Vitamin C May Be Useful to Treat Cancer After All

Aug. 4, 2008— -- WASHINGTON, Aug 4 (Reuters) - Vitamin C might be useful totreat cancer after all, according to a U.S. study published onMonday in which injections of high doses of it greatly reducedthe rate of tumor growth in mice.

The idea that vitamin C, also known as ascorbic acid, couldbe used to treat cancer was advanced in the 1970s by Americanscientist Linus Pauling, who awarded the Nobel Prize inchemistry in 1954.

The notion was controversial and subsequent studies failedto show a benefit. But those studies involved vitamin C givenorally.

The new study by researchers at the U.S. government'sNational Institutes of Health involved injections of vitamin Cto enable greater concentrations of it to get into the system.

The researchers implanted three types of aggressive cancercells into laboratory mice -- ovarian, pancreatic andglioblastoma brain tumors. Mice that were given high-dosageinjections of vitamin C experienced tumor growth only abouthalf that of similar mice that were not given the injections,they said.

"The key finding here is that this is ascorbic acid used asa drug and it appears to have some promise in treating somecancers," Dr. Mark Levine of the NIH's National Institute ofDiabetes and Digestive and Kidney Diseases, who led the study,said in a telephone interview.

The researchers believe the elevated amounts of ascorbicacid generate hydrogen peroxide in the body that acts againstthe cancer cells.

"That hydrogen peroxide leads to death of some cancer cellsand does not seem to kill normal cells. Why that is, we don'tknow," said Levine, whose team's findings were published in theProceedings of the National Academy of Sciences.

Levine said a recent clinical study in Canada in which hewas involved showed that similar high doses of vitamin C can beinjected into people with very minimal side effects.

"The thing that's realistic here is that the concentrationsthat are effective, or similar concentrations, can be achievedin humans," Levine said.