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Vitamin C is one of several antioxidants shown to play a key role in the prevention of many types of cancers. Vitamin C maintains collagen, a protein necessary for the formation of skin, ligaments and bones. It also enhances the immune system, helps heal wounds and mend fractures, and aids in resisting some types of bacterial and viral infections.
A Nutritional Approach to Immunity
Many studies show that immune function depends on nutrients found primarily in whole, unprocessed foods.  Researchers have also confirmed that physical activity and a healthy emotional state are essential for proper immune function. [3, 4] A healthy diet and lifestyle may be the cornerstones of a strong immune system, but what specific measures can be taken when a person is faced with an immune challenge such as the annual cold and flu season?
Breathe Easy with Vitamin C
An investigation of lung health in rural China goes one step further than previous studies and finds that even smokers can benefit from vitamin C. Hu Guizhou, Ph.D., of Cornell University in Ithaca, New York, and Xin Zhang of the Chinese Academy of Preventive Medicine in Beijing compared the lung capacity of 3,085 people in 69 rural Chinese counties with their vitamin C intake. Vitamin C intake ranged from as much as 295 mg/day to as little as 42 mg/day. People with more vitamin C in their diet had greater lung volumemeaning they could exhale more air than those eating less of the vitamin. In fact, for each 100 mg/day increase of vitamin C, lung volume increased 22 mL. This study, completely controlled for smoking, determined the increase was the same in smokers and nonsmokers alike.
French Court Lifts Vitamin C Restrictions
After ten years of appeals and counter-appeals, a court in the central French province of Maine-et-Loire has ruled that vitamin C should not be considered a drug even in doses many times above the existing safety limit.
Media Overlooks Human Studies on Vitamin C
A Response to the Inaccurate Science Article which claimed Vitamin C could cause
DNA Damage ~ Researchers at the University of Pennsylvania Center for Cancer Pharmacology and the news media overlooked five current human studies that disprove the notion that high-dose vitamin C causes DNA damage. Instead, the media exploited one test-tube study, published in the June 15, 2001 issue of Science, whose researchers concluded that the daily equivalent of 200 mg vitamin C could potentially cause cancer.
Vitamin C Lengthens Lifespan
Although vitamin C has long been considered the premier antioxidant, studies linking the vitamin to increased survival rates have been inconclusive. However, a major study conducted by researchers at Cambridge University School of Clinical Medicine in the U.K. and published in Lancet offers evidence that vitamin C saves lives.
Effects of Multinutrient Supplementation on Antioxidant Defense Systems
in Healthy Human Beings
J Nutr Biochem 2001 (Jul); 12 (7): 388395
Oxidative damage involved in the pathogenesis of many diseases, such as cardiovascular disease, cancer and diabetics. The antioxidant defense system plays an important role in protecting body from oxidative damage. Numerous studies have been shown that a single vitamin or mineral supplementation has the beneficial effect on the antioxidant defense system. However, the overall combined effect of multinutrient supplementation on antioxidant defense system remains to be clarified. In the present double blind, placebo-controlled study, the antioxidative defense system was measured in 34 healthy subjects before and after multinutrient supplementation.
Apoptosis-inducing Activity of Vitamin C and Vitamin K
Cell Mol Biol 2000 (Feb); 46 (1): 129143
Vitamin C shows both reducing and oxidizing activities, depending on the environment in which this vitamin is present. Higher concentrations of vitamin C induce apoptotic cell death in various tumor cell lines including oral squamous cell carcinoma and salivary gland tumor cell lines, possibly via its prooxidant action.
Vitamin Nutrition and Gastroesophageal Cancer
J Nutr 2000 (Feb); 130 (2S Suppl): 338S339S
In a study on 29,584 subjects, combination of Vitamin E, Beta-carotene and Selenium significantly decreased mortality rate from stomach cancer, primarily due to the decrease in deaths resulting from adenocarcinomas of the gastric cardia.
Ascorbic Acid in the Prevention and Treatment of Cancer
Alternative Medicine Review 1998 (Jun); 3 (3): 174186 ~ FULL TEXT
Proposed mechanisms of action for ascorbic acid (ascorbate, vitamin C) in the prevention and treatment of cancer include enhancement of the immune system, stimulation of collagen formation necessary for "walling off" tumors, inhibition of hyaluronidase which keeps the ground substance around the tumor intact and prevents metastasis, prevention of oncogenic viruses, correction of an ascorbate deficiency often seen in cancer patients, expedition of wound healing after cancer surgery, enhancement of the effect of certain chemotherapy drugs, reduction of the toxicity of other chemotherapeutic agents such as Adriamycin, prevention of free radical damage, and neutralization of carcinogenic substances.
The Pro-oxidant and Antioxidant Effects of Vitamin C
Alternative Medicine Review 1998 (Jun); 3 (3): 170173 ~ FULL TEXT
The paper entitled, "Vitamin C Exhibits Pro-oxidant Properties," which appeared recently in the journal Nature has attracted considerable attention. Authors Podmore, Griffiths, Herbert, et al describe the potential pro-oxidant effects of daily supplementation with 500 mg of vitamin C on DNA base oxidation in vivo.  Their conclusion raises concern because a vast number of individuals regularly supplement their diets with vitamin C in the belief that it has antioxidant effects.
Vitamin C and Chiropractic
J Manip Physiol Ther 1985 (Jun); 8 (2): 95103
A review of the literature relating to possible clinical implications of ascorbic acid (AA) supplementation was conducted. Factors requiring a higher AA intake include smoking, alcohol ingestion, stress, diabetes mellitus, pregnancy, and certain drugs, including oral contraceptives, some antibiotics, acetylsalicylate and anti-inflammatory medications. AA has been found to significantly increase wound healing, reduce the inflammatory response, lessen respiratory distress, enhance immune function and serve to benefit many common conditions including osteoarthritis. It is concluded that vitamin C supplementation could be utilized for many conditions seen by chiropractors.
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