Manganese performs a number of essential roles in cellular function and human metabolism. At the biochemical level, manganese functions both as a constituent of metallo-enzymes and an enzyme activator. It is an important constituent of an enzyme called manganese superoxide dismutase (MnSOD) which helps protect tissues against oxidative damage.

Manganese deficiencies are relatively rare in humans, but research in animal models predicts possible contributions to bone and joint abnormalities, impaired pancreatic function, ataxia, reduced growth, impaired reproductive performance, and abnormal carbohydrate and lipid metabolism.

While manganese is abundant and widely distributed in nature, only trace amounts are required by the human body. The best food sources tend to be nuts, cereals, and dried fruit.