Vitamin C - Information and Sources

Vitamin C is also known as ascorbic acid and is a water soluble vitamin. It has a number of functional roles including aiding wound healing, aiding the absorption of iron from the intestines and as a powerful antioxidant. Although vitamin C is an important antioxidant, in the presence of certain metal ions and oxygen it could be pro-oxidant.

Vitamin C is a very labile micronutrient and is easily destroyed by oxygen, heat, light, metal ions and increased pH. Deficiency of vitamin C presents as scurvy characterised by bleeding from the mucous membranes, spots, pallor, depression, loss of teeth and oozing wounds.

There is much debate on the requirements of vitamin C, whether these need to be sufficient to prevent scurvy with some reserve, or whether higher levels are more optimal to reduce risk of disease. The reference intake is 40mg per day, but there are claims, with some evidence, that levels much higher than this are beneficial. Much of this pertains to vitamin C's antioxidant ability. Smokers have lower blood vitamin C levels, so should ensure an intake higher than 40mg per day. Vitamin C is found in a wide range of plant foods though, and eating a varied diet will ensure adequate intake.

One area of debate is the proposed use of vitamin C supplementation in preventing the onset or reducing the severity of the common cold. This is far from proven, yet it's almost accepted by many people that you mega dose with vitamin C supplements if you feel a cold coming on. Although mega doses are advocated by some, caution needs to be noted. High doses can cause diarrhoea, indigestion and kidney stones and may also be pro-oxidant in some circumstances.

Vitamin C is a very labile vitamin and is lost through leeching out into water, through high temperatures and food processing. It is only present in small amounts in animal foods, but is widespread in plant foods. Main fruit and vegetable sources are:

  • Avocado (½) - 14mg
  • Blackberries (15) - 16mg
  • Gooseberries (10) - 26mg
  • Grapefruit (½) - 27mg
  • Lemon (¼) - 20mg
  • Mango - 56mg
  • Melon, cantaloupe (½) - 54mg
  • Melon, honeydew (¼) - 29mg
  • Melon, water (¼) - 20mg
  • Orange - 93mg
  • Pineapple (1 slice) - 31mg
  • Raspberries (15) - 18mg
  • Strawberries (100g) - 60mg
  • Tangerine - 21mg
  • Beansprouts (85g) - 16mg
  • Peppers, raw (45g) - 45mg
  • Tomatoes, raw (150g) - 30mg
  • Grapefruit juice (200ml) - 56mg
  • Orange juice (200ml) - 70mg
  • Pineapple juice (200ml) - 16mg
  • Blackcurrant cordial (45ml) - 95mg
  • Tomato juice (200ml) - 40mg
  • Broccoli, boiled (95g) - 32mg
  • Brussel sprouts, boiled (115mg) - 46mg
  • Cauliflower, boiled (100g) - 20mg
  • Potatoes, boiled (150g) - 14mg
  • Chips (250g) - 26g
  • Potatoes, baked (140g) - 14mg
  • Potatoes, mashed (170g) - 14mg
  • Spinach, boiled (130g) - 33mg
  • Swede, boiled (120g) - 20mg