Availability of plum-vinegar (umezu) calcium in rats

Abstract

Plum-vinegar calcium is a byproduct of producing "plum wine". The present study was designed to compare the availability of calcium in plum-vinegar calcium (PV) with calcium carbonate (CAR) and calcium citrate (CIT). Rats were given diets containing one of 3 calcium sources at a level of 50% or 100% of calcium requirement for 4 weeks. Femur was collected and we measured defatted weight, density, ash weight, ash density and calcium content. All bone parameters increased with dietary calcium in rats given each calcium source. Femoral defatted weight, density, ash weight, and ash density were higher in PV group than in CAR group (p<0.05) when dietary calcium was low. These parameters did not differ between PV group and CIT group. When dietary calcium was high, femoral defatted weight was higher in CIT group than in the other groups (p<0.05) and the bone parameters did not differ between PV group and CAR group. We suggested that the availability of plum-vinegar calcium or calcium citrate was higher than calcium carbonate when intake of calcium source was low. Calcium citrate showed higher availability than the other calcium sources at high intake of calcium source but the advantage of plum-vinegar calcium disappeared. High content of sodium may interfere with calcium availability in plum-vinegar calcium when its intake is high.