Antioxidant/Oxidant Balance as a novel approach to evaluate the effect on serum of long-term intake of plant antioxidant-rich foods

Serum Antioxidant/Oxidant Balance (AOB), calculated as Antioxidant Capacity (AC)/Peroxide Level (PxL) ratio, was applied for the first time to two long-term small pilot studies: a three-week and eight-week investigations, regarding the intake of 250 g/day cherry puree and a diet including several food antioxidants, respectively. Serum AC was assayed by the new LOX-FL and the widely used ORAC and TEAC methods; PxL was evaluated by an alkylamine reaction with peroxides. While AC assays were unable to show positive effect of antioxidants (even 7-9% AC decrease was sometimes observed), AOB was able to highlight very well the expected improvement of serum antioxidant status (ranging from +22% to +40%), thus showing reliability of the new approach whatever the kind of plant food antioxidants. This is consistent with the capability of AOB approach to simultaneously account for AC and for the AC fraction not directly measurable, as consumed to lower serum oxidation status.