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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.