Taking various vitamin supplements can shorten your lifespan, or so says a University of Minnesota study published last fall. In fact, the study found that taking a multivitamin could reduce life expectancy by 2.2 percent.

That might not sound like a lot, but it could add up to a few years depending on how long you live. Also alarming were two different studies released around the same time that stated taking a calcium supplement could increase your risk of heart disease. These are just a few isolated studies, but they give pause for thought.

"The evidence is not quite strong enough to say that taking vitamins is a health risk," says Carolanne Nelson, a registered dietitian and an associate nutrition professor at the University of Prince Edward Island in Charlottetown. "But there is no health benefit for the average person taking them either."

Who is Average?
By "average," Nelson means Canadians who generally eat healthfully, or close to Eating Well with Canada's Food Guide. However, since only 43 percent of Canadian adults eat the recommended five daily servings of fruit and vegetables (the foods with the most nutrients), it's not hard to see why vitamins have become a fallback. Susan Whiting, a professor of nutrition and dietetics at the University of Saskatchewan, thinks that, for many, a multivitamin will not cause harm.

The fact is, there isn't enough data available to say whether any particular Canadian is lacking in specific nutrients (one exception being vitamin D levels), says Whiting. To further complicate matters, "the science does show us that the people who take vitamins and minerals are the people who don't need them because they are already health conscious," she says.

Too Much of a Good Thing
The danger may result from getting too much of some vitamins and minerals, says Speros Dorovenis, a pharmacist and the pharmacy manager at Maple Leaf Gardens Loblaw Pharmacy in Toronto. Our bodies aren't able to flush out some excess vitamins beyond certain upper limits, which if exceeded can cause dangerous side effects. For example, too much calcium may increase the risk of kidney stones, indigestion and constipation.

Photography by Ryan Brook.