OJ is tops because of the vitamins, folic acid, and phytochemicals -- plus, kids just love the taste. And if your little ones won't drink milk, calcium-fortified juice will help them meet their daily requirement. About four ounces a day is plenty, though. Drinking too much can pack on the calories.
Next-best choice: Grape juice, the purple kind, for its disease-fighting phytonutrients. But beware of juice blends. They're often simply sugary drinks with fruit flavor and little nutritional value. Check labels.
Picky-eater idea: Make a kiddie cocktail: Add seltzer to OJ, and garnish with a fun straw.