Evidence Level
Moderate
Manganese research is limited compared to other minerals. A key study by Strause et al. (1994, n=59) found that a combination of manganese (5mg), calcium, zinc, and copper significantly improved spinal bone density in postmenopausal women over 2 years compared to calcium alone. Animal studies consistently demonstrate that manganese deficiency impairs bone growth, cartilage formation, and glucose tolerance. The primary safety concern is neurotoxicity: occupational exposure studies in miners and welders (inhaled manganese) show Parkinson-like symptoms, though oral supplement toxicity at reasonable doses (<11mg/day) has not been documented in healthy individuals.