The social phenomenon of the growing number of elderly patients with bone disease or fractures attributable to osteoporosis is closely associated with an increase in the number of bedridden elderly, and is a causative factor in the rise of the total cost of national health care. We hypothesized that the excellent effects of cow’s milk on bone health might not be limited to an abundance of calcium, and investigated substances in milk that regulate bone remodeling to enhance bone mineral density. We successfully identified the “milk basic protein” (MBP) component of milk, which has a direct effect on the strengthening on bones. MBP stimulated proliferation of osteoblasts involved in bone formation and collagen production and also suppressed the activity of osteoclasts involved in bone resorption. The supplementation of some daily foods with MBP has made it possible to maintain properly balanced bone remodeling and to increase bone mineral density in human volunteers. MBP is expected to be a functional component in helping to maintain human bone health.