Influence of dietary protein and vitamin B12 on the toxicity and carcinogenicity of aflatoxins in rat liver.

The influence of dietary protein content and dietary vitamin B12 supplement on the hepatotoxicity and carcinogenicity of aflatoxin in rat liver was studied. In animals fed a low-protein diet, aflatoxin induced extensive toxic and carcinogenic effects. Cirrhosis was significantly prevented to a certain level by vitamin B12 administration, but the incidence of cholangiofibrosis and hyperplastic nodules was unchanged. No toxic effect was observed in animals receiving high-protein diet with no vitamin B12 supplement in this study (33 weeks). Only one rat bearing a hepatoma was observed in this group. However, hepatoma and hyperplastic nodules were found in the group receiving high-protein diet plus vitamin B12. Cholangiofibrosis and cirrhosis were not observed in the high-protein group regardless of vitamin B12 administration.