Vitamin C (ascorbic acid) is a water-soluble vitamin and one of the body's key antioxidants. It is needed for the synthesis of collagen, carnitine and some neurotransmitters, supports immunity and improves the absorption of iron from plant food.
The body cannot make vitamin C and does not store it for long, so it must be obtained from food every day. A prolonged deficiency leads to scurvy.
Why vitamin C is needed
Vitamin C's main role is taking part in the synthesis of collagen, the protein that holds together skin, blood vessels, gums and bones and aids wound healing. As an antioxidant it neutralizes free radicals, supports immunity and is needed to form carnitine and neurotransmitters. A separate practical benefit — it converts non-heme (plant) iron into a better-absorbed form, helping with iron deficiency.
Deficiency and scurvy
With an intake below 10 mg a day, scurvy develops in about a month. Its signs are fatigue, bleeding and inflamed gums, poor wound healing, pinpoint hemorrhages, weakness of the connective tissue. In developed countries overt scurvy is rare, but mild deficiency is possible with a monotonous diet, smoking and alcohol abuse.
Sources and myths
Vitamin C is plentiful in bell pepper, citrus fruits, kiwi, broccoli, strawberries, Brussels sprouts. It breaks down with heat, so prolonged boiling reduces its content. Megadoses do not prevent colds (at best they slightly shorten their duration), and exceeding the upper limit of 2000 mg/day can cause GI upset. For most people a varied diet is enough.
Reference ranges
Vitamin C is water-soluble and is barely stored, so it is needed daily. Recommended dietary allowances (RDA) for adults:
| Men | 90 mg/day |
| Women | 75 mg/day |
| Smokers | +35 mg/day above the norm |
| Upper limit | 2000 mg/day |
| Risk of scurvy | less than 10 mg/day |
Calculate using this marker
Calculators where Vitamin C (ascorbic acid) is used directly:
Frequently asked questions
Does vitamin C help against colds?
Regular intake does not prevent colds in most people, but it may slightly shorten their duration. Taking it once you are already ill usually gives no noticeable effect.
Are large doses of vitamin C dangerous?
The upper safe limit for adults is 2000 mg a day. Exceeding it most often causes GI upset (diarrhea, abdominal pain), and in predisposed people — a risk of oxalate stones.