Vitamin C (Ascorbic Acid)
Vitamin C
Snapshot
Vitamin C is a water‑soluble antioxidant essential for collagen synthesis, immune support, iron absorption, and protection against oxidative stress.
What is Vitamin C (Ascorbic Acid)?
Vitamin C, or ascorbic acid, is a vital nutrient and potent reducing agent that participates in enzymatic hydroxylation reactions, neutralizes free radicals, and regenerates other antioxidants such as vitamin E.
Where It Comes From
Dietary vitamin C is abundant in citrus fruits, berries, kiwi, peppers, broccoli, and leafy greens. Supplemental forms include ascorbic acid, sodium ascorbate, calcium ascorbate, and lipid‑encapsulated formulations for improved tolerance.
Key Nutrients & Compounds
Provides ascorbic acid and its oxidized form dehydroascorbic acid, both of which interconvert in vivo and support prolyl and lysyl hydroxylase enzymes for collagen formation, and serve as cofactors for neurotransmitter and carnitine synthesis.
Health Benefits
Vitamin C accelerates wound healing by promoting stable collagen cross‑linking; enhances immune defenses through phagocyte function and lymphocyte proliferation; improves non‑heme iron absorption in the gut; and protects lipids, proteins, and DNA from oxidative damage.
Recommended Dosage
The Recommended Dietary Allowance is 90 mg/day for men and 75 mg/day for women. Smokers require an additional 35 mg/day. Therapeutic doses of 500–2,000 mg/day are used for antioxidant support, with tolerance varying by individual.
How to Use It
Take vitamin C supplements with meals to reduce gastrointestinal discomfort. For divided dosing in higher regimens, spread intake throughout the day to maintain plasma levels and optimize cellular uptake.
Who Should Use It?
Individuals with low fruit and vegetable intake, smokers, those under acute stress or infection, and people seeking enhanced antioxidant and immune support may benefit from supplementation.
Possible Interactions or Cautions
High‑dose vitamin C can cause diarrhea, gastrointestinal upset, or increase oxalate kidney stone risk in susceptible individuals. It may elevate iron levels; caution in hemochromatosis. Large doses can interfere with certain laboratory tests.
Final Thoughts
Vitamin C is a cornerstone nutrient for connective tissue integrity, immune resilience, and antioxidant protection. Balanced dietary intake usually suffices, with supplements tailored to individual needs and tolerance.
Scientific Studies
Carr AC, Frei B. Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans. Am J Clin Nutr. 1999;69(6):1086–1107. https://doi.org/10.1093/ajcn/69.6.1086
Hemilä H, Douglas RM. Vitamin C and acute respiratory infections. Int J Tuberc Lung Dis. 1999;3(10):756–761. https://pubmed.ncbi.nlm.nih.gov/10539054/
Padayatty SJ, Levine M. New insights into the physiology and pharmacology of vitamin C. CMAJ. 2001;164(3):353–355. https://www.cmaj.ca/content/164/3/353