM) and walnut-enriched meat (WM) products may exert potential beneficial health effects with respect to conventional meat products. OBJECTIVE To compare the effects of consuming WM vs CM on reduced and oxidized glutathione, lipoperoxides, α- and γ-tocopherol levels, and paraoxonase (PON-1), catalase (CAT), and superoxide dismutase (SOD) activities in 22 volunteers (mean age 54.8 years and body mass index 29.6 kg/m(2)) at high cardiovascular risk carrying different PON-1 192/55 polymorphisms. DESIGN The study was a 5-week nonblinded, randomized, crossover, controlled trial. RESULTS In general term, WM vs CM improved the volunteers' antioxidant status, with several result modifications occurring after the WM period. CM consumption increased oxidized glutathione and decreased PON-1 activity (at least p < 0.05). When WM vs CM effects were compared, SOD, CAT, and PON-1 enzyme activities increased (at least p < 0.05) in PON-1 192QQ carriers. γ-tocopherol levels and SOD and PON-1 activities increased in PON-1 192QR+RR carriers besides the significant decrease of lipoperoxide levels. In PON-1 55LM+MM carriers, the intervention increased significantly all the investigated enzyme activities and glutathione levels, whereas PON-1 55LL carriers increased their PON-1 activities. CONCLUSIONS WM consumption should be preferred to CM. The intake of WM vs CM increased PON-1 but the effect upon other antioxidant enzymes and substrates varied depending on the individual's PON-1 polymorphism. PON-1 192QR+RR carriers appear the targets for WM consumption as they increased enzyme activities and γ-tocopherol levels and decreased lipoperoxides.