Vitamin C
Vitamin C (ascorbic acid) is a water-soluble vitamin and a powerful antioxidant. It supports the immune system, collagen production, iron absorption, and protects cells against oxidative stress.
What is vitamin C?
Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that functions as one of the body’s most important antioxidants. Humans cannot produce vitamin C themselves and must obtain it through diet.
Functions
- Immune system — Vitamin C strengthens the immune system by supporting the production and function of white blood cells. It can reduce the duration of colds by 8-14%.
- Collagen synthesis — Vitamin C is required for the production of collagen, the protein that builds skin, tendons, ligaments, and blood vessels.
- Antioxidant — Neutralises free radicals and protects cells against oxidative stress. Also regenerates vitamin E.
- Iron absorption — Vitamin C increases the absorption of non-heme iron (from plants) by up to 6 times.
Forms
- Ascorbic acid — Standard form, effective and inexpensive. May irritate sensitive stomachs.
- Ester-C — pH-neutral, gentle on the stomach. Contains vitamin C metabolites.
- Liposomal vitamin C — Encapsulated in lipids for maximum absorption. More expensive but higher bioavailability.
- Sodium ascorbate — Buffered form, good for sensitive stomachs.
Dosage
RDI: 75-90 mg per day. Optimal: 500-1000 mg per day. During colds, 1000-2000 mg per day may reduce symptom duration. Upper limit: 2000 mg per day.
Swedish recommendations (National Food Agency)
The National Food Agency recommends the following daily intake of vitamin C:
| Age group | Recommended intake |
|---|---|
| Children 2–5 years | 30 mg |
| Children 6–9 years | 40 mg |
| Children 10–13 years | 50 mg |
| Adolescents 14–17 years | 60–70 mg |
| Adults 18+ years | 75 mg |
| Pregnant women | 85 mg |
| Lactating women | 100 mg |
| Smokers | +40 mg extra |
Source: National Food Agency, NNR 2023. Smokers require more vitamin C due to increased oxidative stress.
Frequently asked questions about Vitamin C
Hur mycket vitamin C behöver man per dag?
Kan man ta för mycket vitamin C?
Related entries
Antioxidant
Antioxidants are substances that protect cells against free radicals and oxidative stress. Key antioxidants include vitamin C, E, selenium, glutathione, and CoQ10.
Collagen
Collagen is the body's most abundant protein, constituting about 30% of all protein. It provides structure to skin, tendons, cartilage, bones, and blood vessels. The body's collagen production decreases with age.