Calciferols

vitamins of the D group, closely related to sterols in chemical structure.

Calciferols are found in the form of ergocalciferol (vitamin D₂) and cholecalciferol (vitamin D₃), which are produced by the irradiation with ultraviolet rays of ergosterol and dehydro-cholesterol, respectively. Ergocalciferol has been found in very small quantities in plant products. Cholecalciferol is contained chiefly in products of animal origin (cheese, butter, egg yolk, beef liver, cod and halibut livers, herring, salmon, tuna). Calciferols regulate calcium and phosphorus metabolism in the body.