Medical experts explain how much vitamin D you should be taking per day, the differences between vitamin D2 and D3, and how much vitamin D is too much. Vitamin D deficiency means that you don’t have enough vitamin D in your body. It's common and primarily causes issues with your bones and muscles. Learn how to spot vitamin D deficiency symptoms, what foods are high in vitamin D, how much to take daily, and whether D2 or D3 is best for you. Learn more about Vitamin D uses, effectiveness, possible side effects, interactions, dosage, user ratings and products that contain Vitamin D. Vitamin D3 helps your body absorb calcium, which is essential for healthy bones. Direct sunlight, foods like fatty fish and fortified dairy, and supplements are good sources of Vitamin D3 A doctor. Vitamin D overview for health professionals. Research health effects, dosing, sources, deficiency symptoms, side effects, and interactions here. Overt vitamin D deficiency, characterized by hypocalcemia and/or hypophosphatemia and rickets and osteomalacia in children and osteomalacia in adults, is now uncommon in most developed countries (see Epidemiology and etiology of osteomalacia and Clinical manifestations, diagnosis, and treatment of osteomalacia in adults ). Vitamin D is a group of structurally related, fat-soluble compounds responsible for increasing intestinal absorption of calcium and phosphate, along with numerous other biological functions. [1][2] In humans, the most important compounds within this group are vitamin D 3 (cholecalciferol) and vitamin D 2 (ergocalciferol). [2][3] Vitamin D is an essential micronutrient that's an important part of a healthy diet. Learn what types of foods are rich in vitamin D. Vitamin D is a nutrient the body needs, along with calcium, to build bones and keep them healthy. The body can absorb calcium only if it has enough vitamin D. Calcium is a major part of bones. Vitamin D also has many other uses in the body. It supports immune health and helps keep muscles and brain cells working.