How much do we know about Vitamin-C ?

Vitamin C

　

© Elson M. Haas M.D. 
(Excerpted from Staying Healthy with Nutrition:
The Complete Guide to Diet and Nutritional Medicine
Published by Celestial Arts)
from: http://www.healthy.net/scr/Article.asp?Id=2134&xcntr=1

Vitamin C (Ascorbic Acid) is a very important essential nutrient—that is, we must obtain it from diet. It is found only in the fruit and vegetable foods and is highest in fresh, uncooked foods. Vitamin C is one of the least stable vitamins, and cooking can destroy much of this water-soluble vitamin from foods. In recent years, the C of this much-publicized vitamin has also stood for controversy. With Linus Pauling and others claiming that vitamin C has the potential to prevent and treat the common cold, flus, and cancer, all of which plague our society, concern has arisen in the medical establishment about these claims and the megadose requirements needed to achieve the hoped-for results. Some studies suggest that these claims have some validity; however, there is more personal testimony from avid users of ascorbic acid than there is irrefutable evidence. There has also been some recent research that disproves the claims about treatment and prevention of colds and cancer with vitamin C. However, in most cases, studies showing vitamin C to be ineffective used lower dosages than Dr. Pauling recommended. Overall, vitamin C research is heavily weighted to the positive side for its use in the treatment of many conditions, including the common cold. C also stands for citrus, where this vitamin is found. It could also stand for collagen, the protein "cement" that is formed with ascorbic acid as a required cofactor. Many foods contain vitamin C, and many important functions are mediated by it as well. Vitamin C is a weak acid and is stable in weak acids. Alkalis, such as baking soda, however, destroy ascorbic acid. It is also easily oxidized in air and sensitive to heat and light. Since it is contained in the watery part of fruits and vegetables, it is easily lost during cooking in water. Loss is minimized when vegetables such as broccoli or Brussels sprouts are cooked over water in a double boiler instead of directly in water. The mineral copper, in the water or in the cookware, diminishes vitamin C content of foods. Ascorbic acid was not isolated from lemons until 1932, though the scourge of scurvy, the vitamin C deficiency disease, has been present for thousands of years. It was first written about circa 1500 B.C. and then described by Aristotle in 450 B.C. as a syndrome characterized by lack of energy, gum inflammation, tooth decay, and bleeding problems. In the 1700s, high percentages of sailors with the British navy and other fleets died from scurvy, until James Lind discovered that the juice of lemons could cure and also prevent this devastating and deadly disease. The ships then carried British West Indies limes for the sailors to consume daily to maintain health, and thus these sailors became known as "limeys." Other cultures of the world discovered their own sources of vitamin C. Powdered rose hips, acerola cherries, or spruce needles were consumed regularly, usually as teas, to prevent the scurvy disease. In earlier times, humans consumed large amounts of vitamin C in their fresh and wholesome native diet, as apes (another species that does not make vitamin C) still do. Most other animals, except guinea pigs, produce ascorbic acid in the liver from glucose, and in relative amounts much higher than we get from our diets today. For this reason, Dr. Pauling and others feel that our bodies need somewhere between 2,000 and 9,000 mg. of vitamin C daily. These amounts seem a little high to me, given the basic food values of vitamin C. Some authorities feel we need 600–1,200 mg. daily based on extrapolations from the historical herbivore, early-human diet. These levels can be obtained today by eating sufficient fresh food; a diet that includes foods with high levels of vitamin C can provide several grams or more per day.

