Document Type

Article

Publication Title

Journal of the International Society of Sports Nutrition

Abstract

Following a comprehensive review, the International Society of Sports Nutrition (ISSN) has developed an official position on the role of dietary antioxidants in exercise and sport. Antioxidants play a complex, context-dependent role in vivo; they can facilitate recovery from exercise but may also hinder training adaptations when consumed at supraphysiological doses. While endogenous antioxidant systems can effectively maintain redox balance, dietary sources, particularly whole foods, can help mitigate excessive oxidative stress following intense/heavy training or inadequate recovery. The influence of dietary antioxidants depend on timing, dosage, type, and individual factors. The ISSN’s official position encompasses the following: (1) Redox balance exists on a spectrum, with mild oxidative eustress driving beneficial physiological adaptations and excessive oxidative distress impairing health, recovery, and performance; (2) Moderate levels of exercise-induced reactive oxygen and nitrogen species (ROS/RNS) can support training adaptations but excessive levels can result in muscle damage, inflammation, and reduced physical performance and immune function; (3) Endogenous and exogenous antioxidants protect cells by neutralizing free radicals and reducing oxidative damage to biomolecules; (4) FDA labeling for “antioxidant” claims applies to nutrients with established RDIs and demonstrated antioxidant activity; this typically includes vitamins C and E, β-carotene (a source of vitamin A), selenium, zinc, copper, and manganese; (5) While dietary antioxidants show potential for both direct and indirect effects, the evidence varies, and their use should be tailored to individual performance or recovery goals; (6) Long-term exercise augments endogenous antioxidant defense and should be the primary strategy for enhancing redox capacity before considering supplementation; (7) Whole foods and beverages rich in flavonoids, polyphenols, carotenoids, vitamins, and minerals are preferred antioxidant sources; (8) Dietary supplementation is best reserved for nutrient insufficiencies or deficiencies, inadequate dietary intake, or periods of high training distress; (9) Responses to supplementation vary by individual factors, such as training status, baseline antioxidant capacity, demo-graphics, diet, and injury risk, with some antioxidant compounds offering cognitive, behavioral, or physical-related benefits; and (10) Creatine monohydrate (i.e. 0.1 g/kg/ day), omega-3 fatty acids (1000–6000 mg/day EPA+DHA for 6–12 weeks), tart cherry (480 mg powder or 60–90 mL juice/day for 7–14 days), and astaxanthin (4–12 mg/day for 4–12 weeks) rank among the top nutrients for their antioxidant effects, with moderate- to high-quality evidence supporting their use in recovery or performance without interfering with training adaptations. Most others show weak or low efficacy. This position promotes an individualized, evidence-based approach, recognizing that small to moderate exercise-induced oxidative stress aids adaptation, while excess oxidative stress causes harm; it also emphasizes food-forward and dietary supplementation strategies.

Research Highlights

  • The Problem: Researchers are addressing the complex, context-dependent role of dietary antioxidants in exercise, specifically the conflict between facilitating recovery and potentially blunting necessary physiological training adaptations. 

  • The Method: The International Society of Sports Nutrition (ISSN) conducted a comprehensive literature review and critical analysis of existing research to establish official consensus rankings (weak, moderate, or high evidence) for various antioxidant compounds in relation to performance and recovery. 

  • Quantitative Finding: Creatine monohydrate is effective at 0.1 g/kg/day; omega-3 fatty acids require 1000–6000 mg/day (EPA+DHA) for 6–12 weeks; tart cherry juice or powder (480 mg/day or 60–90 mL juice) is recommended for 7–14 days; astaxanthin is effective at 4–12 mg/day for 4–12 weeks; endurance training increases SOD1 and SOD2 activity by 20%–112% and GPx activity by 20%–177%.

  • Qualitative Finding: Redox balance exists on a spectrum where mild oxidative eustress supports health and adaptation, while excessive oxidative distress from overtraining or poor nutrition impairs performance and immune function; whole food sources are preferred over supplements to avoid interfering with natural hormone signaling; response to supplementation varies based on individual training status, age, sex, and baseline antioxidant capacity.

DOI

https://doi.org/10.1080/15502783.2026.2629828

Publication Date

2-2026

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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