The physiological function of vitamin C

Vitamin C is also called the L-ascorbic acid, is a water-soluble vitamins, to treat scurvy and has the acidity, so called ascorbic acid. In the lemon juice, green plants, and high levels of tomato. Ascorbic acid is a single oblique lamellar or needle crystal, easy to be oxidized and the dehydrogenation of the bad blood generated acid, acid, dehydrogenation of the bad blood still has the vitamin C effect. In alkaline solution, the dehydrogenation of the bad blood acid molecule of the lactone ring easily be hydrolyzed to diketones Angulo acid. This compound in animals can not become a lactone structure. The last generation in the human body together to form sulfuric acid or sulfuric acid ester from the urine discharge. Therefore, the dione Angulo acid no longer has the physiological activity.
Holst 1907, the Norwegian chemist found in the lemon juice in 1934 was to obtain the pure product, is now available for synthetic. Vitamin C is the most unstable of a vitamin, because it is easily oxidized, in food storage or cooking process, even when the chopped fresh vegetables, vitamin C can be destroyed. Traces of copper, iron ions can accelerate the pace of destruction. Therefore, only fresh vegetables, fruits or raw PICKLES is a rich source of vitamin C. It is colorless crystals, melting point 190 ~ 192 ℃, soluble in water, acidic aqueous solution, the chemical nature of the more lively, when exposed to heat, alkali and heavy metal ions easy to degrade, so it is not available copper pots cooking and heating for too long.
The vast majority of plants and animals, can be found in the body's own synthesis of vitamin C. But the people, primates, and guinea pigs due to the lack of the L-Angulo acid into vitamin C, enzymes, not synthetic vitamin C, and must be from food intake, if the diet deficient in vitamin C, will occur scurvy. At this time due to stromal cells generate barriers bleeding, teeth loose, wound healing is not easy, easy to fractures and other symptoms. As the vitamin C in the human body a longer half-life (approximately 16 days), so food does not contain vitamin C, food 3 to 4 months to appear scurvy. Because vitamin C susceptible to oxidation and reduction, it is generally believed that the natural role should be associated with this characteristics. Vitamin C and collagen synthesis of normal, in vivo tyrosine metabolism and iron absorption are directly related. Vitamin C's primary function is to help complete the redox reaction of the body, improve the ability of human sterilization and detoxification capacity. The long-term lack of vitamin C will get scurvy,. Eat more fruits and vegetables to meet the body's vitamin C needs. Vitamin C in the promotion of a solid structure of brain cells, prevent brain cell structure relaxation and contraction play a considerable role, and be able to transport nutrients to prevent neural tube plug thin, variable thin, flaccid. Intake of adequate amounts of vitamin C can improve the permeability of nerve thin tube, so that the brain the successful and timely access to nutritional supplements, so that improved mental, intelligence increase. According to Nobel Prize winner Pauling's research, serving high-dose vitamin C in preventing colds and cancer have a certain effect. However, it was suggested that there was ferrous ions (Fe2 +) the presence of vitamin C can promote free radical generation, and therefore that the application of a large number is unsafe.
The daily demand: adult daily intake needs 50 ~ 100mg. That half of the guava, 75 g pepper, 90 grams of broccoli, 2 kiwi fruit, 150 grams of strawberries, one grapefruit, half a papaya, 125 g of fennel, 150 grams of cauliflower can be 200 ml orange juice.
Effects: Vitamin C can capture free radicals, in this can prevent such as cancer, arteriosclerosis, rheumatism and other diseases. In addition, it can also enhance immunity and, to the skin, gums and nerves is also beneficial.
Side effects: To date, vitamin C was not considered harmful, because the kidney can excrete the extra vitamin C out of the new U.S. study published report said the body of vitamin C a large number of the negative cycle of wound healing. Daily intake of more than 1000 mg of vitamin C can cause diarrhea, kidney stones and cases of infertility, or even to cause genetic defects.
Vitamin C, adverse reactions
According to domestic and international studies have shown that, with the increasing dosage of vitamin C increased, resulting in an increasing number of adverse reactions.
Diarrhea. Take 1 to 4 grams per day of vitamin C, you can make a small bowel movement acceleration, abdominal pain, diarrhea embolism.
Bleeding. Long-term high level of oral vitamin C, will occur nausea, vomiting and so on. At the same time, due to an increase in gastric acid secretion, can promote stomach and duodenal ulcer pain got worse, can lead to severe gastric mucosal hyperemia, edema, which led to bleeding.
Stone. A lot of vitamin C into the body, most of the liver metabolism has been broken down, the final product as oxalic acid, oxalic acid excretion from the urine as oxalate; others found that daily oral administration of 4 grams of vitamin C, in 24 hours, urine oxalate content will surge from 58 mg to 620 mg. If the continued use, increased oxalate is easy to form a urinary tract stones.
Gout. Gout is due to occur in vivo purine metabolism disorder caused by a disease, mainly manifested as excessive concentration of uric acid in the blood, resulting in joints, connective tissue and kidneys, etc. a series of symptoms. The large doses of vitamin C, can cause sharp increase in uric acid, induced gout.
Baby-dependent. Continuous large number of pregnant women taking vitamin C, cause the fetus to become drug dependent. After birth, if not to the baby taking a lot of vitamin C, scurvy may occur, such as lack of energy there, gingival swelling and bleeding, subcutaneous bleeding; even the gastrointestinal tract, urinary tract bleeding and other symptoms.
Children's orthopedic disease. A large number of children taking vitamin C, may be suffering from bone disease, and the higher incidence.
Infertility. Women of childbearing age consume large quantities of vitamin C (such as the daily dose is greater than 2 g pm), will reduce fertility.
Immune systems are weak. Long-term large doses of vitamin C, can reduce the phagocytic function of leukocytes, so that the body decreased disease resistance.
Allergic reaction. Mainly as a rash, nausea, vomiting, severe anaphylactic shock can occur, it can not be abused.