Essentiality of Manganese for Bone Health: An Overview and Update

The evidence regarding a deficiency of manganese (Mn) in humans is scarce. So the aim of this narrative review was to consider the state of the art on the relation between manganese and bone health in humans and the effectiveness of manganese supplementation (alone or with other micronutrients) on bone mineralization. This review included 4 eligible studies. All the literature published is in agreement in showing that osteoporotic women have lower serum Mn levels than women with normal bone mineral density, thus confirming the essential role of manganese in the synthesis of cartilage and bone collagen, as well as in bone mineralization and confirming the studies on the animal model. Considering the human studies that evaluated the effectiveness of an oral Mn supplement for a long period (2 years) on the bone mineral density of menopausal women, both of the clinical trials showed that bone loss was significantly greater in the placebo group than in the group taking supplementation, equal to 5.0 mg Mn/day in the study by Strause, and equal to 2.5 mg Mn/day in the study by Saltman, considering, however, that supplementation was represented by a set of microelements (Mn, copper, and zinc) and by calcium.