Antioxidants and Exercise Performance: With a Focus on Vitamin E and C Supplementation

Abstract

Antioxidant supplementation, including vitamin E and C supplementation, has recently received recognition among athletes as a possible method for enhancing athletic performance. Increased oxidative stress during exercise results in the production of free radicals, which leads to muscle damage, fatigue, and impaired performance. Despite their negative effects on performance, free radicals may act as signaling molecules enhancing protection against greater physical stress. Current evidence suggests that antioxidant supplementation may impair these adaptations. Apart from athletes training at altitude and those looking for an immediate, short-term performance enhancement, supplementation with vitamin E does not appear to be beneficial. Moreover, the effectiveness of vitamin E and C alone and/or combined on muscle mass and strength have been inconsistent. Given that antioxidant supplements (e.g., vitamin E and C) tend to block anabolic signaling pathways, and thus, impair adaptations to resistance training, special caution should be taken with these supplements. It is recommended that athletes consume a diet rich in fruits and vegetables, which provides vitamins, minerals phytochemicals, and other bioactive compounds to meet the recommended intakes of vitamin E and C.

Effects of Vitamin E and Coenzyme Q10 Supplementation on Oxidative Stress Parameters in Untrained Leisure Horses Subjected to Acute Moderate Exercise

“…Similar results have been reported in sport horses [53,56,57,68]. The inconsistency of results regarding the effects of vitamin E supplementation on exercise-induced oxidative stress appears to reflect a variety of factors, including the amount, duration, form, and frequency of vitamin E supplementation; the type and timing of exercise; the age and fitness of the subjects; the vitamin E status of the subjects prior to the studies; and the methodology used to assess oxidative stress [8,41,50,58,66,69]. Nevertheless, it should be emphasised that there is limited evidence to support the use of vitamin E in human athletes [70].…”

“…Antioxidant supplementation can have both beneficial and pro-oxidant effects [4,7,44]. In addition, it may hinder or prevent important signalling adaptations to exercise training [12,13,50].…”

“…Vitamin E (α-tocopherol) is one of the most well-studied and widely used antioxidant supplements in exercise research in humans [8,13,41,50,51] and horses [34,45,47,49,[52][53][54][55][56][57][58][59]. This exogenous antioxidant is one of the most potent free radical scavengers [60][61][62].…”

Supplementation with Vitamins C and E and Exercise-Induced Delayed-Onset Muscle Soreness: A Systematic Review

“…While it has been long known that high concentrations of free radicals lead to oxidative damage, it has more recently been shown that the increased ROS levels induced by exercise also play a physiological role [ 17 , 18 , 19 ]. ROS and reactive nitrogen species (RNS) behave as molecular messengers through their interactions with redox-sensitive proteins that regulate processes such as insulin sensitivity, growth factor signaling, vasodilatation, and the immune response [ 18 ].…”

Effects of Dietary Strategies on Exercise-Induced Oxidative Stress: A Narrative Review of Human Studies

“…Instead of single antioxidative sources, it might be speculated that the intake of natural foods rich in antioxidants of phytochemicals (e.g., fruits and vegetables) might represent a more beneficial approach for enhancing the antioxidant status during exercise [ 26 ]. Along with their high antioxidant content, specific diets, including products such as oatmeal, dark chocolate, and mixed fruit beverages may also contain additional bioactive compounds which are not found in single-dose pharmacological antioxidant supplements but can act synergistically to reveal more beneficial effects than a single dose of antioxidant supplements [ 27 , 28 ]. Additionally, these compounds are more accessible than specific isolated antioxidants.…”