Minerals

Manganese

By All The Nutrients Editorial Team Published: 5 min read

Manganese is a trace mineral that functions as a cofactor for numerous enzymes and as a component of manganese superoxide dismutase (MnSOD) — the primary antioxidant defence within mitochondria. It is essential for bone development, carbohydrate and amino acid metabolism, and the synthesis of connective tissue. The Adequate Intake (AI) is 2.3 mg/day for adult men and 1.8 mg/day for adult women — no RDA has been set due to insufficient data. Manganese is unique among trace minerals in that deficiency from diet is virtually unknown in humans, while toxicity from inhalation (occupational exposure) or contaminated groundwater is a well-recognised public health concern. See the top food sources of manganese from USDA data.

Daily Value

2.30 mg

FDA 2020

Top Source

Beverages, UNILEVER, SLIMFAST Shake Mix, high protein, whey powder, 3-2-1 Plan,

269 mg

What Does Manganese Do?

  • Antioxidant defence in mitochondria via MnSOD — manganese superoxide dismutase (MnSOD, SOD2) is located within the mitochondrial matrix, where it neutralises superoxide radicals — the primary reactive oxygen species generated by the electron transport chain. Since mitochondria produce 90% of cellular energy but also generate substantial oxidative byproducts, MnSOD is arguably the most important antioxidant enzyme in the body. Cells exposed to high metabolic stress (liver, heart, skeletal muscle) express particularly high levels of MnSOD.
  • Bone matrix formation and mineralisation — manganese activates glycosyltransferases — enzymes required for the synthesis of glycosaminoglycans (chondroitin sulfate, heparan sulfate) that form the proteoglycan matrix of cartilage and bone. These glycoproteins create the structural scaffold onto which calcium hydroxyapatite is deposited during bone mineralisation. Manganese deficiency in animal models consistently produces skeletal abnormalities, shortened long bones, and impaired cartilage development.
  • Carbohydrate metabolism — pyruvate carboxylase — pyruvate carboxylase, a manganese-dependent enzyme, converts pyruvate to oxaloacetate — a critical step in gluconeogenesis (making glucose from non-carbohydrate sources) and in replenishing TCA cycle intermediates. This enzyme is particularly important in the liver during fasting and in the brain, where continuous glucose supply is critical.
  • Amino acid catabolism — arginase — arginase, the final enzyme of the urea cycle that converts arginine to urea (excreting excess nitrogen) and ornithine, is a manganese metalloenzyme. Adequate manganese supports normal nitrogen metabolism and detoxification of ammonia from protein catabolism.

Signs of Manganese Deficiency

Dietary manganese deficiency has not been reliably documented as a clinical syndrome in free-living humans. The small number of experimental depletion studies in humans produced mild dermatitis, hair colour changes, reduced clotting factors, and bone abnormalities — all reversible upon repletion. The body tightly regulates manganese through intestinal absorption and biliary excretion. Groups at potential risk include people with very low dietary variety, those eating diets dominated by refined foods (processing removes manganese from grains), and individuals with certain gastrointestinal malabsorption conditions.

  • Dietary deficiency is essentially unknown in free-living humans under normal dietary conditions
  • In experimental depletion: transient dermatitis, hair colour changes (hypopigmentation), and abnormal clotting factor responses
  • Impaired bone growth and density in animal models; possibly relevant in humans with severely restricted diets
  • Glucose intolerance — pyruvate carboxylase impairment may reduce gluconeogenic capacity
  • Reduced MnSOD activity — increasing mitochondrial oxidative stress (measured biochemically, not clinically apparent)

How to Get the Most from Manganese

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Phytic acid in whole grains reduces manganese absorption — but these foods are still good sources

Whole grains and legumes contain phytic acid (phytate) that binds manganese and reduces its absorption. Despite lower bioavailability (3–8% from plant foods vs 5% from animal sources — both low), whole grains, legumes, nuts, and seeds are still the richest dietary manganese sources. The body adapts by increasing absorption when intake is low and excreting more through bile when intake is high. Soaking, sprouting, and fermenting foods reduces phytate and improves mineral bioavailability.

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Iron and calcium supplements can reduce manganese absorption

High-dose iron or calcium supplements (especially calcium >500 mg taken with meals) can inhibit manganese absorption by competing for shared intestinal transporters (DMT1). Manganese absorption is typically 3–8%; concurrent iron supplementation can reduce this further. This interaction is unlikely to cause deficiency but is relevant for people with borderline manganese status taking high-dose mineral supplements.

Common Manganese Questions

What does manganese do in the body?

Manganese is a cofactor for several key enzymes: manganese superoxide dismutase (MnSOD) — the primary mitochondrial antioxidant; pyruvate carboxylase — essential for gluconeogenesis and TCA cycle function; arginase — required for the urea cycle and protein metabolism; and glycosyltransferases — needed for bone and cartilage matrix synthesis. It also plays a role in blood clotting factor synthesis.

Which foods are highest in manganese?

The richest sources per 100g are: cloves (60 mg), mussels (6.8 mg), hazelnuts (6.2 mg), wheat germ (13.3 mg), oat bran (5.6 mg), brown rice cooked (1.8 mg), chickpeas (2.2 mg), spinach (0.9 mg), pineapple (0.9 mg), and black pepper (12.8 mg). Whole grains, nuts, seeds, and shellfish dominate the rankings.

Can you get too much manganese?

Yes — manganese toxicity (manganism) is a well-documented occupational hazard from chronic inhalation of manganese dust (mining, welding, steel manufacturing). Symptoms resemble Parkinson's disease: tremor, rigidity, mask-like face, gait disturbance, and psychiatric changes. Dietary manganese toxicity from food alone is very rare; the Tolerable Upper Intake Level (UL) is 11 mg/day for adults. Contaminated groundwater in parts of Bangladesh and other countries has caused neurological manganese toxicity from drinking water.

How much manganese do I need per day?

The Adequate Intake (AI) is 2.3 mg/day for adult men and 1.8 mg/day for adult women, rising slightly during pregnancy (2.0 mg) and breastfeeding (2.6 mg). Most people consuming a diet including whole grains, legumes, and nuts easily meet this target. The UL is 11 mg/day — easily exceeded only with high-dose supplement use, not from food.

Is manganese the same as magnesium?

No — these are completely different minerals. Magnesium (Mg) is the fourth most abundant mineral in the body, required in gram quantities (~400 mg/day RDA) for over 300 enzyme reactions, ATP function, and neuromuscular transmission. Manganese (Mn) is a trace mineral required in much smaller amounts (~2 mg/day AI) for specific cuproenzymes and antioxidant defence. They are frequently confused because of similar names but have distinct biological roles and food sources.