Intake of unused palm olein and palm olein used in frying does not affect calcium and phosphorus bioavailability in rats

Palm oil is widely used as a cooking medium. This study was undertaken to e xamine whether extensive use leading to the formation of polar compounds ha s any effect on calcium and phosphorus balances. Three isocaloric diets con taining 8% olive oil (O), palm olein (P) and palm olein from 80 repeated po tato frying uses (PF) without turnover, and which nearly reached the Limit of 25% polar compounds allowed by law, were prepared and given to three gro ups of growing rats during a study period of 28 days. Body weight and food intake were monitored and faeces and urine were collected to calculate calc ium and phosphorus balances during the last week of the study. At the end o f the experiment the animals were killed and their livers, serum and carcas es stored. No differences were observed between food intake, body weight an d food efficiency of rats which consumed palm olein, whether unused or used in frying, and the control group (O). The liver mass index was higher in P F than O rats. No significant differences were observed in apparent absorpt ion and retention of calcium and phosphorus. Faecal calcium (p = 0.065) and the percentage of phosphorus absorbed (p = 0.084) showed a tendency to inc rease in rats fed diets with both unused and used palm olein and could be d ue to the known higher affinity of fat for Ca than P. No variations in seru m calcium and carcase calcium and phosphorus levels were seen. The conclusi on of this study was that consumption of palm olein, whether unused or used in frying, does not alter calcium and phosphorus bioavailability. (C) 2000 Society of Chemical Industry.