About 37,000 lives a year would be saved if more Canadians simply increased their daily vitamin D intake to recommended levels, says a study funded by a non-profit group dedicated to raising awareness of the vitamin.
The study estimates that increased vitamin D blood levels would reduce incidence of a variety of conditions, including cardiovascular diseases, multiple sclerosis, pneumonia and cancer.
The researchers also say increasing levels of the vitamin among Canadians would save Canada's health system about $14.4 billion.
The study notes that most Canadians don't have anywhere near enough vitamin D stored in their bodies. Blood calcidiol tests have revealed most of us have an average level of 67 nanomoles per litre of the vitamin in our bloodstream.
Statistics Canada reported last month that 10 per cent of Canadians had "inadequate" levels of the vitamin, which they defined as concentrations below 37.5 nmol/L.
Those standards were set in 1997 and are currently getting a second look by Institutes of Medicine.
Concentrations above 75nmol/L have recently been proposed for optimal health. Using that threshold, the StatsCan study found only one-third of the population (33 per cent of males and 37.8 per cent of females) had optimal levels.
For this latest study, the researchers say in order to achieve significant disease reductions, Canadians would need to increase their levels to 105 nanomoles per litre. They estimate that among Canadians aged six to 79, only 10 per cent are at, or above, that level.
The study estimates that the benefits of increased vitamin D levels would include:
- decreased cancer rates of 25 per cent by increasing national vitamin D levels from 75 to 105 nmol/L
- lowered risk of cardiovascular disease by 25 per cent if levels are increased from 62.5 to 105 nmol/L
- a 60 per cent improvement in insulin sensitivity if vitamin D levels were increased from 25 to 75 nmol/L
- reduced risk of developing multiple sclerosis and reduced symptoms in those already diagnosed
- reduced risk of pneumonia by 30 per cent, by reducing the "cytokine storm" response following respiratory infections
- reduced risk of Cesarean section by about 50 per cent, by strengthening the uterine muscles
- improved fetal development
"The result of this study strongly suggests the personal and economic burden of disease in Canada could be significantly reduced if optimal vitamin D levels are increased," said William B. Grant, the primary author of the study, which appears in the journal Molecular Nutrition & Food Research.
"These results should increase interest by individuals, researchers, organizations and agencies in Canada in assessing the health benefits of higher vitamin D production and intake."
The sun is the best source for vitamin D, but because of the climate in Canada, most Canadians can't produce vitamin D from the sun for as long as six months of the year. Because diet alone cannot provide enough vitamin D, most experts now recommend supplements and sensible sun exposure when possible.
The report didn't spell out the amount of vitamin D people would need to take to reach the blood levels recommended by the authors.
The amount needed would vary from person to person, since those with dark skin absorb less from the sun than those with pale skin.
The Canadian Cancer Society advises that adults living in Canada should consider taking 1,000 international units (IU) of the vitamin a day during the fall and winter. They added that people who are olde, have dark skin, or who don't go outside often should take 1,000 IU/day all year round.
"This study clearly shows why Canadians need to know their vitamin D blood levels so they can take steps to optimize their health and reduce their risks," said Dr. Susan J. Whiting, of the University of Saskatchewan.
The Institute of Medicine is currently working on setting new dietary reference intakes for vitamin D; Canadian experts are involved in that process. A report is expected by the early fall.
The study was funded by The Vitamin D Society, a Canadian non-profit group that seeks to increase awareness of the many health conditions linked to vitamin D deficiency.
