vitamin D softgels pouring out of bottle with sun shining
Sarah Biren
Sarah Biren
April 16, 2024 ·  5 min read

Doctors Warn of Vitamin D Supplement “Overdosing” – Man Hospitalized After Losing 28 Pounds

A middle-aged man in the United Kingdom was hospitalized after months of nausea, vomiting, and abdominal pain. He had also lost 28 pounds (12.7 kilograms) during that time. The symptoms had begun one month after the man started an extensive vitamin regimen recommended by a private nutritionist. According to the case study published in the British Medical Journal, the man was taking a shockingly high amount of vitamin D. Although the vitamin is crucial for wellbeing, it is possible to over-supplement and cause toxicity.

Man Hospitalized After “Overdosing” on Supplements

The man’s supplement regimen included daily doses of 150,000 international units (IU) of vitamin D. This is considerably higher than the daily 600 IU recommendation from Mayo Clinic. Additionally, he was taking 20 other supplements, which included over the recommended amount of folate, vitamin K2, and omega-3. The doctors found high serum creatinine levels, a waste product normally removed from the body, indicating that his kidneys were affected and contributing to his symptoms, including tinnitus, leg cramps, dry mouth, and increased thirst.

The man also had other health issues, including tuberculosis, chronic sinusitis, bacterial meningitis, hydrocephalus, and an inner ear tumor that caused deafness in that ear. When the symptoms arose, the man stopped taking the supplements, but the symptoms persisted. Blood tests ordered by his family doctor showed very high levels of calcium and vitamin D levels seven times higher than the average healthy amount. The man recovered for eight days in the hospital while being re-hydrated through intravenous fluids while his kidneys healed. [1]

A common misconception with dietary supplements, including vitamin D, is that if some is good, then taking more is better,” says Shelby Yaceczko, an advanced practice clinical dietitian at the Center for Human Nutrition at the University of California, Los Angeles. “Unfortunately, that is not the case and although it’s important to maintain normal vitamin levels, it’s also very important to avoid taking higher doses than what is considered safe.” [2]

Read: Which Form of Supplemental Magnesium Should You Take?

Vitamin D Toxicity

According to Yaceczko, “overdosing” on vitamin D can cause symptoms like constipation, bone pain, vomiting, fatigue, and abnormal heart rhythm. To avoid this, routine blood tests are needed to find and correct nutritional deficiencies. Without any monitoring, taking high quantities of supplements can become risky. (The case study didn’t explicitly state whether the man took routine blood tests.)

However, Dr. Heather Tick, a clinical professor of family medicine and professor of integrative pain medicine at the University of Washington in Seattle, questions the case study. “Everything he was on — it was a lot of stuff,” she said. But “usually you need to be taking high doses of vitamin D for much longer, not just a month,” before experiencing symptoms of toxicity.  Similarly, Yaceczko indicates that “vitamin D toxicity can happen between 1 [to] 4 months depending on several factors as well as the mega-dose quantity the individual is taking.”

Therefore, Tick speculates on the possibility that the man had an underlying health condition that made him amass vitamin D and cause toxicity more quickly. “A case study is like putting together pieces of a puzzle, where some of the pieces are missing,” Tick said. For instance, the authors did not specify the type of vitamin D the patient was taking. Vitamin D2 and D3 accumulate differently in the body, and knowing this detail could shed more light on the patient’s condition. “More investigation was warranted — possibly by a rheumatologist or endocrinologist,” Tick said. “It is difficult to know how all the factors intersect. The picture is not totally clear from the available information.”

Should You Take Vitamin D Supplements?

Despite this worrying report, it’s important to remember that vitamin D is a vital nutrient and should be supplemented when needed. In fact, people are commonly deficient. Problems arise when people ingest more than recommended without any medical supervision. You don’t have to worry about overdosing if you rely on food and sunshine for your daily dose of vitamin D. But supplements can pose a potential risk, albeit the risk is extremely low at recommended doses. Vitamin D is fat-soluble, which means it accumulates in the body instead of passing through quickly. But to cause vitamin D toxicity, people would have to take doses over 10,000 IU a day over an extended period. Ideally, people should not consume more than 4,000 IU per day. [3]

Most people who take a vitamin D supplement don’t need more than 600 or 800 IU a day; although some health conditions do require higher doses. It’s always better to get vitamin D from food sources instead of supplements, like fortified dairy products, fatty fish, eggs, and wild mushrooms. People with a well-balanced diet may not need any supplementation. However, people at risk of a deficiency include those over 65 years of age, have a darker complexion, are obese, live in a dark or wintery climate, have health conditions that interfere with vitamin absorption, or have diets that exclude vitamin D-rich foods (like vegans or people with dairy allergies)

If you suspect you have a deficiency, talk to your doctor about getting a blood test. Additionally, if you take vitamin D supplements, disclose that to health professionals; they could interact with certain medications and underlying health conditions. [4]

A note on nutritionists:

It’s also important to note the difference between dieticians and nutritionists. In the United States, dieticians must have certification from the Academy of Nutrition and Dietetics. However, certification for nutritionists varies. In fact, some states do not require nutritionists to have any certificate, so it’s possible for anyone to give untrained and unregulated nutrition advice. Always check qualifications and experience before working with nutritionists, nutrition coaches, health coaches, and fitness instructors. [5] For more information on vitamin D, visit the NIH website.

Keep Reading: Signs of Vitamin B-12 Deficiency You Should Never Ignore


  1. “Vitamin D intoxication and severe hypercalcaemia complicating nutritional supplements misuse.BMJ Journals. Alamin Alkundi. June 7, 2022.
  2. “Man’s ‘overzealous’ vitamin D use led to overdose, hospitalization.Live Science. Donavyn Coffey. July 14, 2022
  3. “Do You Need a Vitamin D Supplement? Everything to Know.” Everyday Health. Sheryl Huggins Salomon. October 4, 2022
  4. “Taking too much vitamin D can cloud its benefits and create health risks.” Harvard Health Publishing. April 7, 2022
  5. “What is the difference between nutritionists and dietitians?Medical News Today. Louisa Richards. August 4, 2020