Illustration: Christopher Silas Neal
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"Vitamin C Prevents Colds"
It's true that if you don't have enough C, you'll get sick—but with scurvy, not a runny nose. Carroll and Vreeman hypothesize that this bug-fighting theory began when we discovered the vitamin's link to that infamous sailors' affliction, in 1932; if C could prevent one illness, the logic likely went, perhaps it could prevent others, too. But dozens of studies have found no difference in the number or duration of colds suffered by people who take C and those who don't. What is the best way to stay cold-free? "Nothing beats hand washing," Carroll says.