There are 206 bones in the human body and the skeleton comprises 20 percent of total body weight. The human skeleton is strong yet light, and almost perfectly adapted for the movement, protection and manipulative functions it performs. Maintaining strong, healthy bones can be accomplished by getting the recommended amount of bone-building nutrients--including calcium and vitamin D, being physically active and maintaining body weight in a healthy range.
Fracture incidence has increased by 32 percent in boys and 56 percent in girls in the last generation.1 This is likely due to the increase in childhood obesity, replacing milk with other beverages such as soda and juice and decreasing levels of physical activity.
During the teenage and young-adult years, it is important to achieve the highest peak bone mass (PBM) possible to reduce the likelihood of breaking a bone and developing osteoporosis later in life. PBM is attained by 30 years of age, however, 40 percent of total lifetime bone mass is accumulated just during adolescence.2
Physical activity is also key to bone health. Weight-bearing activities such as jogging, walking and dancing are specifically good for bone health. Teens can assess their level of physical activity by completing the Teen BEAT, Basic Exercise & Activity Tracker.
Overweight children break more bones than normal-weight children,3 and children who break a bone at an early age have more future broken bones. Body weight may contribute to fracture risk by placing extra burden on bones during falls. Overweight children also often lack the recommended levels of physical activity.
Dietary calcium, a key nutrient in milk, has been shown to be a major factor associated with fracture risk. A multitude of studies has shown that increasing dairy or calcium intakes during childhood and adolescence enhances bone health at various skeletal sites,4 particularly in those populations with low calcium intakes.5
Unfortunately, dietary intake surveys repeatedly show that many children fail to meet the dietary recommendations for calcium. Nine out of 10 girls and 6 out of 10 boys aged 12-19 do not consume adequate calcium in their diet.6
Most of the calcium in our diets--about two-thirds--comes from milk and milk foods. Various studies show that consuming milk foods throughout childhood and adolescence improves bone density--the biggest predictor of fractures. Children who consume three cups of milk and dairy foods daily and are physically active for one hour on most days are likely to maintain strong bones and good health.7
Take the Calcium Quiz to see if you are getting enough calcium in your diet.
Vitamin D is often referred to as the "sunshine" vitamin because our bodies can make it when our skin is exposed to the sun. About 10 to 15 minutes of sun exposure per day on our face, hands and arms—without sunscreen—is enough to meet our needs. Vitamin D is essential to bone health because it helps with absorption of calcium. Deficiency in vitamin D in children can cause rickets and in older adults could cause muscle weakness and falls.
Read more about vitamin D here: Vitamin D: What You Need to Know About the Sunshine Vitamin.
Khosla S et al. JAMA 2003;17;290(11):1479-85.
Greer FR, Krebs NF and Committee on Nutrition. Pediatrics 2006;117:578-585.
Goulding A et al. J Bone Miner Res 2005;20(12):2090-6.
Miller GD, Jarvis JK, McBean LD. Handbook of dairy foods and nutrition, 3rd ed. CRC Press, 2007.
Wosje KS, Specker BL. Nutr Rev 2000;58:253.
What We Eat in America. NHANES 2005-06. USDA, ARS.
Dietary Guidelines for Americans 2010, 7th ed. 2010: healthierus.gov/dietaryguidelines