Dietary D-psicose, a Rare Sugar, Shows No Modifying Effects in a Medium-term Liver Carcinogenesis Bioassay in F344 Male Rats

D-psicose, a C-3 epimer of D-fructose, is present in very small quantities in commercial carbohydrate complexes and agricultural products, and is therefore called a rare sugar. The effects of D-psicose on diethylnitrosamine (DEN)-induced hepatocarcinogenesis were examined in male F344 rats using a rat medium-term bioassay based on the two-step model of hepatocarcinogenesis. The modifying potential was determined by comparing the numbers and areas/cm2 of induced glutathione S-transferase placental form (GST-P) positive foci in the liver with those of a corresponding group (control) of rats given DEN alone. Increased relative liver weights were found in the 1% D-psicose treatment group as compared with the basal diet group, while no significant change occurred in the 0.1% D-psicose, 0.01% D-psicose, and 1% D-fructose groups. D-psicose did not significantly alter the numbers and area/cm2 of GST-P positive liver cell foci observed after DEN initiation. The results thus demonstrate that D-psicose shows neither promoting nor preventive potential for liver carcinogenesis in our medium-term bioassay.