Vitamin C, also known as ascorbic acid, has been evaluated in many clinical trials over several decades. The majority of these studies concluded that supplementation of ascorbic acid in cancer patients had little to no effect on disease prevention or on life expectancy and quality. Before treating serious conditions, such as cancer, with vitamin regimens, consult an oncologist first.
Vitamin C
Vitamin C, also known as L-ascorbic acid, is found to some extent in all fruits and vegetables and is used as an essential antioxidant and a cofactor in many enzymatic reactions. Medical research has confirmed the importance of this vitamin in wound healing by forming collagen, an important protein used to make skin, scar tissue, tendons, ligaments, and blood vessels. Vitamin C is also vital for the repair and preservation of cartilage, bones and teeth.
Cancer
Cancer, referred to medically as neoplasm, is a set of diseases in which cells endure uncontrolled growth beyond regular limits, invade and destroy neighboring tissues, and sometimes metastasize, in which the cells travel to other locations in the body through lymph or blood. Cancers are purportedly an environmental disease brought on by lifestyle in the majority of cases with a smaller fraction directly due to heredity. Common factors leading to cancer include diet, obesity, infections, radiation, lack of physical activity and environmental pollutants such as tobacco usage. These environmental factors can promote or amplify irregularities in the control of regulatory genes leading to uncontrolled cell growth, and the progression of cancer.
Research Purporting Benefits of Vitamin C Supplementation
Vitamin C in cancer therapy research was initiated by the renowned scientist Linus Pauling, when he co-authored an article in the October 1976 issue of the "Proceedings of the National Academy of Science." Pauling and colleagues designed a study to evaluate ascorbic acid intake to potentiate various resistance factors in terminal cancer patients. They conducted a clinical study comparing a control group, receiving accepted cancer treatments, with an experimental group, who had received the same standard treatment in addition to Vitamin C supplementation. They concluded that the patients treated with the supplements had increased survival rates of approximately fourfold, surviving 210 days after treatment began compared to only 50 days for the control group. This study has been criticized for the choice of participants entering into each group, where healthier individuals were suspected of being more prevalent in the experimental group.
Contradictory Evidence
In an article appearing in the January 2011 issue of the "World Journal of Gastroenterology," researchers examined the relationship between vitamin C in food consumption and stomach cancer rates in Poland. The study correlated the incidence of gastric cancer with the consumption of vegetables, fruit, vitamin C and salt. The study found that consumption of vegetables and fruits rich in vitamin C did present a decrease in the frequency of the disease, but cautioned that this decrease could possibly also be linked to reduction in salt intake.
A journal article appearing in the January 2009 issue of the "Journal of the American Medical Association" stated that no previous trials in men at normal risks of cancer has examined vitamin C alone in the prevention of cancers. The researchers evaluated whether long-term vitamin E or C supplementation decreases the risk of prostate and total cancer events among men in a randomized, double-blind, placebo-controlled trial that began in 1997 and continued for 10 years. They enrolled almost 15,000 male physicians in the U S, aged 50 years or older. During a follow-up, there were almost 2000 confirmed cases of cancers. They found that there was no significant effect of vitamin C on the frequency of total cancer or prostate cancer compared with a control group. The study concluded that neither vitamin E nor vitamin C had a significant effect on colorectal, lung, or other site-specific cancers and there is no evidence to support the use of vitamin C for the prevention of cancer in middle-aged men.
References
- "World Journal of Gastroenterology"; Impact of diet on long-term decline in gastric cancer incidence in Poland; M Jarosz et al.; January 2011.
- "Proceedings of the National Academy of Science"; Supplemental ascorbate in the supportive treatment of cancer: Prolongation of survival times in terminal human cancer; E Cameron and L Pauling; October 1976.
- "Journal of the American Medical Association"; Vitamins E and C in the prevention of prostate and total cancer in men: the Physicians' Health Study II randomized controlled trial; J Gaziano et al.; January 2009.
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