This is a reader-friendly overview of Vitamin D. For more details, see our health professional fact sheet on Vitamin D. Show
For information on vitamin D and COVID-19, see Dietary Supplements in the Time of COVID-19. What is vitamin D and what does it do?Vitamin D is a nutrient you need for good health. It helps your body absorb calcium, one of the main building blocks for strong bones. Together with calcium, vitamin D helps protect you from developing osteoporosis, a disease that thins and weakens the bones and makes them more likely to break. Your body needs vitamin D for other functions too. Your muscles need it to move, and your nerves need it to carry messages between your brain and your body. Your immune system needs vitamin D to fight off invading bacteria and viruses. How much vitamin D do I need?The amount of vitamin D you need each day depends on your age. Average daily recommended amounts are listed below in micrograms (mcg) and International Units (IU): Life StageRecommended AmountBirth to 12 months10 mcg (400 IU)Children 1–13 years15 mcg (600 IU)Teens 14–18 years15 mcg (600 IU)Adults 19–70 years15 mcg (600 IU)Adults 71 years and older20 mcg (800 IU)Pregnant and breastfeeding teens and women15 mcg (600 IU)What foods provide vitamin D?Very few foods naturally contain vitamin D. Fortified foods provide most of the vitamin D in the diets of people in the United States. Check the Nutrition Facts label for the amount of vitamin D in a food or beverage.
Can I get vitamin D from the sun?Your body makes vitamin D when your bare skin is exposed to the sun. Most people get at least some vitamin D this way. However, clouds, smog, old age, and having dark-colored skin reduce the amount of vitamin D your skin makes. Also, your skin does not make vitamin D from sunlight through a window. Ultraviolet radiation from sunshine can cause skin cancer, so it’s important to limit how much time you spend in the sun. Although sunscreen limits vitamin D production, health experts recommend using sunscreen with a sun protection factor (SPF) of 15 or more when you’re out in the sun for more than a few minutes. What kinds of vitamin D dietary supplements are available?Vitamin D is found in multivitamin/multimineral supplements. It is also available in dietary supplements containing only vitamin D or vitamin D combined with a few other nutrients. The two forms of vitamin D in supplements are D2 (ergocalciferol) and D3 (cholecalciferol). Both forms increase vitamin D in your blood, but D3 might raise it higher and for longer than D2. Because vitamin D is fat-soluble, it is best absorbed when taken with a meal or snack that includes some fat. Am I getting enough vitamin D?Because you get vitamin D from food, sunshine, and dietary supplements, one way to know if you’re getting enough is a blood test that measures the amount of vitamin D in your blood. In the blood, a form of vitamin D known as 25-hydroxyvitamin D is measured in either nanomoles per liter (nmol/L) or nanograms per milliliter (ng/mL). One nmol/L is equal to 0.4 ng/mL. So, for example, 50 nmol/L is the same as 20 ng/mL.
In the United States, most people have adequate blood levels of vitamin D. However, almost one out of four people have vitamin D blood levels that are too low or inadequate for bone and overall health. Some people are more likely than others to have trouble getting enough vitamin D:
What happens if I don’t get enough vitamin D?In children, vitamin D deficiency causes rickets, a disease in which the bones become soft, weak, deformed, and painful. In teens and adults, vitamin D deficiency causes osteomalacia, a disorder that causes bone pain and muscle weakness. What are some effects of vitamin D on health?Scientists are studying vitamin D to better understand how it affects health. Here are several examples of what this research has shown: Bone health and osteoporosis Getting recommended amounts of vitamin D and calcium from foods (and supplements, if needed) will help maintain healthy bones and prevent osteoporosis. Taking vitamin D and calcium supplements slightly increases bone strength in older adults, but it’s not clear whether they reduce the risk of falling or breaking a bone. Cancer Clinical trials suggest that while vitamin D supplements (with or without calcium) may not affect your risk of getting cancer, they might slightly reduce your risk of dying from this disease. More research is needed to better understand the role that vitamin D plays in cancer prevention and cancer-related death. Heart disease Depression Multiple sclerosis Type 2 diabetes Weight loss Can vitamin D be harmful?Yes, getting too much vitamin D can be harmful. Very high levels of vitamin D in your blood (greater than 375 nmol/L or 150 ng/mL) can cause nausea, vomiting, muscle weakness, confusion, pain, loss of appetite, dehydration, excessive urination and thirst, and kidney stones. Extremely high levels of vitamin D can cause kidney failure, irregular heartbeat, and even death. High levels of vitamin D are almost always caused by consuming excessive amounts of vitamin D from dietary supplements. You cannot get too much vitamin D from sunshine because your skin limits the amount of vitamin D it makes. The daily upper limits for vitamin D include intakes from all sources—food, beverages, and supplements—and are listed below in micrograms (mcg) and international units (IU). However, your health care provider might recommend doses above these upper limits for a period of time to treat a vitamin D deficiency. AgesUpper LimitBirth to 6 months25 mcg (1,000 IU)Infants 7–12 months38 mcg (1,500 IU)Children 1–3 years63 mcg (2,500 IU)Children 4–8 years75 mcg (3,000 IU)Children 9–18 years100 mcg (4,000 IU)Adults 19 years and older100 mcg (4,000 IU)Pregnant and breastfeeding teens and women100 mcg (4,000 IU)Does vitamin D interact with medications or other dietary supplements?Yes, vitamin D supplements may interact with some medicines. Here are several examples:
Tell your doctor, pharmacist, and other health care providers about any dietary supplements and prescription or over-the-counter medicines you take. They can tell you if the dietary supplements might interact with your medicines. They can also explain whether the medicines you take might interfere with how your body absorbs or uses other nutrients. Vitamin D and healthful eatingPeople should get most of their nutrients from food and beverages, according to the federal government’s Dietary Guidelines for Americans. Foods contain vitamins, minerals, dietary fiber, and other components that benefit health. In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients (for example, during specific life stages such as pregnancy). For more information about building a healthy dietary pattern, see the Dietary Guidelines for Americans Where can I find out more about vitamin D?
DisclaimerThis fact sheet by the National Institutes of Health (NIH) Office of Dietary Supplements (ODS) provides information that should not take the place of medical advice. We encourage you to talk to your health care providers (doctor, registered dietitian, pharmacist, etc.) about your interest in, questions about, or use of dietary supplements and what may be best for your overall health. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice. What is the difference between vitamin D and vitamin D3?There are quite a few differences between vitamin D and vitamin D3, but the main difference between them is that vitamin D is a fat-soluble vitamin that regulates calcium and phosphorous levels in the body, whereas the vitamin D3 is the natural form of vitamin D produced by the body from sunlight.
Can you have too much vitamin D?In addition, taking a supplement that contains too much vitamin D can be toxic in rare cases. It can lead to hypercalcemia, a condition in which too much calcium builds up in the blood, potentially forming deposits in the arteries or soft tissues. It may also predispose people to painful kidney stones.
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