The Flu Fighters.

Byline: editor: Abigail Walch

Powders and potions, shots and pills--can anything really supercharge your immunity? Jancee Dunn reveals the most promising remedies to ward off the season's ills.

If everyone seems to be sick this winter, it's because they are. More than 200 known viruses can cause the common cold--and if your friends are like mine, they've gone beyond the national average of two to four a year and have upgraded to one season-long supercold, to be relentlessly passed back and forth as everyone crowds inside during the chilly months.

Not that going outdoors provides relief. Researchers at Mount Sinai School of Medicine in New York have just discovered that the reason the flu is more prevalent in winter is that when the atmosphere is cold and dry, the flu viruses, which float in tiny droplets, are able to lurk in the air longer.

And so, as we tensely await a spring thaw, people gather their remedies like medieval villagers warding off the plague, stocking up on vitamins, powders, and potions. We certainly don't lack for choice: Americans spend $7 billion annually on vitamins and minerals. There is seemingly no product that cannot be vitamin "enhanced," from diet soda to T-shirts. (Last September, one intrepid company introduced the first vitamin E--enriched cigarette .) But in a culture where everything is vitaminized, can any supplement truly aid in fending off colds and flu? Is it actually possible to power your immunity?

Most of us raise a weary eyebrow at the avalanche of dubious, unregulated remedies that erupts from the aisles of pharmacies and health-food stores. But some investigation reveals that a few things can actually help you detach from the Kleenex box.

I start my inquiry with two products that deliver large doses of vitamins, particularly C: E-Boost, a tablet added to water that models guzzled backstage at last year's New York shows, and Emergen-C, the fizzy powder beloved by frequent travelers. Elizabeth Somer, R.D., an Oregon-based dietitian who specializes in women's nutrition, says that they're worth taking at the first sign of a cold. "There's no evidence to show that vitamin C in large doses will prevent the cold," she says, "but it may have a slight effect on reducing its severity and how long it lasts." Vitamin C has been found to help white blood cells fight off infection, and don't forget vitamin E, which is missing from Emergen-C's original formula and E-Boost (the E stands for energy, not the vitamin), as it also shores up immunity.