Fructooligosaccharides stimulate the growth of Bifidobacteria, which cleave
isoflavone glycosides to yield corresponding aglycones, and convert metabolites by enhancing enterohepatic recirculation of
isoflavones in rats. In the present study, we determined the synergistic effect of dietary
isoflavone glycosides and fructooligosaccharides on postgastrectomy
osteopenia in rats. Nine-week-old male Sprague-Dawley rats were gastrectomized (n = 20) or
sham operated, (control, n = 5) and then randomly assigned to 5 diet groups:
sham-a purified diet control, gastrectomized-control, gastrectomized-
isoflavone (0.2%
isoflavone glycosides), gastrectomized-fructooligosaccharides (7.5% fructooligosaccharides), and
isoflavone and fructooligosaccharides (0.2%
isoflavone glycosides + 7.5% fructooligosaccharides). After 6 weeks, the rats were killed and biological samples were collected. In gastrectomized rats, fructooligosaccharides prevented femoral bone fragility, but
isoflavone without fructooligosaccharides did not inhibit postgastrectomy
osteopenia.
Isoflavone and fructooligosaccharides exhibited a synergistic in the distal metaphyseal trabecular bone, indicated by peripheral quantitative computed tomography. Moreover, fructooligosaccharides increased
calcium absorption and
equol production from
daidzein in gastrectomized rats. These results indicate that
isoflavone alone did not inhibit postgastrectomy
osteopenia, but the combination of
isoflavone and fructooligosaccharides improved the inhibition of trabecular bone loss by increasing
calcium absorption and
equol production through fructooligosaccharides supplementation.