Iron, vitamins could affect physical fitness in adolescents

Adolescence is an important time not only for growing but for acquiring healthy habits that will last a lifetime, such as choosing foods rich in vitamins and minerals, and adopting a regular exercise regimen. Unfortunately, several studies have shown that adolescents' intake of important nutrients, as well as their performance on standard physical fitness tests, has fallen in recent years. Because nutrition and fitness are intertwined—for example, iron forms part of hemoglobin, which carries oxygen to muscles, and antioxidants such as vitamin C aid in rebuilding damage after intense training—these two findings could be related. In a new study, researchers have found that adolescents' blood levels of various micronutrients are correlated with how well they performed in certain physical fitness tests. Though these results don't prove causality, they suggest a new relationship between different measures of adolescent health.

The article is entitled "Iron and Vitamin Status Biomarkers and its Association with in Adolescents. The HELENA Study." and is online at http://bit.ly/Q2j6lJ. It appears in the online edition of the Journal of Applied Physiology, a publication of the American Physiological Society.

Researcher Luis Gracia-Marco of the University of Zaragoza, Spain and his colleagues relied on data from a larger, long-term research project known as the Healthy Lifestyle in Europe by in Adolescents Cross-Sectional Study, or HELENA-CSS. Part of this study, which involved thousands of volunteers between the ages of 12.5 and 17.5 in cities scattered across Europe, gathered nutrition and physical fitness data. Blood samples taken in one third of the volunteers (n=1089) were tested for a variety of micronutrients, including hemoglobin, indicative of iron intake, soluble transferrin receptor, serum ferritin, retinol, vitamin C, beta-carotene, alpha-tocopherol, vitamin B6, cobalamin, holo-transcobalamin, plasma folate, RCB folate and vitamin D. The volunteers' physical fitness was also assessed through 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 (VO2max). When looking for correlations between the micronutrient levels and physical fitness, they took into account the adolescents' age, time of year, latitude of the city they lived in, body mass index, age of menarche in females, and amount of regular physical activity (using accelerometers).

The researchers found that blood levels of certain micronutrients were intimately connected with the volunteers' performance on the physical fitness tests. For cardiorespiratory fitness, concentrations of hemoglobin, retinol, and vitamin C in males and beta-carotene and vitamin D in females was associated with VO2max. For muscular fitness, concentrations of hemoglobin, beta-carotene, retinol, and alpha-tocopherol in males and beta-carotene and vitamin D in females was associated with performing better on the standing long jump test.

The authors suggest that studies connecting micronutrients, such as the ones they measured, with physical fitness in any population has been controversial and limited. This is especially true for adolescents, a group that's often difficult to gather information on. This new study, they say, is one of the first to find connections between micronutrients and physical fitness in this age group, with the strength of controlling the results for a complete set of relevant confounders. Yet, they note that more research still needs to be done.

"The associations between physical fitness and iron or status observed in this cross-sectional study in should be followed up by a study specifically designed to evaluate causal relationships," the authors write.

Related Stories

Study points to health disparities in physical fitness

date Jun 04, 2011

An Indiana University study examining disparities in physical fitness levels between older adults who are patients of safety net community health centers (CHC) and those who are members of a medically affiliated fitness center ...

Fidgeting your way to fitness

date Jun 28, 2011

Walking to the photocopier and fidgeting at your desk are contributing more to your cardiorespiratory fitness than you might think.

Physically fit kids do better in school

date Jan 28, 2009

A new study in the Journal of School Health found that physically fit kids scored better on standardized math and English tests than their less fit peers.

Recommended for you

Increased morbidity, mortality in food system industries

date 4 hours ago

(HealthDay)—Occupational morbidity and mortality are elevated across food system industries compared with nonfood system industries, according to a study published online May 12 in the Journal of Occupational an ...

Three issues to consider before selecting EHR

date 5 hours ago

(HealthDay)—Work flow, features and functionality, and technical infrastructure should all be considered in advance of selecting an electronic heath record (EHR) system, according to an article published ...

Research letter: Indoor tanning rates drop among US adults

date 6 hours ago

Indoor tanning rates dropped among adults from 5.5 percent in 2010 to 4.2 percent in 2013, although an estimated 7.8 million women and 1.9 million men still engage in the practice, which has been linked to increased cancer ...

Stunting remains a challenge in South Africa

date 7 hours ago

Stunting remains stubbornly persistent in South Africa, despite economic growth, political and social transitions, and national nutritional programmes, says a Wits-led research team.

User comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.