Manganese deficiency is very rare in humans, and its signs have not been firmly established. Most people get enough from shellfish, nuts, whole grains, legumes, leafy vegetables and tea. Excess manganese, mainly from inhaled dust or contaminated water, is the better documented problem.
Common symptoms
Signs of deficiency in humans have not been firmly established
Very limited evidence suggests skin rashes, hair depigmentation, lower serum cholesterol and higher alkaline phosphatase in men
Altered mood and increased premenstrual pain have been reported in women
Bone demineralization and poor growth have been suggested in children
At-risk groups
No known groups of people are likely to have inadequate manganese intakes
People with chronic liver disease or iron deficiency are more vulnerable to manganese excess, not deficiency
When to see a doctorLow manganese from diet alone is very rare, so symptoms blamed on it usually have another cause. Seek care for tremor, unsteadiness, muscle spasms or new mood and memory changes, especially with welding or mining work, high-manganese well water or liver disease, because these can signal manganese excess. Talk to a doctor before taking more than 11 mg a day.