Effect of germinated barley foodstuff administration on mineral utilization in rodents

Germinated barley foodstuff (GBF), which is derived from the aleurone and scutellum fractions of germinated barley, is rich in water-insoluble dietary fiber, which reportedly modulates mineral absorption in vivo. This study was conducted to examine whether GBF affects mineral absorption. We performed three experiments. In experiment 1, female ICR mice (4 weeks old) were fed a diet supplemented with 10% GBF or cellulose (CE; as a control) for 24 weeks. Body weight and food intake were recorded twice weekly. On the last experimental day, serum biochemical parameters, including electrolyte parameters, were determined, and major digestive organs were examined histopathologically. In experiment 2, male Sprague-Dawley rats (5 weeks old) were fed the CE and GBF diets, with the mineral content of the CE diet adjusted to the same level as that in the GBF diet, for 14 days, and the intake and fecal excretion of minerals (calcium, Ca; magnesium, Mg: Iron, Fe; Phosphate, P) were determined for the last 3 days. In experiment 3, the binding of Ca and Mg to GBF or cellulose and the release of Ca and Mg from GBF or cellulose was measured in phosphate buffer (pH 6.8). Long-term administration of GBF did not affect the growth rate of mice. GBF did not inhibit the absorption of Ca and Mg, and rather promoted the absorption of Ca and Mg by the gastrointestinal tract. The absorption of Fe and P was not attenuated by GBF administration, and GBF contained only a low level of phytic acid. GBF did not inhibit mineral absorption, differing from the effect of other dietary fibers, and is expected to be useful as a dietary source of Ca and Mg.