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.