Vitamin C
Ascorbic Acid
also known as Ascorbic acid, Ester-C
A water-soluble vitamin that humans, unlike most mammals, cannot make for ourselves — somewhere along our evolutionary history we lost the gene to produce it, so we depend entirely on food. Vitamin C is essential for collagen production, immune function, and as a major antioxidant. The story of how British sailors using citrus fruit conquered scurvy is one of the foundational stories of nutrition science.
Recommended daily intake
- Adult Men · 90 mg
- Adult Women · 75 mg
- Smokers Add · additional 35 mg/day
- Pregnancy · 85 mg
- Lactation · 120 mg
Upper intake limit
2,000 mg/day for adults
Signs of deficiency
- Easy bruising and bleeding gums
- Slow wound healing
- Fatigue, irritability
- Joint pain
- Dry skin and brittle hair
- Severe deficiency causes scurvy
- Essential for collagen production — the protein scaffold that holds skin, blood vessels, bones, and connective tissue together
- Major water-soluble antioxidant in the body
- Recycles vitamin E back to its active form
- Dramatically improves the absorption of non-heme iron from plant foods — pair iron-rich plants with citrus or peppers
- Supports immune function — particularly the activity of white blood cells
- May modestly shorten the duration and severity of common colds, especially in people under physical stress
- Required for the body to make several neurotransmitters and to convert tryptophan to serotonin
- Found abundantly in citrus, peppers, broccoli, strawberries, kiwi, and many other fresh fruits and vegetables
Very high doses (typically over 2,000 mg/day) cause loose stools, nausea, and abdominal cramping
High doses can increase the risk of kidney stones in susceptible people
Use caution in people with hemochromatosis (iron overload condition) — C boosts iron absorption
Use caution with certain chemotherapy drugs
May reduce the effectiveness of niacin's lipid effects in cholesterol management
Can interfere with some lab tests — let providers know about high-dose supplementation
Liposomal and IV forms achieve much higher blood levels than oral — different safety considerations apply
Megadose protocols (10,000+ mg) have not shown the cancer benefits early advocates predicted
Research
- Morpho-anatomical changes and physio-biochemical responses of Carex siderosticta under water stress.
- Multi-targeted pyrazole scaffolds: synthesis, mechanistic insights, and therapeutic potential in anticancer, antioxidant, and anti-inflammatory applications.
- Investigation for regulation of DNA-programmed nanoflower-shaped gold nanozymes and its multi-mode detection of ascorbic acid.
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