The antioxidant effect of a diet rich in Maillard reaction products is attenuated after consumption by healthy male adolescents.: In vitro and in vivo comparative study

BACKGROUND: Maillard reaction products (MRPs) are widely consumed as a part of the human diet. A 2 week randomised two-period crossover trial to determine whether MRP intake affects the antioxidant defence system in male adolescents (11-14years, n = 18) was carried out using two diets rich and poor in MRPs (brown diet, BD, and white diet, WD, respectively). Fasting blood samples were collected after the dietary intervention periods to measure oxidative status. The in vitro antioxidant activity of the diets was also assessed. RESULTS: The BD had stronger in vitro antioxidant activity to scavenge free radicals and greater ability to reduce lipid peroxidation. However, in the in vivo assay, markers of oxidative damage (serum thiobarbituric acid-reactive substances and erythrocyte hydroperoxides) and antioxidant defence parameters (serum antioxidants and enzymatic activities of catalase, superoxide dismutase and glutathione peroxidase) were unchanged after the dietary treatments. Only treatment of biological samples with external oxidants revealed higher values of the antioxidant capacity after consumption of the MRP-rich diet. CONCLUSION: In spite of the higher antioxidant activity of the BD shown in vitro, consumption of diets rich in MRPs does not seem to modify oxidative status in healthy male adolescents. However, a protective effect against induced oxidation was shown. (C) 2008 Society of Chemical Industry.