Ascorbic acid is readily absorbed from the intestines, ideally about 80–90 percent of that ingested. It is used by the body in about two hours and then usually out of the blood within three to four hours. For this reason, it is suggested that vitamin C supplements be taken at four-hour intervals rather than once a day; or it may be taken as time-released ascorbic acid. Vitamin C is used up even more rapidly under stressful conditions, with alcohol use, and with smoking. Vitamin C blood levels of smokers are much lower than those of nonsmokers given the same intakes. Other situations and substances that reduce absorption or increase utilization include fever, viral illness, antibiotics, cortisone, aspirin and other pain medicines, environmental toxins such as DDT, petroleum products, or carbon monoxide, and exposure to heavy metals such as lead, mercury, or cadmium. Sulfa antibiotics increase elimination of vitamin C from the body by two to three times. Some ascorbic acid is stored in the body, where it seems to concentrate in the organs of higher metabolic activity. These include the adrenal glands (about 30 mg.), pituitary, brain, eyes, ovaries, and testes. A total of about 30 mg. per pound of body weight. We likely need at least 200 mg. a day in our diet to maintain body stores—much more if we smoke, drink alcohol, are under stress, have allergies, are elderly, or have diabetes. Vitamin C is a very complex and important vitamin. The recommended amounts vary more widely than those for any other nutrient, ranging from 100–80 or 100 grams daily, depending on the condition. C is also the most commonly supplemented vitamin among the general public, because of either the popular press or its good effect, or because of the other common C—the "cold." Sources: The best-known sources of vitamin C are the citrus fruits—oranges, lemons, limes, tangerines, and grapefruits. The fruits with the highest natural concentrations are citrus fruits, rose hips, and acerola cherries, followed by papayas, cantaloupes, and strawberries. Good vegetable sources include red and green peppers (the best), broccoli, Brussels sprouts, tomatoes, asparagus, parsley, dark leafy greens, cabbage, and sauerkraut. There is not much available in the whole grains, seeds, and beans; however, when these are sprouted, their vitamin C content shoots up. Sprouts, then, are good foods for winter and early spring, when other fresh fruits and vegetables are not as available. Animal foods contain almost no vitamin C; though fish, if eaten raw, has enough to prevent deficiency symptoms. Natural vitamin C supplements are usually made from rose hips, acerola cherries, peppers, or citrus fruits. Vitamin C can be synthesized from corn syrup, which is high in dextrose, much as it is made from glucose in most other animals’ bodies. Synthetic ascorbic acid, though it can be concentrated for higher doses than natural extracts, is still usually made from food sources. Sago palm is another fairly new source of vitamin C supplements. It is used primarily as a lower allergenic source than the corn-extracted ascorbic acid. Functions: One important function of vitamin C is in the formation and maintenance of collagen, the basis of connective tissue, which is found in skin, ligaments, cartilage, vertebral discs, joint linings, capillary walls, and the bones and teeth. Collagen, and thus vitamin C, is needed to give support and shape to the body, to help wounds heal, and to maintain healthy blood vessels. Specifically, ascorbic acid works as a coenzyme to convert proline and lysine to hydroxyproline and hydroxylysine, both important to the collagen structure. 　 Vitamin C also aids the metabolism of tyrosine, folic acid, and tryptophan. Tryptophan is converted in the presence of ascorbic acid to 5-hydroxytryptophan, which forms serotonin, an important brain chemical. Vitamin C also helps folic acid convert to its active form, tetrahydrofolic acid, and tyrosine needs ascorbic acid to form the neurotransmitter substances dopamine and epinephrine. Vitamin C stimulates adrenal function and the release of norepinephrine and epinephrine (adrenaline), our stress hormones; however, prolonged stress depletes vitamin C in the adrenals and decreases the blood levels. Ascorbic acid also helps thyroid hormone production, and it aids in cholesterol metabolism, increasing its elimination and thereby assisting in lowering blood cholesterol. Vitamin C is an antioxidant vitamin. By this function, it helps prevent oxidation of water-soluble molecules that could otherwise create free radicals, which may generate cellular injury and disease. Vitamin C also indirectly protects the fat-soluble vitamins A and E as well as some of the B vitamins, such as riboflavin, thiamine, folic acid, and pantothenic acid, from oxidation. Ascorbic acid acts as a detoxifier and may reduce the side effects of drugs such as cortisone, aspirin, and insulin; it may also reduce the toxicity of the heavy metals lead, mercury, and arsenic. Vitamin C is being shown through continued research to