Vitamin C and the common cold but it has halved the frequency of colds in people under heavy short-term physical stress. There is no effect of taking vitamin C in doses up to 8 grams per day after a cold has already begun. Vitamin C was identified in the early part of the twentieth century, and there was much interest in its possible effects on various infections including the common cold. A few controlled trials on the effect of vitamin C on the common cold were carried out already in the 1940s, the earliest of these appears to be a placebo-controlled trial published in 1945. The
Vitamin Lind's discovery, however, was not widely accepted by individuals in the Royal Navy's Arctic expeditions in the 19th century, where it was widely believed that scurvy could be prevented by practicing good hygiene, regular exercise, and maintaining the morale of the crew while on board, rather than by a diet of fresh food. As a result, Arctic expeditions continued to be plagued by scurvy and other deficiency diseases. In the early 20th century, when Robert Falcon Scott made his two expeditions to the Antarctic, the prevailing medical theory at the time was that scurvy was caused by "tainted" canned food.