Effect of dietary fat on diethylnitrosamine induced hepatocarcinogenesis in Wistar rats

In a diethylnitrosamine (DEN) induced hepatoma model, the effect of fish oil, a rich source of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and ground nut oil, a rich source of oleic acid (OA) and linoleic acid (LA), was studied. Both 20% fish oil and ground nut oil inhibited DEN-induced hepatocarcinogenesis in rats. Contrary to general belief, an inverse correlation was observed between the development of neoplastic nodules and the amount of lipid peroxides formed in the high fat (20% fish oil and ground nut oil) diet groups, indicating that the higher the lipid peroxides formed, the lower the incidence of liver tumours in DEN-treated animals. Results of the analysis of liver fatty acid composition of the phospholipid fraction suggested that DEN and fish oil treatment can inhibit the activity of the delta-6- and 5-desaturases. It is concluded from the results of the present study that a ‘high fat’ diet and lipid peroxidation can modulate DEN-induced hepatocarcinogenesis in rats.