title: Difficulties with vitamin D nutrition research: objective targets of adequacy, and assays for 25-hydroxyvitamin D.
authors.forename: R
authors.initials: R
authors.lastname: Vieth
authors.forename: G
authors.initials: G
authors.lastname: Carter
mesh_terms: D006801:Humans; D018673:Nutrition Policy; D009751:Nutritional Requirements; D014481:United States; D014807:Vitamin D / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000097:blood*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D