Vitamin C is necessary for the production of collagen, an important type of connective tissue. Collagen creates the structural framework of the skin to promote skin integrity, helping to effectively keep unwanted substances from entering the body.
In addition to supporting skin integrity and antioxidant health, vitamin C is essential for the optimal functioning of white blood cells.** During an immune response, white blood cells go through a process of rapid division and multiplication. Vitamin C supports the production of the important B and T cells of the adaptive immune response. It also helps special types of cells of the innate immune system called phagocytes do their job, engulfing unwanted compounds.
The Recommended Dietary Allowance (RDA) for adults is between 75-90 mg per day depending on gender, but some experts recommend a daily intake of at least 200 mg/day for healthy individuals.
Daily intake of 200 mg supports respiratory health. Note that while this amount provides adequate support for most healthy individuals, actively multiplying and dividing white blood cells may have even higher requirements of vitamin C.