BETA-CAROTENE SUPPLEMENTATION RESULTS IN AN INCREASED SERUM AND COLONIC MUCOSAL CONCENTRATION OF BETA-CAROTENE AND A DECREASE IN ALPHA-TOCOPHEROL CONCENTRATION IN PATIENTS WITH COLONIC NEOPLASIA

The aim of this study was to evaluate the colonic mucosal beta-caroten e (BC) concentration following supplementation with BC and to determin e if an increase in BC concentration influences vitamin E (alpha-tocop herol) status. The concentration of BC and alpha-tocopherol was assess ed in serum and colonic tissue obtained from subjects with a history o f colonic polyps or resected cancer (Dukes A, B1, or B2). Serum and mu cosal biopsy samples were obtained prior to and following 3 months dai ly p.o. supplementation with 30 mg of BC or placebo. The concentration of BC was significantly increased in serum and colonic mucosa from bo th polyp and cancer subjects following supplementation as compared to presupplementation values and values from subjects receiving a placebo . The concentration of alpha-tocopherol in serum from cancer subjects was significantly decreased in samples obtained at the end of 3 months of BC supplementation as compared to placebo-matched controls. In BC- supplemented polyp subjects the tissue concentration of alpha-tocopher ol was also significantly decreased relative to presupplementation val ues. The results indicate that BC supplementation does result in a sig nificant accumulation of BC in the colonic mucosa but that the alpha-t ocopherol concentration in both serum and colonic tissue may be compro mised by an increased intake of BC. The mechanism for the decrease in alpha-tocopherol in conjunction with the increase in BC will require f urther study in order to develop strategies which will prevent vitamin E deficiency in BC-supplemented individuals.