The effect of dietary lactulose on experimental large bowel cancer

The hypothesis that feeding of lactulose might reduce large bowel tumour development was tested in an animal model. One hundred rats were divided into groups fed either a standard rat diet with water 'ad libitum', or the same diet but with 3.3% lactulose added to the drinking water. Large bowel tumours were induced by weekly injections of 1,2 dimethylhydrazine (DMH). There was no significant difference between the number of tumours found in the standard diet or the lactulose-treated groups. This result does not seem to support the colonic flora - bile salt theory of large bowel carcinogenesis.