According to the American College of Sports Medicine up to 50% of athletes use nutritional supplements. Among the most popular supplements nowadays are antioxidants, used to improve performance and fight against Exercise-Induced Muscle Damage (EIMD) and fatigue.
Two of the most popular antioxidants are vitamin C and vitamin E, capable of neutralising the reactive oxygen species (ROS) derived from intense exercise. Despite their extensive use most athletes consume adequate levels daily (Vitamin C: 75 mg/day females – 90 mg/day males; Vitamin E: 15 mg/day) in the diet through fruits, vegetables, and nuts, among other sources.
Some authors suggest that the transient rise of ROS with exercise is beneficial. Thus, antioxidant supplementation could impair athletes training adaptations, instead of helping them.
A recent review has investigated the effects of vitamin E and C supplementation on exercise performance. Their main findings are described below.
- Muscle strength and function are not affected.
- Individuals with vitamin C deficiency increase exercise performance with supplementation.
- Effects on endurance are confuse.
- During high intensity intervals acute supplementation improves performance (less oxidative stress and faster recovery).
- Chronic supplementation may impair training adaptations and future exercise performance.
- Chronic supplementation with vitamin E (with or without vitamin C) impairs athletic performance and is not currently recommended for athletes (except for those training at high altitude).
- Acute antioxidant supplementation improves performance in high intensity/short recovery intervals exercise, conditions where an IMMEDIATE enhancement of performance is pursued.
- To ensure antioxidants needs athletes should focus on consuming a diet high in them (fruits, vegetables, nuts…) instead of using supplements.
- Determining the oxidative state of athletes would allow personalized supplementation.
Antioxidants and Exercise Performance: With a Focus on Vitamin E and C Supplementation. Higgins MR, Izadi A, Kaviani M. Int J Environ Res Public Health. 2020 Nov 15; 17(22):8452. doi: 10.3390/ijerph17228452.