Vitamin C, E reduce DNA damage induced by breast cancer chemotherapy
By David Liu, PHD
Thursday Dec 6, 2012 (foodconsumer.org) -- Breast cancer patients who are receiving chemotherapy may be better off taking vitamin C and vitamin E supplements as a study in Journal of Clinical Pharmacy and Therapeutics shows that these vitamins reduce DNA damage induced by the cancer treatment.
Vitamin C is water soluble and vitamin E is oil soluble and both together can prevent lipid peroxidation in also any tissue they can reach. Breast cancer per se and chemotherapy both can generate reactive oxygen/nitrogen species - part of the side effects associated with acute or chronic chemotherapy that reduce the total antioxidant capacity in the patient.
The study led by Dr N. Banu at Department of Biochemistry, Faculty of Life Sciences, A M University in Aligarh, UP, India and colleagues showed using of vitamin C and vitamin E can restore the normal antioxidant status in breast cancer patients. Reactive oxygen species, which can be neutralized by antioxidants, can damage DNA and induce cancer development.
At the baseline of the randomized 5-month study, researchers measured the activity of various antioxidant enzymes including superoxide mismutase, catalase, glutathione-S-transferatase and glutathione reductase and the concentration of lipid peroxidation end products including malondialdehyde and reduced glutathione in 40 untreated stage II breast cancer patients and additional controls. Determined were also DNA damage using alkaline single cell gel electrophoresis.
Then some untreated breast cancer patients received chemotherapy alone and some other patients received both the same chemotherapy and 5000 mg of vitamin C and 400 mg in gelatin capsules of vitamin E for 18 weeks. At the end of the treatments, antioxidant enzymes, oxidation products, and DNA damage were measured again.
As a result, untreated breast cancer patients were found to have significantly lower levels of antioxidant enzymes, reduced glutathione, and more lipid peroxidation and DNA damage, compared with health controls. Similar but less severe patterns were found in patients receiving chemotherapy alone.
However, breast cancer patients who received both chemotherapy and vitamin C and vitamin E supplements were able to maintain all the measured biomarkers close to normal while the levels of antioxidant enzymes were increased significantly and the levels of malondialdehyde and DNA damage induced by breast cancer and anti-cancer chemotherapy were significantly reduced, compared with untreated patients and patients who received chemotherapy alone.
The researchers concluded "Co-administration of VCE restored antioxidant status, lowered by the presence of breast-cancer and chemotherapy. DNA damage was also reduced by VCE (vitamin C and vitamin E). The results suggest that VCE should be useful in protecting against chemotherapy-related side-effects."
Breast cancer is expected to be diagnosed in more than 230,000 American women in 2012 and the disease is expected to kill about 37,000 in 2012, according to the National Cancer Institute.
Antioxidants, particularly vitamin C have been found also protective against DNA damage induced by radiation used in diagnostic tools and cancer treatments.
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