Версия для печати

Description

Vitamin C, also known as ascorbic acid, is a water-soluble nutrient. Although fairly stable in acid solution, it is normally the least stable of vitamins and is very sensitive to oxygen. Its potency can be lost through exposure to light, heat, and air, which stimulate the activity of oxidative enzymes.

A primary function of vitamin C is maintaining collagen, a protein necessary for the formation of connective tissue in skin, ligaments, and bones. Vitamin C plays a role in healing wounds and burns because it facilitates the formation of connective tissue in the scar. Vitamin C also aids in forming red blood cells and preventing hemorrhaging. In addition, vitamin C fights bacterial infections and reduces the effects on the body of some allergy-producing substances. For these reasons, vitamin C is frequently used in preventing and treating the common cold.

Vitamin C has significant relationships with other nutrients. It aids in the metabolism of the amino acids phenylalanine and tyrosine. Vitamin C converts the inactive form of folic acid to the active form, folinic acid, and may have a role in calcium metabolism. In addition, vitamin C protects thiamine, riboflavin, folic acid, pantothenic acid, and vitamins A and E against oxidation. It protects the brain and spinal cord from destruction by free radicals.

Large concentrations of vitamin C are found in the adrenal glands, and the vitamin is essential in the formation of adrenalin. During stress, the level of adrenal ascorbic acid is rapidly used up.

The intestinal absorption of iron is greatly increased by adequate vitamin C. Vitamin C is present in most fresh fruits and vegetables.

Absorption and Storage

The level of ascorbic acid in the blood reaches a maximum in 2 or 3 hours after ingestion of a moderate quantity, then decreases as it is eliminated in the urine and through perspiration. Most vitamin C is out of the body in 3 or 4 hours. Increased urinary output of vitamin C resulting from larger intake of the vitamin does not mean body tissues are saturated. The blood level of vitamin C will return to its average level in 12 to 13 hours regardless of the amount ingested. To maintain adequate serum level, the vitamin should be taken throughout the day. Excess vitamin C carried to the bladder may prevent bladder cancer.

Because vitamin C is a "stress vitamin," it is used up even more rapidly under stressful conditions. Man, apes, and guinea pigs are among the very few animals that need vitamin C in their foodstuffs, because they are unable to meet body needs by synthesis and must rely upon a dietary source.

Taken orally, most of the vitamin is absorbed through the mucous membranes of the mouth, stomach, and upper part of the small intestine. The larger the dose, the less is absorbed. For example, 80 percent of less than 250 milligrams ingested is absorbed; a dose of up to 2 grains results in about 50 percent absorption. Therefore it is best to take vitamin C in small doses several times a day. In therapeutic treatment, injection of several grams of sodium ascorbate into the bloodstream is more effective than the same amount taken by mouth.

The normal human body when fully saturated contains about 5000 milligrams of vitamin C, of which 30 milligrams are found in the adrenal glands, 200 milligrams in the extracellular fluids, and the rest distributed in varying concentrations throughout the cells of the body. The body's ability to absorb vitamin C is reduced by smoking, stress, high fever, prolonged administration of antibiotics or cortisone, inhalation of DDT or fumes of petroleum, and ingestion of aspirin or other pain killers. Sulfa drugs increase urinary excretion of vitamin C by two or three times the normal amount. Baking soda creates an alkaline medium that destroys vitamin C. In addition, drinking excessive amounts of water will deplete the body's vitamin C. Cooking in copper utensils will

Dosage and Toxicity

The National Research Council recommends 60 milligrams of vitamin C for adults. The requirement may vary due to differences in weight, amount of activity, rate of metabolism, ailments, and age. Periods of stress, such as anxiety, infection, injury, surgery, burns, or fatigue, increase the body's need for this vitamin.

Individuals who are hypoglycemic or are on a high-protein diet need more vitamin C, as these conditions interfere with the vitamin's metabolism. Persons with high copper or iron blood levels need a larger intake of vitamin C. Any condition that elevates the serum copper increases the need for sufficient C, including schizophrenia, smoking, use of the contraceptive pill, menstruation, and the last months of pregnancy.

It is better to take frequent small doses of the vitamin instead of a single large dose, because the body can absorb only a certain amount during a given period of time. Ingestion of above 100 milligrams of vitamin C at one time results in decreased efficiency of absorption and an increased rate of excretion of unmetabolized ascorbic acid.

When vitamin C is given for therapeutic reasons, dosage is very important. Too little will have little or no effect. Dr. Frederick Klenner recommends 30 grams a day as necessary for proper response. When megavitamin doses of vitamin C are given it is important that calcium intake be increased.

Large doses may have side effects in some persons. Symptoms can be a slight burning sensation during urination, loose bowels, intestinal gas, and/or skin rashes. When any symptom occurs, dosage should be reduced. It may help to take the vitamin after a meal, which is also better for proper assimilation. If symptoms persist, various kinds of C may be tried.

Large doses of C should not be taken by people with a tendency to formation of oxalate stones, or cystinuria, unless it is in the form of sodium ascorbate. Sodium ascorbate does not affect the acidity of the urine and aids in oxalate excretion.

Some people have a rare genetic disease that forms kidney stones when large amounts of C are taken. These people need to reduce their intake of the vitamin. Vitamin C can give blood sugar tests, except the hexokinase test, or glucose oxidase test, a false reading. Lowering the dose level of vitamin C after ingestion of high doses can result in symptoms of scurvy. Therefore, reduction of the vitamin should be done slowly over a period of time until the body has adjusted.

