VITAMIN D

           

               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.