Dietary Intakes and Supplement Use in Pre-Adolescent and Adolescent Canadian Athletes

TL;DR

In 168 Canadian athletes aged 11–18, median energy intakes ranged from 2159 kcal/day in 11–13-year-old females to 2905 kcal/day in 14–18-year-old males, with vitamin D and potassium below recommendations in all groups and iron, folate, and calcium below recommendations in older females. Supplement use was widespread (100% reported some use), but the authors conclude supplementation is generally unnecessary except possibly vitamin D and carbohydrates during long exercise sessions.

Key findings

• Median energy intake varied from 2159 kcal/day (1717–2437) in 11–13-year-old females to 2905 kcal/day (2291–3483) in 14–18-year-old males. Carbohydrate and protein intakes were 8.1 (6.1–10.5) and 2.4 (1.6–3.4) g/kg body weight in males 11–13 years; 5.7 (4.5–7.9) and 2.0 (1.4–2.6) in females 11–13 years; 5.3 (4.3–7.4) and 2.0 (1.5–2.4) in males 14–18 years; and 4.9 (4.4–6.2) and 1.7 (1.3–2.0) in females 14–18 years.
• Median vitamin D intakes were below the RDA and potassium was below the AI for all athlete groups. Females 14–18 years had intakes below the RDA for iron 91% (72–112), folate 89% (61–114), and calcium 84% (48–106). Sodium intakes exceeded the upper limit in 89% of males 11–13 years, 65% of females 11–13 years, 83% of males 14–18 years, and 69% of females 14–18 years.
• Multivitamin-multiminerals, vitamin C, vitamin D, sport bars, and protein powders were the most commonly consumed supplements on a regular basis. Protein powder use increased with age: regular use was 18% in 14–18-year-olds vs. 10% in 11–13-year-olds. No athletes reported regular energy drink use, but occasional use was 27% in 14–18-year-olds vs. 3% in 11–13-year-olds.

Methods

• Male (n = 84) and female (n = 103) athletes aged 11–18 years were recruited from Alberta through sporting communities and the public school system; “athlete” was defined as competing at the city level or higher and training ≥5 h per week. The FBQ was completed by 187 participants, but low-energy reporters were removed, leaving 168 analyzed.
• Participants completed an online 24-h food recall (Food Behaviour Questionnaire) and a dietary supplement questionnaire covering sport foods, vitamin/mineral supplements, fatty acid supplements, plant extracts, probiotics, and ergogenic aids. Nutrient intakes were compared with Dietary Reference Intakes by age/gender; supplement use was quantified as regular, occasional, or never.
• Analyses included Kruskal–Wallis with Dunn’s post-hoc tests, one-way ANOVA with Bonferroni post-hoc comparisons where data were normal, and Pearson’s Chi-squared tests with Cramer’s V; p < 0.05 was considered significant.

Limitations

• Stated: results are based on a single 24-h food recall; there was low reliability for a few dietary supplements (vitamin E, vitamin-enriched water, glutamine, sport drinks, recovery drinks, probiotics, sport gels/gummies, and caffeine pills); physical stages of maturation were not assessed; DRI recommendations are generalized and not specific to individuals or athletic pursuits; multiple comparisons at a 5% significance level mean up to 5% of results could be due to chance; and underreporting may still be present despite removing low-energy reporters.
• Evident: the supplement questionnaire was originally delivered face-to-face, and the electronic format had only fair to moderate agreement for some items; the 24-h recall did not include other sport foods and supplements (except sport drinks) because they could not be linked to the Canadian Nutrient File, so nutrient intakes from those products are not captured.
• Evident: the sample was recruited from one Canadian province and primarily included athletes competing at community/provincial levels, so findings may not generalize to other regions or elite young athletes.