Manganese

The 10 to 20 mg of manganese contained in the adult human body are concentrated in tissues rich in mitochondria. Manganese is a component of many enzymes. Manganese is associated with the formation of connective and skeletal tissues, growth and reproduction, and carbohydrate and lipid metabolism. Manganese helps your body utilize several key nutrients such as biotin, thiamin, ascorbic acid, and choline; keep your bones strong and healthy; help your body synthesize fatty acids and cholestorol; maintain normal blood sugar levels; promote optimal function of your thyroid gland; maintain the health of your nerves; protect your cells from free-radical damage. 

Men absorb less manganese than women, a difference is related to iron status. Heme iron has no influence on manganese status, but diets, high in nonheme iron were associated with lower serum manganese values, higher urinary manganese losses, and somewhat lower activity of a manganese-dependent enzyme called superoxide dismutase. Manganese is transported bound to a macroglobin, transferrin, and transmanganin. Excretion of manganese occurs mainly in the feces after secretion into the intestine via the bile.

The richest sources of manganese are whole grains, legumes, nuts, instant coffee and tea. Fruits and vegetables are moderately good sources. Animal tissues, seafood and dairy products are poor sources. Human milk is relatively low in manganese. Median manganese intakes approximated the recommended intake for men and women but were too low for adolescent girls.

Manganese toxicity has developed in miners as a result of absorption of manganese through the respiratory tract. The excess, which accumulates in the liver and central nervous system, produces Parkinson-like symptoms.

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. 

Dietary reference intake

Infants 0.3-1.2 mg/day

Children 1.2-1.5 mg/day

Adolescents 1.9-2.2 (boys)-1.6 (girls) mg/day

Adults 1.8 (women)-2.3 (men) mg/day

Pregnant 2 mg/day

Lactating 2 mg/day

Manganese content of selected foods

Spelt, 4 oz (2.12 mg)

Brown rice, 1 cup (1.76 mg)

Garbanzo beans, cooked, 1 cup (1.69 mg)

Mustard greens, cooked, 1 cup (0.4 mg)

Pumpkin seeds ¼ cup (1.5 mg)

Kale, cooked, 1 cup (0.54 mg)

Raspberries, 1 cup (0.82 mg)

Pineapple, 1 cup (1.53 mg)

Spinach, cooked, 1 cup (1.68 mg)

Cinnamon, 2 tsp (0.91 mg)

Maple syrup, 2 tsp (0.44 mg)

Cloves, 2 tsp (1.26 mg)

Collard greens, cooked, 1 cup (0.83 mg)

Grapes, 1 cup (0.66 mg)

Eggplant, raw, 1 cup (0.2 mg)

Tea, 1 cup (0.52 mg)

Deficiency

Weight loss

High blood sugar levels

Transient dermatitis

Occasionally nausea and vomiting

Change in hair color (loss color)

Low cholesterol levels

Hearing loss

Slow hair growth

Reproductive system difficulties

Toxicity

Headaches

Dizziness

Hepatic dysfunction