Teenagers need Exercise & Sunshine: Vitamin D Supplements Recommended
The television commercials of tanned, active young men and women enjoying outdoors activities, especially the beach, effectively compel us to warmer climates during the winter months. When skies are cloudy, temperatures are cool, and conditions can be downright wet or cold, people yearn to feel the sun warming their bodies. It feels good. It is good because vitamin D supports bone and muscle health. Especially important for teenagers.
Because of the importance of skeletal growth during adolescences, Black and colleagues measured vitamin D status of Australian teenagers (1,045) at 14 and 17y of age. They report Caucasian ethnicity, summer, more frequent exercise, lower BMI, higher calcium intake, and higher family income were associated with significantly higher serum 25(OH)D3 concetrations. Unlike Hill and colleagues who found lower vitamin D status in girls, differences were not observed between males and females. Average vitamin D concentrations exceeded 75 nmol/L. Despite a warmer climate in Australia than Great Britain, Ireland or Canada (and better vitamin D status), 12% still had year-round serum 25(OH)D3 concentrations < 50 nmol/L.
The Institute of Medicine recommends 600 IU daily for 14-18y old adolescents. Cashman and colleagues conducted two randomized, placebo-controlled, double-blind, year-long intervention trials in 228 adolscent girls. Serum 25(OH)D3 concentrations increased linearly with vitamin D intake, 2.43 nmol/L per 40 IU vitamin D3 consumed daily. Or to paraphrase, the regression predicted it took 744 IU daily to be in the 97.5th percentile of having a serum 25(OH)D3 above 50 nmol/L.
Adolescence is the foundation for life. Bone and muscle development occurs during this period. Low vitamin D intake is associated with the risk of developing stress fractures in adolescent females.
Physical activity and diet are especially important for children and teenagers. For those not living in warm climates and spending time outdoors in the sunshine, vitamin D fortified foods and use dietary supplements are recommended.
Black LJ, Burrows SA, Jacoby P, Oddy WH, Beilin LJ, Ping-Delfos WCS, Marshall CE, Holt PG, Hart PH, Mon TA. Vitamin D status and predictors of serum 25-hydroxyvitamin D concentrations in western Australian adolescents. 2014 Br J Nutr doi: 10.1017/S000711451400186X
Hill TR, Cotter AA, Mitchell S, Boreham CA, Dubitzky W, Murray L, Flynn A, Robson PJ, Wallace JM, Kiely M, Cashman KD. Vitamin D status and its determinants in adolescents from the Northern Ireland Young Hearts 2000 Cohort. 2008 Br J Nutr 99:1061-7 doi: 10.1017/S0007114507842826
Cashman KD, FitzGerald AP, Viljakainen HT, Jakobsen J, Michaelsen KF, Lamberg-Allardt, Molgaard C. Estimation of the dietary requirement for vitamin D in healthy adolescent white girls. 2011 Am J Clin Nutr doi: 10.3945/ajcn.110.006577
Sonneville KR, Gordon CM, Kocher MS, Pierce LM, Ramappa A, Field AE. Vitamin D, calcium, and dairy intakes and stress fractures among female adolescents. 2012 Arch Pediatr Adolesc Med doi: 10.1001/archpediatrics.2012.5