After seeing a private nutritionist, the man began taking more than 20 over-the-counter supplements every day, including 50,000 international units (IU) of vitamin D three times a day. This is a dose hundreds of times higher than the standard dietary recommendations.
Within a month, the man began suffering from nausea, abdominal pain, diarrhea and repeated bouts of vomiting, along with leg cramps and ringing in the ears.
The man, whose name was not released, heard about the supplements from a radio talk show and contacted the nutritionist on the show afterward, said Dr. Alamin Alkundi, co-author of the report and an endocrinologist at William Harvey Hospital in East Kent in the U.K., who treated the man.
“Registration by the regulator is optional for UK dietitians and their title is not protected, so anyone can practice as a dietitian,” Alcundi said in an email.
Unlike water-soluble vitamins, which the body can easily eliminate, vitamin D and its cousins A, E, and K are stored in the body’s liver and fat cells until needed. Consuming more than the recommended daily dose can lead to toxic levels.
The man in the case was taking a daily dose of 150,000 IU of vitamin D, which is “375 times the recommended amount,” Alkundi said. The UK National Health Service generally recommends 400 IU of vitamin D per day for children over 1 year of age and adults.
The man stopped taking the supplements when his symptoms started, but his condition did not improve. By the time he was sent to the hospital two months later, he had lost 28 pounds (12.7 kg) and his kidneys were in trouble. Tests showed he had overdosed on vitamin D, a condition called hypervitaminosis D.
Recommended daily levels
The body needs vitamin D. The main job of the vitamin is to help the body absorb calcium from the intestines – in fact, the body cannot absorb calcium if vitamin D is not present. The vitamin also plays a role in immune health, brain cell activity and muscle function.
In the United States, 15 micrograms or 600 IU of vitamin D per day is recommended for adults up to age 69, according to the National Institutes of Health. For adults over the age of 70, the dose increases to 20 micrograms or 800 IU each day. The recommended amount for infants, children and adolescents was recently doubled by the American Academy of Pediatrics to 10 micrograms or 400 IU per day. A 2017 study found that 3% of Americans consume more than the tolerable upper limit of 4,000 IU per day for adults, putting themselves at risk of toxicity. About 18% took more than 1000 IU daily.
Too much vitamin D in the blood leads to hypercalcemia, which occurs when the level of calcium in your blood is above normal. The man in the BMJ study was diagnosed with hypercalcemia, which can weaken your bones, create kidney stones, and interfere with your heart and brain.
The man was hospitalized for eight days and treated with drugs to lower the calcium levels in his blood. A follow-up two months later found that his blood calcium levels had dropped to near normal. While the man’s vitamin D level also improved significantly, it was still high, Alkundi said.
“A plan was put in place to periodically monitor both parameters in the clinic to track the declining levels to normal levels. We had contact with him and he reported (feeling) much better, but he is not back to normal yet,” Alkundi said.
“He is very anxious for his story to be known to warn others,” Alcundi added.
Signs of excess vitamin D can include drowsiness, confusion, lethargy and depression, and in more severe cases it can lead to stupor and coma. The heart may be affected: Blood pressure may rise and the heart may begin to beat erratically. In severe cases, the kidneys can go into renal failure. Hearing and vision may be affected.
Where to get vitamin D
The body produces enough vitamin D when the skin is exposed to sunlight. In fact, going outside in a bathing suit for 10 to 15 minutes in the summer “will generate 10,000 to 20,000 IU of vitamin D3 in adults with fair skin pigmentation,” according to the AAP.
However, exposure to strong midday sunlight is not recommended due to the risk of skin cancer, so dermatologists and the AAP say it’s best to use sunscreen if you’re going to be exposed for an extended period of time. Sunscreens can reduce the body’s ability to process vitamin D.
Vitamin D supplementation may not be necessary for many children and teens, the AAP said, because many foods such as milk, eggs, cereal, and orange juice are often fortified with vitamin D. Infants should be given 400 IU of supplemental vitamin D daily, starting in the first few days of life and continuing until the baby is weaned onto vitamin D-fortified milk or formula, the AAP recommends.
If vitamin D supplements are being considered, daily levels of vitamin D obtained from food should be factored into the decision, experts caution. In addition to fortified foods, eggs, cheese, shiitake mushrooms, salmon, swordfish, tuna, rainbow trout, and beef liver contain vitamin D, as does cod liver oil.
Anyone concerned about their vitamin D levels should get them checked by a doctor, experts say.
“Patients are encouraged to seek the opinion of their general practitioners regarding any alternative therapy or over-the-counter medication they may be taking or wish to start,” Alkundi said.
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