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Vitamin C: Your Ultimate Health Insurance

by Hans R. Larsen, MSc ChE

Hans LarsenWhen tallying the achievements of medical research in the latter part of the 20th century one discovery will stand out - the discovery that vitamin C is uniquely important to the health and well-being of humans. Vitamin C was first isolated in 1928 by the Hungarian biochemist and Nobel prize winner Dr. Szent-Gyorgyi. Vitamin C plays an important role as a component of enzymes involved in the synthesis of collagen and carnitine; however, its most vital role is no doubt that of the primary, water-soluble antioxidant in the human body(1,2,3).

Two-time Nobel prize winner, Dr. Linus Pauling was the first to realize vitamin C's crucial importance in the maintenance of a healthy immune system. In 1970 he proposed that regular intake of vitamin C in amounts far higher than the officially sanctioned RDA (Recommended Daily Allowance) could help prevent and shorten the duration of the common cold. Although the medical establishment immediately voiced their strong opposition to this idea, many ordinary people believed Dr. Pauling and began taking large amounts of vitamin-C. Most immediately noticed a great decrease in the frequency and severity of their colds(4).

Recent medical research has confirmed Dr. Pauling's original idea. Not only does a high vitamin C intake markedly reduce the severity of a cold, it also effectively prevents secondary viral or bacterial complications. Vitamin C works by stimulating the immune system and protecting against damage by the free radicals released by the body in its fight against the infection(1,5,6).

Dr. Pauling recommended vitamin C intakes of 1000 mg/day or more. The official RDA is 60 mg/day (100 mg/day for smokers). So who is right? How much do we need? To answer this question it is crucial to realize that the RDA is not, in anyway, based on what is required for optimum health. The RDA is simply the amount required to avoid scurvy, the most obvious deficiency disease. Actually the RDA is based on the vitamin C content of the average diet. The logic goes somewhat like this: "The average "healthy" North American diet provides about 60 mg/day of vitamin C, so since scurvy is virtually unknown in the USA today 60 mg/day must be adequate." So much for science!

Many experts are now realizing that the RDA of 60 mg/day is far too low to provide for optimum health and protection against disease. A team of medical researchers at the National Institutes of Health in the USA recently completed a study designed to determine the vitamin C requirements of healthy, young men. They found that a minimum intake of 1000 mg/day was required to completely saturate the blood plasma with vitamin C. They also found that vitamin C should be taken in divided doses throughout the day as urinary excretion increases rapidly when individual doses exceed 500 mg. The researchers conclude that the RDA should be raised to 200 mg/day. This amount of vitamin C can be obtained from a diet containing five daily servings of fresh fruit and vegetables; unfortunately, less than 15 per cent of children and adults in the USA actually consume such a diet(3,7).

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While 200 mg/day of vitamin C may be sufficient to maintain a reasonable health status in healthy, young men, it is clear that such a relatively low intake is far from adequate for older and sick people. It is also evident that far greater amounts are required to provide optimum protection against degenerative diseases such as cancer and heart disease.

It has long been accepted that a diet rich in vitamin C from fruits and vegetables provides protection against cancer and heart disease(1,8-28). However, very little evidence has been available as to whether that supplementation with vitamin C can increase this protective effect. This, however, is now changing. Researchers from the National Institute on Aging report that elderly people who take vitamin C and E supplements have a 50 per cent lower risk of dying prematurely from disease than do people who do not supplement(29). A Californian study concluded that people who consume more than 750 mg/day of vitamin C reduce their risk of dying prematurely by 60 per cent(30). Italian researchers have concluded that older people, especially the sick are exposed to a much higher level of oxidative stress than are younger people and that their low blood levels of vitamin C reflect this(31). Other researchers have found that people who suffer from asthma, arthritis, cancer, diabetes, and heart disease have much lower levels of vitamin C in their blood than do healthy people(8,32-34).

Large doses (1-2 g/day) of vitamin C have been found to reduce asthma symptoms significantly. Recent studies have shown that vitamin C concentrations in the blood from rheumatoid arthritis patients are extremely low and that vitamin C may protect against further damage to inflamed joints(32,33,35).

