Manganese is needed for the formation of healthy skin, nerves, bones and cartilage. It also works in conjunction with zinc and copper to activate an antioxidant named superoxide dismutase, which prevents free radicals from destroying cell organs. It helps activate enzymes that regulate blood sugar, energy metabolism and function of the thyroid gland. The best dietary sources of manganese are nuts, whole grains, dried fruits, pineapples and leafy green vegetables. Beets, beans and brown rice are other good sources.
Manganese deficiency is extremely rare.
Some animal studies have shown that a diet devoid of manganese can lead to slow or stunted growth, skeletal abnormalities and paralysis. Other studies have linked manganese deficiency to osteoporosis, loss of hair color, and impaired growth of hair and nails. Research has also suggested that individuals with cirrhosis may not be able to properly excrete manganese. Patients with this condition should not take manganese supplements. Recommended Dietary Allowances, 10th ed.