Manganese, a trace mineral that your body uses in many enzyme systems, is found widely in nature, but occurs only in trace amounts in your tissues. Your body contains a total of 15-20 milligrams of manganese, most of which is located in your bones, with the remainder found in your kidneys, liver, pancreas, pituitary glands, and adrenal glands.

Manganese can:

• Activate enzymes: Manganese activates the enzymes that help your body use several key nutrients including biotin, thiamine, vitamin C, and choline. It is a catalyst in the synthesis of fatty acids and cholesterol, it facilitates protein and carbohydrate metabolism, and it may also help your body produce sex hormones and maintain reproductive health. In addition, manganese activates the enzymes known as glycolsyltranserferases and xylosyltransferases, which are important in forming bone. Manganese may also be involved in the production of the thyroid hormone known as thyroxine and in maintaining the health of nerve tissue.
• Form metalloenzymes: Manganese has additional functions as a constituent of the following metalloenzymes (enzymes that contain a metal ion in their structure):
  • Arginase, the enzyme in your liver responsible for creating urea, a component of urine
  • Glutamine synthetase, an enzyme involved in the synthesis of glutamine
  • Phosphoenolpyruvate decarboxylase, an enzyme that helps metabolize blood sugar
  • Manganese-dependent superoxide dismutase, an enzyme with antioxidant activity that protects your tissues from the damaging effects of free radicals.This enzyme is found exclusively inside your mitochondria (oxygen-based energy factories inside most of your cells).

Because manganese plays a role in a variety of enzyme systems, manganese deficiency can affect many physiological processes, and can cause nausea, vomiting, high blood sugar, skin rash, loss of hair color, excessive bone loss, low cholesterol levels, dizziness, hearing loss, and a poorly functioning reproductive system. Severe manganese deficiency in infants can cause paralysis, convulsions, blindness, and deafness, and may lead to impaired growth, skeletal abnormalities, and defects in carbohydrate and fat metabolism. In addition, manganese deficiency may lead to ataxia, a movement disorder characterized by lack of muscle coordination and balance caused by poor development of the otoliths, the structures in the inner ear that are responsible for equilibrium. However, manganese deficiency is very rare in humans, and does not usually develop unless manganese is deliberately eliminated from the diet. In addition, magnesium may substitute for manganese in certain enzyme systems if manganese is deficient, thereby allowing your body to function normally despite the deficiency.

Poor dietary intake of manganese is probably the most common cause of manganese deficiency. However, other factors can contribute to a need for more manganese. Like zinc, manganese is a mineral that you can excrete in significant amounts through sweat, and people who go through periods of excessive sweating may be at increased risk for manganese deficiency. In order to transport manganese, your liver needs to properly form bile, and you must have proper circulation of bile, so people with chronic liver or gallbladder disorders may need more manganese in their diets.

High doses of manganese may inhibit the absorption of iron, copper, and zinc. Alternatively, high intakes of magnesium, calcium, phosphorus, iron, copper, and zinc may inhibit the absorption of manganese.

Industrial workers who are exposed to manganese dust may develop nervous system problems similar to Parkinson’s disease. Symptoms of manganese toxicity do not usually appear even at high levels of dietary intake; however, in severe cases of excessive manganese consumption, humans can develop a syndrome called “manganese madness,” characterized by hallucinations, violent acts, and irritability. Over-consumption of manganese is also associated with impotence. Manganese toxicity is most likely to occur in people with chronic liver disease, because your liver plays an important role in eliminating excess manganese from your body. In 2000, the Institute of Medicine at the National Academy of Sciences established the following Tolerable Upper Intake Levels (UL) for manganese of 11 milligrams for adults.

Excellent food sources of manganese include spelt, brown rice, chickpeas, spinach, pineapple, pumpkin seeds, tempeh, soybeans, oats, cloves, wheat, lentils, lima beans, navy beans, cinnamon, almonds, sesame seeds, quinoa, walnuts, collards, raspberries, dried peas, pinto beans, kidney beans, black beans, green peas, peanuts, tofu, buckwheat, sunflower seeds, grapes, chard, sweet potato, cashews, strawberries, kale, blueberries, yams, turnip greens, millet, beets, maple syrup, and leeks. Very good sources of manganese include mustard greens, winter squash, potatoes, blackstrap molasses, ground flax seeds, turmeric, bananas, garlic, Brussels sprouts, corn, black pepper, thyme, green beans, asparagus, tomatoes, onions, eggplant, summer squash, and shiitake mushrooms. Good sources of manganese include broccoli, cranberries, oregano, cauliflower, fennel, carrots, miso, Romaine lettuce, cumin, crimini mushrooms, cabbage, celery, mustard seeds, bell peppers, basil, peppermint, soy sauce, cucumber, dill, cayenne pepper, and figs.

Food Sources of Manganese

Significant amounts of manganese can be lost in food processing, especially in the milling of whole grains to produce flour, and in the cooking of beans. Three and one half ounces of raw navy beans, for example, start out with about 1 milligram of manganese. This amount drops by 60% to 0.4 milligrams after cooking.

This blog uses the latest nutritional data available from the USDA (United States Department of Agriculture), and the FDA (United States Food and Drug Administration), as well as nutritional data provided by food growers and manufacturers about their products. We believe the information on this website to be accurate. However, we are not responsible for typographical or other errors. Nutrition information for recipes is calculated by Living Cookbook based on the ingredients in each recipe based on statistical averages. Nutrition may vary based on methods of preparation, origin and freshness of ingredients, and other factors.

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