Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body.
Vitamin D toxicity is usually caused by large doses of vitamin D supplements — not by diet or sun exposure. That's because your body regulates the amount of vitamin D produced by sun exposure, and even fortified foods don't contain large amounts of vitamin D.
The main consequence of vitamin D toxicity is a buildup of calcium in your blood (hypercalcemia), which can cause nausea and vomiting, weakness, and frequent urination. Vitamin D toxicity might progress to bone pain and kidney problems, such as the formation of calcium stones.
Treatment includes stopping vitamin D intake and restricting dietary calcium. Your doctor might also prescribe intravenous fluids and medications, such as corticosteroids or bisphosphonates.
Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity. This level is many times higher than the U.S. Recommended Dietary Allowance (RDA) for most adults of 600 IU of vitamin D a day.
Doses higher than the RDA are sometimes used to treat medical problems such as vitamin D deficiency, but these are given only under the care of a doctor for a specified time frame. Blood levels should be monitored while someone is taking high doses of vitamin D.
As always, talk to your doctor before taking vitamin and mineral supplements.
April 17, 2020
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- Vitamin D. Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/. Accessed March 20, 2020.
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- Vitamin D. Natural Medicines. https://naturalmedicines.therapeuticresearch.com. Accessed March 20, 2020.
- Marcinowska-Suchowierska E, et al. Vitamin D toxicity — A clinical perspective. Frontiers in Endocrinology. 2018; doi:10.3389/fendo.2018.00550.