MARTIN MITTELSTAEDT

From Saturday's Globe and Mail

April 28, 2007 at 1:20 AM EDT

For decades, researchers have puzzled over why rich northern countries have cancer rates many times higher than those in developing countries — and many have laid the blame on dangerous pollutants spewed out by industry. But research into vitamin D is suggesting both a plausible answer to this medical puzzle and a heretical notion: that cancers and other disorders in rich countries aren't caused mainly by pollutants but by a vitamin deficiency known to be less acute or even non-existent in poor nations. Those trying to brand contaminants as the key factor behind cancer in the West are "looking for a bogeyman that doesn't exist," argues Reinhold Vieth, professor at the Department of Nutritional Sciences at the University of Toronto and one of the world's top vitamin D experts. Instead, he says, the critical factor "is more likely a lack of vitamin D."