<P> Vitamin D is a group of fat - soluble secosteroids responsible for increasing intestinal absorption of calcium , magnesium , and phosphate , and multiple other biological effects . In humans , the most important compounds in this group are vitamin D ( also known as cholecalciferol ) and vitamin D ( ergocalciferol ) . Cholecalciferol and ergocalciferol can be ingested from the diet and from supplements . Only a few foods contain vitamin D . The major natural source of the vitamin is synthesis of cholecalciferol in the skin from cholesterol through a chemical reaction that is dependent on sun exposure ( specifically UVB radiation ) . Dietary recommendations typically assume that all of a person 's vitamin D is taken by mouth , as sun exposure in the population is variable and recommendations about the amount of sun exposure that is safe are uncertain in view of the skin cancer risk . </P>
<P> Vitamin D is a group of fat - soluble secosteroids responsible for increasing intestinal absorption of calcium , magnesium , and phosphate , and multiple other biological effects . In humans , the most important compounds in this group are vitamin D ( also known as cholecalciferol ) and vitamin D ( ergocalciferol ) . Cholecalciferol and ergocalciferol can be ingested from the diet and from supplements . Only a few foods contain vitamin D . The major natural source of the vitamin is synthesis of cholecalciferol in the skin from cholesterol through a chemical reaction that is dependent on sun exposure ( specifically UVB radiation ) . Dietary recommendations typically assume that all of a person 's vitamin D is taken by mouth , as sun exposure in the population is variable and recommendations about the amount of sun exposure that is safe are uncertain in view of the skin cancer risk . </P>
this vitamin may be synthesized as a result of sunlight exposure
this vitamin may be synthesized as a result of sunlight exposure
Vitamin D
Vitamin D