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minerals (nutrition)
manganese (Mn)
Nutrition
definition
Manganese:
» overview:
A trace mineral.
Found particularly in mitochondria, Manganese manganese is a component of several enzymes, including glutamine synthetase, pyruvate carboxylase, and mitochondrial superoxide dismutase (SOD).
» metabolism:
Manganese is poorly absorbed. Less than 1% of dietary intake is used by the body. Citrate enhances absorption
» Chinese:
Nourishes the Yin; benefits the Jing (Essence); nourishes the Jin (sinews and tendons); strengthens the Bones; benefits the hearing.
» function:
Manganese is needed for connective tissue and bone function, including skin integrity, skeletal development, and ear otolith development.
In skeletal development
Bone remodeling: Manganese may work with vitamin K by enhancing alpha c carboxylation of glutamate side chains. These are vital for the binding of calcium ions in the bone.
Pancreatic and brain function.
In mitochondria, manganese may protect the membranes from oxidative damage by acting with SOD.
Activator of enzymes necessary for utilization of biotin, Vitamins B-1 and C
Formation of urea
Formation of thyroxin
» requirements:
Estimated safe and adequate daily dietary intake (ESADDI) (1989): 2-5 mg per day.
Average daily intake in the U.S.: 3 mg per day
» food sources:
Rich food sources include nuts and whole grains, particularly the outer coating of nuts and grains (bran), especially those high in the germ moiety.
Also, egg yolks, seeds, and green vegetables, spinach, beets, Brussel sprouts, blueberries, oranges, grapefruit, apricots, peas, kelp.
Meat poultry, fish, and dairy are generally poor sources.
Best Food Sources of Manganese:
Food Amount Mg.
Flour, whole wheat 1/2 cup 2.6
Pease, dried, cooked 1/2 cup 2.0
Rice, brown raw 1/4 cup 1.9
Barley 1 cup 1.5
Rye, whole, uncooked 1 cup (100 g) 1.3
Buckwheat, dry 1 cup 1.3
Banana 1 med 1.1
Pecans 1/4 cup 1.0
Brazil nuts 1/4 cup 0.5
Spinach, cooked 1/2 cup 0.75
Almonds 1/4 cup 0.7
Rhubarb 1 cup 0.7
Beans, dried 1/2 cup 0.7
Lettuce, shredded 1 cup 0.68
Oats, dry 1 cup (80 g) 0.6
Sweet potato 1 med 0.6
Corn 1/2 cup 0.56
Beets, diced 3 oz 0.41
Spinach, raw 1 cup 0.41
Liver 3 oz 0.41
Kale 1/2 cup 0.33
Walnuts 1/4 cup 0.2
Peanuts 1/4 cup 0.2
Raisins 1/4 cup 0.1
(USDA: Composition of Foods. USDA Handbook # 8. Washington DC, ARS, USDA, 1976-1986)
» deficiency:
Manganese is not commonly deficient.
Magnesium can substitute for many manganese functions.
Symptoms of deficiency include sterility, skeletal abnormalities, glucose intolerance, and ataxia. Other symptoms noted are temporary inflammations of the skin, nausea and vomiting.
Decreased serum levels have been found in diabetics, epileptics, people with osteoporosis, and in people with pancreatic insufficiency.
» therapeutics:
Arthritis
Connective tissue damage
Bone repair: Certain non-healing fractures may respond to the supplementation of manganese. Bill Walton, the famous center for the Portland Trailblazers, had chronic stress fractures in his feet. He retired from basketball for a while. It was then found that he had a hereditary decrease in his body stores of manganese. After supplementation with manganese, he was able to return to playing professional basketball for a few more years. (Marz, p. 145, 1997)
Epilepsy: Animal studies show a deficiency of manganese results in seizures.
Diabetes
Myasthenia gravis
Schizophrenia
Allergies
Asthma
Multiple sclerosis
» dosage:
Maintenance dose: 20 mg
Therapeutic dose: 2-50 mg
» toxicity:
Parkinsons-like neurological symptoms can develop if manganese is inhaled. Other symptoms associated with manganese inhalation include psychiatric symptoms such as hallucinations and violent actions.
There are few toxic symptoms associated with large ingested intakes of manganese. Over 100mg/day may cause nausea
Signs and symptoms of toxicity include: weakness, psychological and motor difficulties, irritability, impotence; seen in industrial exposure to manganese dust.
» antagonists:
Antibiotics
High doses of magnesium, calcium, iron, copper, and zinc may inhibit the absorption of manganese.
» interactions:
Manganese may interfere with the absorption of iron, copper, and zinc.
Conversely, high doses of magnesium, calcium, iron, copper, and zinc may inhibit the absorption of manganese.
footnotes
Kirschmann and Dunne, pp. 80-81
Marz, Russell. Medical Nutrition From Marz. Second Edition. Portland, OR. 1997.
USDA: Composition of Foods. USDA Handbook #8. Washington DC, ARS, USDA, 1976-1986.