E. They claim that these vitamins improve general well being, strengthen the immune system and may delay the development and progression of serious disease. Opponents claim that vitamins, especially antioxidants, can reduce the effectiveness of many chemotherapy drugs and that not enough is known to advocate vitamin use for patients undergoing treatment. The majority of studies done to this date have examined the role of vitamin supplements in the prevention of various types of cancer. Researchers who have looked at the interaction of vitamins with chemotherapy have not been able to agree on whether the vitamins are beneficial or harmful. Much of the debate focuses around the antioxidant properties of some vitamins.
Antioxidants act like vacuum cleaners within the body, removing reactive oxygen species.
Some researchers are concerned because many of the chemotherapy drugs need the reactive oxygen species to effectively fight tumors. If patients undergoing treatment take supplements that further raise the amount of antioxidants in their body, there may be fewer ROS left for the chemotherapy drugs to use. Some researchers believe that in the long run vitamin supplements may reduce the efficacy of chemotherapy treatment, even though they may help patients have less immediate symptoms during treatment. Much of this debate is theory and predictions based on what is known about antioxidants and chemotherapeutic drugs. To date, no definitive human studies have demonstrated the long-term effects, one way or the other, of combining oral antioxidants and chemotherapy drugs.