Researchers Determine How Vitamin C Harms Cancer Cells


Most vitamin C therapies used for cancer involved taking the nutrient orally. This may explain why vitamin C treatments for cancer have an inconsistent history, according to University of Iowa (UI) researchers.

When vitamin C, or ascorbate is given intravenously, bypassing the digestive and excretory systems, blood levels of vitamin C are 100 to 500 times greater than with oral vitamin C ingestion. This super-elevated concentration of vitamin C is necessary for diminishing cancer cells.

Earlier UI laboratory and animal studies showed that extremely high vitamin C levels kill cancer cells without harming normal cells. Last December, the journal Redox Biology published a recent UI study by researcher Garry Buettner and colleagues revealing how high concentrations of vitamin C can destroy tumors.

The investigative team discovered that vitamin C readily breaks down in the body, and that process generates hydrogen peroxide, a substance that can harm tissue and DNA. Further, they noticed that normal cells were far more adept at removing the hydrogen peroxide than the tumor cells.

“Thus, cancer cells are much more prone to damage and death from a high amount of hydrogen peroxide,” said Buettner, a professor of radiation oncology. “This explains how the very, very high levels of vitamin C used in our clinical trials do not affect normal tissue, but can be damaging to tumor tissue.”

The UI research also revealed that an enzyme called catalase is the primary mechanism used by cells to dispose of the hydrogen peroxide created by vitamin C breakdown. Cells with less catalase activity are more vulnerable to demise when exposed to concentrated vitamin C levels.

“Our results suggest that cancers with low levels of catalase are likely to be the most responsive to high-dose vitamin C therapy, whereas cancers with relatively high levels of catalase may be the least responsive,” says Buettner.

Future UI research plans include working to discover methods for determining catalase levels in tumors.

Source: Jennifer Brown/Iowa Now
Photo credit: andriuXphoto


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