[Vitamins and therapy of malignancies].

Conditioning therapy preceding bone marrow transplantation usually consists of high-dose chemotherapy and total body irradiation. This is associated with acute and delayed toxic effects for several tissues, possibly related to peroxidation processes and exhaustion of antioxidants. Therefore, plasma of 22 patients was examined for alpha- and gamma-tocopherol (vitamin E), the carotenoids beta-carotene and lycopene, retinol, and ascorbic acid before, during and after conditioning chemotherapy for bone marrow transplantation. 18 of the patients received total body irradiation as well. Retinol and ascorbic acid have been given intravenously in a multiple of the recommended doses (Deutsche Gesellschaft für Ernährung (DGE) and Recommended Dietary Allowance (RDA), respectively). The doses chosen were sufficient to maintain the initial plasma concentrations of these vitamins. However, alpha-tocopherol (in RDA doses) and beta-carotene (no RDA established) concentrations deteriorated after the conditioning therapy (20% and 50% loss, respectively). The loss of these lipid-soluble antioxidants has been considered to result from lipid peroxidation, since lipid peroxide concentrations in plasma increased concurrently. On the basis of these results we performed interventions studies in order to investigate the effect of high-dose supplementation on antioxidant status. We compared the loss of antioxidants and the toxicity in two groups of patients undergoing bone marrow transplantation: The first group without and the second group with oral supplementation of high doses of alpha-tocopherol (825 mg daily), ascorbic acid (450 mg daily) and beta-carotene (45 mg daily) for three weeks prior to chemo- and radiotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)