vitamin D

vitamin D An oil-soluble steroid vitamin that promotes absorption and metabolism of calcium and phosphorus and that is essential for tooth and bone growth. Under normal conditions of sunlight exposure, no dietary supplementation is necessary because sunlight promotes adequate vitamin D synthesis in the skin. Vitamin D is added to many common dairy products and breads, and it can also be found in saltwater fish and egg yolks. Deficiency can lead to osteomalcia (softening of bone) in adults and bone deformity (rickets) in children. The daily adult requirement is 10 micrograms.