Dietary Supplement Intake and Factors Associated with Increased Use in Preadolescent Endurance Runners

The prevalence of dietary supplement intake among preadolescent endurance runners is currently unknown.

Our aim was to describe use of dietary supplements, higher-risk supplements, and sport foods among preadolescent endurance athletes and identify associated characteristics of dietary supplement users in this population.

This was a retrospective, cross-sectional study.

Participants were 2,113 preadolescent endurance runners (male: n = 1,255, female: n = 858; mean age ± standard deviation = 13.2 ± 0.9 years).

Use of dietary supplements, higher-risk dietary supplements, and sport foods on 2 or more days per week during the past year.

Mann-Whitney U tests, χ² tests, univariate and multivariate analyses.

Twenty-six percent (n = 551) of preadolescent runners used dietary supplements on 2 or more days per week during the past year; 1.3% (n = 27) reported taking higher-risk supplements. Compared with male runners, female runners reported higher use of 1 or more supplements (32.5% vs 21.7%; P < .001) and 4 or more supplements (4.0% vs 1.9%; P = 0.005), multivitamin/minerals (24.2% vs 14.4%; P < .001), vitamin D (12.4% vs 5.6%; P < .001), calcium (8.9% vs 4.8%; P < .001), iron (3.1 vs 1.1%; P < .001), probiotic supplements (8.2% vs 1.3%; P < .001), and diet pills (0.5% vs 0.0%; P = .02). Male runners reported higher use of creatine (1.3% vs 0.0%; P < .001) and sport foods, including protein bars and drinks (19.5% vs 8.4%; P < .001), energy bars (23.5% vs 9.7%; P < .001), and carbohydrate-electrolyte drinks (27.9% vs 13.3%; P < .001) than female runners. Factors independently associated with a higher likelihood for dietary supplement use included weight loss in the past year, female (vs male) gender, following a vegetarian diet, skipping meals, attempting to gain weight, and history of a running-related bone stress injury.

More than one-quarter of preadolescent runners regularly consumed dietary supplements. Behaviors consistent with dietary restriction and history of bone stress injury were associated with higher likelihood for supplement use. Further work to understand supplement use patterns and potential value for nutrition education is advised to optimize health of preadolescent runners.