Lactoferrin – A Potential Anabolic Intervention in Osteoporosis

Osteoporosis or porous bone was first described by Fuller Albright approximately 70 years ago as having “too little bone in the bone”. Bone tissue is maintained throughout life by being continually replaced and in osteoporosis bone resorption exceeds bone formation resulting in bone loss. The majority of current treatments for osteoporosis are antiresorptive, decreasing osteoclast activity and preventing further bone loss. Therapeutic agents that activate osteoblasts and increase bone formation have the potential benefit of restoring bone rather than only preventing further deterioration, but only a small number of safe anabolic therapies are currently available. Milk is a rich biological fluid that contains many growth factors and provides nutrition at a time of very rapid skeletal growth and development in the neonate, and was therefore considered as a possible source of factors with anabolic effects on bone. Investigations of fractions of whey proteins extracted from milk identified lactoferrin as a bone-active factor. Lactoferrin is an iron-binding glycoprotein which as well as being present in milk is found in other epithelial secretions. It is a pleiotropic factor with potent antimicrobial and immunomodulatory activities, and shows anabolic effects in bone at physiological concentrations. In a number of recent studies in humans and experimental animals dietary lactoferrin supplementation improved bone mineral density, bone markers and bone strength. The current chapter discusses the structure and function of lactoferrin, the bone-effects of lactoferrin in vitro and in vivo, and the potential use of lactoferrin for the improvement of bone health.