Abstract
BACKGROUND: DNA is constantly exposed to reactive oxygen species (ROS), spontaneously arising during the normal oxygen metabolism. ROS may result in temporary as well as permanent modifications in various cellular components such as lipids, proteins and DNA, which may have deleterious consequences. Demonstrating that a dietary supplementation of antioxidants can reduce oxidative DNA damage may provide evidence for the value of such supplementation in prevention of cancer and age related diseases. FINDINGS: The present study was conducted to address whether tomato juice protects against ROS induced by extensive physical exercise in untrained individuals. As a marker of oxidative stress, serum levels of 8-oxodG were monitored using a modified ELISA. An intervention was performed involving 15 untrained healthy subjects who performed a 20 min physical exercise at 80% of maximum pulse using an ergometer bicycle. Blood samples were taken before and one hour after the exercise. The procedure was repeated after 5 weeks with a daily intake of 150 ml tomato juice and followed by a 5 weeks wash-out period and another 5 weeks with a daily intake of tomato juice. The results indicated that a daily intake of tomato juice, equal to 15 mg lycopene per day, for 5 weeks significantly reduced the serum levels of 8-oxodG after an extensive physical exercise. CONCLUSION: These data strongly suggest that tomato juice has a potential antioxidant effect and may reduce the elevated level of ROS induced by oxidative stress.