A Southern Cross survey (opens new window) suggested some 1.56m New Zealanders regularly took the products. About 750,000 had done so for at least five years.

University of Otago's Professor Jim Mann said:

"It's basically the rich folks, who are worried about their health and take supplements. And perhaps the poor folk who are not so worried about their health don't take supplements, because they can't afford it."

New Zealand Nutrition Foundation dietician Sarah Hanrahan said supplement overuse could have toxic effects:

"For example, fat soluble vitamins are stored in the body for months and can reach toxic levels and too much iron can increase the risk of serious illness." "You need to be particularly careful if you take several supplements, as the total amounts may add up to high doses."

Fish oil or Omega 3, multivitamins and Vitamin C were the most popular vitamin choices