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As young athletes increasingly turn to supplements for a competitive edge, new research warns that most supplement claims are based on adult studies, posing unknown risks to their growing bodies.

Study: Use of Nutritional Strategies, Bioactive Compounds, and Dietary Supplements in Young Athletes: From Evidence to Potential Risks—A Narrative Review. Image credit: matimix/Shutterstock.com

Unlike adult athletes, young athletes present unique nutritional challenges as they undergo rapid growth and development and intensive exercise training. Yet, few studies specifically focus on sports nutrition in children. A recent narrative review published in Nutrients examines the place of bioactive supplements in the training of young athletes.

The need for sports nutrition in young athletes

Bioactive supplements for athletes include omega-3 fatty acids, curcumin, caffeine, creatine, and antioxidant vitamins.

Young athletes typically use supplements based on the recommendations for adult athletes. However, adolescents differ markedly from adults, growing and undergoing rapid and profound hormonal changes. Significant alterations in body composition and metabolism accompany organ maturation.

Physiologically, prepubertal athletes depend far more on an increase in heart rate to increase cardiac output than adults, who rely more on stroke volume. Unlike adults, children respond to exercise by increased ventilation. Children also rely more heavily on fat oxidation during endurance training than adults.  

Young athletes engaged in training and competition, especially at elite levels, as opposed to recreational sports, need a unique blend of nutrients. Their diet must support growth, development, overall health, and athletic performance.  Nutritional guidelines designed for adult athletes fall short of these requirements.

Notably, dehydration, insufficient energy intake, and lack of essential macro- and micro-nutrients, put young athletes at risk for severe adverse health outcomes. These include delayed maturation, impaired reproductive function, poor bone development, short stature, eating disorders, and injury.

Supplement use in young athletes

Adolescents in sports are increasingly using supplements due to peer pressure or the fear of falling behind others. Without professional guidance, they may not know what these contain, how to use them, or the associated risks, such as inadvertent drug violations.

Despite being unethical and risky, banned drug use occurs in up to 3% of adolescent athletes and will become more common. Most youngsters feel that their competitors are using prohibited drugs, making it seem normal and acceptable.

Study results

The current review sought to identify and analyze the various nutritional strategies used in young athletes. Notably, the International Olympic Committee (IOC) consensus statement discounts the evidence that most supplements enhance either performance or health.

Most evidence for supplement use comes from adult studies and is often weak or inconclusive. Long-term safety studies are notably limited for adolescent use. Moreover, sex and genetic differences may affect the outcomes of bioactive use from person to person. 

Currently, there are no quantitative parameters to assess the impact of nutritional strategies on young athletes. Children’s energy intake will likely be adequate if they meet their standard growth and development markers.

Adequate energy intake is crucial in young athletes, and relative energy deficiency in sport (RED-S) is a recognized condition that impacts physiological functions needed for health and athletic performance, especially during the growing years. Multiple adverse outcomes have been reported, including impairment of reproductive function, psychological well-being, and performance.

National dietary guidelines for adults are adapted to determine energy intake according to use in adolescents, since the evidence indicates that no additional energy is required to fuel their metabolism. Fat consumption also follows adult guidelines.

Micronutrients like vitamin D and calcium are essential to avoid deficiencies and prevent poor health. They ensure peak bone mass of 90% built up by 18, but do not enhance performance. For example, a single 200,000 IU dose of vitamin D improved jumping ability and speed in vitamin D-deficient young soccer players. At the same time, routine use in sufficient individuals showed no apparent benefit. Iron in bioavailable form may help young female athletes prevent iron deficiency and improve physical performance.

Ergogenic substances of benefit in adult athletes include caffeine, which improves anerobic performance; β-Alanine (a precursor of carnosine), which prevents acidosis during high-intensity exercise; and dietary nitrates (especially from beetroot juice), which enhance available nitric oxide in muscle tissue, increasing muscle efficiency and blood flow. These substances have known or biologically plausible mechanisms of action. However, evidence for their use in adolescents remains limited, with mixed or inconclusive results.

Curcumin and vitamin C are potent antioxidants and anti-inflammatory molecules. They may promote recovery from exercise, but chronic high-dose use could limit training adaptation. Conversely, omega-3 fatty acids are suitable for overall health and muscle protein synthesis, and their intake should be encouraged in all adolescents via two helpings of fatty fish per week. Supplements should be required only if fish intake is deficient.

The study suggests that specific bioactives may benefit post-training recovery, promote immune function, and enhance performance in young athletes. However, these benefits remain largely theoretical or based on limited data from small-scale or adult-based studies. Bioactive use should be part of a comprehensive dietary and nutritional program, and only under expert supervision.

Importantly, bodies like the International Society of Sports Nutrition (ISSN) acknowledge potential benefits of supplements like creatine in adolescents. However, current data is limited, and more rigorous studies are needed.

Unregulated and unsupervised supplement use could lead to their misuse, toxicity, and failing drug tests because of contamination with banned substances. Without individualized care, this could cause dependency, poor body image, and performance pressure, impairing the adolescent athlete’s mental and emotional well-being. This is especially difficult to justify in recreational sport settings.

Today, the need is to regulate supplement use by young athletes, raise awareness among the adolescent athlete’s family and coaches, and provide regular overall checkups. This will ensure that young athletes make informed decisions.

Future extensive, well-designed studies are critical to provide evidence of safety and efficacy before it is possible to routinely recommend ergogenic compounds, multivitamins, antioxidants, omega-3 fatty acids, and other anti-inflammatory or immunomodulatory agents like curcumin.

Conclusions

Some bioactives, like caffeine, may show promise in young athletes as health and performance-boosting substances, but there is little evidence to recommend their routine use in this group. Despite their growing use, more research is needed among children to ensure that performance-enhancing supplements used in this population are safe, effective, and appropriate for their unique needs.

“In this context, the role of a well-balanced, age-appropriate diet should always take priority over supplementation, particularly in growing individuals with unique physiological needs. Moreover, rather than focusing solely on isolated nutrients, interventions aimed at improving the overall dietary patterns of young athletes… may have greater long-term health and performance benefits, with fewer risks and side effects. “

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