Deficiency Effects and Symptoms

Signs of deficiency are shortness of breath, impaired digestion, poor lactation, bleeding gums, weakened enamel or dentine, tendency to bruising, swollen or painful joints, nosebleeds, anemia, lowered resistance to infections, and slow healing of wounds and fractures. Severe deficiency results in scurvy. Breaks in the capillary walls are signs of vitamin C deficiency, and clots usually form at the point of the break. Therefore a lack of vitamin C is a probable cause of heart attacks and strokes initiated by clots. The blood level of ascorbic acid is known to be lowered by smoking. Nicotine added to a sample of human blood of known ascorbic acid content decreased the ascorbic acid content of the blood by 24 to 31 percent.

Alcoholics have a very low C serum level because so much of the vitamin is used to destroy the toxic effects.

Beneficial Effect on Ailments

Vitamin C plays an important role in preventing and relieving scurvy. Vitamin C promotes fine bone and tooth formation while protecting the dentine and pulp. It reduces the effects on the body of some allergy-producing substances. Vitamin C is frequently used in the prevention and treatment of the common cold.

The lubricating fluid of joints (synovial fluid) becomes thinner (allowing freer movement) when the serum levels of ascorbic acid are high. Therefore arthritic patients given vitamin C may find some relief of pain. It is an important nutrient in treating wounds because it speeds up the healing process. Ascorbic acid may lower blood cholesterol content of patients with arteriosclerosis. The serum cholesterol level in individuals has been reduced 35 to 40 percent by vitamin C.

The need for vitamin C increases with age due to a greater need to regenerate collagen. With age, the sex glands develop a greater need for vitamin C and will draw it from other tissues, leaving these tissues

vulnerable to disease. Therefore proper supplementation will help reduce depletion. Vitamin C is important in all stressful conditions. The tissue requirements for ascorbic acid are increased under conditions of increased metabolism.

Vitamin C stimulates the production of interferon and acts as an inactivator against viruses including herpes, vaccinia, hepatitis, polio, encephalitis, measles, and pneumonia. This is accomplished because vitamin C, catalyzed by copper ions, reduces oxygen molecules to molecules that, in turn, attack the nucleic acid of the virus. This same mechanism, plus the fact that vitamin C increases the power of the body's defense systems, works against bacteria, including the bacterias responsible for tuberculosis, diphtheria, tetanus, staph-ylococcus, and typhoid fever.

If enough vitamin C has been given to saturate the tissues, it will enter cells where dormant viruses are and destroy them. For more than 25 years, Dr. Frederick Klenner of Reidsville, North Carolina, has been using vitamin C to treat viral diseases. His treatment involves administration, either intravenously or by mouth, of 20 to 40 grams vitamin C daily.

Massive doses of vitamin C have been used to cure drug addicts, including users of heroin, methadone, and barbiturates. Chiropractor Alfred F. Libby of Santa Ana, California, has successfully administered 25 to 85 grams of sodium ascorbate, a version of vitamin C, for 4 days, then reduced the dose to 5 grams of sodium ascorbate and 5 grams of ascorbic acid. The treatment eases heroin withdrawal, helps to restore proper appetite and restfulness, and helps to eliminate abnormal thought patterns.

Vitamin C has been found to be of value in minimizing the effects of environmental pollution, including carbon monoxide, cadmium, mercury, lead, iron, copper, arsenic, benzene, and some pesticides.

Physicians in Scotland report that vitamin C counteracts bleeding in the gastrointestinal tract caused by aspirin or alcohol. The bleeding may also continue or restart if sufficient C is not available for wound healing.

Vitamin C prevents the formation of carcinogenic nitrosamines from nitrites and nitrates found in some foods. Vitamin C has been successfully used to treat snake and spider bites, insect stings and rabies. Vitamin C is important for recovery from heart attacks by preventing free radical damage. However, the heartwill take so much of the vitamin from other body tissues that sufficient supplementation is essential.

Dr. Carl PfeifFer reports that vitamin C has an anti-anxiety effect on the nervous system. He uses the vitamin in treating schizophrenia. Studies have shown that psychiatric patients have an unusually high need for vitamin C. Vitamin C treatment results in improvement of depression and paranoia.

Vitamin C is essential for stimulating the immune system, enabling the body to resist diseases including cancer. Some individuals taking 10 grams of C a day have reportedly been cured of their cancer. Other terminal cancer patients lived four times longer than those in a control group.

Dr. James Greenwood at Baylor University has reported from his observations that a more-than-average intake of vitamin C helps preserve the integrity of inter-vertebral disks and helps prevent back problems. Vitamin C has been used in tests determining its effect on intelligence. A study using control groups of children resulted in a 3.6 IQ rise when a 50 percent increase of vitamin C intake was administered.

Low outdoor temperatures increase the body's need for vitamin C. The vitamin, in part, improves the metabolism of tyrosine and phenylalanine, precursors of such heat-raising hormones as the thyroid.

Laboratory tests on monkeys have shown that vitamin C can protect against frostbite. Russian studies have shown vitamin C to slow the aging process. Russian athletes use the vitamin to build muscle tissue. Vitamin C can reduce the amount needed of some drugs, including L-Dopa and painkillers given to cancer patients. The vitamin prevents certain enzymes from breaking down the natural painkilling compounds of the brain.

Vitamin C helps victims of shock from injury, electric shock, and lightning. It prevents prickly heat and heat stroke. Leukemia, pancreatitis, and rheumatic heart disease respond well to vitamin C therapy. Powdered vitamin C mixed with water to form a paste and then applied on the skin will clear up poison ivy or oak in 24 hours if adequate oral doses of the vitamin are taken at the same time.