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Vitamin C & Colds

September 7, 2009

Does vitamin C really prevent the common cold?


Does vitamin C prevent colds? I’m Bob Hirshon and this is Science Update.

Many people take vitamin C every day because they’ve heard that it prevents the common cold. But listener Brian Gratwicke of Washington, D.C. wants to know if that’s really true. So we turned to epidemiologist Harri Hemilä of the University of Helsinki for a Reality Check. He says an analysis of a large number of studies has shown that vitamin C is actually ineffective at preventing the common cold in most people.

HARRI HEMILÄ (University of Helsinki):
It doesn’t help to take vitamin C regularly.

But he says the supplement probably does have some benefit once you already have a cold.

HARRI HEMILÄ (University of Helsinki):
It is shortening the duration of colds and making the symptoms less severe.

He adds that vitamin C has been shown to prevent colds in people like marathon runners, who are routinely under a large amount of stress. And if you’ve got an urban legend that needs a reality check, write to us at our website, I’m Bob Hirshon, for AAAS, the science society.