Vitamin C

Proper name Ascorbic acid
Category Vitamin
Functions Connective tissue - Collagen and elastin formation are dependent on vitamin C. Collagen and elastin are the building material of bone matrix, cartilage, tendons, ligaments, dentin, skin, capillary walls and other forms of connective tissue. Collagen is the most abundant protein in the human body, accounting for 25-30% of total body protein. Antioxidant - Vitamin C donates hydrogen ions to neutralize free radicals. Vitamin C is water soluble and is present in all body fluids and tissues. It is especially important in protecting the brain against the aging effects of free radicals. Vitamin C also helps to regenerate the antioxidant capacity of vitamin E. Hormones - Assists in the synthesis of carnatine and many peptide hormones; serotonin, thyroxine, norepinephrine as well as corticosteroids and receptors for the neurotransmitter, acetylcholine. Blood - Assists in the formation of hemoglobin by aiding the absorption of iron and separating iron from ferritin so that the iron is available to be incorporated in hemoglobin. Anti-infection - Vitamin C stimulates the production of interferons, proteins that protect cells from viral attack. Vitamin C has been used effectively to treat the common cold, herbes, viral hepatitis, poliovirus, etc. Meta-analysis of 14 placebo controlled studies on the common cold show vitamin C reduces the severity of symptoms and reduces the duration of colds by 35%. Vitamin C increases the production of white blood cells (neutraphils, lymphocytes and natural killer cells) as well as the production of antibodies IgA, IgG and IgM. Stress and healing - Vitamin C assists in synthesis of adrenal hormones needed to cope with stress; adrenalin, noradrenalin, cortisol and histamine. These hormones assist in coping with fever, illness, burns and exposure to cold, radiation, high altitude, radiation exposure, fractures and wounds. Allergies and asthma - Vitamin C inhibits the release and enhances degradation of histamine, thus having an anti-histamine effect. Vitamin C also inhibits phosphodiesterase (similar to the action of some asthma medications). Cardiovascular - Vitamin C increases HDL (the "good" cholesterol) while decreasing LDL (the "bad" cholesterol) and total cholesterol by converting them to bile acids for excretion. It decreases lipoprotein(a), a factor in the production of atherosclerotic plaque. Vitamin C also dissolves atherosclerotic plaques by forming water soluble compounds that can be excreted (exchanges sodium for calcium in the plaque to form two water-soluble compounds). Cancer prevention - Plasma vitamin C levels are inversely correlated with gastrointestinal and cervical cancers. Vitamin C reduces cervical dysplasia and is claimed to inhibit bladder cancer. Vitamin C prevents the formation of nitrosamines (a tumor inducing factor found in meats) and other free radicals. Vitamin C protects tissue integrity by maintaining normal collagen formation and by inhibiting hyaluronidase (an enzyme found in malignant tumors that allows cancer to be more invasive).
RDA 60 mg per day, 100 mg per day for smokers, pregnant or lactating women, or persons suffering from infection, stress or fever.
Therapeutic dose Dr Linus Pauling routinely recommended 16,000 mg for a 150 pound adult, based on the observation that a primate would eat that much and other mammals would manufacture that much. Higher doses have been used therapeutically. Dr Cameron advocates "bowel tolerance" dosing, i.e., taking increasing amounts of vitamin C until soft stools and flatulence are induced, then reducing the dose just below the production of those symptoms. Many people take 500 to 1,000 mg per day. Toxicity Excessive intake of vitamin C induces diarrhea which generally inhibits continued overdosing. The mineral ascorbate forms are less acidic and generally better tolerated. Vitamin C does bind with divalent cations including; iron, calcium and heavy metals such as lead, arsenic and mercury, cadmium and nickel. While vitamin C is therefore useful in reducing heavy metal poisoning, prolonged high doses may lead to possible deficiencies of calcium and iron. In some individuals, vitamin C produces excess amounts of oxalic acid which theoretically, could cause kidney stone formation. Persons with a history of gout, kidney stones or kidney disease should not take doses of vitamin C above the RDA without consulting a physician.
Deficiency symptoms Scurvy, a hemorrhagic disease characterized by diffuse bleeding and bruising, joint and limb pain, swollen painful bleeding gums with teeth falling out, hemorrhages inside bones causing them to thicken and fracture easily, poor wound healing and muscle weakness. Anemia
Toxicity No known toxicity.
Best forms  Esterified C (calcium ascorbate and dehydroascorbate with 3 metoblites: calcium threonate, xylonate and lyxonate), Ascorbyl palmitate, Ascorbic acid is less expensive but contains sodium. The addition of 4 to 1 bioflavenoids to C enhances absorbtion and retention of C
Food sources Fresh fruits and vegetables, especially citrus fruits, strawberries, cantaloupe, currents, blueberries, papaya, tomatoes, peppers, leafy greens, broccoli and Brussels sprouts.
Lab tests Vitamin C can be assayed by testing leucocyte ascorbic acid. Vitamin C interferes with measurement of serum glucose and occult blood in the stool.
Drug interactions Vitamin C is depleted by Aspirin, Bumetamide, Choline Magnesium Trisalicylate, Corticosteroids, Ethacrynic Acid, Furosemide, Oral contraceptives, Torsemide.
Nutrient interactions Assists in the absorption of iron and the synthesis of carnatine (an amino acid).

In all animals other than primates (including humans) vitamin C is made from glucose. Presumably, our primate ancestors didn't need to make their own vitamin C as they were getting enough from their diet. Vitamin C is concentrated in the adrenals, brain, liver, pancreas, thymus and spleen. It is unstable, easily oxidized and destroyed by cooking, oxygen and alkalis. Vitamin C is absorbed in the small intestine. Absorption is impaired in persons deficient in hydrochloric acid or suffering from bleeding of the GI tract. The body stores as much as 4 grams of vitamin C. Excess amounts are excreted in the urine.

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