Assistant professor of nutritional sciences, Sibylle Kranz, claims that "While there is calcium in fortified orange juice, it is not as bioavailable as that found in milk." She also adds that "Although the recommendations are all for low fat dairy, people are still consuming great amounts of whole fat dairy products."
Researchers found that 43 to 51 percent of dairy consumed by younger children was from whole fat sources and only 5 to 11 percent were from non-fat dairy. Older children consumed 35 to 36 percent from whole-fat dairy and 11 to 13 percent from non-fat dairy foods.
Researchers believe the additional calories found in whole-fat versus reduced-fat dairy products can add to the current problems of childhood obesity. A cup of milk provides 250 to 300 milligrams of calcium and 32 percent of the calcium is bioactive and used by the body. Soy milk and fortified orange juice at 300 milligrams of calcium are only about 25 percent available.
Dairy products are the best sources of calcium for children, but Kranz notes that low fat-dairy like yogurt, milk, and cheese should be emphasized. She suggests that non-fat, non-sugared flavored milk products with a little cocoa powder or blended fruits could be one way to introduce a calcium rich, low-fat dairy source to children.