VITAMIN D

          

               

         

               Vitamin D is a fat-soluble vitamin available from some

          foods, as well as from sunlight.

         

               Functions: Forms the hormone 1,

          25-dihydrocholecalciferol, which aids in the absorption and

          metabolism of calcium and phosphorus for bone and tooth

          formation.

         

               Sources: Sunlight (which stimulates vitamin D

          production in the skin), fatty fish, fish liver oils,

          vitamin D-fortified milk, egg yolk, and butter.

         

               Deficiency: In children, vitamin D deficiency causes

          rickets, a disease in which weak bones lead to bowlegs,

          knock-knees, and other bone deformities. The disease is

          rarely seen in the United States because milk and other

          foods are fortified with vitamin D and because children

          usually get some sun exposure. In the elderly, especially

          those in extended-care facilities, vitamin D deficiency has

          been associated with calcium loss from bones.

         

               Excess: High intakes may cause vomiting, diarrhea, and

          weight loss and lead to calcium deposits in various organs.

          Children are especially susceptible, but anyone can have

          adverse effects from high daily doses.