Chemotherapy and radiation therapy result in increased free radical formation and depletion of tissue antioxidants. In a study with 24 bone marrow transplant patients, plasma glutathione (GSH) and alpha- and gamma-tocopherol concentrations decreased and the GSH redox state became more oxidized after conditioning chemotherapy.

Plasma cysteine concentrations were unchanged, whereas cystine concentrations increased.

Plasma vitamin C and zinc concentrations and GSH peroxidase activity increased over time. Plasma alpha-tocopherol concentrations were lower in patients given standard parenteral nutrition.

There were no differences in other plasma antioxidants between groups. CONCLUSIONS: A significant decline in GSH-glutathione disulfide, cysteine-cystine, and vitamin E status occurs after chemotherapy and bone marrow transplant.

Standard parenteral nutrition does not improve antioxidant status compared with administration of micronutrients alone.

Further evaluation of parenteral nutrition formulations to support patients undergoing high-dose chemotherapy and bone marrow transplants are needed.

Jonas, C.R. et al. Am J Clin Nutr 2000 Jul;72(1):181-9.