Another object of both adoration and derision in cold and flu science is vitamin C—championed by Linus Pauling, the two-time Nobel Prize-winning American chemist. In 1970, Pauling exalted the vitamin's effects in preventing and alleviating cold and flu symptoms, basing his claim on the positive results of a placebo-controlled trial that he conducted on schoolchildren in a skiing camp in the Swiss Alps. Since then, popping chewable vitamin C tablets has become a cold-season ritual. Yet subsequent studies on the vitamin's effectiveness have produced mixed results. In meta-analyses of more than 30 clinical trials that have included over 10,000 participants, researchers have observed no difference in the severity of colds contracted during vitamin C supplementation. On the brighter side, they have noted a small yet statistically significant reduction in the duration of the illness. So it seems that Pauling wasn't entirely off base—though perhaps a bit overzealous regarding the size of the vitamin's benefit. Meanwhile, both Vigna and Thing are optimistic about vitamin C as a cold defense—"especially at a higher dose than might be normal, at least a 1,000 milligrams a day," says Thing.
Meanwhile, both experts recommend taking a supplement that most of us don't always associate with cold and flu season: vitamin D. Deficiency in vitamin D—common in as many as three-quarters of Americans—can leave one susceptible to a host of ailments, from colds and flus to osteoporosis and even cancer. "I recommend it daily to support your immune system," says Vigna.
You lose most of your body heat through your head.
We can thank the US Army for generating a myth that is so beloved among the maternal set. In the 1950s, the military conducted a series of vaguely thought-out experiments to measure the loss of body heat in volunteers. They dressed their subjects in Arctic survival suits—without hats—and set them loose into the bitter cold. Since the soldiers' heads were the only exposed parts of their bodies, wonder of wonders, a good deal of heat escaped from their noggins. This prompted the Army to publish its "findings" in a survival manual, setting in motion the legend that the body can lose 40 to 45 percent of its heat through the head. In truth, the head doesn't give off any more heat than any other area of the body; because it accounts for about 10 percent of the body's surface, that's how much heat will escape from it when the entire body is unprotected. Yet the myth lives on, usually in a more exaggerated form: Claims of an 80 to 90 percent loss of body heat through the head are commonplace in the parlance of the day.
Yet despite its faulty logic, this little nugget of pseudoscience offers some sound advice. The head and face are in fact more sensitive to cold than many other parts of the body—so no matter the percentage of heat they hold, you'll simply feel warmer with those parts covered. And in cold and flu season, extra outerwear can only be a good thing. "Your body is working hard to keep its average temperature while you're outside in the cold," says Vigna. "So, yes—wearing a hat helps you to retain body heat. If you're sick on top of that, your body is working overtime; with a hat on, your body has spare time to do what it needs to do to get better."