disorders of nutrition
Vitamin D Deficiency
Causes ofVitamin DDeficiency
Vitamin Ddeficiency usually occurs in people who are not exposed to sunlight and who do not consume enoughvitamin Din their diet. Natural (unfortified) foods alone rarely provide enoughvitamin Dto prevent deficiency. Foods that are fortified withvitamin Dand supplements ofvitamin Dcan help prevent deficiency when exposure to sunlight is inadequate. The most common cause ofvitamin Ddeficiency is Inadequate exposure to sunlight Thus,vitamin Ddeficiency occurs mainly among people who do not spend much time outdoors: older people and people who live in an institution such as a nursing home. The deficiency can also occur in the winter at northern and southern latitudes or in people who keep their bodies covered, such as Muslim women. Because breast milk contains only small amounts ofvitamin D, breastfed infants who are not exposed to enough sunlight are at risk of the deficiency and rickets. Some experts recommend that the arms and legs or the face, arms, and hands should be exposed to direct sunlight for 5 to 15 minutes at least 3 times a week, but some people, such as those who have darker skin or are older, may need more exposure to sunlight. However, many dermatologists do not recommend increased sunlight exposure because risk of skin cancer is increased. When the skin is exposed to enough sunlight, the body usually forms enoughvitamin D. However, certain circumstances increase the risk ofvitamin Ddeficiency even when there is exposure to sunlight: The skin forms lessvitamin Din response to sunlight in certain groups of people. They include people with darker skin, older people, and people who use sunscreen. from foods. In Overview of Malabsorption , people cannot absorb fats normally. They also cannot absorb to an active form. Certain kidney and liver disorders and several rare hereditary disorders (such as Hypophosphatemic Rickets ) interfere with this conversion, as do certain drugs, such as some antiseizure drugs and 