Supplementing Your Cold Defenses

Last Editorial Review: 1/30/2005

If you've got a cold, what should you take? Purveyors of alternative medicine offer a dazzling array of choices.

By Lynda Liu
WebMD Feature

If you've got a cold, what should you take? Purveyors of alternative medicine offer a dazzling array of choices; only a few have science behind them. In this, the second of a three-part series on alternative medicine for colds, we'll look at supplements.

Take your runny nose to the vitamin display of any drug store and you?ll find preparations promising to ease. But science is scarce in the supplement industry, and it?s not easy to know what to try and what to sneeze at.

Two things are for certain. One, we'd all like a quick fix for this condition. And two, there isn't one. Most adults experience two to four colds each year, and most children get six to ten, according to the U.S. National Institute of Allergy and Infectious Diseases (NIAID). There's no cure for the cold, and although over-the-counter drugs may bring relief, it's usually at the cost of side effects like drowsiness.

Which is why so many people scour the shelves for a supplement that will help fight a cold, or help keep it away in the first place. Here's a rundown of the supplements we've found that have the most evidence in their favor.

Thinking Zinc and Seeking C

Zinc lozenges: In test tubes, zinc prevents cold viruses from reproducing themselves. But as for its ability to fight the disease in the human body, the jury is still out, even after 11 double-blind, placebo-controlled studies. Five studies found that zinc had beneficial effects and six did not.

And all these studies had possible flaws. The ones that found zinc useless may have used formulations that are inactive in the human body. Those that came down in favor of zinc may have used a placebo that did not taste like the active pill. (If participants could tell the difference, then some of those who got the real thing may have benefited because of the psychological boost of knowing they were getting real zinc instead of placebos, rather than from any disease-fighting properties of the mineral itself.)

If you want to give zinc a chance, you can follow the lead of the best-known of the pro-zinc studies, the one conducted by the Cleveland Clinic and published in the July 15, 1996 issue of the Annals of Internal Medicine. Within 24 hours of coming down with cold symptoms, 50 people began dissolving Cold-Eeze zinc lozenges in their mouths every two hours while they were awake. Those taking the zinc lozenges recovered in an average of 4.4 days, compared with 7.6 days for those who had been given placebos. But be aware that some participants experienced nausea and bad-taste reactions.

Vitamin C: The late Dr. Linus Pauling was a famous and enthusiastic advocate of vitamin C and its healing powers. But the many studies conducted on vitamin C and the common cold have varied widely in their results. A 1999 Australian National University review (conducted for the Cochrane Database of Systematic Reviews) of 30 major trials found no consistent evidence that taking vitamin C prevents colds. However, the review did find that study subjects who took vitamin C after coming down with a cold recovered more quickly (on average, about half a day faster) and possibly experienced milder symptoms.

If you want to try vitamin C yourself, you need to realize that no one has set dosage guidelines. A study of 622 people, published in the April 5, 1975 issue of the Canadian Medical Association Journal, found that those who took 1,500 mg on the first day of a cold and 1,000 mg on each of the following four days spent 25 percent fewer days indoors because of their cold than those who were given a placebo.

Beyond Vitamins and Minerals

A couple of other supplements show some signs of stimulating the immune system. But no one so far has tested how they actually affect colds.

Fish oil capsules: If you don?t eat fish regularly, taking fish oil capsules in the winter may help protect you against a cold, says Ray Sahelian, M.D., the author of The Common Cold Cure. Both laboratory and clinical studies have suggested that fish oil capsules boost the immune system. In a 1995 Patras University study published in Cancer Detection and Prevention, cancer patients who took 18 grams of fish oil daily for 40 days had a significant drop in a type of cell that works to suppress the immune system.

Probiotics: Sold in capsules and liquids, probiotics contain live microorganisms (bacteria or yeast) that are supposed to help maintain balance in your intestinal flora. But they may also provide another benefit. One double-blind study from the University of Turku in Finland, published in December 1998 in Clinical and Experimental Allergy, found that an intestinal bacterial strain added to milk stimulated white blood cells in healthy participants. If you?re going to buy a probiotic, look for one that contains bifidus and acidophilus, advises Sahelian.

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