Numerous studies have shown that an adequate intake of vitamin C is effective in lowering the risk of developing cancers of the breast, cervix, colon, rectum, esophagus, larynx, lung, mouth, prostate, and stomach(7,11,12,14,16-23,36).

Daily supplementation with 500 mg of vitamin C for 10 years or more has been found to cut the risk of developing bladder cancer by 60 per cent(37). The spread of breast cancer (metastasis) is now believed to be predominantly due to free radical damage which can be controlled through intake of increased amounts of vitamin C(38). Supplementation with 3 g/day of vitamin C has been found to effectively prevent further polyp growth in colon cancer and a vitamin C intake of more than 157 mg/day has been found to reduce the risk of developing colon cancer by 50 per cent(19,39).

Drs. Pauling and Cameron pioneered the use of large doses of vitamin C (>10 g/day) in the treatment of cancer patients. From their experiments at the Vale of Leven Hospital in Scotland they concluded that terminal cancer patients who received large, daily doses of vitamin C along with their regular treatment lived much longer than patients who did not receive vitamin C; they also had less pain and in general, a much improved quality of life(8).

Dr. Hoffer of Victoria, Canada later expanded on the Pauling/Cameron treatment protocol by adding large amounts of vitamin E, niacin, other B vitamins, beta-carotene, and some minerals. Those of Dr. Hoffer's cancer patients who followed this regimen lived, on the average, about 16 times longer than those who did not(8).

Dr. Pauling believed that vitamin C combats cancer by promoting collagen synthesis and thereby preventing growing tumors from invading adjacent tissue(8). Many researchers now believe that vitamin C prevents cancer by deactivating free radicals before they can damage DNA and initiate tumor growth while others believe that vitamin C may sometimes act as a prooxidant helping the body's own free radical defense mechanism destroy tumors in their early stages(11-14,16,40). Whatever the mechanism, it is now clear that vitamin C is effective in preventing cancer, alleviating its symptoms, and in some cases, halting its progress.

Although the fact that diabetics are vitamin C deficient has been clearly established, large scale clinical trials are still needed to determine whether supplementation with large doses of vitamin C is safe and beneficial. Some smaller trials have found that supplementation with 2 g/day lowered fasting glucose levels (a beneficial effect) and reduced capillary fragility in diabetics. Megadoses of vitamin C may, however, be toxic in diabetics with certain kidney disorders(10,34).

Vitamin C lowers blood pressure and cholesterol levels, helps thin the blood and protect it against oxidation and works in close synergism with vitamin E(9,25,41-45). Vitamin C also helps prevent atherosclerosis by strenghtening the artery walls through its participation in the synthesis of collagen, and by preventing the undesirable adhesion of white blood cells to damaged arteries(9,46,47). An adequate intake of the vitamin is highly protective against stroke and heart attack(28,48,49).

A recent study shows that people who supplement with more than 700 mg/day of vitamin C have a 62 per cent lower risk of dying from heart disease than do people with a daily intake of 60 mg/day or less(49). Supplementation with 2 g/day of vitamin C has been found to reduce adhesion of monocytes (white blood cells) to the lining of blood vessels and thereby reduce the risk of atherosclerosis(46,47,50). Vitamin C supplementation (2 g/day) also effectively reverses the vasomotor dysfunction often found in patients with atherosclerosis(51). Some very recent research carried out in Japan has shown that restenosis (reclosing of opened arteries) after angioplasty can be significantly reduced by supplementing with ascorbic acid (500 mg/day)(52).

Supplementing with vitamin C has been found to significantly lower the risk of cataracts and glaucoma and some very recent work has shown that open angle glaucoma can be reversed by supplementing with large doses of vitamin C(53,54).

Vitamin C supplementation (1000 mg/day) has also been found to significantly decrease the risk of developing pressure sores in surgical patients(55).

