When it comes to what the average person believes about colds , there seems to be as many misconceptions as cold medicines on a drugstore shelf. And now that the winter cold and flu season is in full swing, we turned to Thomas Tallman, DO, an emergency medicine physician and cold and flu expert at the Cleveland Clinic, to set us -- and you -- straight on prevention and treatment.

Cold viruses do not require a weakened immune system. The most common cold -related myth, Tallman says, is that colds strike only those whose immune systems are not running at full capacity. That is simply not true, he says. "You can be healthy as an ox and still get a cold."

Vitamin C and zinc probably don't keep colds at bay. When threatened with a cold, Tallman says, "people reach for the vitamin C or zinc. While some studies suggest these supplements might help shorten cold symptoms , others show they don't. Tallman doesn't think there's enough evidence to support their use, and the National Center for Complementary and Alternative Medicine , a division of the NIH, concurs.

Does Dry or Cold Air Cause Colds?

Dry air does not cause colds. Many people believe that hot, dry air can dry up the mucus in your nasal passages, leaving you more susceptible to colds. Not true, says Tallman. As far as colds are concerned, he says, "It doesn't matter what the humidity is." If you are already sick, though, moist air can help ease congestion and coughing, making your suffering a bit more bearable.

Cold weather also does not cause colds -- at least not directly. Despite its name, the common cold is not caused by cold. "It doesn't have any effect at all," says Tallman. "There's no correlation." In fact, you may be more likely to "catch your death of cold" indoors, where it's warm and crowded than outdoors in the chilly air. People in close quarters are more readily exposed to carriers of the viruses that cause colds. "If one person in a household gets sick, it will spread easily," Tallman says.