Manganese

Manganese is a trace mineral, meaning it’s needed in tiny amounts—but its contributions to health are anything but small. It acts as a cofactor, which is a helper molecule that activates many important enzymes. These enzymes control energy production, antioxidant defense, and the processing of proteins, fats, and carbohydrates. Manganese also supports bone formation, reproductive health, and the development of the nervous system.

Your body absorbs manganese from food, especially from whole grains, nuts, leafy vegetables, and tea. However, absorption is limited—usually less than 10%—and varies depending on your iron levels and diet. For instance, if you’re iron-deficient, your body tends to absorb more manganese. This happens because manganese and iron share similar transport systems in the gut.

Once in the bloodstream, manganese travels to the liver, where most of it is either stored or excreted into bile (a digestive fluid made by the liver). Some manganese gets delivered to energy-producing parts of cells called mitochondria, especially in organs that use a lot of energy—like the brain, pancreas, and liver. The rest gets stored in bone or pigmented tissues like the retina and skin.

In the body, manganese becomes part of enzymes such as:

• Manganese superoxide dismutase (MnSOD) – an antioxidant enzyme that neutralizes harmful oxygen byproducts inside mitochondria
• Arginase – helps break down the amino acid arginine
• Glutamine synthetase – helps make glutamine, a key fuel source for brain cells
• Pyruvate carboxylase – helps convert food into energy

When Deficiency or Excess Occurs

Too much manganese can be neurotoxic, especially when it bypasses normal digestive regulation—like through inhalation in industrial settings (welding, mining) or IV feeding. This can lead to a condition called manganism, which mimics Parkinson’s disease. Symptoms include tremors, difficulty walking, mood changes, and memory loss. The reason is that manganese tends to accumulate in a part of the brain called the basal ganglia, which helps control movement. Manganese toxicity from food is virtually unheard of. However, occupational exposure, contaminated water, or excessive supplementation can pose a danger. The tolerable upper intake level (UL) for adults is 11 mg/day. Some people may absorb more due to low iron status or liver disease, both of which reduce the body’s ability to regulate manganese levels.