Abstract
The effect of long-term dietary calcium supplementation on fecal mineral excretion was examined in four-week-old male Wistar rats. The rats were divided into two groups, and fed different doses of calcium (0.5% and 1.5% calcium) in the diet for 10 weeks. Feces were collected during 5 days after 3 and 10 weeks, and fecal weight and mineral contents (Ca, Mg, P, Fe, Cu, Zn, Na, K) were measured. Final weight and food efficiency rate were found to decrease with dietary calcium supplementation. A high calcium level in the diet increased the fecal weight and fecal excretion of magnesium, phosphorus, iron and copper, but did not affect the fecal excretion of zinc, sodium and potassium. Apparent absorption of magnesium, phosphorus and iron decreased with dietary calcium supplementation. It is considered that calcium supplemenation disturbed iron absorption with resulting fecal excretion of iron. This phenomenon reflected the lower hemoglobin value in the high-calcium diet group. These results suggest that long-term dietary calcium supplementation in rats may deplete magnesium, phosphorus and iron.
