“Overdose” of vitamin D supplements is possible and harmful, doctors warn BMJ Case Reports after treating a man who needed hospital admission for his excessive vitamin D intake.
“Hypervitaminosis D,” as it was previously known to the disease, is on the rise and is linked to a wide range of potentially serious health problems, they point out.
The case concerns a middle-aged man whose family doctor referred him to the hospital after complaining of recurrent vomiting, nausea, abdominal pain, cramps in the legs, tinnitus (also in the ear), dry mouth, increased thirst, diarrhea and weight loss. (28 pounds or 12.7 kg).
These symptoms had been around for almost 3 months and had started about a month after starting an intensive regimen of vitamin supplements on the advice of a nutritional therapist.
The man had had several health problems, including tuberculosis, a tumor of the inner ear (left vestibular schwannoma), which had caused deafness in this ear, an accumulation of fluid in the brain (hydrocephalus), bacterial meningitis and chronic sinusitis. .
He had been taking high doses of over 20 over-the-counter supplements each day that contained: 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 a day (daily need 200-500 mg), in addition to other supplements of vitamins, minerals, nutrients and probiotics.
Once the symptoms developed, she stopped taking her daily supplement cocktail, but her symptoms did not go away.
The results of the blood tests ordered by his family doctor revealed that he had very high calcium levels and slightly elevated magnesium levels. And his vitamin D level was 7 times higher than the level needed for sufficiency.
Tests also indicated that his kidneys were not functioning properly (acute kidney injury). The results of several x-rays and scans to check for cancer were normal.
The man remained in hospital for 8 days, during which he was given intravenous fluids to cleanse his system and treated with bisphosphonates, drugs commonly used to strengthen bones or reduce excessive levels of calcium in the blood.
Two months after being discharged from the hospital, his calcium level had returned to normal, but his vitamin D level was still abnormally high.
“Globally, there is a growing trend of hypervitaminosis D, a clinical condition characterized by elevated serum vitamin D3 levels,” with women, children, and surgical patients most likely to be affected, the authors write.
Recommended vitamin D levels can be obtained from diet (e.g., mushrooms, fatty fish), sunlight exposure, and supplements.
“Given its slow rotation (half-life of approximately 2 months), during which vitamin D toxicity develops, symptoms can last 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. They include drowsiness, confusion, apathy, psychosis, depression, stupor, coma, anorexia, abdominal pain, vomiting, constipation, peptic ulcers, pancreatitis, high blood pressure, abnormal heart rhythm, and kidney abnormalities, including kidney failure.
Other associated features have also been reported, such as keratopathy (inflammatory eye disease), joint stiffness (arthralgia), and hearing loss or deafness, they add.
This is only one case and, although hypervitaminosis D is on the rise, it is still relatively uncommon, the authors warn.
However, complementary therapy, including the use of dietary supplements, is popular and people may not realize that an overdose of vitamin D is possible or the possible 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.