stimulate the immune system; through this function, along with its antioxidant function, it may help in the prevention and treatment of infections and other diseases. Ascorbic acid may activate neutrophils, the most prevalent white blood cells that work on the frontline defense in more hand-to-hand combat than other white blood cells. It also seems to increase production of lymphocytes, the white cells important in antibody production and in coordinating the cellular immune functions. In this way also, C may be helpful against bacterial, viral, and fungal diseases. In higher amounts, ascorbic acid may actually increase interferon production and thus activate the immune response to viruses; it may also decrease the production of histamine, thereby reducing immediate allergy potential. Further research must be done for more definitive knowledge about vitamin C’s actions in the prevention and treatment of disease. Uses: There are a great many clinical and nutritional uses for ascorbic acid in its variety of available supplements. C for the common cold is indeed used very widely; its use in the treatment of cancer is more controversial, probably because of the seriousness of the disease and the political environment within the medical system—anything nutritional or alternative in regard to cancer therapy is looked upon with skepticism by orthodox physicians. For the prevention of cancer, there is reason for more optimism about the usefulness of vitamin C (as well as the other antioxidant nutrients—vitamin E, selenium, beta-carotene, and zinc) because of its effect in preventing the formation of free radicals (caused mainly by the oxidation of fats), which play a role in the genesis of disease. Given the functions of vitamin C alone, it has a wide range of clinical uses. For the prevention and treatment of the common cold and flu syndrome, vitamin C produces a positive immunological response to help fight bacteria and viruses. Its support of the adrenal function and role in the production of adrenal hormones epinephrine and norepinephrine can help the body handle infections and stress of all kinds. Because of this adrenal-augmenting response, as well as thyroid support provided by stimulating production of thyroxine (T4) hormone, vitamin C may help with problems of fatigue and slow metabolism. It also helps counteract the side effects of cortisone drug therapy and may counteract the decreased cellular immunity experienced during the course of treatment with these commonly used immune-suppressive drugs. 　 Because of ascorbic acid’s role in immunity, its antioxidant effect, the adrenal support it provides, and probably its ability to make tissues healthy through its formation and maintenance of collagen, vitamin C is used to treat a wide range of viral, bacterial, and fungal infections and inflammatory problems of all kinds. I have used vitamin C successfully in many viral conditions, including colds, flus, hepatitis, Herpes simplex infections, mononucleosis, measles, and shingles. Recently, vitamin C has been shown in some studies to enhance the production and activity of interferon, an antiviral substance produced by our bodies. To affect these conditions, the vitamin C dosage is usually fairly high, at least 5–10 grams per day, but it is possible that much smaller doses are as effective. Vitamin C is also used to treat problems due to general inflammation from microorganisms, irritants, and/or decreased resistance; these problems may include cystitis, bronchitis, prostatitis, bursitis, arthritis (both osteo- and rheumatoid), and some chronic skin problems (dermatitis). With arthritis, there is some suggestion that increased ascorbic acid may improve the integrity of membranes in joints. In gouty arthritis, vitamin C improves the elimination of uric acid (the irritant) through the kidneys. Ascorbic acid has also been helpful for relief of back pain and pain from inflamed vertebral discs, as well as the inflammatory pain that is sometimes associated with rigorous exercise. In asthma, vitamin C may relieve the bronchospasm caused by noxious stimuli or when this tight-chest feeling is experienced during exercise. Vitamin C’s vital function in helping produce and maintain healthy collagen allows it to support the body cells and tissues and bring more rapid healing to injured or aging tissues. Therefore, it is used by many physicians for problems of rapid aging, burns, fracture healing, bedsores and other skin ulcers and to speed wound healing after in-jury or surgery. Peptic ulcers also appear to heal more rapidly with vitamin C therapy. The pre- and postsurgical use of vitamin C supplementation can have great benefits. With its collagen function, adrenal support, and immune response support, it helps the body defend against infection, supports tissue health and healing, and improves the ability to handle the stress of surgery. Vitamin A and zinc are the other important pre- and postsurgical nutrients shown by research to reduce hospitalization time and increase healing rates, thereby preventing a