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July 11, 2022 - Signs and Side Effects of Vitamin D Deficiency and Overdose


Signs and Side Effects of Vitamin D Deficiency and Overdose

July 11, 2022 Puzzle Piece

Vitamin D plays an important role in maintaining overall health.  It’s necessary for the growth and development of muscle cells, proper functioning of the innate and adaptive immune system, maintenance of the health of the skeletal system, and as a pro-hormone, etc. Therefore, insufficient, or deficient levels of vitamin D may increase risk of disease and infection, bone demineralization, poor wound healing, and many other negative health outcomes.

A very conservative estimate is there is a vitamin D deficiency or insufficiency in 50% of U.S. adults. It is safe to say the entire world population is vitamin D deficient as well.  Factors that increase the risk of vitamin D deficiency include:
  • skin color
  • where you live
  • your ability to absorb vitamin D
  • sun exposure
  • medical conditions
  • body weight
  • nutrient and supplement intake
Because vitamin D insufficiency and deficiency are common, many people use vitamin D supplements to maintain healthy vitamin D levels.  Although uncommon, vitamin D toxicity (hypervitaminosis D, vitamin D intoxication) can occur from accidental overdose, prescription errors in writing or interpreting and misuse of high-dose vitamin D supplements.  Vitamin D toxicity is more common in people with certain medical conditions. These include:
  • granulomatous disorders
  • congenital disorders
  • some lymphomas
  • dysregulated vitamin D metabolism
The only way to know your D status is to have periodic blood tests to monitor levels.  The accepted levels are 30 – 100 ng/mL.  I like mine near the 100 level.

Elevated blood levels
for vitamin D to reach toxic or dangerous levels in the body, needs to exceed 100 nanograms (ng) per mL.  Hypervitaminosis D is defined at serum levels of over 150mg/mL.

Recommendations on optimal vitamin D levels vary, but research suggests that levels between 30–60 ng/mL are likely optimal from mainstream thinking and may help protect against illness and disease.

In a 2020 case report, a 56-year-old woman who took an average of 130,000 IU of vitamin D per day for 20 months in hopes of improving symptoms of multiple sclerosis was hospitalized for symptoms including nausea, vomiting, and muscle weakness.  Her vitamin D levels were discovered to be 265 ng/mL.  Note that 130,000 IU is over 30 times the generally recommended safe upper limit of 4,000 IU per day.

Even though toxicity is unlikely if you keep your daily intake levels below 10,000 IU per day and avoid excessively high intakes of vitamin D supplements, experts recommend that people with typical vitamin D levels do not exceed 4,000 IU of vitamin D per day.  If you do not test, you do not know where your levels are.  People who are low or deficient in vitamin D typically need to take much higher levels than the current Tolerable Upper Intake Level (UL) of 4,000 IU per day to reach and maintain optimal vitamin D levels.

Vitamin D levels greater than 100 ng/mL may be harmful. Toxicity symptoms have been reported at extremely high blood levels in cases where people took megadoses of vitamin D supplements for extended periods of time.

Elevated blood calcium levels

Vitamin D helps your body absorb calcium from the food you eat. In fact, this is one of its most important roles.  However, if your vitamin D intake is excessive, your blood calcium may reach levels that can cause unpleasant and potentially dangerous symptoms. The symptoms of vitamin D toxicity are primarily related to hypercalcemia (excessively high blood calcium levels).  Symptoms of hypercalcemia include:
  • digestive distress, such as vomiting, nausea, constipation, and stomach pain
  • fatigue, dizziness, hallucinations, and confusion
  • loss of appetite
  • excessive urination
  • kidney stones, kidney injury, and even kidney failure
  • high blood pressure and heart abnormalities
  • dehydration
The normal range of blood calcium is 8.5–10.8 mg/dL.  Hypercalcemia typically develops after people take large doses of vitamin D for a prolonged period.  Hypercalcemia can be life threatening and requires immediate medical attention.  Hypercalcemia can lead to altered mental status in people with vitamin D toxicity.  People with vitamin D toxicity–induced hypercalcemia commonly have symptoms like confusion, depression, agitation, unresponsiveness, and psychosis. In extreme cases, coma has been reported.

In a 2021 case report, a 64-year-old man accidentally took 200,000 IU of vitamin D per day because he misunderstood medication instructions. He showed altered mental status and other serious symptoms related to hypercalcemia.  He remained agitated and confused for the first 10 days of his stay in the hospital, but his symptoms gradually improved as his calcium levels dropped. It took about 18 days for his calcium to return to expected levels.

In some cases, vitamin D toxicity can result in kidney injury and even kidney failure. This is because having too much vitamin D in the body can lead to high levels of calcium, which can lead to water loss through too much urination and calcification of the kidneys.  Hypercalcemia can also cause the blood vessels of the kidneys to constrict, which leads to decreased kidney function.

Indeed, many studies have reported moderate-to-severe kidney injury in people who develop vitamin D toxicity.  Interestingly, a vitamin D deficiency can also harm the kidneys and lead to severe complications in those with kidney disease. That’s one reason why maintaining optimal blood levels of vitamin D is critical. Deficiency is very common. In fact, estimates suggest that about 1 billion people worldwide are deficient in vitamin D.

To repeat, the only way to tell if you’re insufficient, deficient, or in excess is to have a healthcare professional test your vitamin D levels at least once to twice per year.

Our favorite Vitamin D is Dr Harris’s OHS DAK1K2, which as all the factors for absorption and proper calcium distribution throughout the body.  I take 2 every day in the morning!


Yours in Health and Wellness,

John W Brimhall, DC, FIAMA, DIBAK, Formulator

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