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Vitamin D tablets: How much testing is necessary? (Roger Hallett/The Globe and Mail)
Vitamin D tablets: How much testing is necessary? (Roger Hallett/The Globe and Mail)

Vitamin D: finding the right level Add to ...

The most reliable test for vitamin D measures a form of the nutrient in blood known as 25-hydroxyvitamin D.

People are deficient if they have less than 27.5 nanomoles of 25-hydroxyvitamin D per litre of blood. Amounts under 37.5 nmol/litre are inadequate for good bone health.

Many experts believe that levels should be 75 nmol/litre or more to reduce the risk of cancer and other diseases. Only about a third of Canadians are above this threshold.

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Most of the vitamin D people have is made in their skin after exposure to strong summertime sunshine.

Humans living near the equator would naturally have levels around 130 to 150 nmol/litre. Toxic levels are above 375.

 

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