Vitamin D supplement 'overdosing' is possible and harmful, warn doctors

The results of blood tests ordered by his family doctor revealed that he had very high levels of calcium and slightly raised levels of magnesium. And his vitamin D level was 7 times over the level required for sufficiency. The man stayed in hospital for 8 days, during which time he was given intravenous fluids to flush out his system and treated with bisphosphonates-drugs that are normally used to strengthen bones or lower excessive levels of calcium in the blood. Two months after discharge from hospital, his calcium level had returned to normal, but his vitamin D level was still abnormally high.

Nevertheless, complementary therapy, including the use of dietary supplements, is popular, and people may not realise that it's possible to overdose on vitamin D, or the potential consequences of doing so, they say. This case report further highlights the potential toxicity of supplements that are largely considered safe until taken in unsafe amounts or in unsafe combinations, they conclude.

Reference: Vitamin D intoxication and severe hypercalcaemia complicating nutritional supplements misuse doi 10.1136/bcr-2022-250553; BMJ Case Reports.