The Cold Facts

Flu Shots and Zinc

Get a flu shot and you'll be safe from the bug for the year.

Fact The influenza vaccine provides the best insurance against contracting the flu, but it's no guarantee: studies in healthy young adults show it fails to protect up to 30 percent of the time. Its effectiveness varies because influenza viruses are constantly mutating, so vaccine manufacturers working nine months in advance are not always able to perfectly match the strains that will circulate in the U.S. during the December to March flu season.

Still, the flu shot is recommended for people age 50 and older, pregnant women, and those with chronic illnesses. Though the vaccine may be less effective in the elderly or people whose health is otherwise compromised, it helps prevent serious complications for those who do get infected. But remember -- it takes two weeks for the body to build immunity.

Zinc lozenges are the sweetest-tasting way to shorten the length of a cold.

Fact Of the dozen studies conducted on the effects of zinc, a best-seller during the cold and flu season, half found that sucking on zinc lozenges every few hours sped recovery from the common cold, but half found they didn't help at all. While popping lozenges may seem harmless, too much zinc -- over 150 mg a day -- may actually reduce the body's ability to fight infection. Excess zinc also can lower "good" cholesterol.

Still, optimism is growing about an over-the-counter nasal gel with zinc now in drugstores, marketed under the names Zicam and Zinc-Up. A study of 213 patients found the gel shortened a cold's duration -- to two days, compared to nine with a placebo -- when taken within 24 hours of the onset of symptoms. The gel, sold in a pump bottle, attacks colds by delivering zinc to the nasal passage, where infection begins, researchers say. The zinc ion binds to the virus, preventing it from attaching to the nasal lining. Researchers say it's impossible to overdose on the gel, which costs about $10, and it doesn't cause the aftertaste associated with lozenges.