The effect of
vitamin A deficiency on the carcinogenicity of betel quid was studied, using long-term feeding of
vitamin-A-deficient and -sufficient diets with and without betel nut and
calcium hydroxide in ACI rats. A high incidence of
focal epithelial hyperplasia was observed in the upper digestive tract (tongue, buccal oral mucosa, esophagus, and forestomach) of rats in the group given the
vitamin-A-deficient diet mixed with betel nut and
calcium hydroxide. The
vitamin-A-deficient group also showed a high incidence of squamous
papilloma in the tongue, buccal mucosa, and forestomach. The incidence of hyperplastic lesions of the tongue and buccal oral mucosa was significantly higher in this group than in the group receiving the
vitamin-A-sufficient diet with betel nut and
calcium hydroxide. These results suggest that the
vitamin-A-deficient condition enhanced the growth of epithelial
hyperplasia that was due to the administration of the betel quid ingredients. However,
vitamin A did not protect against the development of altered liver cell foci, which were frequently seen with a small number of hepatocellular
neoplasms in all groups given the diets containing betel nut and
calcium hydroxide (both
vitamin-A-deficient and -sufficient groups).