New research, published in the Journal of Applied Physiology, has found that adolescents’ blood levels of various micronutrients are correlated with their performance in physical fitness tests. Although the results don’t suggest any causes, they do show a new relationship between different measures of adolescent health.

Most people acquire healthy habits in their adolescence that they will carry through adulthood, for example, they start choosing foods high in vitamins and minerals and developing a regular exercise routine. According to recent studies, adolescents’ performance on standard physical fitness tests, as well as their intake of important nutrients, has decreased over the years.

The authors suggest that these findings could be related because physical fitness and nutrition are intertwined. For example, iron forms part of hemoglobin, which carries oxygen to muscles, and antioxidants like vitamin C help rebuild damager after a difficult training session.

Data that had been previously used in a larger, long-term research project called the Healthy Lifestyle in Europe by Nutrition in Adolescents Cross-Sectional Study, or HELENA-CSS, was also used by Luis Gracia-Marco of the University of Zaragoza, Spain and his team in this study.

Thousands of people all across Europe between the ages of 12.5 and 17.5 volunteered for this study, which gathered nutrition and physical data. In other to test for a variety of micronutrients, including retinol, vitamin C, beta-carotene, alpha-tocopherol, vitamin B6, cobalamin, serum ferritin, soluble transferrin receptor, holo-transcobalamin, plama folate, RCB folate, vitamin D, and hemoglobin.

A standing jump test was performed by the volunteers in order to test their lower-body muscular strength, and a 20 meter shuttle run test which tested their cardiovascular fitness through maximal oxygen consumption (VO2max). The age of the adolescents, time of year, body mass index, latitude of the city they lived in, age of menarche in females, and amount of physical activity were factors all taken into account while looking for connections between physical fitness and micronutrient levels.

Results showed:

  • For cardiorespiratory fitness, concentrations of retinol, vitamin C, and hemoglobin in males and vitamin D and beta-carotene in females was associated with VO2max.
  • For muscular fitness, concentrations of beta-carotene, region, hemoglobin, and alpha-tocopherol in males and vitamin D and beta-carotene in females was associated with a better performance on the standing long jump test.

According to the experts, studies trying to connect micronutrients, such as the the study they conducted, with physical fitness in any population has unfortunately been limited and controversial. This seems to be true for adolescents because it is always difficult to gather information on them. The authors said this is one of the first studies on this age group able to find a connection between micronutrients and physical fitness. They added that they had the strength of controlling the results for a complete set of relevant confounders. However, more research on the subject still needs to be done.

The researchers concluded:

“The associations between physical fitness and iron or vitamin status observed in this cross-sectional study in adolescents should be followed up by a study specifically designed to evaluate causal relationships.”

Written by Sarah Glynn