Airborne cold remedy: Does it prevent colds?

Some people swear by Airborne, a popular herbal cold remedy that's sold over-the-counter in many drugstores. But there's no conclusive evidence that this product or any of its ingredients prevent colds or shorten their duration.

Airborne cold remedy claims to boost your immune system — which supposedly helps you fight off cold germs — with a blend of herbs and vitamins, including magnesium, zinc, selenium, forsythia, echinacea, manganese and vitamins A, C and E. Only three of these ingredients have been studied as possible cold treatments with mixed results:

• Echinacea. A National Center for Complementary and Alternative Medicine study released in 2005 found that echinacea did little to prevent or shorten colds. But testing herbs is difficult, and scientists say more research is necessary.
• Vitamin C. Although vitamin C doesn't appear to prevent colds in most people, taking large doses — up to 5,000 milligrams — at the beginning of a cold may reduce the severity of symptoms. Lower doses — 200 to 300 milligrams — may shorten a cold's duration. Just what constitutes an optimum dose isn't clear, but amounts in excess of 2,000 milligrams a day may cause nausea and diarrhea.
• Zinc. Most studies indicate that zinc reduces the duration of cold symptoms but doesn't prevent colds. However many of the zinc studies — both those that find the mineral beneficial and those that do not — have been flawed.

As is often the case with many nutritional supplements, there is just not enough quality research available to make a decision regarding any actual benefits of Airborne. Also, since Airborne is considered a nutritional supplement, it is subject to relatively limited oversight from the Food and Drug Administration. Talk to your doctor before starting any new nutritional supplement.