Bone is a dynamic tissue that undergoes continual adaptation during vertebrate life to preserve skeletal size, shape, and structural integrity and to regulate mineral homeostasis. Bone mass is skillfully regulated through osteoclasts and osteoblasts. Bone mass is reduced through decreased osteoblastic bone formation and increased osteoclastic bone resorption. This decrease induces osteoporosis. Bone loss is also caused in various pathophysiologic states including inflammatory condition, obesity, diabetes, and cancer cell bone metastasis. In addition, malnutrition or undernutrition is often observed with increasing ages and is strongly implicated in the pathogenesis and consequences of bone fracture in the osteoporotic elderly. Nutritional and functional food factors may play a pivotal role in maintaining bone health, and this will be expected as a new biomedical treatment for osteoporosis.