Sport nutrition, redox homeostasis and toxicity in sport performance

Abstract

The health benefits of exercise are widely accepted and have been used to prevent and treat chronic diseases. Exercise, however, is also associated with production of reactive oxygen and nitrogen species (RONS) which, when in excess, can exert toxic effects such as oxidation of lipids and proteins as well as DNA damage. Because unfavourable effects can be found due to a redox status imbalance, dietary supplementation has been used in an attempt to protect and enhance exercise performance. In this review, we performed a thorough PubMed search for human studies with dietary supplements. We review recent studies on the effects of vitamin C, vitamin E (focussing on the effects of these vitamins during chronic exercise only), polyphenols (resveratrol and green tea extract) and N-acetylcysteine. Furthermore, we present data of the effects of protein supplementation and, more specifically, whey protein, which has drawn attention lately due to its antioxidant properties. Protein ingestion seems to be promising not only by scaling down the redox status perturbations after exercise but also by leading to better exercise performance. How these two are related is something that needs to be determined in future studies. In addition, as diet can modulate the composition of the gut microbiota and a possible crosstalk between the gut and mitochondria might take place, an attempt was made to elucidate the possible role of the gut microbiota on mitochondria-related RONS production during exercise. It seems that exercise could positively influence the human gut microbiota composition by increasing diversity and favouring the increase of relative abundances of health-promoting microbial species. At the moment, it is not clear whether a definite recommendation in favour or avoidance of the reviewed supplements could be made. Supplementation in athletes with deficiencies and in greater need, such as overtraining, is definitely something that needs to be determined in future studies. © 2019 Elsevier B.V.