Vitamin C is truly a wonder nutrient and there is no doubt that many of the serious degenerative diseases plaguing the civilized world today can be prevented or even reversed through an adequate intake of this essential vitamin. The current RDA of 60 mg/day is clearly far too low and the proposed new RDA of 200 mg/day, while perhaps adequate for healthy, young males, would seem to be quite inadequate for older people and certainly way too low for sick people. As a matter of fact, a scientific advisory panel to the U.S. Government sponsored Alliance for Aging Research recently recommended that all healthy adults increase their vitamin C intake to 250-1000 mg/day(24). A daily intake of 250-1000 mg of vitamin C may be adequate for preventive purposes, but far larger quantities are required in halting or reversing cancer and heart disease. Although there has been some concern that people suffering from hemochromatosis (a tendency to iron overload) may be sensitive to high dosages of vitamin C most researchers now agree that vitamin C is entirely safe even in daily quantities of 10 g or more(3,56,57). An adequate intake of vitamin C is surely the best and most cost effective health insurance available today!

  1. Sies, Helmut and Stahl, Wilhelm. Vitamins E and C, beta-carotene, and other carotenoids as antioxidants. American Journal of Clinical Nutrition, Vol. 62, December 1995, pp. 1315S-21S
  2. Levine, Mark. New concepts in the biology and biochemisty of ascorbic acid. New England Journal of Medicine, Vol. 314, April 3, 1986, pp. 892-902
  3. Levine, Mark, et al. Determination of optimal vitamin C requirements in humans. American Journal of Clinical Nutrition, Vol. 62, 1995, pp. 1347S-56S
  4. Pauling L. Vitamin C and the Common Cold. Freeman, San Francisco, CA, 1970
  5. Hemila, Harri. Vitamin C and the common cold. British Journal of Nutrition, Vol. 67, 1992, pp. 3-16
  6. Jeng, Kee-Ching G., et al. Supplementation with vitamins C and E enhances cytokine production by peripheral blood mononuclear cells in healthy adults. American Journal of Clinical Nutrition, Vol. 64, December 1996, pp. 960-65
  7. Levine, Mark, et al. Vitamin C pharmacokinetics in healthy volunteers: Evidence for a recommended dietary allowance. Proceedings of the National Academy of Sciences USA, Vol. 93, No. 8, April 16, 1996, pp. 3704-09
  8. Cameron, E. and Pauling L. Cancer and Vitamin C. Camino Books Inc., Philadelphia, PA, 1993
  9. Rath, Matthias. Eradicating Heart Disease. Health Now, San Francisco, CA, 1993
  10. Goldberg, Burton. Alternative Medicine: The Definitive Guide. Future Medicine Publishing, Puyallup, WA, 1993
  11. Block, Gladys. The data support a role for antioxidants in reducing cancer risk. Nutrition Reviews, Vol. 50, No. 7, July 1992, pp. 207-13
  12. Frei, Balz. Reactive oxygen species and antioxidant vitamins: mechansims of action. American Journal of Medicine, Vol. 97, Suppl. 3A, September 26, 1994, pp. 5S-13S
  13. Gershoff, Stanley N. Vitamin C (ascorbic acid): New roles, new requirements? Nutrition Reviews, Vol. 51, No. 11, November 1993, pp. 313-26
  14. Block, G. Epidemiologic evidence regarding vitamin C and cancer. American Journal of Clinical Nutrition, Vol. 54, December 1991, pp. 1310S-14S
  15. Johnston, Carol S. Vitamin C elevates red blood cell glutathione in healthy adults. American Journal of Clinical Nutrition, Vol. 58, 1993, pp. 103-5
  16. Uddin, Shahab and Ahmad, Sarfraz. Antioxidants protection against cancer and other human diseases. Comprehensive Therapy, Vol. 21, No. 1, 1995, pp. 41-45
