The vitamin C is a Vitamine water-soluble sensitive to heat.

Chemically speaking, they are the L-ascorbic acid and its salts, the ascorbates (most current being calcium and sodium ascorbates).

Action

The vitamin C is a enzymatic cofactor implied in a certain number of physiological reactions (Hydroxylation). It is necessary in the synthesis of the Collagène and the red globules and contributes to the Immune system. She also plays a part in the metabolism of the Fer. In oxidized form, it crosses the hemato-encephalic barrier to reach the brain and with several bodies with strong concentrations of vitamin C. Very fragile in solution, it is destroyed in contact with the air, by the light or heat. It is about a Antioxydant, molecule able to counter the harmful oxidant action like the free radical . For this purpose, one also employs the shape R of the ascorbic acid which, contrary to the form L, does not present a vitamin activity.

Synthesis

Whereas the majority of the mammals are able to synthesize it in their liver or their kidneys (it is thus not a Vitamine for them), majority of the Primate S (of which the human being), the Guinea-pig and certain birds or fish are unable. This is the result of a change Génétique, which has occurred 40 million years ago, blocking the transformation of the Glucose into ascorbic acid. The animals deprived of this capacity of synthesis of the vitamin C must thus draw it from their Alimentation.

Advised contributions

One in general advises a daily contribution of 75 Mg for the woman and 90 Mg for the man. The other primates which, like the human ones, do not produce a vitamin C, consume some between: 2000 and: 8000 Mg per day. Their food is closer than ours to than it was when the gene responsible for the capacity to produce vitamin transferred a.c., at our common ancestor. This fact constitutes the base of several handing-over in question of current AJR, in particular by Pauling (see low). The recommended daily contribution (AJR) passed from 60 Mg to 110 Mg récemment ^{(desired reference)} . The smokers have increased requirements in vitamin C, because the Tabagisme reduces the rate of vitamin C in the organization. An orange brings on average 53 Mg of vitamin C (40 to 80 Mg by 100 G).

A contribution of less than 10 Mg per day can cause the Scorbut.

For amounts higher than 500 mg/j, an increase in production of oxalic acid would induce a risk of oxalate renal calculi.

Certain authors consider that the nutritional contributions recommended should be at least 200 Mg, which corresponds to approximately five fresh fruits per day. Holding of the Medicine orthomoléculaire whose Linus Pauling recommends them a consumption of: 3000 with: 18000 Mg per day and more in the event of disease, while basing itself, on the one hand, on what the other primates consume and, on the other hand, on what the animals able to produce of the ascorbate produce when they undergo a stress. Such amounts must be taken in several times because of the capacity limited of the organization to absorb them in a given duration. A too fast consumption of vitamin C in the form of acid gives place to a Diarrhée light and benign, whose interest is to indicate the amount required by the organization.

Therapeutic uses

According to several therapeutists and researchers making use of pharmacological amounts of ascorbate, if this molecule is managed " in an adequate form, by means of adapted techniques, in sufficiently frequent amounts, sufficiently high amounts, conjunction with certain agents and for one period suffisante" , it can prevent and even, often, cure a great number of diseases, current or rare, mortals or not, in particular the influenza and the diseases coronary.

Synthesis of cholesterol

A study going back to 1986 indicates that the vitamin C could have a big role in the regulation of the synthesis of the Cholestérol.

Vitamin C and lead

In 1939, one announced that 34 workers having absorbed Plomb had been treated by means of the vitamin C. Recently, a study on animals showed that the vitamin C had a protective effect against the intoxication with lead in the fields of the function nervous and muscular. Among smokers, administration of 1000 Mg of vitamin a.c. allowed an average reduction of 81% of the blood lead concentrations, while 200 Mg remained without effect. The authors thus concluded that the supplementation of vitamin C could represent a way economic and practical cause a drop in the lead concentrations in blood. Newspaper of Association medical American has published study concluding that association reverses between lead and vitamin C in blood, as noted in investigation of scale national, if it were shown that it is causal, would in general have an impact in the field of the public health.

Autism

The supplementation of Vitamin C decreases the severity of the symptoms in the children reached of Autisme.

Traumatology

The appearance of the syndrome of Défaillance multiviscérale, which for the traumatologists is one of the principal signs heralding the death, less often appears among patients receiving of the vitamin C; this vitamin decreases also the durations of stays to the intensive care.

Fertility

At unfertile men, one showed that a supplement of vitamin C improved quality of sperm (morphology and motility of the Spermatozoïdes) and increased the number of spermatozoa.

Diseases and immunizing dysfunctions related to the age

The diseases related to the age and the immunizing dysfunctions which are associated there could, according to a Canadian official journal, being limited by the absorption of supplements of vitamin C.

Syndrome of acquired immunodéficience (AIDS): preliminary studies

One of the diseases whose possible treatment by pharmacological amounts of ascorbate is discussed the most is the AIDS. The hard controversy since more than 16 years, i.e. since the publication of a study showing that the ascorbate, in amounts not-poisons for the man, stopped the replication of the HIV, in a newspaper as respected as the Proceedings off National Academy off Sciences of the United States. Other studies followed and supported these results, but no clinical study of scale was undertaken.

Intestinal tolerance

The intestinal tolerance indicates the quantity of vitamin C which can be absorptive by the intestine in a given time. When this quantity is reached, the vitamin C not absorptive is eliminated in the saddles. During its way, it attracts water in the intestine what produces a momentary diarrhea. This is one of the reasons for which one cannot poison oneself with vitamin C.

It will be noted that the quantities produced by the animals vary according to their state of stress and health; a stressed or sick animal can produce several tens of grams per day. One can put in parallel this variable production of ascorbate in the animals with the variability of the intestinal tolerance at the human being. When human sick or is stressed, its intestinal tolerance with the vitamin C increases, which enables him to absorb more vitamin C than in normal weather. The variability of the intestinal tolerance suggests a need increased for the organization in vitamin C during the time of stress or diseases, as one observes it in the animals which synthesize the vitamin C.

History

• At the fifth century BC, Aristote knew already the symptoms of the scurvy.

• In 1227, Gilbertus de Aguila recommends to the sailors to embark stocks of Fruit S and Légume S fresh to prevent the scurvy.
• It is only at the 18th century which one discovers that the consumption of Citron S prevents this disease. James Lind, a Scottish doctor carried out what is regarded as the first scientific test: having divided 12 scorbutic sailors into six groups of two, it managed with each group a different substance, the nutrition of the groups being in addition identical. These substances were: the Cider, of the sulphuric Acid , of the Vinegar, a grass concoction and spices, sea water and orange S and lemons. Only the last group quickly cured scurvy.
• In 1928, Albert Szent-Gyorgyi insulated the vitamin C.
• Synthétisé in 1934, by Walter Norman Haworth.

Production

The annual worldwide production of L-ascorbic acid is of: 80000 tons, of which the half is used in the drug companies and parapharmaceutic, 25% in the agroalimentary one like conservative (E300, E301, E302), 15% in the manufacture of drinks, the remainder being used for the nutrition of the animals.

At the plants, the synthesis of the vitamin a.c. place indifferently in all the cells of the plant. The fruits of the Argousier are exceptionally rich in vitamin C.

In the animals which of it are able, the synthesis takes place mainly in the Foie, but all the other cells have of it the capacity, which remains however very limited.

Contents of vitamin C

It should be noted that the contents below are median values which can vary notably according to the varieties of the fruit and vegetables indicated. (Method evaluation: .)

References

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