Fructo-oligosaccharides enhance the mineral absorption and counteract the adverse effects of phytic acid in mice.

OBJECTIVE: We explored the effects of fructo-oligosaccharides (FOS) and phytic acid (PA) on the absorption of minerals and their interaction. METHODS: A 3 x 2 factorial experiment was designed to evaluate the effects of FOS (in the presence or absence of PA) on the apparent absorption rate of minerals and the mineral status (plasma, hepatic, and bone) in mice. Sixty Kun-Ming mice were randomized into six groups: basal diet group; basal diet+1% PA group (PA); basal diet+0.8 g/kg of body weight FOS group (FOS1); FOS1+1% PA group (FOS1+PA); basal diet+2.5 g/kg of body weight group (FOS2); and FOS2+1% PA group (FOS2+PA). The mice received FOS by gavage for consecutive 4 wk, and the PA was added in the diet. The mice were housed individually in the last week. The food intake was recorded and the feces were collected for calculation of the apparent absorption rate. Then the mice were sacrificed, the ceca were removed and weighed, and the cecum contents were used for the detection of pH and short-chain fatty acids. The blood, liver, and the left femur were collected for the measurement of the minerals. RESULTS: FOS supplementation resulted in the enlargement of the cecum and increased cecal acidification (P<0.01). In addition, FOS effectively boosted the apparent absorption rate of calcium (FOS1, +7%; FOS2, +9%, P<0.05), magnesium (FOS1, +26%; FOS2, +19%, P<0.05), and iron (FOS1, +17%; FOS2, +22%, P<0.05), and restored the PA-impaired magnesium and iron apparent absorption rates (P<0.01). In addition, FOS significantly increased hepatic zinc levels (P<0.01) and femoral magnesium levels (P<0.01). CONCLUSION: These data indicate that FOS effectively enhances the mineral apparent absorption rate and counteracts the deleterious effects of PA.