Incidence of brain tumors in rats fed aspartame

The brain tumorigenicity of aspartame (APM) and of its diketopiperazine (DKP) was studied in 860 SCL Wistar rats. APM at dietary levels of 1 g/kg, 2 gK/, 4 g/kg or APM + DKP (3:1) 4 g/kg was fed for 104 weeks. One atypical astrocytoma was found in a control rat and 2 astrocytomas, 2 oligodendrogliomas and 1 ependymoma were scattered among the 4 test groups. There was no significant difference in the incidence of brain tumors between control and test groups. It is concluded that neither AMP nor DKP caused brain tumors in rats in this study.