From the Guidelines
Vitamin D toxicity, also known as hypervitaminosis D, typically occurs when blood levels exceed 200 ng/mL, and common symptoms include nausea, vomiting, poor appetite, constipation, weakness, and weight loss, as well as more serious manifestations such as kidney problems and hypercalcemia 1. The condition is usually caused by excessive supplement intake, rather than sun exposure or food sources alone, as the body regulates naturally produced vitamin D. Some of the key symptoms of vitamin D toxicity include:
- Nausea and vomiting
- Poor appetite
- Constipation
- Weakness
- Weight loss
- Kidney problems, such as increased urination, kidney stones, and kidney damage
- Bone pain
- Calcium deposits in soft tissues
- Mental symptoms, such as confusion, disorientation, and difficulty concentrating It is essential to note that vitamin D toxicity can be prevented by avoiding excessive supplement intake and monitoring blood levels regularly. If vitamin D toxicity is suspected, it is crucial to stop supplementation immediately and seek medical attention, as treatment may require intravenous fluids, corticosteroids, or medications to lower blood calcium levels 1.
From the Research
Common Symptoms of Vitamin D Toxicity
The common symptoms of vitamin D toxicity include:
- Confusion
- Apathy
- Recurrent vomiting
- Abdominal pain
- Polyuria
- Polydipsia
- Dehydration 2
- Hypercalcemia, which can lead to acute renal failure 3, 4
- Hypervitaminosis A, which can be unrelated to diet and possibly caused by renal failure related to hypercalcemia induced by vitamin D toxicity 3
Laboratory Findings
Laboratory testing may reveal:
- Asymptomatic hypercalcemia caused by the intake of vitamin D, even in doses recommended for the general population and considered safe 2
- Elevated serum 25-hydroxyvitamin D [25(OH)D] concentrations, with levels higher than 150 ng/ml (375 nmol/l) being the hallmark of vitamin D toxicity due to vitamin D overdosing 2
- Elevated levels of 25(OH)D do not strongly correlate with clinical symptoms or total serum/plasma calcium levels 5
Risk Factors
The risk of vitamin D toxicity may be increased by:
- Self-administration of vitamin D in doses higher than recommended for age and body weight or even higher than the established upper limit intake values 2
- Inadvertent or improper intake of extremely high doses of pharmacological preparations of vitamin D 2
- Excessive production of an active vitamin D metabolite in granulomatous disorders, lymphomas, or congenital disorders such as Williams-Beuren syndrome 2
- Increased use of over-the-counter vitamin D supplements 3, 4, 6