(CNN) — A British man’s vitamin D overdose is a warning to people considering adding vitamin supplements to their lives, according to an article published Tuesday in the journal BMJ Case Reports.
After a visit to 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. That’s a dose hundreds of times higher than standard nutritional recommendations.
Within a month, the man began to experience nausea, abdominal pain, diarrhea and repeated bouts of vomiting, as well as leg cramps and ringing in his ears.
The man, whose name was not released, learned about the supplements on a radio talk show and then contacted the show’s nutritionist, said Dr. Alamin Alkundi, a co-author of the report and an endocrinologist at William Harvey Hospital in East Kent. in the UK, who treated the man.
“Regulatory registration is not compulsory for nutritionists in the UK and their title is not protected, so anyone can practice as a nutritionist,” Alkundi said in an email.
Unlike water-soluble vitamins, which can be easily eliminated by the body, vitamin D and its cousins, vitamins A, E and K are stored in the body’s liver and fat cells until needed. Consumption well above the RDA can build up to toxic levels.
The man in the case study was taking a daily dose of 150,000 IU of vitamin D, which was “375 times the recommended amount,” Alkundi said. The UK National Health Service typically recommends 400 IU of vitamin D daily for children over 1 year of age and adults.
The man stopped taking the supplements when his symptoms began, but his condition did not improve. When he was referred to the hospital two months later, he had lost nearly 30 pounds and his kidneys were in trouble. Tests showed that he had overdosed on vitamin D, a condition called hypervitaminosis D.
Recommended daily levels of vitamin D
The body needs vitamin D. The vitamin’s main job is to help the body absorb calcium from the intestines; in fact, the body cannot absorb calcium unless vitamin D is present. Vitamin D 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 70 years of age and older, the dose is increased to 20 micrograms or 800 IU per day. The recommended amount for infants, children and adolescents was recently doubled by the American Academy of Pediatrics (AAP) is 10 micrograms or 400 IU per day.
A 2017 study found that 3% of Americans took more than the tolerable upper limit of 4,000 IU daily for adults, putting them at risk for toxicity. Approximately 18% took more than 1,000 IU per day.
Too much vitamin D in the blood causes hypercalcemia, which occurs when the level of calcium in the blood is above normal. The man in the BMJ case study was diagnosed with hypercalcemia, which can weaken bones, create kidney stones, and interfere with heart and brain function.
The man was hospitalized for eight days and was treated with medication 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 had also improved significantly, it was still high, Alkundi said.
“A plan was put in place to periodically monitor both parameters at the clinic to track declining levels to normal levels. We had contact with him and he reported (feeling) much better, but still not back to normal,” Alkundi said.
“He is very keen for his story to be known to alert others,” added Alkundi.
Signs of too much vitamin D can include drowsiness, confusion, lethargy and depression, and in more severe cases can lead to stupor and coma. The heart may be affected: blood pressure may rise and the heart may begin to beat irregularly. In severe cases, the kidneys can go into renal failure. Hearing and vision may be affected.
Where to get vitamin D naturally?
The body makes enough vitamin D when the skin is exposed to sunlight. In fact, going out in a bathing suit for 10 to 15 minutes during the summer “will generate 10,000 to 20,000 IU of vitamin D3 in adults with light skin pigmentation,” according to the AAP.
However, exposure to strong midday sunlight isn’t recommended because of the risk of skin cancer, so dermatologists and the AAP say it’s best to wear sunscreen if you’ll be out for an extended period of time. Sunscreens can reduce the body’s ability to process vitamin D.
Many children and teens may not need vitamin D supplements, the AAP said, since many foods such as milk, eggs, cereal and orange juice are often fortified with vitamin D. Babies should be given give 400 IU of supplemental vitamin D daily, starting in the first days of life and continuing until the baby is weaned to vitamin D-fortified milk or formula, the AAP advised.
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 be evaluated by a doctor, experts say.
“Patients are encouraged to seek the opinion of their general practitioners regarding any alternative therapies or over-the-counter medications they may be taking or wish to start,” Alkundi said.