Shea oleine, an oil fraction derived from the nut of the tree Butyrospermum parkii, is used as a frying oil. As part of a series of studies, this investigation examined the carcinogenic potential of 15% (w/w)
shea oleine in comparison with 15% (w/w) sheanut oil, and
palm oil following dietary administration to rats over 104 weeks. The assessment comprised an evaluation of mortality, clinical signs,
body weight, food intake, clinical pathology, organ weights and macroscopic and histopathological examination plus tumour type and incidence evaluation. Results showed that
shea oleine produced no adverse effects and no evidence of tumorigenic potential compared to other commercially available sheanut and palm
oils in the rat. Notable differences were confined to reduced
body weight gain and food intake, reduced
cholesterol and increased
alkaline phosphatase levels, reduced heart weight and an increased incidence of pulmonary
lipidosis with
shea oleine diets. The latter effect may reflect a naturally lower incidence of this finding with
palm oil diets. Tumour findings, specific to
shea oleine diets, were restricted to an increase in the number of
hepatomas for females, pancreatic exocrine
adenomas for males and skin
keratoacanthomas for males fed
shea oleine diets. The increase in the incidence of
hepatomas with treatment was thought to be related to the high fat content of the diets. The incidence of these tumour findings was similar to that given in published data for the Wistar rat, or the 'in house' values for tumour incidence in rats fed high-fat diets. In conclusion, none of the findings in this study were considered to be adverse effects. In comparison with other commercially available edible
oils,
shea oleine showed no tumorigenic potential following dietary administration at 7.5 g/kg/day in the rat.