High-dose injections of vitamin C, also known as ascorbate or ascorbic acid, reduced tumor weight and growth rate by about 50 percent in mouse models of brain, ovarian, and pancreatic cancers, researchers from the National Institutes of Health (NIH) report in the August 5, 2008, issue of the Proceedings of the National Academy of Sciences. The researchers traced ascorbate's anti-cancer effect to the formation of hydrogen peroxide in the extracellular fluid surrounding the tumors. Normal cells were unaffected.
Natural physiologic controls precisely regulate the amount of ascorbate absorbed by the body when it is taken orally. "When you eat foods containing more than 200 milligrams of vitamin C a day--for example, 2 oranges and a serving of broccoli--your body prevents blood levels of ascorbate from exceeding a narrow range," says Mark Levine, M.D., the study's lead author and chief of the Molecular and Clinical Nutrition Section of the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the NIH.