Overdoing it on this popular supplement can lead to a host of serious health issues, which one man learned the hard way.
Per a study published in the journal BMJ Case Reports, the unidentified middle-aged man was admitted to the hospital with complaints of vomiting, nausea, abdominal pain, leg cramps, tinnitus, dry mouth, increased thirst, diarrhea and an inexplicable 28-pound weight loss.
After initial tests ruled out infection, it was found that the man’s body had accumulated toxic levels of vitamin D — a condition known as hypervitaminosis D.
According to the study authors, this case highlights a steady increase in overexposure to the sun-simulating supplement.
“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 report noted.
Vitamin D, which is found naturally in food and sunlight, helps the body absorb calcium, thereby fortifying the bones and teeth. It also boosts immune health, brain activity and muscular function.
However, too much vitamin D can cause hypercalcemia — an overabundance of calcium in the bloodstream — which can weaken bones, cause kidney stones and hinder heart and brain function.
In addition to the symptoms described in this case, the study authors note that the effects of hypercalcemia can manifest as drowsiness, confusion, apathy, psychosis, depression, stupor, coma, anorexia, constipation, peptic ulcers, pancreatitis, high blood pressure, abnormal heart rhythm and renal failure.
Other pathologies associated with hypervitaminosis D include inflammatory eye disease, joint stiffness and hearing loss or deafness.
In this case, the patient took more than 20 over-the-counter supplements after meeting with a private nutritionist. His regimen included 150,000 international units (IU) of vitamin D a day — over 200 times the recommended amount.
The National Institutes of Health recommends 600 IU of vitamin D per day for adults up to age 69 and 800 IU for adults age 70 and up.
Meanwhile, the CDC notes that there are “disagreements” about dosage but recommends 200 IU up to age 50, 400 IU for those 51 to 70 and 600 IU for people older than 70.
The patient in question reported that he had been experiencing his anguishing symptoms for nearly three months, noting that they began about a month after he started his vitamin protocol.
Although he ceased his supplementation as soon as symptoms developed, the man’s issues did not dissipate.
Study authors note that this timeline is consistent with vitamin D toxicity.
“Given its slow turnover (half-life of approximately two months), during which vitamin D toxicity develops, symptoms can last for several weeks,” they warned.
Blood tests revealed the man had extremely high levels of calcium, elevated levels of magnesium and vitamin D levels that were seven times higher than the recommended limit.
Further tests ruled out the possibility of cancer but showed that the patient’s kidneys were not functioning properly.
During his eight-day stay in the hospital, the man was given IV fluids to flush his system and treated with bisphosphonates to lower his calcium levels.
Two months after discharge, the patient’s calcium levels had normalized, but his vitamin D levels remained concerningly high because, unlike other vitamins, vitamin D is stored in the liver and fat cells and does not leave the system quickly.
While hypervitaminosis remains relatively rare, the study authors maintain that raising awareness of the risk is crucial for prevention.
“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 concluded.
