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Vitamin C

How many times have you heard it said that taking large amounts of vitamin C will prevent or cure a cold? Science has yet to prove this is true, but vitamin C is important in fighting infections. Vitamin C (also known as ascorbic acid) works as an antioxidant to protect our bodies from damage, is involved in the growth of our bones, tendons, ligaments and skin and increases the absorption of iron from our foods (particularly from vegetarian sources).

How much vitamin C do we need?

 Age (years)RDI*Vitamin C (mg/day)
Infants and toddlers1-335
Children and adolescents4-835
9-1840
Adults19-70+45
Pregnant women14-1855
19-5060
Breastfeeding women14-1880
19-5085

Who needs more and why?

Smoking causes vitamin C to be used up much more quickly by the body, so smokers need to add an extra 35 milligrams per day to the RDI because of the great stress on their lungs from oxidative damage and toxic by-products of cigarette smoke. Adding an extra piece of fruit to the daily diet would more than cover this extra requirement for vitamin C.

Vitamin C content of foods

Food itemVitamin C
1 red capsicum240
1 grapefruit94
1 kiwifruit85
10 strawberries50
1 orange46
1 boiled kūmara 30
1 tomato30
1 cup boiled silverbeet27

Vitamin C deficiency

Severe deficiency of vitamin C can lead to scurvy, causing bleeding gums, poor wound healing and bone damage. This is why Captain Cook stocked up on vitamin C-rich limes to stop scurvy running rife amongst his sailors on long sea voyages. It is also why British sailors became known as ‘Limeys’ in North America. This deficiency is rare in New Zealand, although may occur very occasionally in older people.

Vitamin C supplements

Vitamin C supplements are usually unnecessary as it is easy to obtain enough from common foods – see the table above. As vitamin C is a water-soluble vitamin, any excess will be excreted in your urine. While vitamin C toxicity is very rare, taking supplements containing more than 2,000 mg per day can lead to stomach upsets and diarrhoea.

Last modified: January 26, 2022