Along with the other fat soluble vitamins A, E and K, vitamin D dissolves more easily in oil than in water. This gives vitamin D the duel identity as a fat-soluble vitamin and a hormone.
Vitamin D is required for the normal growth and development of bones and teeth in children.
Normal muscle contraction and nerve function is supported by vitamin D. Studies have shown possible anti-cancer properties, especially for myeloid leukemia, breast and colon cancers. Being exposed to sunlight for fifteen minutes, three times a week can provide adequate amounts of vitamin D. For the elderly or those in northern climates, not exposed to adequate sunlight, an intake of 400-800 I.U. daily is recommended. Vitamin D is fat soluble so excess amounts are stored by the body. Supplements containing more than 400 I.U. are generally not required and should not be taken unless ordered by a physician. Vitamin D should not be taken without calcium.