Royal jelly (RJ) is an essential food for queen bees, and it reportedly has estrogen-like
activity. The objective of this study was to evaluate the effect of RJ intake on bone quality
with a focus on the posttranslational modifications of type I collagen. RJ was fed to
ovariectomized (OVX) rats for 12 weeks. RJ intake did not affect OVX-induced reduction
in bone volume at the femur epiphysis; however, the reduction of collagen crosslinks
(pyridinoline and deoxypyridinoline), which represent an aspect of bone quality, were
significantly mitigated. In cultured MC3T3-E1osteoblasts, RJ treatment did not affect cell
proliferation, cell differentiation, matrix formation, or mineralization. However, RJ
treatment did stimulate expression of plods, which encode lysyl hydroxylase isoforms that
control the collagen crosslinking pathway, and it also affected collagen crosslinking. These
results indicate that oral intake of RJ could improve bone quality by modulating the
posttranslational modification of type I collagen