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.