Avoid Vitamin C Supplements During Cancer Therapies

Though there are several approaches a cancer patient and his or her physician can take toward eliminating the cancer, all therapies have one common goal - killing the cancerous cell. To kill the cell, the function of its mitochondria must be interrupted.

At this point in time, it is almost impossible to isolate only cancerous cells and avoid damage to nearby healthy cells. It’s the damage to the healthy cells that leaves cancer patients weakened, sick, and frail as a result of the cancer-killing treatments.

Many cancer patients turn to the protective powers of antioxidants to offset the effects of cell-destroying cancer treatments in the hope of remaining as healthy as possible during treatment. One very potent antioxidant, vitamin C, is frequently taken in supplement form and in very high doses but the findings of a recent study conducted by researchers at Memorial Sloan-Kettering Cancer Center suggest getting the best results from cancer-fighting therapies may be achieved by avoiding vitamin C supplements during treatment.

Reporting their findings in the October 1 issue of the medical journal, Cancer Research, published by the American Association of Cancer Research, the research team says the vitamin, when taken in supplement form, may actually block the effect of the cancer treatment and spare the cancerous cell altogether. Their research was done with mice and mice cells but the way vitamin C affects cancerous cells in mice may also occur in humans.

Mitochondria is considered the power plant that fuels the cell. When mitochondria becomes damaged, as is desired in cancer treatments, the cell dies. Some drugs used for chemotherapy produce oxygen free radicals, unpaired molecules of oxygen that kill cells in a process known as oxidation. The value of antioxidants to a healthy person is their ability to eliminate naturally occurring oxygen free radicals before cellular damage can happen, thereby extending the lifespan of the cell.

Controversy surrounds the use of vitamin C supplements during cancer treatment, though, with some theorists suggesting vitamin C may absorb and neutralize the oxygen free radicals before they get the chance to damage the mitochondria in cancer cells. It is this theory the Memorial Sloan-Kettering research team explored.

Vitamin C must be converted to a form called dehydroascorbic acid (DHA) in order to enter a cell. The research team pretreated cancerous mice cells with DHA and then tested a wide assortment of common chemotherapy drugs on them, some of which are designed to deliberately produce cell-killing oxygen free radicals. The amount of DHA with which the mice cells were treated was equivalent to the amount a person taking high-potency vitamin C supplements would likely consume.

When the DHA-treated cancer cells were compared with untreated cancer cells, every chemotherapy drug tested did not perform as well in the pretreated cells as it did in untreated cells. Cell cultures showed fewer cancer cells dying, by as much as 30% to 70% depending upon which drug was administered, in the cells treated with DHA.

To strengthen their findings, the research team implanted both treated and untreated cells in mice that were free of cancer. The tumors produced by the treated cells grew much more rapidly than the tumors produced by untreated cancer cells.

Thinking the vitamin C might be neutralizing the oxygen free radicals before the cancerous mitochondria could be damaged, the research team explored the mechanisms at play. Neutralization was not the problem, however. The research showed that the vitamin C was actually revitalizing mitochondria weakened by chemotherapy drugs, saving it from destruction and preventing the desired cure from cancer, a finding that augments the team’s previous studies.

The effect of vitamin C on cancer therapies has been the subject of extended research by this team. Previous studies have suggested cancer cells have the ability to convert more vitamin C into DHA than healthy cells do. Once inside, DHA is converted once again into vitamin C, which becomes trapped inside the cells and accumulates, and protects the cancerous cell’s mitochondria from the destructive forces of chemotherapy.

While a healthy diet is crucial to overcoming cancer, including a diet naturally rich in vitamin C and other antioxidants, the research team expressed concern that enhancing an otherwise healthy diet with vitamin C supplements in large doses may actually do more harm than good, by hindering the ability of the cancer-fighting therapies a patient is undergoing.

Source: American Association for Cancer Research

Filed under: Cancer, Supplements

Tags: vitamin C

Comments

2 Responses to “Avoid Vitamin C Supplements During Cancer Therapies”

tom on October 6th, 2008 11:27

The Article should be avoid chemotherapy while taking Vitamin C; actaully avoud chemotherapy altogether!
Greg Wirth - How Antioxidants Work on October 12th, 2008 8:06

Vitamin D has been shown to be more effective free radical scavenger during chemotherapy. None the less, taking a broad spectrum multi-vitamin supplement during chemo treatments is far more effective at apaptosis of cancer cells than of singular supplements.