Exposure to sunlight provides the best source of vitamin D. During most seasons, 10 to 15 minutes of exposure to the sun near midday is enough. However, if you're dark-skinned, if it's winter or if you live in northern latitudes, you might not be able to get enough vitamin D from sun exposure. In addition, because of skin cancer concerns, infants and young children, especially, are warned to avoid direct sun or to always wear sunscreen and protective clothing. To prevent rickets, make sure your child eats foods that contain vitamin D naturally — fatty fish such as salmon and tuna, fish oil and egg yolks — or that have been fortified with vitamin D, such as: Infant formula Cereal Bread Milk, but not foods made from milk, such as some yogurts and cheese Orange juice Check labels to determine the vitamin D content of fortified foods. If you're pregnant, ask your doctor about taking vitamin D supplements. Guidelines recommend that all infants should receive 400 IU a day of vitamin D. Because human milk contains only a small amount of vitamin D, infants who are exclusively breast-fed should receive supplemental vitamin D daily. Some bottle-fed infants may also need vitamin D supplements if they aren't receiving enough from their formula.