International Society of Sports Nutrition supports clinically backed antioxidant supplements

At a Glance

ISSN published an evidence-based approach to antioxidant supplement recommendations for sports and active nutrition.

Ingredients with substantiation for benefiting athletes include tart cherry, omega-3s, astaxanthin and creatine.

Future ingredients of interest include ashwagandha and urolithin A, although more research is needed.

Antioxidants are common in sports nutrition and active nutrition dietary supplements, ranging from fruit extracts to vitamins and fatty acids. However, the benefits of some of these components are not yet well supported by scientific evidence.

Therefore, the International Society of Sports Nutrition (ISSN) has published a position stand on antioxidants, outlining its evidence-based recommendations.

The ISSN reviewed and analyzed the clinical evidence (or lack thereof) for a variety of antioxidant components, including vitamins, plant extracts, amino acids, and fatty acids.

Key points of the position stand include:

There is a range of oxidative stress. While moderate stress (benign stress) may be beneficial, excessive stress can cause problems, including inflammation and muscle damage.

Dietary antioxidants can counteract oxidative stress, but the evidence for all antioxidant components is not conclusive.

Natural foods are the preferred source of antioxidants, but supplements also have their place in situations of intense training or inadequate diet.

The use of antioxidants should be adjusted according to individual needs and training plans.

Components beneficial to sports nutrition include omega-3 fatty acids, astaxanthin and sour cherries.

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Why did the ISSN take a position on antioxidants?

“The ISSN, as an academic-oriented sports nutrition society, publishes a number of position stands, which are basically the synthesis of evidence-based research that then is distilled into useful and applicable tidbits for consumers, coaches, registered dietitians, athletic trainers and the populace,” said Douglas Kalman, Ph.D., R.D., clinical associate professor at Nova Southeastern University and ISSN cofounder.

Kalman noted exercise induces oxidative stress and produces free radicals, which in turn cause cytokine inflammatory responses.

“If exercise induces oxidative stress, will antioxidants help enhance recovery? And can they positively impact performance as well?” Kalman asked.

Antioxidants are often considered a remedy to oxidative stress and neutralizing free radicals within the body. While some oxidative stress is beneficial and improves cell adaptability, too much oxidative stress could be harmful.

“We know that there is a correlation between the effects of oxidative stress on the body over time and incidence and occurrence of a variety of various diseases, cardiovascular and neurological,” Kalman said.

Can too much of a good thing be bad?

Although antioxidants can reduce inflammation and alleviate muscle soreness, excessive intake of any beneficial substance can have negative effects.

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"Indeed, there is a limit beyond which antioxidants can actually become pro-oxidants," said Kalman, citing vitamin C as an example.

"Vitamin C has antioxidant effects at lower doses and is recognized as an antioxidant," he said. "But at higher concentrations, it actually induces oxidative stress and oxidative damage."

Although Kalman acknowledges that the situation for athletes is somewhat special, he emphasized the importance of balancing oxidative stress without completely suppressing it.

"We have normal fluctuations in stress responses... So we need to allow this response, rather than over-suppressing it and shutting it down," said Kalman. "There is a balance between antioxidants and oxidative stress."

Can ordinary people, not just athletes, benefit from antioxidants?

"The answer is yes," said Kalman. He mentioned that there is scientific evidence suggesting that antioxidants beneficial to athletes also have other health benefits, such as the melatonin naturally present in tart cherries, or the promotion of eye health by astaxanthin.

Although the International Society for Sports Nutrition (ISSN) stance supports a food-first approach, Kalman acknowledged that antioxidant supplements have benefits for many aspects of human health.

Kalman also mentioned that creatine is not only beneficial for athletes but also for everyone, noting that creatine is a non-traditional antioxidant. Consumers and researchers outside the sports field have also paid significant attention to creatine.

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When asked about what components might emerge in the future of sports nutrition, Kalman mentioned， Ayurvedic herbs， and urolithin A， but more research is needed to determine their benefits for sports performance and recovery.