As many as 70 per cent of Canadians use dietary supplements, but a new study finds advice from stores that sell them is unscientific and in some cases unsafe. (iStock)

A Canadian study has found that staff in health food stores routinely give advice aimed at selling expensive supplements instead of supporting the health of the consumer.

The study, published in the Journal of the American College of Nutrition, was conducted by Athabasca University between 2002 and 2008.

University students visited 192 health food stores and 56 pharmacies across Canada seeking advice on supplements and specific medical conditions.

Misleading advice 88 per cent of the time

In 88 per cent of cases the health food stores provided advice that was either unscientific or poorly supported by science.

"When people go into health food stores and ask for advice on dietary supplements in the great majority of times they're going to get misleading advice to lead them to buy expensive and unnecessary supplements," said Norman Temple, the lead author of the study.

By contrast, pharmacies offered advice backed by solid science 73 per cent of the time.

The study suggests that because pharmacists have several years of rigorous training and must adhere to a code of ethics they and their staff are far less likely to give misleading advice.

In an interview with CBC News, Temple said staff in health food stores lack training in nutrition and medical science.

"They certainly hire people fresh off the street that are no more qualified than somebody pouring coffee in Tim Hortons. That's certainly the case," he said.

Athabasca University is a distance learning institution based in Alberta with students all over Canada. Fourth-year nutrition students were assigned to visit health food stores and pharmacies armed with questions about the effectiveness of a specific supplement, as well as asking what advice the clerk would offer for a specific medical condition.

In one example 75 per cent of health food store staff stated that shark cartilage can help cure cancer, an opinion not supported by science. Staff in pharmacies made no such claims.

'The dominant motivation here is to sell. Sell, sell, sell.'—Norman Temple, study author

Temple said the health food stores consistently flogged expensive supplements over less costly alternatives or simple lifestyle changes.

"If you follow the money chain the dominant motivation here is to sell. Sell, sell, sell. To get money like a lousy used car dealer, get money by selling overpriced supplements that people don't want and boost the bottom line, this is very very clearly what is going on here."

Bad advice can harm health

The advice given can sometimes be damaging to health, according to Temple. "One possible danger is you may have some condition that needs medical treatment, but instead of going to your doctor, you go to a health food store and there's a delay in seeking treatment because you waste your time taking supplements that don't work."

Previous studies done in the U.S., Canada and Great Britain have come up with similar findings.

Surveys conducted over the past decade have found 40 to 70 per cent of Canadians are regular users of dietary supplements.

Temple says his finding supports the need for tighter controls of the health food and supplement industry.

The study was done by Athabasca University and its students. No outside agencies or companies contributed in any way to the research.