Pinto bean hull extract supplementation favorably affects markers of bone metabolism and bone structure in mice

Hulls from dry edible beans are rich in phenolic compounds recognized as possessing antioxidant activity. The aim of this study was to characterize antioxidant properties of bean hull extract (BHE) and to determine whether BHE supplementation (at 400 or 800 mg/kg for 3 months) affects serum biochemical markers and bone structure in 12-month-old male C57BL/6 mice. Mice supplemented with 800 mg BHE/kg had lower serum tartrate-resistant acid phosphatase and parathyroid hormone concentrations than those on control diet or supplemented with 400 mg BHE/kg. BHE supplementation caused slight decrease in oxidized glutathione concentration in blood (P = 0.07). Compared to the control group, BHE supplementation at 800 mg/kg for 3 months improved bone structural indices, bone mineral density and trabecular thickness in the third lumbar vertebra. These results suggest that BHE supplementation may have beneficial effects on bone health in mice by decreasing bone resorption.