Most boys double their lean body mass between the ages of 10 and 17 years. Because growth and change is so rapid during this period, the requirements for all nutrients increase. This is especially true of calcium and iron. Adolescents need to take in at least 1200 mg of calcium per day during the adolescent growth spurt to build strong bones to last a lifetime. Some brands of orange juice are fortified with calcium.
Calcium is also available in dietary supplements.
Adequate calcium intake during adolescence results in fewer teenage broken bones. More importantly, it increases maximum bone density, reducing the risk for osteoporosis later in life, especially in postmenopausal women. People reach maximal bone density while they are adolescents or young adults and then gradually lose bone mineral for the rest of their lives. The more they start with, the more they will end up with. Most teens consume less than 1,000 mg of calcium per day.