Hepatotoxic effects of Stevia rebaudiana leaf extract and commercial stevia on rats: a comparative study

The popularity of stevia is high, especially among diabetics and those looking to reduce their calorie-intake. The aim of this study was to compare the effects of a commercially-available stevia and of a Stevia rebaudiana leaf extract on the liver function and histology of rats. After preparing the Stevia rebaudiana leaf extract, 60 healthy adult male rats were randomly separated into three groups: untreated control, commercial stevia treatment (25 mg/kg), and Stevia rebaudiana leaf extract treatment (25 mg/kg). Our results show that after 60 days of treatment (oral administration), a significant elevation of the alanine aminotransferase (ALT) levels was observed in the commercial stevia-treated group, suggesting potential effects on liver function. The Stevia rebaudiana leaf extract-treated group also exhibited increased ALT levels. Moreover, the aspartate aminotransferase (AST) levels were found significantly increased in both of these treatment groups (when compared to the control group). Alkaline phosphatase levels were not found altered between groups. Histological-examinations, in spite of the elevated ALT and AST levels, exhibited no abnor¬malities in the liver. Although stevia is generally regarded as safe, this study underlines the importance of considering the type and form of stevia when evaluating its effects on liver health. Further study is warranted so as to elucidate the specific components and mechanisms responsible for the observed variations in liver enzymes, and to confirm the overall safety of stevia products.