ABSTRACT
This chapter reviews the available evidence on the use of polyphenols as antioxidants in sport and try to discuss what the road ahead should look like. From a biosynthetic viewpoint, the enzyme phenylalanine ammonia lyase catalyses the deamination of phenylalanine to cinnamic acid, the precursor of the polyphenols. NF-E2-related factor 2 is a transcription factor which binds to the antioxidant response element in cells and thus regulates enzymes involved in antioxidant functions or detoxification. The concept that physical activity induces oxidative stress which needs to be counteracted by increased intakes of antioxidants is—apparently—well anchored in professionals and amateurs. The near totality of such pieces of ‘information’ underscores the need to add antioxidants to the athlete’s diet, pointing to polyphenol-rich food or supplements as a valuable source of free radical scavengers. In the case of polyphenols, it indicates that they could most likely have an indirect antioxidant action.
