The earliest experience of using high-dose vitamin C (intravenous [IV] and oral) for cancer treatment was by a Scottish surgeon, Ewan Cameron, and his colleague, Allan Campbell, in the 1970s. This work led to a collaboration between Cameron and the Nobel Prize–winning chemist Linus Pauling, further promoting the potential of vitamin C therapy in cancer management.[2,3] As a result, two clinical trials of oral vitamin C were conducted in the late 1970s and early 1980s.[4,5]
(Refer to the Human Studies section of this summary for more information about these early studies.)
Pharmacokinetic studies later revealed substantial differences in the maximum achieved blood concentrations of vitamin C based on the route of administration. When vitamin C is taken orally, plasma concentrations of the vitamin are tightly controlled, with a peak achievable concentration less than 300 µM. However, this tight control is bypassed with IV administration of the vitamin, resulting in very high levels of vitamin C plasma concentration (i.e., levels up to 20 mM).[6,7] Further research suggests that pharmacologic concentrations of ascorbate, such as those achieved with IV administration, may result in cell death in many cancer cell lines.
Health care practitioners attending complementary and alternative medicine conferences in 2006 and 2008 were surveyed about usage of high-dose IV vitamin C in patients. Of the 199 total respondents, 172 had administered vitamin C to patients. In general, IV vitamin C was commonly used to treat infections, cancer, and fatigue.
- Cameron E, Campbell A: The orthomolecular treatment of cancer. II. Clinical trial of high-dose ascorbic acid supplements in advanced human cancer. Chem Biol Interact 9 (4): 285-315, 1974. [PUBMED Abstract]
- Cameron E, Pauling L: Supplemental ascorbate in the supportive treatment of cancer: Prolongation of survival times in terminal human cancer. Proc Natl Acad Sci U S A 73 (10): 3685-9, 1976. [PUBMED Abstract]
- Cameron E, Pauling L: Supplemental ascorbate in the supportive treatment of cancer: reevaluation of prolongation of survival times in terminal human cancer. Proc Natl Acad Sci U S A 75 (9): 4538-42, 1978. [PUBMED Abstract]
- Creagan ET, Moertel CG, O'Fallon JR, et al.: Failure of high-dose vitamin C (ascorbic acid) therapy to benefit patients with advanced cancer. A controlled trial. N Engl J Med 301 (13): 687-90, 1979. [PUBMED Abstract]
- Moertel CG, Fleming TR, Creagan ET, et al.: High-dose vitamin C versus placebo in the treatment of patients with advanced cancer who have had no prior chemotherapy. A randomized double-blind comparison. N Engl J Med 312 (3): 137-41, 1985. [PUBMED Abstract]
- Padayatty SJ, Sun H, Wang Y, et al.: Vitamin C pharmacokinetics: implications for oral and intravenous use. Ann Intern Med 140 (7): 533-7, 2004. [PUBMED Abstract]
- Hoffer LJ, Levine M, Assouline S, et al.: Phase I clinical trial of i.v. ascorbic acid in advanced malignancy. Ann Oncol 19 (11): 1969-74, 2008. [PUBMED Abstract]
- Verrax J, Calderon PB: Pharmacologic concentrations of ascorbate are achieved by parenteral administration and exhibit antitumoral effects. Free Radic Biol Med 47 (1): 32-40, 2009. [PUBMED Abstract]
- Padayatty SJ, Sun AY, Chen Q, et al.: Vitamin C: intravenous use by complementary and alternative medicine practitioners and adverse effects. PLoS One 5 (7): e11414, 2010. [PUBMED Abstract]