Over the years, vitamin C has been so common to us all, we have grown aware of its major role in our daily lives. In fact, scientists at the University of Iowa have identified that delivery system is an important factor in enabling this water-soluble vitamin to kill cancer cells.
The most common type of vitamin C therapy is via oral route. Recent studies in UI have proven that vitamin C can be found in higher quantities in the blood when given intravenously. Vitamin C blood levels are 100-500 times when injected directly compared when taken orally. The reason for high bioavailability is because intravenous route bypasses normal gut metabolism and excretion.
According to the research, the "super-high" levels of vitamin C in the bloodstream is important to its function in fighting cancer cells.
Garry Buettner, IU redox biology specialist, confirmed in his earlier studies that extremely high levels (millimolar) of vitamin C selectively kills cancer cells over normal cells. Results have been observed in the test tube and in mice.
Physicians in UI hospitals are testing this new information in clinical trials for lung cancer and pancreatic cancer. The clinical trials involve combining high-dose and vitamin C administered intravenously with the standard chemotherapy or radiation therapy.
Results of earlier phase 1 trials show that the treatment is well-tolerated and safe. It also showed positive signs go improving patient outcomes. The recent larger trials are testing the treatments ability to improve survival.
Buettner and his co-researchers further emphasized on the biological processes involved to prove how high-does vitamin C (also known as ascorbate) fights and kills cancer cells- this new study was specifically published in the December issue of the Redox Biology journal.
The study gives a detail on the molecular property of vitamin C to break down easily, releasing hydrogen peroxide which is also known as a reactive oxygen specie that can damage tissues and the DNA.
The study further demonstrates the selective capacity of normal cells to remove the damaging hydrogen peroxide than tumor cells.
"In this paper we demonstrate that cancer cells are much less efficient in removing hydrogen peroxide than normal cells. Thus, cancer cells are much more prone to damage and death from a high amount of hydrogen peroxide," confirmed 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." Buettner is also a member of Holden Comprehensive Cancer Center at the University of Iowa.
Study results have further proven that enzyme catalase is the central pathway the will remove the hydrogen peroxide produced when vitamin C decomposes. It can therefore be concluded that cells with minimum amounts of catalase activity are more subjected to damage and death when exposed to high concentrations of vitamin C.
"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," Buettner added.