number of potential complications. Vitamin C is also used to aid those withdrawing from drug addictions, addictions to such substances as narcotics and alcohol, as well as nicotine, caffeine, and even sugar—three very common addictions and abuses. High-level ascorbic acid may decrease withdrawal symptoms from these substances and increase the appetite and feeling of well-being. For this reason, it may be helpful in some depression and other mental problems associated with detoxification during withdrawal. Vitamin C also may reduce the effects of pollution, likely through its antioxidant effect, its detoxifying help, and its adrenal and immune support; specifically, it may participate in protecting us from smog, carbon monoxide, lead, mercury, and cadmium. Vitamin C is a natural laxative and may help with constipation problems. In fact, the main side effect of too much vitamin C intake is diarrhea. For iron-deficiency anemia, vitamin C helps the absorption of iron (especially the nonheme or vegetable-source iron) from the gastrointestinal tract. In diabetes, it is commonly used to improve the utilization of blood sugar and thereby reduce it, but there is no clear evidence that regular vitamin C usage alone can prevent diabetes. There are some preliminary reports that ascorbic acid may help prevent cataract formation (probably through its antioxidant effect) and may be helpful in the prevention and treatment of glaucoma, as well as certain cases of male infertility caused from the clumping together of sperm, which decreases sperm function

Vitamin C has a probable role in the prevention and treatment of atherosclerosis and, thereby, in reducing the risks of heart disease and its devastating results. It has been shown to reduce platelet aggregation, a factor important in reducing the formation of plaque and clots. Ascorbic acid has a triglyceride- and cholesterol-reducing effect and, more important, may help to raise the "good" HDL. This action needs further investigation, though the research is supportive so far. I haven’t even mentioned the prevention of scurvy, which really takes very little vitamin C, about 10 mg. per day. This disease used to be a big concern and was often fatal unless the victim ate some citrus or other fresh fruit and vegetables containing a small amount of vitamin C. I do not really want to approach the cancer and vitamin C issue; it deserves a book by itself. However, if we closely analyze the functions (antioxidant, immune support, interferon, tissue health and healing) that vitamin C performs in the body, along with the still mysterious influences of higher-dose ascorbic acid intake, we can see how vitamin C may have a positive influence in fighting and preventing cancer, our greatest twentieth-century medical dilemma. Deficiency and toxicity: For most purposes, vitamin C, or ascorbic acid, in its many forms of use is nontoxic. It is not stored appreciably in our body, and most excess amounts are eliminated rapidly through the urine. However, amounts over 10 grams per day that some people use and some doctors prescribe are associated with some side effects, though none that are serious. Diarrhea is the most common and usually is the first sign that the body’s tissue fluids have been saturated with ascorbic acid. Most people will not experience this with under 5–10 grams per day, the amount that is felt to correlate with the body’s need and use. Other side effects include nausea, dysuria (burning with urination), and skin sensitivities (sometimes sensitivity to touch or just a mild irritation). Hemolysis (breakage) of red blood cells may also occur with very high amounts of vitamin C. With any of these symptoms, it is wise to decrease intake. There is some concern that higher levels of vitamin C intake may cause kidney stones, specifically calcium oxalate stones, because of increased oxalic acid clearance through the kidneys due to vitamin C metabolism. This is a rare case, if it does exist, and I personally have not seen, nor do I know any doctors who have seen, kidney stone occurrence with people taking vitamin C. Only people who are prone to form kidney stones or gout should give this any thought. If there is concern, supplementing magnesium in amounts between half and equaling that of calcium intake (which should be done anyway with calcium supplementation) would reduce that risk, at least for calcium-based stones. I usually suggest using a buffered vitamin C preparation with calcium and magnesium, which alleviates this concern. As far as deficiency problems go, the once fairly common disease called scurvy is very rare these days. However, early symptoms of scurvy or vitamin C deficiency are more likely in formula-fed infants with little or no C intake or in teenagers or the elderly who do not eat any fresh fruits and vegetables. Smokers with poor diets and people with inflammatory bowel disease more often have lower vitamin C blood levels. Other people commonly found to be low in ascorbic acid include alcoholics, psychiatric patients, and patients with fatigue.

