Manganese is an essential mineral needed only in small amounts, and a varied diet of whole grains, nuts, legumes, greens, and tea usually supplies enough. It is clearly essential, but taking more than enough shows no added benefit. Its safe window is narrow: too much, especially with liver problems, can harm the brain. (Full Review)
| Marker | Target | Why |
|---|---|---|
| Whole-blood manganese | ~4–15 µg/L (73–273 nmol/L) | Best available index of body manganese status and overload |
| Ferritin (iron stores) | 30–100 ng/mL | Low iron increases manganese absorption and raises accumulation risk |
| Liver-function panel (ALT, AST, bilirubin) | ALT/AST < 25 U/L; normal bilirubin | Impaired bile flow raises manganese retention and toxicity risk |
| Fasting glucose / HbA1c | Fasting glucose 70–90 mg/dL; HbA1c < 5.4% | Places manganese in the context of its U-shaped link with glucose control |
| Brain MRI pallidal index (only if overload suspected) | No abnormal T1 signal in the globus pallidus | Detects brain manganese accumulation before overt symptoms |
Cadence: Higher-risk (occupational exposure or intravenous feeding): whole-blood manganese and liver-function tests at baseline, ~3 months, then every 6–12 months. Routine low-dose supplementation: reassess overall intake every 12 months.