Butyrate-producing Lactococcus lactis–fermented goat cheese enhances bone health and reduces osteoporotic bone loss

Osteoporosis has emerged as a major public health concern, exacerbated by a global aging population. Although pharmaceutical agents, dairy products, and probiotics have shown potential in managing osteoporosis, safer and more effective therapeutic options remain limited. In this study, Lactococcus lactis 3-1 was identified as a bone health-promoting strain, exhibiting high butyrate production, upregulation of osteogenic genes (RUNX2, BGLAP, and ALP), and enhancement of pre-osteoblast MC3T3-E1 differentiation and calcium nodule formation. Moreover, L. lactis 3-1 demonstrated cheese-making potential through goat milk fermentation, achieving optimal texture and palatability with a 70% skim milk formulation. The intervention with L. lactis 3-1-fermented goat cheese significantly improved bone morphological parameters (femur length, weight, and diameter) and enhanced bone mechanical strength in disuse-induced osteoporotic rats. Micro-computed tomography analysis revealed a 74.88% increase in bone mineral density in the L. lactis 3-1 cheese group, accompanied by significant improvements in trabecular architecture. These enhancements included increased bone volume fraction, trabecular number, and trabecular thickness, along with decreased structure model index and trabecular separation. Additionally, the fermented goat cheese treatment increased trabecular bone area by 71.01% and reduced osteoclast-positive areas by 66.84%, indicating enhanced bone formation and reduced resorption. These findings suggest that L. lactis 3-1-fermented goat cheese may be a promising and sustainable probiotic-based approach for osteoporosis management.