Vitamin D tabletsRoger Hallett
Two-thirds of Canadians do not have enough vitamin D for overall health and disease prevention, according to a landmark Statistics Canada study.
In addition, one in 10 Canadians have "inadequate" concentrations of the vitamin for bone health. And 4 per cent are vitamin D deficient, a serious condition that can cause rickets in children and osteoporosis in adults.
The findings are contained in the first national survey measuring Canadians' levels of the so-called sunshine vitamin, which has been linked to everything from a reduced cancer risk to boosting the immune system against the flu.
"Vitamin D is increasingly becoming more and more important, or so the research is showing," said Kellie Langlois, a Statscan research analyst who co-wrote the study. "We're finding a lot of evidence that it's, in fact, higher levels that are contributing to more optimal health."
Statistics Canada found that while 10 per cent of Canadians -- more than 1.1. million people -- have inadequate or deficient concentrations of vitamin D, a whopping 65 per cent are below the cut-off suggested in recent studies as desirable for overall health and disease prevention.
In addition, Statscan found that 41 per cent of Canadian adults had high total cholesterol, which is a risk factor for heart disease. Levels were highest among older people: 54 per cent of Canadians aged 60 to 79 had high cholesterol, compared to 27 per cent of those aged 20 to 39.
The findings are from the Canadian Health Measures Survey, which collected information from 5,600 Canadians between 2007 and 2009. Researchers conducted direct physical measurements, including drawing participants' blood.
The national statistics agency found that males were more likely to have deficient levels of vitamin D, at 5 per cent compared to 3 per cent among females. Young men had the lowest levels: Seven per cent of men aged 20 to 39 had deficient levels of the nutrient, which helps the body absorb calcium and phosphorus to build and maintain strong bones and teeth.
Statscan defined vitamin D deficiency as a concentration below 27.5 nanomoles per litre (nmol/L) while inadequacy for bone health was a concentration below 37.5 nmol/L. However, recent studies recommend a concentration of 75 nmol/L or above for overall good health and disease prevention.
Health Canada currently advises 200 to 600 IU of vitamin D a day, depending on age. However, given the recent research, Health Canada and the United States government have jointly asked an expert panel whether this recommendation needs to be updated. A decision is expected in July or August.
Low blood levels of the vitamin is a common condition among people in northern parts of the world, such as Canada. During fall and winter's meagre sunlight, it isn't possible to make the nutrient the natural way: in bare skin exposed to strong ultraviolet light.
The study says Canadians with darker skin are more likely to have lower vitamin D levels because it is more difficult for them to obtain the nutrient through sun exposure.
The link to light is the reason the nutrient is dubbed the sunshine vitamin, although small amounts are found in fortified foods, such as milk, and naturally in oily cold-water fish such as salmon. Larger amounts are contained in over-the-counter vitamin supplements.