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Check manganese intake vs AI — see mg/day, % of AI and food sources.
Check manganese intake vs AI — see mg/day, % of AI and food sources.
Enter values above and click Calculate — results will appear here with the formula explained.
Manganese carries an Adequate Intake rather than an RDA — 2.3 mg daily for men, 1.8 mg for women 19 and older — because the evidence base cannot support an Estimated Average Requirement, the prerequisite for an RDA. AI means observed intakes of apparently healthy populations, a softer anchor than an RDA: landing near 100% is reassuring, landing at 70% is not proof of deficiency the way sub-RDA intake would be for nutrients with established EARs.
Functionally, manganese is a cofactor for enzymes in bone formation, carbohydrate and amino-acid metabolism, and the antioxidant enzyme manganese superoxide dismutase (MnSOD) that defends mitochondria against free radicals. Deficiency is rare in practice precisely because the mineral is widespread in plant foods — documented cases come almost exclusively from experimental depletion or total parenteral nutrition without supplementation, not from ordinary diets.
Food supply makes hitting the AI easy: whole grains and grain products, nuts and seeds, legumes, leafy green vegetables, tea and shellfish such as mussels all contribute meaningfully, and heavy tea drinkers often clear the AI from tea alone. Vegetarian patterns routinely exceed the AI several-fold with no action required — this is a nutrient of sufficiency for most eaters, and the calculator's main value is confirming that rather than finding gaps.
Absorption is where manganese interacts with its mineral neighbors: manganese and iron share transport pathways, so high-dose iron supplements taken with meals can depress manganese uptake, and very high manganese intakes can in turn impair iron status — the reason the existing FAQ flags iron. Space large single-mineral doses apart (iron with vitamin C away from manganese-rich meals) rather than stacking them at breakfast.
Toxicity comes almost entirely from outside food. The tolerable upper intake level is 11 mg daily from food, water and supplements combined — roughly 5× the AI, a margin ordinary diets never approach. Real manganese neurotoxicity (manganism, a parkinsonian syndrome) is an inhalation story: welders, miners and ferroalloy workers breathing manganese dust and fumes, plus rare cases from contaminated well water or long-term parenteral nutrition. Food manganese has not produced toxicity in healthy adults; supplement megadoses and dusty occupations are the scenarios that warrant attention, not spinach.
Supplements deserve skepticism here. Standalone manganese pills solve a problem most people do not have, and multi-mineral formulas already include it — adding more on top narrows the margin toward the UL for zero demonstrated benefit. Get it from oats, brown rice, chickpeas, hazelnuts and tea; reserve testing and supplementation for clinician-directed cases (parenteral nutrition, malabsorption, or documented occupational exposure).
Check manganese intake vs AI — see mg/day, % of AI and food sources. Formula: AI: M 2.3, F 1.8 mg. Example: With 2.5 mg intake against the male AI of 2.3 mg: 2.5 ÷ 2.3 × 100 ≈ 108.7% — sufficient with margin.
Manganese carries an Adequate Intake rather than an RDA — 2.3 mg daily for men, 1.8 mg for women 19 and older — because the evidence base cannot support an Estimated Average Requirement, the prerequisite for an RDA. AI means observed intakes of apparently healthy populations, a softer anchor than an RDA: landing near 100% is reassuring, landing at 70% is not proof of deficiency the way sub-RDA intake would be for nutrients with established EARs.
Functionally, manganese is a cofactor for enzymes in bone formation, carbohydrate and amino-acid metabolism, and the antioxidant enzyme manganese superoxide dismutase (MnSOD) that defends mitochondria against free radicals. Deficiency is rare in practice precisely because the mineral is widespread in plant foods — documented cases come almost exclusively from experimental depletion or total parenteral nutrition without supplementation, not from ordinary diets.
Food supply makes hitting the AI easy: whole grains and grain products, nuts and seeds, legumes, leafy green vegetables, tea and shellfish such as mussels all contribute meaningfully, and heavy tea drinkers often clear the AI from tea alone. Vegetarian patterns routinely exceed the AI several-fold with no action required — this is a nutrient of sufficiency for most eaters, and the calculator's main value is confirming that rather than finding gaps.
Absorption is where manganese interacts with its mineral neighbors: manganese and iron share transport pathways, so high-dose iron supplements taken with meals can depress manganese uptake, and very high manganese intakes can in turn impair iron status — the reason the existing FAQ flags iron. Space large single-mineral doses apart (iron with vitamin C away from manganese-rich meals) rather than stacking them at breakfast.
Toxicity comes almost entirely from outside food. The tolerable upper intake level is 11 mg daily from food, water and supplements combined — roughly 5× the AI, a margin ordinary diets never approach. Real manganese neurotoxicity (manganism, a parkinsonian syndrome) is an inhalation story: welders, miners and ferroalloy workers breathing manganese dust and fumes, plus rare cases from contaminated well water or long-term parenteral nutrition. Food manganese has not produced toxicity in healthy adults; supplement megadoses and dusty occupations are the scenarios that warrant attention, not spinach.
Supplements deserve skepticism here. Standalone manganese pills solve a problem most people do not have, and multi-mineral formulas already include it — adding more on top narrows the margin toward the UL for zero demonstrated benefit. Get it from oats, brown rice, chickpeas, hazelnuts and tea; reserve testing and supplementation for clinician-directed cases (parenteral nutrition, malabsorption, or documented occupational exposure).
With 2.5 mg intake against the male AI of 2.3 mg: 2.5 ÷ 2.3 × 100 ≈ 108.7% — sufficient with margin. A second case: a woman consuming 1.5 mg reaches 1.5 ÷ 1.8 × 100 ≈ 83.3% — slightly under AI, easily closed with a serving of oats or chickpeas rather than a supplement.
Last reviewed: September 2026 · Report an error