Manganese

Manganese is an essential trace mineral that works as a cofactor for a small number of important enzyme systems. The body contains only about 10–20mg in total, with about a quarter to two-fifths in the bones and the rest concentrated in the liver, pancreas, kidneys, and brain. Despite these small amounts, manganese is involved in energy production, antioxidant defense in the mitochondria, cartilage and bone formation, wound healing, and blood sugar regulation. Deficiency is very rare, because manganese is widespread in plant foods — but excess manganese is a well-known neurotoxin, mainly through industrial exposure, and occasionally through drinking water, medical feeding, or liver disease.

Key Mechanisms

Manganese superoxide dismutase (Mn-SOD): mitochondria produce reactive oxygen species (ROS) as an unavoidable by-product of aerobic energy production. Mn-SOD is the main antioxidant enzyme inside the mitochondria, neutralizing superoxide radicals before they damage mitochondrial membranes, proteins, and DNA. It complements the copper-zinc SOD that works in the rest of the cell. Because mitochondria are such a major source of ROS, Mn-SOD is a front-line defense, not a backup.

Pyruvate carboxylase: this manganese-dependent enzyme converts pyruvate to oxaloacetate — a key step in gluconeogenesis (making glucose from non-carbohydrate sources) and in topping up the TCA (Krebs) cycle when it needs replenishing. This makes manganese part of the machinery that maintains blood sugar and aerobic energy production.

Glycosyltransferases: manganese is needed by enzymes that build glycosaminoglycans — the long chain-like sugar molecules that make up much of the cushioning substance of cartilage, bone matrix, and connective tissue.

Arginase and prolidase: arginase, a manganese enzyme in the liver, carries out the final step of the urea cycle, which removes nitrogen from protein breakdown. Prolidase, another manganese-dependent enzyme, recycles the amino acid proline, which is needed to make collagen — one reason manganese matters for wound healing.

Glutamine synthetase: in the brain, manganese is a cofactor for glutamine synthetase, which converts the neurotransmitter glutamate into glutamine. Manganese’s close involvement in brain chemistry also helps explain why too much of it is harmful to the brain (see Excessive Doses below).

AI (Adequate Intake)

Manganese has an Adequate Intake rather than an RDA, because there isn’t enough evidence to set precise requirements.

Source: US National Academies, via the NIH Office of Dietary Supplements. The daily value used on food labels is 2.3mg.

ODA (Optimal Daily Allowance)

Meet the AI — 1.8–2.3mg a day for adults — from food. Diets that include whole grains, nuts, seeds, legumes, and tea typically provide around 2–6mg a day without any effort, and people eating mostly plant foods often get more. There’s no evidence that higher intakes help athletes or anyone else, and supplements beyond the small amount in a multivitamin are rarely needed — unlike many minerals, manganese’s main risk is too much, not too little.

Found In (per 100g)

Nuts, seeds, whole grains, legumes, shellfish, and leafy greens are the main sources. Refining strips out much of the manganese in grains — whole wheat bread contains more than three times as much as white bread. Pineapple is a notable fruit source, and cloves and other spices are extremely concentrated, though they’re used in such small amounts that they contribute relatively little. Tea is also a major source for regular drinkers, though manganese from tea may be less well absorbed. Meat, poultry, fish, and dairy contain little manganese.

Helps With

• Antioxidant defense in the mitochondria via Mn-SOD
• Energy production and blood sugar regulation, through pyruvate carboxylase
• Building cartilage, bone, and connective tissue, through glycosaminoglycan synthesis
• Wound healing and tissue repair, partly through proline recycling for collagen
• Removing nitrogen waste from protein breakdown, through arginase in the urea cycle
• Neurotransmitter metabolism and brain function, via glutamine synthetase
• Fat and carbohydrate metabolism

For Athletes and Active People

Manganese’s relevance to athletic performance is real but indirect — it supports the systems that underpin training rather than directly driving performance.

Mitochondrial antioxidant capacity: intense training increases ROS production in the mitochondria, and endurance training increases the number of mitochondria — one of the key aerobic adaptations. Mn-SOD is part of how mitochondria handle that load. Manganese is very unlikely to be a limiting factor on a whole-food diet, but athletes who eat mostly refined grains instead of whole grains may get less than they assume.

Joint and cartilage health: manganese’s role in glycosaminoglycan synthesis sits alongside vitamin C, collagen-building amino acids, and copper in the nutritional foundation for cartilage — part of a complete picture, not a primary intervention. One caution: some glucosamine and chondroitin joint supplements also contain manganese, sometimes 10mg or more per daily dose. Combined with a manganese-rich diet and a multivitamin, these can push intake close to or above the 11mg upper limit, so check the label.

Blood sugar during prolonged exercise: pyruvate carboxylase contributes to gluconeogenesis, which becomes an increasingly important glucose source during long efforts as glycogen stores run down.

For most athletes eating a varied diet that includes whole grains, nuts, legumes, and vegetables, manganese intake is adequate without any special effort, and supplements offer no proven benefit.

Insufficient Doses

Deficiency is very rare — so rare that its effects in people aren’t well understood. It’s mainly a theoretical concern for people with:

• Severe malabsorption conditions
• Very restricted diets built almost entirely on refined, processed foods
• Rare inherited disorders of manganese transport

High iron intake reduces manganese absorption, because the two share a gut transporter (DMT1) — and conversely, people who are low in iron absorb more manganese. Very high intakes of calcium may also slightly reduce absorption.

The phytate paradox: phytates in whole grains and legumes reduce manganese absorption, but these same foods are among manganese’s best sources. The net effect is still positive — even with lower absorption, people who eat whole grains and legumes get more manganese than people who avoid them.

