The impact of nutrition on oxidative stress in athletes

Exercise can have both beneficial and detrimental effects on oxidative stress, depending on factors such as intensity, duration, and individual characteristics. Particularly, high-intensity and prolonged physical activities increase the production of reactive oxygen species (ROS), which may overwhelm endogenous antioxidant systems and lead to oxidative damage. Assessment of oxidative stress in athletes commonly involves biomarkers such as lipid peroxidation products [Malondialdehyde (MDA), Thiobarbituric acid reactive substances (TBARS)], protein and DNA oxidation indicators [8-hydroxy-2-deoxyguanosine (8-OHdG)], and antioxidant enzyme activities [Superoxide dismutase (SOD), Glutathione peroxidases (GPx), Catalase (CAT)]. Changes in these parameters during or after exercise provide insight into the level of physiological stress. Nutrition plays a crucial role in the management of exercise-induced oxidative stress. Western-type diets, which are typically low in antioxidants and high in saturated fats and processed foods, tend to worsen oxidative stress. In contrast, dietary patterns rich in fruits, vegetables, whole grains, healthy fats, and phytochemicals—such as the Mediterranean diet—have been shown to exert protective effects. Regular consumption of bioactive compounds like lycopene (tomatoes), polyphenols (grape juice, green tea, pomegranate, aronia, beetroot), tocopherols (nuts and seeds), and flavonoids (sour cherry, cocoa) can enhance antioxidant capacity and reduce exercise-induced oxidative damage. However, it is also emphasized that high-dose antioxidant supplementation may impair physiological adaptations and exert pro-oxidant effects. Therefore, a balanced and antioxidant-rich diet based on natural food sources offers a safe and effective approach for managing oxidative stress in athletes without the need for pharmacological interventions.