SEARCH Articles Figures Tables Dietary reference intake vitamin Niacin (vitamin Dietary Reference Intakes Reference Intakes of Vitamins Reference intakes Reference nutrient intakes for vitamin Vitamin A Requirements and Reference Intakes Vitamin B6 Requirements and Reference Intakes Vitamin C Requirements and Reference Intakes Vitamin D (cont reference intakes Vitamin K Requirements and Reference Intakes Vitamin Requirements and Reference Intakes Vitamin intakes