  17. Block, Gladys. Micronutrients and cancer: Time for action? Journal of the National Cancer Institute, Vol. 85, No. 11, June 2, 1993, pp. 846-47
  18. Diplock, Anthony T. Antioxidant nutrients and disease prevention: An overview. American Journal of Clinical Nutrition, Vol. 53, 1991, pp. 189S-93S
  19. Ferraroni, M. et al. Selected micronutrient intake and the risk of colorectal cancer. British Journal of Cancer, Vol. 70, December 1994, pp. 1150-55
  20. Stahelin, H.B., et al. Plasma antioxidant vitamins and subsequent cancer mortality in the 12-year follow-up of the prospective Basel Study. American Journal of Epidemiology, Vol. 133, No. 8, April 15, 1991, pp. 766-75
  21. Blot, William J., et al. Nutrition intervention trials in Linxian, China: Supplementation with specific vitamin/mineral combinations, cancer incidence, and disease-specific mortality in the general population. Journal of the National Cancer Institute, Vol. 85, No. 18, September 15, 1993, pp. 1483-91
  22. Blot, William J., et al. Lung cancer and vitamin supplementation. New England Journal of Medicine, Vol. 331, No. 9, September 1, 1994, p. 614
  23. Han, Jui. Highlights of the cancer chemoprevention studies in China. Preventive Medicine, Vol. 22, September 1993, pp. 712-22
  24. Voelker, Rebecca. Recommendations for antioxidants: How much evidence is enough? Journal of the American Medical Association, Vol. 271, No. 15, April 20, 1994, pp. 1148-49
  25. Whitaker, Julian M. Reversing Heart Disease. Warner Books, NY, 1985
  26. Pandey, Dilip K., et al. Dietary vitamin C and beta-carotene and risk of death in middle-aged men. American Journal of Epidemiology, Vol. 142, No. 12, December 15, 1995, pp. 1269-78
  27. Khaw, Kay-Tee and Woodhouse, Peter. Interrelation of vitamin C, infection, haemostatic factors, and cardiovascular disease. British Medical Journal, Vol. 310, June 17, 1995, pp. 1559-63
  28. Gale, Catherine R., et al. Vitamin C and risk of death from stroke and coronary heart disease in cohort of elderly people. British Medical Journal, Vol. 310, June 17, 1995, pp. 1563-66
  29. Losonczy, Katalin G., et al. Vitamin E and vitamin C supplement use and risk of all-cause and coronary heart disease mortality in older persons. American Journal of Clinical Nutrition, Vol. 64, August 1996, pp. 190-96
  30. Enstrom, James E., et al. Vitamin C intake and mortality among a sample of the United States population. Epidemiology, Vol. 3, No. 3, May 1992, pp. 194-202
  31. Mezzetti, Andrea, et al. Systemic oxidative stress and its relationship with age and illness. Journal of the American Geriatrics Society, Vol. 44, No.7, July 1996, pp. 823-27
  32. Hatch, Gary E. Asthma, inhaled oxidants, and dietary antioxidants. American Journal of Clinical Nutrition, Vol. 61, No. 3, March 1995, pp. 625S-30S
  33. Lunec, J. Blake. The determination of dehydroascorbic acid and ascorbic acid in the serum and synovial fluid of patients with rheumatoid arthritis. Free Radical Research Communications, Vol. 1, No. 1, 1985, pp. 31-9
  34. Will, Julie C. and Byers, Tim. Does diabetes mellitus increase the requirement for vitamin C? Nutrition Reviews, Vol. 54, No. 7, July 1996, pp. 193-202
  35. Halliwell, B., et al. Biologically significant scavenging of the myeloperoxidase-derived oxidant hypochlorous acid by ascorbic acid: Implications for antioxidant protection in the inflamed rheumatoid joint. FEBS Lett., Vol. 213, March 9, 1987, pp. 15-17
  36. Jacobs, Maryce M. Diet, nutrition, and cancer research: An overview, Nutrition Today, May/June 1993, pp. 19-23
  37. Bruemmer, Barbara, et al. Nutrient intake in relation to bladder cancer among middle-aged men and women. American Journal of Epidemiology, Vol. 144, No. 5, September 1, 1996, pp. 485-95
