Doctors warn that “overdosing” on vitamin D supplements is both possible and harmful.
“Hypervitaminosis D” is on the rise and is associated with a wide range of potentially serious health problems.
Doctors are warning that “overdosing” on vitamin D supplements is both possible and harmful after treating a man who needed to be admitted to hospital because of his excessive vitamin D intake. They reported their concerns in the journal BMJ Case Reports.
They point out that “hypervitaminosis D,” as the condition is officially known, is on the rise and is associated with a wide variety of potentially serious health conditions.
This particular case concerns a middle-aged man who was referred to the hospital by his family physician after complaining of repeated vomiting, nausea, leg cramps, abdominal pain, increased thirst, dry mouth, tinnitus (ringing in ears), diarrhea and weight loss (28 lb or 12.7 kg).
Symptoms of hypervitaminosis D include drowsiness, depression, confusion, anorexia, apathy, psychosis, abdominal pain, stupor, coma, vomiting, peptic ulcers, constipation, pancreatitis, irregular heart rhythm, high blood pressure, and renal abnormalities, including renal failure.
These symptoms had been present for almost 3 months and started about 1 month after he started an intensive vitamin supplement regimen on the advice of a nutritionist.
The man had a variety of underlying health problems, including tuberculosis, bacterial meningitis, an inner ear tumor (left vestibular schwannoma) that resulted in deafness in that ear, fluid on the brain (hydrocephalus), and chronic sinusitis.
He was taking high doses of more than 20 over-the-counter supplements each day containing: vitamin D 50,000 mg – the daily requirement is 600 mg or 400 IU; vitamin K2 100 mg (daily requirement 100–300 µg); vitamin C, vitamin B9 (folate) 1000 mg (daily requirement 400 µg); vitamin B2 (riboflavin), vitamin B6, omega-3 2000 mg twice daily (daily requirement 200–500 mg), plus several other vitamin, mineral, nutritional and probiotic supplements.
After his symptoms developed, he stopped taking his daily cocktail of supplements, but his symptoms did not go away.
Blood tests ordered by his family doctor showed that he had extremely high calcium levels and slightly elevated magnesium levels. And the level of vitamin D was seven times higher than needed for sufficient.
Tests also revealed that his kidneys were not working properly (acute kidney injury). The results of various X-rays and scans to check for cancer were normal.
The man remained in the hospital for 8 days, during which time he was given intravenous fluids to flush his system and treated with bisphosphonates, drugs usually used to strengthen bones or lower excessive levels of calcium in the blood.
Two months after discharge from the hospital, his calcium level returned to normal, but his vitamin D level was still abnormally high.
“Globally, there is an increasing trend of hypervitaminosis D, a clinical condition characterized by elevated serum levels of vitamin D3,” with women, children and surgical patients most likely to be affected, the authors wrote.
Sources of Vitman D include oily fish, sunlight exposure, and supplements.
Recommended levels of vitamin D can be obtained from diet (consumption of wild mushrooms and oily fish), skin exposure to sunlight, and supplements.
“Given its slow turnover (half-life of approximately 2 months), during which vitamin D toxicity develops, symptoms may persist for several weeks,” the authors warn.
The symptoms of hypervitaminosis D are many and varied, they point out, and are mostly caused by excess calcium in the blood. These include confusion, somnolence, apathy, psychosis, anorexia, depression, coma, vomiting, abdominal pain, constipation, peptic ulcers, stupor, pancreatitis, abnormal heart rhythm, high blood pressure, and renal abnormalities, including renal failure.
Other associated features, such as keratopathy (an inflammatory eye disease), joint stiffness (arthralgia), and hearing loss or deafness, have also been reported, they added.
This is just one case, and although hypervitaminosis D is on the rise, it is still relatively uncommon, the authors caution.
However, complementary therapy, including the use of dietary supplements, is popular, and people may not realize that it is possible to overdose on vitamin D or its potential consequences, they say.
“This report further highlights the potential toxicity of supplements that are largely considered safe until taken in unsafe amounts or in dangerous combinations,” they conclude.
Reference: “Vitamin D intoxication and severe hypercalcemia complicating dietary supplement abuse” 5 July 2022, BMJ Case Reports.DOI: 10.1136/bcr-2022-250553
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