Enzymes for carbohydrate/fat metabolism, bone formation and antioxidant systems.
Switzerland age 18–65: 3 mg/day.
Whole grains, nuts, legumes, tea and leafy vegetables.
Very rare and poorly characterised in humans; possible bone and metabolic changes.
Everyday symptoms cannot usefully be diagnosed as “manganese deficiency”.
No established specific hair or nail signs.
Severe general malnutrition or rare metabolic settings.
Routine testing is rarely useful; consider specialist clinical context.
Not needed with a varied diet.
Chronic high exposure can damage the nervous system; liver disease increases risk.