Vitamin C

Why you need vitamin C

Vitamin C is a water-soluble vitamin which is also called ascorbic acid. It is an antioxidant that's essential for at least 300 metabolic reactions involved in:

  • The synthesis of collagen, a protein found in skin, ligaments, cartilage and other body tissue.
  • Normal growth and repair
  • Healthy skin, teeth, bones and joints
  • The metabolism of stress hormones

As an antioxidant, vitamin C helps to protect cholesterol in the blood stream from oxidation. As only oxidized cholesterol is linked with hardening and furring up of the arteries (atherosclerosis), vitamin C protects against heart attack and possibly strokes. It also shields genetic material from oxidation and mutation, and helps to protect against cancer.

Vitamin C is such an important antioxidant that many animals make vitamin C themselves. Quite why man is one of the few mammals that has lost, or never acquired the ability to synthesize this vitamin, remains one of the greatest mysteries of human biochemistry. It is thought to have resulted from a genetic accident millions of years ago, and some researchers now believe we suffer from a genetic disease, named hypoascorbaemia (literally meaning low blood vitamin C levels) which increases our risk of viral infections, raised cholesterol levels, coronary heart disease and cancer. Because our primitive ancestors ate a vegetarian diet full of vitamin C-rich plants such as purslane (just 100g of which contained 12mg vitamin E, 27mg vitamin C and 2mg betacarotene), their vitamin C intake was much higher than ours, and has been estimated at 392mg a day. Some researchers believe it may even have been as high as 10g daily . This high dietary intake meant that early humans survived the genetic accident. Modern humans eat a very different diet however, containing much lower levels of this important vitamin.

Research

A ten-year study involving 11,000 people has shown that men with the highest intakes of vitamin C have a 40 per cent lower risk of developing coronary heart disease, and a 35 per cent lower risk of dying from it. For women with the highest intakes of vitamin C, there was a 25 per cent lower risk of coronary heart disease. They were also up to 42 per cent less likely to die from cancer . Various other studies suggest that those with the highest intakes of vitamin C are less likely to develop cancer of the oesophagus, stomach, bladder, lung, larynx, cervix and prostate gland.

Vitamin C is one of the most popular supplements as it can relieve symptoms of the common cold. Taken at a dose of 1g to 6g daily, it can significantly reduce the duration and severity of symptoms by over 20 per cent. Researchers are not certain how it works, but believe its powerful antioxidant action mops up the inflammatory chemicals produced during a viral infection, which improves symptoms and hastens healing.

For certain groups of males - especially school children and students-vitamin C has also been shown to reduce the risk of catching a cold in the first place by as much as 30 per cent. For men doing heavy physical exercise, such as military troops under training and participants in a 90km running race, taking 600mg to 1g vitamin C per day halved the risk of developing cold symptoms.

As vitamin C is involved in the repair of bone and cartilage, as well as acting as a powerful antioxidant, it can slow the progression of osteoarthritis. In one study of 640 men and women, those with moderate to high intakes of vitamin C (two or more times the recommended daily amount) were three times less likely to develop knee pain or see their knee osteoarthritis progress than those with low intakes of vitamin C (up to about twice the recommended daily amount.

How much you need

The EC RDA for vitamin C is 60mg. Increasing numbers of experts feel that a higher intake from 250mg to 3g vitamin C daily is preferable for optimum health. Smokers and those with diabetes mellitus need twice as much vitamin C as non-smokers, as their metabolism generates many more free radicals and harmful antioxidant reactions. Intakes of at least 250mg vitamin C per day are also advisable for those undergoing major surgery - due to its antioxidant role and because of a need for increased collagen production during the healing process.

Signs of deficiency

Lack of vitamin C causes scurvy. A minimum daily intake of 10mg is needed to prevent this - although 20mg per day is needed for proper wound healing. Until recently, scurvy was rare in the Western world but is now becoming more common, especially among teenagers and the elderly.

Symptoms that may be due to vitamin C deficiency include:

  • poor wound healing
  • dry, rough, scaly skin
  • broken thread veins in skin around hair follicles
  • misshapen, tangled, brittle hair
  • scalp dryness
  • hair loss
  • dry, fissured lips
  • easy bruising
  • loose teeth
  • inflamed, bleeding gums
  • bleeding skin, eyes and nose
  • weakness
  • muscle and joint pain muscle and joint pain
  • irritability
  • depression

Foods containing vitamin C include

  • blackcurrants
  • guavas
  • kiwi fruit
  • citrus fruit
  • mangoes
  • green peppers
  • strawberries
  • green sprouting vegetables e.g. broccoli, sprouts, watercress, parsley
  • potatoes

Vitamin C is one of the most unstable vitamins -- up to two thirds is lost by processing, prolonged cooking and storage. It is easily destroyed by cooking and exposure to light. As vitamin C is water-soluble, it is lost from vegetables by boiling in water - some can be reclaimed by using the water to make sauces, gravy, and so on. Better still, vegetables should be steamed or boiled with minimal water.


Comments

Posted by Sophie Parnell on Wed, Feb 16th, 2011
It appears I have an allergy to vit C - is this rare...everytime I consume Vit C I get blisters appearing on my hands, painful small blisters.    Please advise.
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Posted by lin on Mon, Sep 6th, 2010
I take 6g.vitamin C daily to help with allergies, frequent colds and as an anti-viral 'medicine'.    I read 1g. for every decade is optimum dose.    I'm 60 and cold symptoms now minimal.    I take 3 x 2000 mg. doses morning, noon and evening, at present using 500mg tabs with bioflavonoids and nothing added, usually labelled 'slow release' and more expensive than fizzy or chewable tabs.    I have no ill-effects whatsoever.
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