The symptoms of scurvy are produced primarily by the effects of the lack of ascorbic acid on collagen formation, causing reduced health of the tissues. The first signs of depletion may be related to vitamin C’s other functions as well, where deficiency could lead to poor resistance to infection and very slow wound healing. Easy bruising and tiny hemorrhages, called petechiae, in the skin, general weakness, loss of appetite, and poor digestion may also occur. With worse deficiency, nosebleeds, sore and bleeding gums, anemia, joint tenderness and swelling, mouth ulcers, loose teeth, and shortness of breath could be experienced. During growth periods, there could be reduced growth, especially of the bones. The decrease in collagen may lead to bone brittleness, making the bones more fragile. The progression and health of the teeth and gums are also affected. In breastfeeding women, lactation may be reduced. With the elderly, vitamin C deficiency could enhance symptoms of senility. The bleeding that comes from capillary wall fragility may lead to clotting and increased risk of strokes and heart attacks. An important note is that many medical problems have been found to be associated with low blood levels of vitamin C. These problems include various infections, colds, depression, high blood pressure, arthritis, vascular fragility, allergies, ulcers, and cholesterol gallstones. Most of these symptoms and problems can be easily avoided with minimal supplementation of vitamin C or a diet well supplied with fresh fruits and vegetables. Since the average diet has much less vitamin C than that of our ancestors, it is important for us to be aware of our ascorbic acid intake. Requirements: The RDA for adults is considered to be 60 mg. We need only about 10–20 mg. to prevent scurvy, and there is more than that in one portion of most fruits or vegetables. Infants need 35 mg.; about 50 mg. between ages one and fourteen and 60 mg. afterward are the suggested minimums. During pregnancy, 80 mg. are required; 100 mg. are needed during lactation. Realistically, between 100–150 mg. daily is a minimum dosage for most people. Vitamin C needs, however, are increased with all kinds of stress, both internal (emotional) and external (environmental). Smoking decreases vitamin C levels and increases minimum needs. Birth control pills, estrogen for menopause, cortisone use, and aspirin also increase ascorbic acid requirements. Both nicotine and estrogen seem to increase copper blood levels, and copper inactivates vitamin C. In general, though, absorption of vitamin C from the intestines is good. Vitamin C (as ascorbic acid) taken with iron helps the absorption of iron (and many minerals) and is important in treating anemia, but the iron decreases absorption of the ascorbic acid. Overall, it is probably best to take vitamin C as it is found in nature, along with the vitamin P constituents (discovered later)—the bioflavonoids, rutin, and hesperidin. These may have a synergistic influence on the functions of vitamin C, although there is no conclusive research on humans to support this theory. Vitamin C is the most commonly consumed nutrient supplement and is available in tablets, both fast-acting and time-released, in chewable tablets, in powders and effervescents, and in liquid form. It is available as ascorbic acid, L-ascorbic acid, and various mineral ascorbate salts, such as sodium or calcium ascorbate. One of my favorite formulas, which was developed by Stephen Levine at Nutricology in San Leandro, California, is a buffered powder made from sago palm that contains 2,350 mg. of vitamin C per teaspoon, along with 450 mg. of calcium, 250 mg. of magnesium, and 99 mg. of potassium. It gets into the body quickly and is very easy on and often soothing to the stomach and intestinal lining. The potassium-magnesium combination can often be helpful for fatigue, and this formula is a good vehicle for fulfilling calcium needs. 　 Vitamin C works rapidly, so the total amount we take over the day should be divided into multiple doses (four to six) or taken as a time-released tablet a couple of times a day. When increasing or decreasing vitamin C intake, it is best to do so slowly because our body systems become accustomed to certain levels. Some nutritionists describe a problem of rebound scurvy in infants, especially when a high amount is taken by the mother during pregnancy but then the infant gets very little after birth and so suffers some deficiency symptoms. I have seen nothing confirming this in the literature. Overall, though, it is probably wise to reduce vitamin C intake slowly after taking high amounts, rather than to drop abruptly. My basic suggestion for vitamin C use is about 2–4 grams per day with a typical active and healthy city lifestyle. Based on previous levels in our native diets, Linus Pauling feels that the optimum daily levels of vitamin C are between 2,500 and 10,000 mg. Clearly, requirements for vitamin C vary and may be higher according to state of health, age (needs increase with years), weight, activity and energy levels, and general metabolism. Stress, illness, and injuries further increase the requirements for ascorbic acid. Many authorities suggest that we take at least 500 mg. of vitamin C daily to meet basic body needs. During times of specific illnesses, especially viral infections, doctors who use megadose vitamin C treatment suggest at least 20–40 grams daily, some of it intravenously. Vitamin C has been used safely and effectively in dosages of 10 grams or more dripped slowly (over 30–60 minutes) into the blood to reach optimum tissue levels before excretion, so as to bathe the cells in vitamin C. Some doctors prescribe what is called "bowel tolerance" daily intake of vitamin C—that is, increasing the oral dose until diarrhea results and then cutting back. This level can vary greatly from a few grams to 100 grams or more. The claim is that our body knows what we need and will respond by changing the water balance in the colon when we have had enough. Physician Robert Cathcart has used vitamin C this way in his practice for years to treat many problems, with claimed good success; yet, I do not have the experience to make an adequate conclusion. This practice does, however, add further mystery to the vitamin C controversy. More research is definitely needed regarding ascorbic acid, and new discoveries will likely be made.