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.