Vitamin C (ascorbic acid) is scientifically recognized for its critical role in maintaining the health of mucus membranes, which line various body cavities such as the respiratory tract, gastrointestinal tract, and urogenital tract. Vitamin C is essential for the biosynthesis of collagen, a major structural protein found in epithelial tissues, including those that make up the mucus membranes. Collagen provides strength and integrity to these tissues, facilitating their barrier function and repair processes.

Deficiency in vitamin C results in impaired collagen synthesis, leading to weakened mucus membranes and increased susceptibility to infections and bleeding (as seen in scurvy). Numerous studies and clinical observations have shown that adequate vitamin C intake supports epithelial barrier function and wound healing. Furthermore, vitamin C acts as an antioxidant, protecting epithelial cells from oxidative stress and facilitating immune responses, which are important for maintaining healthy mucus membranes.

Authoritative bodies such as the National Institutes of Health (NIH) and the World Health Organization (WHO) recognize vitamin C's role in supporting connective tissues, including mucus membranes. While most evidence is derived from deficiency states, the scientific basis for vitamin C's support of mucus membranes is strong and underpinned by well-established biochemical pathways and clinical correlations.