Vitamin C is a water-soluble vitamin sensitive to heat and light.
Chemically speaking, it is the L-ascorbic acid and its salts, ascorbates (the most common being the ascorbates sodium and calcium).
Vitamin C is an enzyme cofactor involved in a number of physiological responses (hydroxylation). It is required in the synthesis of collagen and red blood cells and contributes to the immune system. It also plays a role in iron metabolism. Under oxide form, it crosses the blood-brain barrier to enter the brain and several bodies with high concentrations of vitamin C. Very fragile solution, it is destroyed on contact with air, light or heat. It is an antioxidant, a substance that can counteract the harmful effects of oxidants such as free radicals. To this end, it also employs the form of L-ascorbic acid, which, unlike the L-form, shows no activity vitamin.
While most mammals are capable of synthesizing in their liver or kidney (it is not a vitamin for them), the majority of the primates (including humans), the guinea pig and some birds or fish are incapacitated. This is the result of a genetic mutation, there occurred 40 million years ago, blocking the conversion of glucose to ascorbic acid. The animals lacked this ability to synthesize vitamin C should therefore draw in their diet.
It advises usually a daily intake of 75 milligrams for women and 90 milligrams for men. Other primates, like humans, do not produce Vitamin C, consume between 2000 and 8000 mg / day. Their diet is closer than ours from what it was when the gene responsible for the ability to produce vitamin C has mutated, in our common ancestor. This constitutes the basis of several questioned the current RDA, especially by Pauling (see below). The recommended daily allowance (RDA) has increased from 60 mg to 110 mg recently (reference desired). Smokers have increased requirements for vitamin C, because smoking reduces the levels of vitamin C in the body. An orange supply an average of 53 mg of vitamin C (40 to 80 mg per 100 g).
An intake of less than 10 mg per day can cause scurvy.
For doses greater than 500 mg / d, an increase of production of oxalic acid induces a risk of oxalate kidney stones.
Some authors consider that the recommended dietary intake should be at least 200 mg, which corresponds to approximately five fresh fruit per day. Proponents of orthomolecular medicine including Linus Pauling recommend them consumption from 3000 to 18000 mg per day and over in the event of illness, based, first, on what other primates consume, and on the other , about what animals are capable of producing ascorbate occur when under stress. Such doses must be taken several times because of the limited ability of the body to absorb in a given period. A too rapid consumption of vitamin C in the form of acid gives rise to a slight diarrhea and mild, whose interest is to indicate the dose required by the body. The very large doses (more than 3 g / day) can be administered in the form of infusion of sodium ascorbate, but could cause some problems deficiency annexes.
According to several therapists and researchers making use of pharmacological doses of ascorbate, if this molecule is administered "in an appropriate form through appropriate techniques, sufficiently frequent doses, in high enough doses, together with certain agents and for a period sufficient", it can prevent and even, in many cases, cure many diseases, common or rare, fatal or not, including the flu and heart disease.
Synthesis of cholesterol
A survey carried out in 1986 indicated that vitamin C might have an important role in regulating the synthesis of cholesterol.
Vitamin C and lead
In 1939, it was reported that 34 workers have absorbed lead had been treated with vitamin C. Recently, a study on animals showed that vitamin C was protective against lead poisoning in terms of nerve and muscle function. Among smokers, the administration of 1000 mg of vitamin C has allowed an average reduction of 81% of blood concentrations of lead, while 200 mg had no effect. The authors therefore concluded that supplementation of vitamin C could represent an economical and convenient way to bring down levels of lead in their blood. The journal of the American Medical Association published a study concluding that the inverse association between lead and vitamin C in the blood, as found in a survey of national significance, if it is demonstrably causal , would have an impact in terms of public health in general.
Supplementation of vitamin C reduces the severity of symptoms in children with autism .
The emergence of multi-organ failure syndrome, which for Trauma is a major warning signs of death, appears less frequently in patients receiving vitamin C, vitamin also reduces the length of stay in ICU.
In infertile men, it was shown that supplemental vitamin C improved the quality of semen (morphology and mobility of sperm) and increased the number of sperm cells.
Diseases and immune dysfunction related to the age
The age-related diseases and immune dysfunctions associated with them could, according to a Canadian official gazette, be limited by the absorption of supplemental vitamin C.
Acquired Immunodeficiency Syndrome (AIDS): preliminary studies
One of the diseases whose treatment by any pharmacological doses of ascorbate is the most controversial is AIDS. The controversy has lasted for over 16 years, ie since the publication of a study showing that the ascorbate-dose non-toxic to humans, stopping replication of HIV, in the journal Proceedings of National Academy of Sciences of the United States. Other studies have followed and supported these findings, but no large-scale clinical study has been undertaken.
Poisoning by the Amanita
Vitamin C, précocément injected intravenously, is part of the treatment of poisoning phalloïdienne proposed by Dr. Pierre Bastien.
Tolerance intestinal denotes the amount of vitamin C that can be absorbed by the intestine in a given time. When that amount is reached, the non-absorbed vitamin C is excreted in the stool. During his trip, it draws the water in the intestine which produces transient diarrhea. This is one reason why we can not becoming intoxicated with vitamin C.
It should 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. It is drawing a parallel between this production variable ascorbate in animals with the variability of intestinal tolerance in humans. When a man is ill or under stress, its tolerance to intestinal vitamin C increases, which enables it to absorb more vitamin C than usual. The variability of tolerance intestinal suggests a greater need for the body of vitamin C during periods of stress or illness, as we observed in animals that synthesize vitamin C.
* In the fifth century BC. J.-C., Aristotle already knew the symptoms of scurvy. [Ref. Required]
* In 1227, Aguila of Gilbertus recommends that sailors boarding stocks of fresh fruit and vegetables to prevent scurvy. [Ref. Required]
* It was not until the eighteenth century that we discover that the consumption of lemons prevent this disease. James Lind, a physician Scots led what is considered the first scientific test: with 12 sailors scorbutiques divided into six groups of two, it administra each group a different substance, nutrition groups are also identical. These substances were: cider, sulfuric acid, vinegar, a concoction of herbs and spices, from seawater and oranges and lemons. Only the latter group is quickly cured scurvy.
* In 1928, Albert Szent-Gyorgyi isolated vitamin C and he was awarded the Nobel Prize for Medicine in 1937.
* This molecule was synthesized in 1933 by Tadeusz Reichstein then in 1934 by Walter Norman Haworth who received the Nobel Prize in Chemistry in 1937 for the discovery.
The world annual production of L-ascorbic acid is 80000 tonnes [ref. Required], half of which is used in pharmaceutical and pharmaceutical industries, 25% in food preservative (E300, E301, E302), 15% in the manufacture of beverages, the rest being used for feeding animals.
In plants, the synthesis of vitamin C is held indiscriminately in all cells of the plant. The fruits of the sea buckthorn are exceptionally rich in vitamin C.
In animals that are capable, synthesis takes place predominantly in the liver, but all other cells have the capacity, which remains very limited.
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