Dietary Antioxidants During Cancer Chemotherapy: Impact on Chemotherapeutic Effectiveness and Development of Side Effects Kenneth A. Conklin Chemotherapy has long been a cornerstone of cancer therapy. Although extensive research is done on the development of more effective and less toxic antineoplastic agents, much less attention has been paid to factors that may enhance the effectiveness of existing drugs. Nutritional factors may hold a key to enhancing the anticancer effects of chemotherapy and to reducing or preventing certain chemotherapy-induced side effects. This review considers a limited number of dietary supplements that have antioxidant properties or influence cellular antioxidant systems. The emphasis of the review is on those antioxidant supplements that have been most studied with respect to effects on antineoplastic responsiveness or reduction of chemotherapy-induced side effects. Dietary supplements without antioxidant properties may also influence the effects of cancer chemotherapy, and many dietary supplements may influence factors that impact the progression of cancer, such as angiogenesis, metastasis, and immune competence. These issues are not addressed in this review. Abstract Several studies suggest that dietary supplementation with antioxidants can influence the response to chemotherapy as well as the development of adverse side effects that results from treatment with antineoplastic agents. Administration of antineoplastic agents results in oxidative stress, i.e., the production of free radicals and other reactive oxygen species (ROS). Oxidative stress reduces the rate of cell proliferation, and that occurring during chemotherapy may interfere with the cytotoxic effects of antineoplastic drugs, which depend on rapid proliferation of cancer cells for optimal activity. Antioxidants detoxify ROS and may enhance the anticancer effects of chemotherapy. For some supplements, activities beyond their antioxidant properties, such as inhibition of topoisomerase II or protein tyrosine kinases, may also contribute. ROS cause or contribute to certain side effects that are common to many anticancer drugs, such as gastrointestinal toxicity and mutagenesis. ROS also contribute to side effects that occur only with individual agents, such as doxorubicin-induced cardiotoxicity, cisplatin-induced nephrotoxicity, and bleomycin-induced pulmonary fibrosis. Antioxidants can reduce or prevent many of these side effects, and for some supplements the protective effect results from activities other than their antioxidant properties. Certain side effects, however, such as alopecia and myelosuppression, are not prevented by antioxidants, and agents that interfere with these side effects may also interfere with the anticancer effects of chemotherapy. Nutrition and Cancer 37(1):1-16, 2000 © 2000 Lawrence Erlbaum Associates, Inc.] From a discussion in Nutrition and Cancer Int J Cancer, Feb 2001 Am J Epidemiology, 2001 J American College of Nutrition, 10/02 Clinical Breast Cancer, 12/06 Remember we are NOT Doctors and have NO medical training. This site is like an Encylopedia - there are many pages, many links on many topics. Support our work with any size DONATION - see left side of any page - for how to donate. You can help raise awareness of CAM.