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Linda Lazarides'
Nutritional Health Bible
an essential reference book for everyone serious about health and nutrition



Treat Yourself with
Nutritional Therapy

Vitamin C (Ascorbic acid)

Vitamin (water-soluble)

  • UK RNI 40 mg
  • US RDA 60 mg
Functions

  • Aids the absorption of iron from vegetables
  • Antioxidant
  • Collagen formation (maintains healthy connective tissue and bone)
  • Immune system
  • Stress hormone production
  • Tyrosine production
  • Wound healing
Good food sources

  • Broccoli
  • Brussels sprouts
  • Cabbage
  • Fresh fruit, especially citrus
  • Green peppers
  • Kiwi fruit
  • Raw leafy vegetables
  • Tomatoes
Deficiency signs and symptoms

  • Bleeding gums or loose teeth
  • Easy bruising
  • Fatigue
  • Frequent infections (e.g. colds, flu, thrush)
  • Fragile blood vessels
A chronic shortage of vitamin C, even if mild, can promote a wide range of illnesses and diseases since vitamin C is a vital nutrient for the immune system

Preventing deficiency

Fresh fruit and vegetables must be consumed regularly, preferably at the rate of five portions daily, to prevent vitamin C deficiency. Vitamin C is rapidly lost from vegetables when they are boiled, since it leaches out into the cooking water. Steaming, or cooking vegetables quickly, as in stir-frying, minimises losses. Since the cooking water retains the lost vitamin C, this should also be used (e.g. made into soup or stock). The longer fruit and vegetables are stored before consumption, the more vitamin C is lost, for instance 30 per cent of vitamin C in potatoes is lost after 1-3 months' storage. Vitamin C is also lost when the surface of fruit and vegetables is exposed to the air. To minimize this, do not chop them until just before consumption. By the same principle, vitamin C losses are also high from fruit juices. Losses of up to 100 per cent can occur once the container has been opened, shaken, and kept for a week in the refrigerator. Baking soda destroys vitamin C.

Vitamin C in the body is depleted by alcohol consumption, smoking, surgery, trauma, stress, exposure to pollutants, the use of certain medications such as aspirin-based pain-killers, antacids and the contraceptive pill, and by infectious illness. Most researchers now recommend a minimum intake of 200 mg vitamin C daily for smokers and those exposed to tobacco smoke.

Comments

Humans are virtually the only mammals who cannot make their own vitamin C from glucose in their liver. This is because we are lacking the final enzyme which other mammals have. Other mammals can make the equivalent of 13 grams a day of vitamin C within their own bodies - more if under stress. This amount would be impossible to obtain from the diet. The roles of vitamin C in the body, its ready depletion by exposure to pollutants, smoking and stress, and the enhanced immunity afforded by a raised vitamin C intake have led many individuals to take a daily vitamin C supplement.

The view that, because the body excretes supplemented vitamin C, supplementation cannot make any difference to health is now considered outdated. Considerable research now supports the case for maintaining a high tissue saturation level of vitamin C in a variety of situations.

A severe deficiency of vitamin C (blood levels below 0.7 mg/100 ml) results in highly raised blood histamine levels. Vitamin C supplementation to 11 selected volunteers resulted in a reduction of the blood histamine level in every instance (Clemetson CA: Histamine and ascorbic acid in human blood. J Nutr 110(4):662-8, 1980).

SUPPLEMENTATION

In research studies, Vitamin C supplements have been found to:

  • Act as a mild antihistamine
  • Control and cure the common cold
  • Cure some cases of cancer
  • Cure some cases of the blood disease idiopathic thrombocytopenic purpura
  • Enhance the number, size and motility of white blood cells
  • Enhance wound healing
  • Help asthma
  • Help with the clearance of toxic chemicals from the body
  • Improve blood sugar control in diabetics
  • Improve manic depression
  • Inhibit the formation of adrenochrome, which is found at raised levels in schizophrenia
  • Lower blood cholesterol
  • Protect the eye lens against oxidative damage
  • Reverse pre-cancerous conditions
  • With vitamin E, slow the progression of Parkinson's disease.
Preferred form and suggested intake

Recommended preventive health level: 1 gram daily.

Common cold: At the first sign, take 1 level teaspoon (3 grams) of vitamin C powder dissolved in lukewarm water. Repeat every two hours between meals until symptoms subside. (See Factsheet for full instructions.)

For immune enhancement, cancers, or high cholesterol (especially with high lipoprotein A or high apolipoprotein A2 levels): 1 level teaspoon of vitamin C powder dissolved in lukewarm water 2-3 times daily between meals (see cautions below). For Aids and severe viral infections, this amount can be increased to bowel tolerance (see cautions below). Like all water-soluble vitamins, vitamin C is best taken at several intervals daily rather than in one single dose.

The preferred form of supplementation is magnesium ascorbate capsules (for smaller doses) and powder or crystals for a larger daily intake. This is a buffered, non-acidic form which also provides magnesium - a nutrient which is often in short supply in the diet. The magnesium content also helps to prevent vitamin C from combining with minerals and removing them from the intestinal contents.

Cautions

  • Do not take more than 1 gram a day of vitamin C if using the contraceptive pill, since vitamin C competes with oestrogen for excretion mechanisms.
  • When supplementing large amounts of vitamin C, and especially if you are using the acidic form (ascorbic acid), take it away from meals to prevent interference with the absorption of other nutrients. The use of powdered or crystalline vitamin C dissolved in plenty of water is less irritating to the digestive system than large numbers of tablets or capsules.
  • Body levels of copper and other trace elements should be monitored if very large doses of vitamin C are taken on a long-term basis.
  • Excess amounts of vitamin C may cause bowel discomfort and loose motions. If this occurs, reduce your intake. This effect is lessened by taking vitamin C powder or crystals dissolved in warm (not hot) water rather than cold.
  • The theory that vitamin C supplements may cause kidney stones has been disproven. Researchers have found that the high oxalate levels found in test subjects' urine were due to the analysis method used, not to the vitamin C. (Wandzilak et al: Effect of high dose vitamin C on urinary oxalate levels. J Urol 151:834-7, 1994.) However the subjects in this trial were normal individuals. There is some evidence that those who already have a tendency to form oxalate kidney stones should exercise caution with vitamin C supplements.
  • Vitamin C supplements do not cause 'rebound scurvy'. Scurvy is a life-threatening disease caused by long-term severe vitamin C deprivation.
  • Speculation that vitamin C supplements could cause the excessive absorption of iron has also been disproved by a review of the scientific literature. (Bendich A et al: Ascorbic acid safety: analysis of factors affecting iron absorption. Toxicol Lett 51(2):189-201, 1990.)

Adapted from the Nutritional Health Bible by Linda Lazarides
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