has role vitamin (molecular entity) fat-soluble vitamin (role) vitamin D vitamin D vitamer vitamins D MetaCyc:Vitamin-D vitamin Ds CHEBI:27300 Wikipedia:Vitamin_D chebi_ontology D vitamins vitamin D vitamers Any member of a group of fat-soluble hydroxy seco-steroids that exhibit biological activity against vitamin D deficiency. Vitamin D can be obtained from sun exposure, food and supplements and is biologically inactive and converted into the biologically active calcitriol via double hydroxylation in the body. vitamin d hydroxy seco-steroid food supplements, vitamin substances (ec)