Vitamin D is crucial in the building and maintenance of healthy bones and teeth. Vitamin D deficiency is not uncommon, especially in the winter months, as people are not usually exposed to sunlight. Vitamin D is manufactured within the body when direct sunlight converts a chemical in your skin into an active form of the vitamin. Not a lot of foods contain Vitamin D, but you can get it from fortified mild, fortified cereals, and fatty fish like salmon, mackerel, and sardines.