Iron, Vitamins Linked to Teens' Fitness Levels

BETHESDA, MDEuropean researchers discovered a possible link between vitamins and adolescent physical fitness. In a newly released study in the Journal of Applied Physiology online edition, scientists found adolescents blood levels of various micronutrients are correlated with how well they performed in physical fitness tests (J Appl Physiol. 2012 Jun 21.).

The researchers studied European children ages 12 to 17. The adolescents performed a standing long jump test, which assesses lower-body muscular strength, and a 20-meter shuttle run test, which assesses cardiovascular fitness through maximal oxygen consumption (VO_2max). The scientists took blood samples from more than 1,000 of the participants, and looked for various micronutrients, including hemoglobin, indicative of iron intake, soluble transferrin receptor, serum ferritin, retinol, vitamin C, beta-carotene, alpha-tocopherol, vitamin B₆ and vitamin D.

The study found connections between physical fitness and micronutrients, particularly iron. In the shuttle run, concentrations of hemoglobin, retinol, and vitamin C in males and beta-carotene and vitamin D in females were associated with VO_2max. Similarly, better performance in the muscular fitness test pointed toward concentrations of hemoglobin, beta-carotene, retinol, and alpha-tocopherol in males and beta-carotene and vitamin D in females.

Iron's importance has long been touted. In July, a study published in the Canadian Medical Association found iron supplementation decreased fatigue in women who had ferritin levels below 50 µg/L. However, the Centers for Disease Control and Prevention released its Nutrition Report in April, indicating that the U.S. population has good levels of vitamins A and D, and folate in the body, but some groups still need to increase their levels of vitamin D and iron.