“Vitamin C prevents the common cold”

The widespread belief that vitamin C can ward off the common cold largely stems from the influence of Nobel laureate Linus Pauling. In 1970, Pauling published "Vitamin C and the Common Cold," a bestselling book that advocated for high-dose vitamin C supplementation to prevent and treat colds. His esteemed scientific background led many to embrace this idea, despite skepticism from the broader medical community at the time.

Decades of subsequent scientific research, including numerous placebo-controlled trials and meta-analyses, have provided a clearer picture. Regular vitamin C supplementation does not prevent most people from catching a cold. However, for individuals already taking vitamin C regularly, it may slightly reduce the duration of cold symptoms by about 8% in adults and 14% in children, and also lessen their severity. A notable exception is for people undergoing extreme physical stress, such as marathon runners or soldiers in subarctic conditions, who may experience a modest preventative benefit.

The enduring popularity of this belief can be attributed to several factors. Pauling's prominent endorsement undoubtedly played a significant role, as did the general understanding that vitamin C is crucial for overall health and immune function. Many people may also feel better after taking vitamin C due to a placebo effect or the vitamin's antioxidant properties, which contribute to a sense of well-being, reinforcing the misconception despite scientific findings.