Effect of nut consumption on oxidative stress and the endothelial function in metabolic syndrome.

BACKGROUND & AIMS Oxidative stress has a key role in atherosclerosis, cancer and other chronic diseases. Some bioactive compounds in nuts have been implicated in antioxidant activities. OBJECTIVE We assessed how nut consumption affected several markers of oxidation and endothelial function (EF) in metabolic syndrome (MetS) patients. PATIENTS AND METHODS A randomized, controlled, parallel feeding trial was conducted on 50 MetS adults who were recommended a healthy diet supplemented or not with 30 g of mixed nuts (Nut and Control groups, respectively) every day for 12 weeks. The plasma antioxidant capacity (AC), oxidized LDL (oxLDL), conjugated diene (CD) formation, urine 8-isoprostanes, DNA damage assessed by yield of urine 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG), and EF assessed by peripheral artery tonometry (PAT) and biochemical markers, were measured at baseline and the end of the intervention. RESULTS No significant differences in changes between groups were observed in AC, oxLDL, CD, 8-isoprostanes or EF during the intervention, whereas the reduction in DNA damage was significant in the Nut group compared to Control group (P < 0.001). CONCLUSION Nut consumption has no deleterious effect on lipid oxidation. The decrease in DNA damage observed in this study could contribute to explain the beneficial effects of regular nut consumption on some MetS features and several chronic diseases.