It appears that vitamin C supplements don’t have beneficial effects on patients struggling with cancer, according to a new research on animal studies which showed that the vitamin C diminished the effectiveness of several cancer drugs, such as chemotherapy.

Researchers at the Memorial Sloan-Kettering Cancer Center in New York looked at laboratory cancer cells and mice. Before undergoing chemotherapy, mice with tumors were administered vitamin C.

Other studies conducted in the past have indicated that vitamin C helps patients suffering from cancer, considering its antioxidant proprieties. However, a new study suggests the opposite, that the nutrient is likely to help the growth of cancer cells.

Study author Dr. Mark L. Heaney, associate attending physician at MSKCC, together with his colleagues, found that the nutrient reduced the usefulness of the chemotherapy by an estimated 30 to 70%. They also said that vitamin C may have interrupted chemotherapy’s process of damaging cancerous cells and instead, offered them protection.

There's a possibility that taking supplemental vitamin C could have a detrimental effect on cancer treatment," Dr. Heaney said.
On the other hand, nothing seems to point to the fact that the dietary supplement, taken in smaller doses like those found in ordinary multivitamins and natural foods, may be questionable, study author added.

The authors of the study recommend patients with cancer to follow a health diet that doesn’t exclude foods abounding with vitamin C. Those who do that are healthier and have lower mortality from several chronic illnesses. They are only advised not to increase the vitamin C doses, to avoid helping cancer cells expansion.