When we feel like we’re getting sick, most of us will reach for one of those “immunity boosting” products loaded with vitamin C. But are these really effective at fighting the common cold?
Vitamin C was first named in 1928, although at that time the chemical structure was still unknown. It was first identified as an essential nutrient for the prevention of scurvy, a disease that can afflict any animal that does not produce its own vitamin C, including humans. It wasn’t until the 1940s that vitamin C was first identified as being essential for proper immune function.
During infection, vitamin C levels drop in blood plasma and leukocyte immune cells, suggesting an important role for the nutrient in immunity. Vitamin C supplementation has also been shown to enhance several physiological aspects of the immune response, but these studies do not prove that vitamin C reduces your susceptibility to the cold. Fortunately, this has been tested as well.
Much research has been done exploring the effectiveness of vitamin C in reducing incidence, duration, and severity of the common cold and other respiratory infections. Overall, current evidence does not suggest that vitamin C supplementation reduces the incidence or severity of cold in healthy individuals, even at high doses. However, vitamin C supplementation does drastically reduce the incidence of cold under high-stress conditions such as intense exercise or subarctic temperatures.
But that doesn’t make vitamin C useless for us mere mortals. While incidence of cold was not reduced with supplements, the duration of cold does seem to be significantly shortened with additional vitamin C, a feature most of us would take in a heartbeat when feeling under the weather.
To summarize, while large doses of vitamin C are probably not effective for reducing incidence of cold, deficiencies can make you more susceptible. Moreover, when under stressful conditions such as extreme exercise or cold temperatures, additional vitamin C may help strengthen your resistance to respiratory infection.
When it comes to the science of wellness, distinguishing the facts from the urban legends can be tough. That’s why we’ve enlisted Darya Pino – a scientist, foodie, and self-proclaimed geek girl. Check out the ZocDoc Blog every Tuesday to see her bust the biggest myths in health.
Image: Oranges, a Creative Commons Attribution (2.0) image from Kyle McDonald’s photostream.