Vitamin C (L-Ascorbic Acid)

Direct Answer

Vitamin C is a water-soluble electron donor and antioxidant essential for collagen proline/lysine hydroxylation, non-heme iron absorption, and immune phagocyte function. Adult RDA is 90mg (men) / 75mg (women), with a Tolerable Upper Limit of 2,000mg/day.

Source: NIH Office of Dietary Supplements / EFSA Dietary Reference Values · Last reviewed Aug 28, 2026

Specs

Nutrient Type	Water-Soluble Vitamin
Adult RDA / RDI	90 mg (Men) / 75 mg (Women) (+35mg for smokers)
Tolerable Upper Limit (UL)	2,000 mg / day (Avoid osmotic diarrhea)
Chemical Forms	L-Ascorbic Acid, Sodium Ascorbate, Calcium Ascorbate
Primary Biological Function	Prolyl/Lysyl Hydroxylase cofactor (Collagen), ROS scavenger, Carnitine synthesis
Deficiency Condition	Scurvy (Collagen breakdown, capillary fragility, impaired wound healing)
Top Whole Food Sources	Red Bell Pepper, Strawberries, Citrus, Kiwi, Broccoli, Brussels Sprouts
Thermolability	Highly heat- and oxygen-sensitive (degrades rapidly with prolonged boiling)

Non-Heme Iron Reduction & Absorption

Ascorbic acid reduces ferric iron (Fe3+) to soluble ferrous iron (Fe2+) in the acidic duodenum, increasing non-heme plant iron absorption by up to 300% when consumed together.