Vitamin D toxicity, sometimes called a vitamin D overdose, is a rare but potentially dangerous condition. It occurs when someone has too much vitamin D in their body. Vitamin D toxicity is also called hypervitaminosis D.
A vitamin D overdose is typically a side effect of taking large doses of vitamin D supplements. It would not occur because of direct sun exposure or diet.
This article will cover the most common symptoms of too much vitamin D, who is at risk for a vitamin D overdose, rare symptoms, complications, and more.
Vitamin D is a nutrient the body needs for building healthy bones and maintaining bone health. The body cannot absorb calcium—a primary bone health component—without the help of vitamin D.
Vitamin D is naturally available in some foods, including fatty fish like salmon and mackerel, egg yolks, red meat, and liver. Fortified foods have vitamin D added and include fortified milk and cereals. You can also get vitamin D when direct sunlight converts chemicals in your skin into calciferol (active vitamin D).
The common types of vitamin D received from your diet are D2 (ergocalciferol) and D3 (cholecalciferol). They play the same role in the body but come from different sources. Vitamin D2 comes from plant sources, while vitamin D3 comes from animal sources. Vitamin D3 has been found to bind more effectively, making it a stronger source, which allows for lower doses with the same health benefits.
Some people are at a higher risk for a vitamin D deficiency (not having enough vitamin D in the body). They include:
- Those who cannot get outdoors (because they are frail or homebound)
- People living in care facilities (such as a skilled nursing facility) or in correctional facilities
- Those who wear clothing that covers their skin when they are outdoors
- People with dark skin tones
- People whose bodies do not adequately process vitamin D due to a health condition, such as chronic kidney disease or liver disease
Researchers suspect people with dark skin tones get less vitamin D because the higher level of melanin present in darker skin limits the rate of skin synthesis. This is when the top layer of your skin (epidermis) activates (synthesizes) vitamin D when exposed to the sun’s ultraviolet (UV) radiation.
