BETHESDA, MARYLAND. It is now 27 years ago since two Scottish doctors (Cameron and Campbell) reported remarkable results from treating terminal cancer patients with high-dose intravenous vitamin-C infusions. Their cause was later taken up by two-time Nobel Prize winner Dr. Linus Pauling who persuaded the Mayo Clinic to do their own study on the potential benefits of vitamin C. The study was done in 1979 and concluded that vitamin C was of no value in the treatment of terminal cancer. The Mayo researchers used 10 grams/day of oral vitamin C supplementation rather than intravenous infusions. This, says Dr. Mark Levine of the National Institutes of Health, was a crucial difference.
Dr. Levine and his colleagues have found that the body's absorption of orally ingested vitamin C decreases as the dose increases. Thus while 80 per cent of a 100 mg dose is fully absorbed less than 50 per cent of a 1250 mg dose is actually absorbed. Dr. Levine concludes that doses greater than 500 mg contribute little to plasma or tissue stores. He also estimates that even at doses of 1000 mg it is extremely difficult to achieve a blood plasma concentration much above 100 micromol/L. Intravenous infusions, on the other hand, can achieve plasma levels as high as 5000 micromol/L with a dose of 5 to 10 grams. Dr. Levine believes that these high vitamin C levels may indeed be effective in combating cancer and urges further studies and clinical trials.
Padayatty, Sebastian J. and Mark Levine. New insights into the physiology and pharmacology of vitamin C. Canadian Medical Association Journal, Vol. 164, February 6, 2001, pp. 353-55
Hoffer, L. John. Proof versus plausibility: rules of engagement for the struggle to evaluate alternative cancer therapies. Canadian Medical Association Journal, Vol. 164, February 6, 2001, pp. 351-53 (commentary)