The effect of Gypsophila saponins in the diet on mineral status and plasma cholesterol concentration in the rat

Abstract

1. Immature, male Wistar rats were allocated to one of six groups and caged individually. The first group was given a semi-synthetic diet containing 38 mg iron and 55 mg zinc/kg (basal group). The second and third groups were given a diet containing 10 mg Zn and 12 mg Fe/kg respectively (low-Zn and low-Fe groups). Groups four, five and six were given similar diets containing 20 g Gypsophila saponins/kg. After 21 d the Fe and Zn status of the rats was estimated and plasma cholesterol concentration determined. 2. Measurements of whole blood haemoglobin concentration, packed cell volume and liver Fe stores indicated that rats in the basal + saponin and low-Fe + saponin groups had a significantly reduced Fe status when compared with their controls. Rats in the low-Zn + saponin group also showed a trend toward reduced Fe stores. 3. Zn status, as judged by femur Zn concentration, was not adversely affected by the inclusion of Gypsophila saponins in the diet. 4. Consumption of the saponins resulted in a significant reduction in blood cholesterol concentration, with rats in both the low-Fe groups having significantly lower concentrations than their basal and low-Zn counterparts. 5. In view of suggestions that the consumption of saponins should be encouraged because of their ability to lower blood cholesterol, possible effects on Fe metabolism should be investigated further, particularly with respect to the levels and sources of saponin in the human diet.