Vitamin C is an essential micronutrient contributing to a well-functioning immune system. This is because it affects several immune processes in the human body and protects against environmental oxidative stress. Vitamin C deficiency results in impaired immunity and a higher susceptibility to infections. In turn, infections can also influence vitamin C levels due to higher requirements of the body, for instance. Additionally, supplementation with vitamin C shows a beneficial effect in preventing and treating several infectious diseases. More details can be found in the review article.
Carr AC, Maggini S