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Vitamin D toxicity is not a problem

Even at very high intake levels, vitamin D does not appear to cause toxicity, an American study reveals.

Vitamin D toxicity is not a problemSome experts have warned people against taking vitamin D in doses that exceed the recommended daily allowance (RDA), claiming that excess vitamin D may lead to problems such as hypercalcemia, a condition characterized by elevated blood calcium levels that may cause weakness, kidney stones, and brain and heart disturbances. However, a study conducted by Mayo Clinic researchers has shown that vitamin D toxicity is not really an issue. The team of scientists analyzed blood data collected in the period 2002-2011 from patients in the Rochester Epidemiology Project and made some interesting observations.

  • Of 20,308 measurements, eight per cent of the participants had vitamin D levels above 50 ng/mL, and less than one per cent had levels over 100 ng/mL
  • Even among those with high levels of vitamin D (over 50 ng/mL) there was not an increased risk of hypercalcemia or elevated serum calcium
  • Women older than 65 were most likely to have vitamin D levels above 50 ng/mL, as they are often the ones that take supplements
  • The occurrence of vitamin D levels higher than 50 ng/mL increased in the course of the 10-year study period. To begin with, nine out of 100,000 participants belonged in that group. By the end, it was 233 out of 100,000.

It is commonly known that the use of vitamin D supplements in Western countries has increased over the last decade. People take the nutrient to boost bone and immune health and also to lower their risk of diabetes, cancer, cardiovascular disease and other illnesses, as vitamin D has been shown to play a key role in this connection. The Mayo Clinic researchers wanted to investigate if supplementation in high doses had implications for human health but found that toxic levels are actually very rare.


Vitamin D toxicity rare in people who take supplements (report), 30 April 2015

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