The term vitamin D covers a range of compounds including ergocalciferol (vitamin D2 ) and colecalciferol (vitamin D3 ). These two compounds are equipotent and either can be used to prevent and treat rickets.
Simple deficiency of vitamin D occurs in those who have an inadequate dietary intake or who fail to produce enough colecalciferol (vitamin D3 ) in their skin from the precursor 7-dehydrocholesterol in response to ultraviolet light.
Children with dark skin must continue vitamin D prophylaxis for up to 24 months because of their inability to produce enough vitamin D3 in their skin. Dark skin with a high melanin content must be exposed to daylight longer than light skin in order to obtain the same synthesis of vitamin D3 . Vitamin D is also used in deficiency states caused by intestinal malabsorption or chronic liver disease and for the hypocalcaemia of hypoparathyroidism.
Tags: dark skin, deficiency of vitamin d, hypocalcaemia, light skin, melanin, synthesis, vitamin d, vitamin d2, vitamin d3