  38. Malins, Donald C., et al. Progression of human breast cancers to the metastatic state is linked to hydroxyl radical-induced DNA damage. Proceedings of the National Academy of Sciences USA, Vol. 93, No. 6, March 19, 1996, pp. 2557-63
  39. DeCosse, Jerome J., et al. Surgical and medical measures in prevention of large bowel cancer. Cancer, Vol. 40, November 1977, pp. 2549-52
  40. Schwartz, J.L. The dual roles of nutrients as antioxidants and prooxidants: Their effects on tumor cell growth. Journal of Nutrition, Vol. 126, April 1996, pp. 1221S-27S
  41. Trout, David L. Vitamin C and cardiovascular risk factors. American Journal of Clinical Nutrition, Vol. 53, January 1991, pp. 322S-25S
  42. Moran, John P., et al. Plasma ascorbic acid concentrations relate inversely to blood pressure in human subjects. American Journal of Clinical Nutrition, Vol. 57, March 1993, pp. 213-17
  43. Johnston, Carol S., et al. Vitamin C elevates red blood cell glutathione in healthy adults. American Journal of Clinical Nutrition, Vol. 58, August 1993, pp. 103-05
  44. Kagan, Valerian E., et al. Recycling of vitamin E in human low density lipoproteins. Journal of Lipid Research, Vol. 33, March 1992, pp. 385-97
  45. Kontush, Anatol. et al. Antioxidant and prooxidant activity of alpha-tocopherol in human plasma and low density lipoprotein. Journal of Lipid Research, Vol. 37, No. 7, July 1996, pp. 1436-48
  46. Weber, Christian, et al. Increased adhesiveness of isolated monocytes to endothelium is prevented by vitamin C intake in smokers. Circulation, Vol. 93, No. 8, April 15, 1996, pp. 1488-92
  47. Lehr, Hans-Anton, et al. Protection from oxidized LDL-induced leukocyte adhesion to microvascular and macrovascular endothelium in vivo by vitamin C but not by vitamin E. Circulation, Vol. 91, No. 5, March 1, 1995, pp. 1525-32
  48. Woodhouse, P.R. and Khaw, Kay-Tee. Seasonal variations in vitamin C status, infection, fibrinogen and cardiovascular disease - Are they linked? Age and Ageing, Vol. 23, Supplement No. 2, 1994, p. P5
  49. Sahyoun, Nadine R., et al. Carotenoids, vitamins C and E, and mortality in an elderly population. American Journal of Epidemiology, Vol. 144, No. 5, September 1, 1996, pp. 501-11
  50. Heitzer, Thomas, et al. Antioxidant vitamin C improves endothelial dysfunction in chronic smokers. Circulation, Vol. 94, No. 1, July 1, 1996, pp. 6-9
  51. Levine, Glenn N., et al. Ascorbic acid reverses endothelial vasomotor dysfunction in patients with coronary artery disease. Circulation, Vol. 93, No. 6, March 15, 1996, pp. 1107-13
  52. Tomoda, Haruo, et al. Possible prevention of post-angioplasty restenosis by ascorbic acid. American Journal of Cardiology, Vol. 78, No. 11, December 1, 1996, pp. 1284-86
  53. Hankinson, Susan E., et al. Nutrient intake and cataract extraction in women: A prospective study. British Medical Journal, Vol. 305, August 8, 1992, pp. 335-39
  54. Boyd, Herschell H. Eye pressure lowering effect of vitamin C. Journal of Orthomolecular Medicine, Vol. 10, No. 3/4, 1995, pp. 165-68
  55. Taylor, T.V., et al. Ascorbic acid supplementation in the treatment of pressure-sores. The Lancet, September 7, 1974, pp. 544-46
  56. Diplock, Anthony T. Safety of antioxidant vitamins and beta-carotene. American Journal of Clinical Nutrition, Vol. 62, December 1995, pp. 1510S-16S
  57. Meyers, David G., et al. Safety of antioxidant vitamins. Archives of Internal Medicine, Vol. 156, May 13, 1996, pp. 925-35


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