Inhibition of aflatoxin-initiated preneoplastic liver lesions by low dietary protein

The development of aflatoxin B1-induced hepatic preneoplastic lesions was significantly modified by varying the level of dietary casein fed to animals during the post-dosing period. Using gamma-glutamyl transferase staining to identify areas of cellular alteration, we observed that animals fed a 5% casein diet showed a 75% reduction in lesion development as compared to animals fed a 20% casein diet. Increasing the level of dietary casein from 20% to 40% produced no further increase in response. The results of the study, showing an inhibition in the preneoplastic development by a reduction dietary casein after aflatoxin dosing, suggest that low dietary casein inhibits the promotional phase of the ultimate neoplastic response.