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Deficiency of vitamin D can over a period of months cause rickets in children and osteomalacia in adults - a skeletal demineralization especially in the spine, pelvis, and lower extremities. First, vitamin D is converted to 25-OH-D in the liver; it then enters the bloodstream, where it is taken-up by the kidneys. Therefore, the manufacture of 1,25-diOH-D requires the participation of various organs of the body - the liver, kidneys, and skin. These conditions include: living in northern countries; having dark skin; being elderly or an infant, and having little chance to go outside; and covering one's face and body, such as for religious reasons. Although fortified milk and fortified infant formula contain high levels of vitamin D, human breast milk is rather low in the vitamin. If the deficiency occurs for a period of many months or years, however, rickets or osteomalacia may develop. Bone growth occurs through the creation of new cartilage, a soft substance at the ends of bones. Seizures may also occasionally occur in a child with rickets, because of reduced levels of dissolved calcium in the bloodstream. Rickets is diagnosed by X-ray examination of leg bones.
Treatment & Prevention
Rickets and osteomalacia are almost always treated with oral supplements of vitamin D, with the recommendation to acquire daily exposure to direct sunlight. Attempts to acquire sunlight through glass windows fail to help the body make vitamin D. Vitamin D deficiency can be prevented by acquiring the RDA through consuming fortified products or taking supplements in the form of pills. In some older people, a 400 IU supplement may not be enough to result in the normal absorption of calcium; therefore, daily doses of 10,000 IU per day may be needed. For infants who are fed only breast milk (and rarely exposed to sunshine), a daily supplement of 200-300 IU is recommended. Vitamin D treatment results in the return of bone mineralization to a normal rate, the correction of low plasma calcium levels, the prevention of seizures, and a recovery from bone pain.
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