Calcium helps bones grow longer and stronger. It is also essential for nerve conduction, muscle contraction and blood clotting. Stored in the bones and teeth, calcium is the most abundant mineral in your child's body, but the body can't manufacture calcium. So your child's daily requirement of this vital mineral must come from food, beverages, diet supplements or other external sources. About half of all American children don't get the calcium they need to build strong bones¹. That's why it's so important to make sure your child gets at least two to three servings of calcium-rich foods daily. The recommended daily allowance for calcium is 800 mg for children four to eight years old, and jumps to 1,300 mg after a child's ninth birthday. Calcium and vitamin D work hand-in-hand to help build strong bones. Vitamin D's primary role in the body is to aid calcium absorption from the small intestine into the bloodstream. Calcium then travels through the bloodstream to the bones to help them grow. Your child gets vitamin D from two sources — sunlight and diet. The skin manufactures vitamin D after exposure to the sun. However, several factors lessen the skin's production of vitamin D, including using sunscreen² and limiting the amount of time your child spends in the sun. If you live in the northern third of the United States (north of cities such as Salt Lake City, Denver, Indianapolis and Philadelphia), the winter sunlight is not strong enough for vitamin D production during the winter months. That is why it's important to get additional vitamin D from the diet. *USDA Continuing Survey of Food Intakes by Individuals, 1994-96. Table 3. - Nutrient Intakes: Percentages of individuals with diets meeting 100% of the 1989 Recommended Dietary Allowances (RDAs), by sex and age, 2-day average, 1994-6. ²Institute of Medicine. Dietary Reference Intakes. Calcium, Phosphorus, Magnesium, Vitamin D and Fluoride. Washington, D.C.: National Academy Press, 1997.