Bioavailability of Ca, P and Zn and bone mineralization in rats fed yoghurt and soy-yoghurt containing bifidobacteria.

Bioavailability of calcium, phosphorus and Zinc from probiotic dairy foods and other food sources has been an important issue of studies over recent years.
The aim of the present study was designed to asses and to compare therapeutic effect of milk yoghurt and soy yoghurt containing bifidobacteria with regards to their effect on the bioavailability of Ca, P and Zn and bone mineralization in rats.
Eight groups of rats were fed basal diet, cow milk, probiotic-free or probiotic-containing milk yoghurts (Bifidobacterium lactis Bb-12 or Bifidobacterium longum Bb-46), soymilk and soy-yoghurts containing only the above mentioned probiotics for 45 days.
Upon feeding probiotic-containing milk and soymilk yoghurts, rat's serum Ca and P content were about two fold that of control and surprisingly the rat's serum Zn content was about 19-21 fold that of control. The increment of apparent absorption % as compared with control was ranged between 24.7–26.6, 24–38 and 51-70% for Ca, P and Zn, respectively. The above mentioned results clearly demonstrate the enhancement of Ca, P and Zn bioavailability when probiotic diets were fed. A significant increase (n=6;p<0.05) was observed in ash content and breaking force of femur of rats fed probiotic milk-and soy- yoghurts.
Moreover probiotic milk yoghurts were much better than soy-yoghurts fermented by Bifidobacteria in enhancing bioavailability of Ca, P and Zn as well as bone mineralization. These results suggest that intake of probiotic milk-and soy- yoghurts may be useful in enhancing mineral bioavailability and bone properties.