Supplementation With Mixed Fruit And Vegetable Juice Concentrates Attenuates Oxidative Stress Markers In Trained Athletes

Abstract

Intensive exercise enhances the formation of free radicals and other reactive oxygen and nitrogen species (RONS) in animals and humans resulting in the generation of compounds like malondialdehyde (MDA) and carbonyl-proteins (CP). Reduced formation of these oxidative stress parameters during physical exercise by supplementation with antioxidants has not been reported. Purpose To investigate the influence of a) supplementation with mixed fruit and vegetable juice concentrates and b) of exercise duration with a defined intensity on the concentrations of MDA and CP after intense mountain biking for two hours. Methods 5 healthy trained men (male; 37 ± 5yrs; VO2max 55 ± 5mL ± kg−1 ± min−1) supplemented daily with 4 capsules of a phytonutrient preparation from fruits and vegetables. Subjects performed a two hours lasting mountain bike exercise to the top of a mountain (altitude 1500m, distance 30km) at 75% of the individual VO2max, followed by a moderate downhill performance (same route) at 45% of the individual VO2max. Capillary blood was collected from the finger tip before the exercise, on the top of the mountain immediately after intense exercise (=two hours) and the third collection at the end of exercise (=three hours). After collection blood plasma samples were separated by centrifugation at 4 ± C and plasma levels of MDA were measured by a HPLC method, measurement of CP was performed after derivatization with dinitrophenylhydrazine (DNPH) by a chemiluminescence technique. A two-sided Student's t-test was performed for testing the significance of differences with p <0.05 as the criterion for significance. Results Both parameters were significantly decreased before exercise (MDA: 2.43 ± 0.39 vs. 1.64 ± 0.52 μM; CP: 0.46 ± 0.05 nmol/mg protein vs. 0.23 ± 0.02 nmol/mg protein), after 2 hours of intense exercise (MDA: 2.68 ± 0.45 vs. 1.85 ± 0.50 μM; CP: 0.55 ± 0.18nmol/mg protein vs. 0.32 ± 0.019nmol/mg protein) and after prolonged exercise of 3 hours (MDA: 2.47 ± 0.73 to 1.64 ± 0.47 μM; CP: 0.5 ± 0.08nmol/mg protein to 0.33 ± 0.09nmol/mg protein) by supplementation compared to the non supplemented phase. No significant difference in the concentrations of both parameters throughout the time course of exercise was estimated except the CP values between the first and second blood collection in the supplemented phase (CP: 0.29 ± 0.02 nmol/mg vs. 0.315 ± 0.02 nmol/mg). Conclusions Thus we demonstrate a benefit of the supplementation with the phytonutrient preparation concerning oxidative protein damage and lipid peroxidation products in human plasma. The chosen exercise duration at a certain intensity had modest influence to the concentrations of oxidative stress markers.