Possible signs of deficiency: because deficiency so rarely occurs, most of what’s known comes from animal studies and a few small experiments in which volunteers ate very low-manganese diets. In those studies, young men developed a scaly skin rash and lower cholesterol, and women reported more mood changes and pain before their periods. In animals, manganese deficiency impairs bone and cartilage development, growth, and glucose tolerance.

Excessive Doses

Upper limit (UL): 11mg a day for adults, from all sources combined. The limits for children are lower:

Source: US National Academies, via the NIH Office of Dietary Supplements.

Manganism: long-term overexposure to manganese causes a toxic brain syndrome called manganism, which closely resembles Parkinson’s disease. It’s mainly an occupational hazard — affecting manganese miners, welders breathing manganese-containing fumes, and workers in steel, ferroalloy, and battery manufacturing — because inhaled manganese bypasses the gut and liver controls that normally limit how much reaches the body.

Manganese accumulates in the basal ganglia — the brain region affected in Parkinson’s disease — where it disrupts dopamine and glutamate signaling and causes oxidative damage.

Symptoms of manganism:

• Early stage: fatigue, mood changes, irritability, compulsive behavior, and sometimes hallucinations
• Later stage: tremor, muscle rigidity, a mask-like facial expression, a shuffling walk, and slowed movement
• Unlike Parkinson’s disease, manganism generally doesn’t respond well to levodopa (L-DOPA), and the damage may be permanent once established

Other groups at risk of manganese buildup:

• People with liver disease — manganese is excreted mainly in bile, so chronic liver disease and cirrhosis can cause it to build up even at normal intakes. People with liver disease shouldn’t take manganese supplements unless a doctor advises it.
• People on long-term intravenous nutrition — manganese given directly into the bloodstream bypasses the gut’s controls, and buildup in the brain has been reported. Guidelines now recommend lower manganese doses in IV nutrition, with monitoring.
• Infants and young children — whose ability to excrete manganese is less developed.
• People drinking water high in manganese — some private wells and water supplies naturally contain high levels, and studies have linked high manganese in drinking water with lower IQ scores in children. If you rely on well water, it’s worth testing it, especially before using it for infant formula.

Manganese from food isn’t a realistic concern for healthy people — the body adjusts absorption and excretes the excess in bile, and people eating plant-rich diets with high manganese intakes show no ill effects. The concern is mainly with supplements, inhaled manganese, drinking water, and the risk groups above.

Different Types

Standalone manganese supplements are rarely needed — food provides enough for most people, and manganese is included in most multiminerals and many bone and joint formulas. When it is supplemented, common forms include:

• Manganese Bisglycinate / Glycinate — manganese bound to the amino acid glycine; well absorbed and gentle on the stomach.
• Manganese Gluconate — widely used in supplements and generally well tolerated.
• Manganese Citrate — well absorbed and budget-friendly.
• Manganese Picolinate — well absorbed; less common.
• Manganese Sulfate — common in multivitamins and fortified foods; effective, though it may be harsher on the stomach.
• Manganese Ascorbate — often found in glucosamine and chondroitin joint supplements; check the total manganese dose (see above).

Which form for your goal:

How to Take It

For most people, the goal is a good diet rather than supplements: choose whole grains over refined grains, and include nuts, seeds, legumes, and leafy vegetables.

If you take a supplement containing manganese, take it with food to reduce any stomach upset, and keep it apart from high-dose iron supplements. Don’t exceed 11mg a day from all sources — remember that multivitamins and some joint supplements already contain manganese. People with chronic liver disease should avoid manganese supplements unless a doctor specifically recommends them.

Interactions

High iron intake reduces manganese absorption through a shared intestinal transporter — relevant for people taking iron supplements — while iron deficiency increases manganese absorption. Very high calcium intakes may slightly reduce manganese absorption. Phytates reduce absorption from plant foods, but plant foods remain the best sources overall.

Synergy

• Works with calcium, magnesium, and phosphorus in building bone and cartilage — manganese helps make the organic framework that minerals are deposited into.
• Complements copper and zinc in antioxidant defense — manganese SOD protects the mitochondria, while copper-zinc SOD works in the rest of the cell.
• Works with vitamin C in collagen formation — vitamin C stabilizes collagen, and manganese-dependent prolidase recycles proline to build it.
• Works alongside vitamins C and E against oxidative stress, from different angles.

Antagonistic Interactions

• High iron intake reduces manganese absorption — they share the DMT1 transporter.
• Very high calcium intakes may slightly reduce manganese absorption.
• Phytates in whole grains and legumes partly reduce absorption from those meals.
• Liver disease impairs manganese excretion in bile, increasing the risk of buildup.

Food values: USDA FoodData Central — macadamia nuts, raw (Foundation Foods, FDC ID 2515378); pine nuts, raw (Foundation Foods, 2346392); chia seeds (Foundation Foods, 2710819); blue mussels, cooked (SR Legacy, 174217); hazelnuts, raw (Foundation Foods, 2515375); pumpkin seeds (pepitas), raw (Foundation Foods, 2515380); oats, dry (SR Legacy, 173904); English walnuts, raw (Foundation Foods, 2346394); sunflower seeds, raw (Foundation Foods, 2515381); almonds, raw (Foundation Foods, 2346393); dark chocolate, 70–85% cacao (SR Legacy, 170273); 100% whole wheat bread (Foundation Foods, 2758994); tofu, firm (SR Legacy, 172475); chickpeas, cooked (SR Legacy, 173757); brown rice, cooked (SR Legacy, 169704); spinach, boiled (SR Legacy, 168463); white bread, commercial (Foundation Foods, 2758993). AI and upper limits from the US National Academies, via the NIH Office of Dietary Supplements. % Daily Values use the FDA’s current Daily Value of 2.3mg.