ラットにおけるL-トレオン酸カルシウムの生体利用特性

Ca L―threonate（C8H14O10.Ca）is a commercially available Ca ingredient, which is advertized to help deliver Ca more efficiently to the bones and increases the absorption rate of Ca. The purpose of this study was to evaluate the bioavailability of Ca threonate by comparing with that of Ca carbonate（CaCO3）, an ordinary Ca supplement. Female 4 week-old rats were fed purified diets containing either low （0.25％） or adequate （0.5％） level of Ca for 2 weeks. Feces and urine were collected and Ca concentrations were analyzed at the periods of 4-5 d and 11-12 d. When Ca intake was low, the absorption rate of Ca was higher in threonate （97-98％） than carbonate （89-93％）, though the difference was not statistically significant. When Ca intake was adequate, apparent Ca absorption of both ingredients showed similar value, being about 75%. Femur weight and maximum breaking force increased with increasing dietary Ca content, but no difference between threonate and carbonate was observed. These results suggest that bioavailability of Ca threonate is comparable with that of Ca carbonate