Vitamin C cannot be synthesized endogenously and therefore must be consumed in the human diet. This is typically not a problem, as ascorbic acid is abundantly found in fruits and vegetables (while also being present to a lesser extent in milk, liver, and fish) Deficiencies of vitamin C are therefore rare in developed countries, but continue to be concern in those with inconsistent eating patterns – including the elderly, alcoholics, and presons who live alone.
Vitamin C (ascorbic acid) deficiency eventually results in scurvy, disease characterized by hemorrhages, subperiosteal hematomas, bleeding into joint spaces, gingival swelling, secondary periodontal infection, anemia, hyperkeratotic papular rashes, impaired wound healing, and weakened immune response to local infections.
Because ascorbic acid accelerates hydroxylation and amidation reactions, it plays a crucial role in numerous biosynthetic pathways. One of the most important functions of ascorbic acid is its activation of prolyl and lysyl hydroxlase precursors, both of which are necessary for the hydroxylation of procollagen. As collagen impaired by any reduction in available ascorbic acid.
Source: USMLE World 2009
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