Manganese deficiency is essentially unheard of in humans. Manganese is widespread in plant foods (whole grains, nuts, leafy greens, tea), and most adults consume well above the AI from typical diets. The clinically relevant concern with manganese is actually toxicity, especially from contaminated water or long-term parenteral nutrition — excess manganese causes Parkinson-like neurological damage.
Common symptoms
Documented manganese deficiency in humans is extraordinarily rare
In limited experimental studies: dermatitis, mood changes, slow hair/nail growth
In animals: impaired growth, reproductive problems, skeletal abnormalities
Note: most concerning manganese-related issues involve EXCESS, not deficiency
At-risk groups
People on long-term parenteral nutrition without manganese (rare, monitored)
People with extremely restricted diets and malabsorption
Note: routine manganese supplementation is generally unnecessary and may be inadvisable
Manganese TOXICITY is a much more common clinical concern than deficiency
When to see a doctorManganese deficiency from diet alone has not been clinically documented in healthy people, so symptoms attributed to 'low manganese' almost always have a different cause. CRITICAL TOXICITY WARNING: chronic excess manganese — from contaminated drinking water, occupational exposure (welders, miners), or long-term high-dose supplements — causes Parkinson-like symptoms (tremor, rigidity, cognitive decline) called manganism. Avoid manganese supplements unless specifically directed by a doctor.