Taking too much vitamin D can lead to a rare but serious condition called vitamin D toxicity or hypervitaminosis D. The main consequence is elevated calcium levels in the blood (hypercalcemia), which can cause symptoms such as nausea, vomiting, poor appetite, fatigue, dizziness, confusion, increased thirst, and frequent urination. Severe toxicity can result in kidney damage or failure, irregular heartbeats, bone pain, and in extreme cases, coma or death. Vitamin D toxicity usually occurs after taking very high doses of supplements over a long period and is unlikely from diet or sun exposure alone. Treatment involves stopping vitamin D intake and managing calcium levels under medical supervision.
Main Symptoms of Excess Vitamin D
- Nausea, vomiting, and stomach pain
- Loss of appetite and weight loss
- Fatigue, dizziness, confusion, or altered mental state
- Increased thirst and frequent urination
- Constipation or diarrhea
Serious Complications
- Hypercalcemia leading to calcium deposits in soft tissues (kidneys, arteries)
- Kidney damage or kidney failure
- Irregular heart rhythm
- Bone pain and increased fracture risk
- In extreme cases, psychosis, coma, or death
Causes and Risk Factors
- Taking very high doses of vitamin D supplements, often well above recommended levels (e.g., over 10,000 IU daily for several months)
- Supplement dosing errors or mislabeled products
- Long-term use of high-dose vitamin D without medical monitoring
If taking vitamin D supplements, it is important to follow recommended dosages and consult a healthcare provider for appropriate monitoring to prevent toxicity.
