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In the United States, vitamin C for cancer treatment has become something of a cottage industry.
Enthusiastic supporters of vitamin therapies sometimes advertise high-dose vitamin C as a treatment for cancer when medical treatment has failed. Usually advocating doses of 10,000 mg or more, these alternative medicine entrepreneurs tell their customers that they have to take enough vitamin C to begin to feel sick to know that the vitamin is working.
And many people who place their hope in vitamin C still succumb to the disease. The reason why vitamin C usually fails, however, may be the way it is administered.
Forty Years of Vitamin C for Cancer
In the early 1970's. Nobel laureate Linus Pauling conducted several studies of high-dose vitamin C as a non-toxic method of extending the life of terminally ill cancer patients that made headlines around the world. Pauling recruited 2000 people with terminal cancer to be his test subjects for vitamin C treatment of cancer, 1000 receiving 10,000 mg (that is, 10 grams) of vitamin C per day, and the other 1000 receiving a placebo. The patients who received the 10 grams of vitamin C daily lived on average 2-1/2 times as long as those who did not, and Pauling pronounced treatment with vitamin C to be the wave of the future in curing cancer.
The fine print of Pauling's findings was, however, that the study volunteers taking high-dose vitamin C lived an average of 120 days, rather than just 42 days. About 10% of the volunteers taking vitamin C lived more than one year, some as long as 2-1/2 years. Also overlooked in the glowing reports of the results of the study was the fact that the vitamin C was administered by intravenous drip for the first 10 days and only then taken in tablet form.
Oral Vitamin C Neither Cancer Treatment nor Cancer Cure
Linus Pauling's study did not conclude that vitamin C cured cancer. What Pauling discovered was that that vitamin C extended the length very end of life (although not necessarily improving quality of life) in almost all cases. Follow-up studies found no benefit in increasing the dose to more than 10,000 mg daily, and the patients in studies not conducted by Dr. Pauling himself did not live as long as those in Dr. Pauling's clinical trial.
But the modestly successful, aggressively marketed results of the Pauling trial were not to be the end of the story. About the year 2000, a group of Canadian doctors experimented with administering all of the vitamin C by IV. Blood tests showed that 25 times more vitamin C reached cancer cells when the supplement was administered intravenously, compared to giving the vitamin by mouth. The scientists
"Recent evidence shows that oral administration of the maximum tolerated dose of vitamin C (18 g/d) produces peak plasma concentrations of only 220 micromoles/liter, whereas intravenous administration of the same dose produces plasma concentrations about 25-fold higher. Larger doses (50–100 g) given intravenously may result in plasma concentrations of about 14 000 micromolesl/liter. At concentrations above 1000 micromoles/liter, vitamin C is toxic to some cancer cells but not to normal cells in vitro."
In other words, the Canadian research team concluded that it is simply not possible to get enough vitamin C into your body to fight cancer if you take the vitamin orally.
However, when high-dose IV vitamin C was administered to patients who had advanced bladder cancer, advanced kidney cancer, and advanced bladder cancer, the patients achieved remission that lasted four to ten years, not just 120 days.