Administration of caffeic acid worsened bone mechanical properties in female rats.

Natural phenolic acids, commonly present in plants that are normally consumed in the diet, have been reported to exert antiresorptive and/or bone formation increasing activity. The aim of the present study was to investigate the effects of ferulic, caffeic, P-coumaric, and chlorogenic acids on the skeletal system of normal, mature female rats. The phenolic acids (10 mg/kg p. o. daily for 4 weeks) were administered to 3-month-old female Wistar Cmd:(WI)WU rats. Bone mass, mineral and calcium content, macrometric and histomorphometric parameters, and mechanical properties were examined. Phenolic acids had differential effects on the rat skeletal system. Although none of them affected bone macrometric parameters, mass and mineralization, all of them increased the width of femoral trabeculae. Administration of caffeic acid worsened bone mechanical properties (decreasing ultimate load sustained by the femur in three-point bending test). In conclusion, high intake of caffeic acid may unfavorably affect the skeletal system.