Bioavailability of zinc yeast in rats:: Stimulatory effect on bone calcification in vivo

The bioavailability of zinc yeast as a functional food ingredient in rats was investigated. Zinc yeast, zinc sulfate, or zinc oxide was used. Serum zinc concentrations were significantly increased by a single oral administration of 44 zinc yeast, zinc sulfate or zinc oxide at a dose of 10 mg Zn/100 g body weight. A significant increase was observed 1 hr after administration and it was also seen with the lowest dose of Zn 0.5 mg/100 g of zinc yeast or zinc oxide. A single oral administration of zinc yeast, zinc sulfate, or zinc oxide (10 mg Zn/100 g) caused a significant increase in liver zinc content. A significant increase in femoral-diaphyseal and metaphyseal zinc contents was observed with the administration of zinc yeast or zinc sulfate. When zinc yeast or zinc oxide (10 mg Zn/100 g) was orally administered once daily for 7 days to rats, a significant increase in zinc levels in the serum, liver, and femoral-metaphyseal tissues was seen. Femoral-diaphyseal zinc content was significantly increased with the administration of zinc yeast. A significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues occurred with the administration of zinc yeast or zinc oxide. The effect of zinc yeast was greater than that of zinc oxide. This study demonstrated that zinc yeast has high bioavailability in rats, and that its administration induces an anabolic effect on bone calcification in vivo. Zinc yeast may be useful as a functional food ingredient.