Use of Nutritional Strategies, Bioactive Compounds, and Dietary Supplements in Young Athletes: From Evidence to Potential Risks—A Narrative Review

TL;DR

This narrative review summarizes evidence on nutritional strategies, bioactive compounds, and dietary supplements in young athletes aged 8–20, finding some compounds promising for recovery, immune function, or performance but with limited pediatric-specific data. It concludes that current evidence is insufficient to support routine supplementation and emphasizes professional guidance, a balanced diet, and more youth-specific research.

Key findings

• The final synthesis included 21 studies: 6 clinical trials, 12 randomized controlled trials, and 3 systematic reviews/meta-analyses; 8 focused on recovery and muscle soreness, 6 on immune function or antioxidant/anti-inflammatory effects, and 7 on direct performance enhancement.
• Caffeine showed acute ergogenic effects in adolescents: 3–6 mg/kg improved anaerobic performance markers in elite adolescent athletes, low doses (1–3 mg/kg) had task-dependent effects, and 6 mg/kg improved anaerobic performance in highly trained male futsal players (15.9 ± 1.2 years); no side effects were reported in adolescent studies, though sample sizes were limited.
• Creatine studies in young athletes (ages 14.3–20), mostly swimmers and soccer players, generally used loading (20–30 g/day for 4–9 days) followed by maintenance (5 g/day) and showed improvements in sprint ability, muscular strength, power output, sport-specific skills, and repeated high-intensity efforts, with no reported side effects; long-term safety data remain limited.
• Other findings: a single 200,000 IU vitamin D3 mega-dose improved jumping, agility, and running speed in vitamin D-deficient young soccer players, while 2000 IU/day for 12 weeks in swimmers showed no significant difference; beetroot juice showed no significant VO2 max benefit in adolescent soccer players (mean ΔVO2 max 3.13 ± 2.76 vs 4.43 ± 3.47 mL/kg/min, p = 0.42); β-alanine 4.8 g/day for 5–6 weeks improved high-intensity performance in water polo athletes but muscle carnosine was not measured; curcumin 1200 mg/day for 12 weeks reduced muscle pain and fatigue in adolescent athletes, though methodological limitations prevented definitive conclusions.

Methods

• Narrative review of literature published from 1994 to 2024 in PubMed/Medline, Embase, and Scopus; inclusion criteria covered original research, randomized or non-randomized clinical trials, cohort or case-control studies, and meta-analyses involving pediatric/adolescent athletic populations aged 8–20 years and interventions using bioactive compounds or dietary supplements; preclinical and adult studies were included only for mechanistic or contextual purposes.
• Two independent reviewers screened titles and abstracts, reference lists were examined, and data were synthesized narratively around potential benefit, athlete age, and dosage/duration.
• The search initially retrieved 423 articles; after removing 76 duplicates, 347 were screened, 285 excluded, 62 full texts assessed, 41 excluded, leaving 21 studies in the final narrative synthesis.

Limitations

• The paper states that most available evidence derives from adult populations and pediatric-specific data remain limited; current evidence is insufficient to support routine use of bioactive compounds in young athletes, and concerns remain about supplement misuse, lack of professional guidance, and contamination with banned substances.
• The paper notes compound-specific limitations: creatine long-term safety in adolescents is limited, most safety data are self-reported, and studies often lack comprehensive laboratory assessments; β-alanine studies did not measure post-supplementation muscle carnosine; beetroot findings in adolescents are inconclusive; caffeine research is limited and mostly focused on males; curcumin evidence has methodological limitations; and the iron meta-analysis had poor methodological quality in most included interventions.
• Evident from the text: this is a narrative review without quantitative pooling, and the final 21 studies are few and heterogeneous, with many conclusions extrapolated from adult or preclinical data rather than directly demonstrated in young athletes.