What is Manganese?
Manganese, a trace mineral that participates in many enzyme systems in the body, was first considered an essential nutrient in 1931.
What can high manganese foods do for you?
Manganese is found only in trace amounts in human tissues. The human body contains a total of 15 to 20 milligrams of manganese, most of which is located in the bones, with the remainder found in the kidneys, liver, pancreas, pituitary glands, and adrenal glands.
- Help 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 cholesterol.
- 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.
What events can indicate a need for more high manganese foods?
- Poor glucose tolerance (high blood sugar levels).
- Skin rash.
- Loss of hair color.
- Excessive bone loss.
- Low cholesterol levels.
- Hearing loss.
- Reproductive system difficulties.
Manganese activates the enzymes responsible for the utilization of several key nutrients including biotin, thiamin, ascorbic acid, and choline. It facilitates protein and carbohydrate metabolism, and may also participates in the production of sex hormones and maintaining sexual health.
In addition, manganese is important in the formation of bone. It has also been theorized that manganese is involved in the production of the thyroid hormone known as thyroxine and in maintaining the health of nerve tissue.
What are deficiency symptoms for manganese?
Because manganese plays a role in a variety of enzyme systems, dietary deficiency of manganese can impact many physiological processes. In experimental animals, manganese deficiency causes impaired growth, skeletal abnormalities, and defects in carbohydrate and fat metabolism.
In addition, offspring of experimental animals fed manganese deficient diets develop ataxia, a movement disorder characterized by lack of muscle coordination and balance. This condition is caused by poor development of the otoliths, the structures in the inner ear that are responsible for equilibrium.
In humans, manganese deficiency is associated with nausea, vomiting, poor glucose tolerance (high blood sugar levels), skin rash, loss of hair color, excessive bone loss, low cholesterol levels, dizziness, hearing loss, and compromised function of the reproductive system. Severe manganese deficiency in infants can cause paralysis, convulsions, blindness, and deafness.
It is important to emphasize, however, that manganese deficiency is very rare in humans, and does not usually develop unless manganese is deliberately eliminated from the diet. In addition, it has been suggested that magnesium substitutes for manganese in certain enzyme systems if manganese is deficient, thereby allowing the body to function normally despite the deficiency.
Although symptoms of manganese toxicity do not typically appear even at high levels of dietary intake, in severe cases of excessive manganese consumption individuals can develop a syndrome called "manganese madness," characterized by hallucinations, violent acts, and irritability.
Overconsumption of manganese is also associated with impotency.
Manganese toxicity is most likely to occur in people with chronic liver disease, as the liver plays an important role in eliminating excess manganese from the body.
In 2000, the Institute of Medicine at the National Academy of Sciences established the following Tolerable Upper Intake Levels (UL) for manganese.
- Infants: not established (no supplemental manganese should be given)
- 1 to 3 years: 2 milligrams
- 4 to 8 years: 3 milligrams
- 9 to 13 years: 6 milligrams
- 14 to 18 years, including pregnant and lactating women: 9 milligrams
- Greater than 19 years, including pregnant and lactating women: 11 milligrams
How do cooking, storage, or processing affect 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.
Poor dietary intake of manganese appears to be 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 can be excreted in significant amounts through sweat, and invididuals who go through periods of excessive sweating may be at increased risk for manganese deficiency.
Proper formation of bile in the liver, and proper circulation of bile through the body are also required for manganese transport. As a result, individuals with chronic liver or gallbladder disorders may need more dietary manganese.
What health conditions require special emphasis on manganese?
Manganese may play a role in the prevention and/or treatment of the following medical conditions:
- Heart disease
- Learning disabilities
- Multiple sclerosis
- Myasthenia gravis
- Premenstrual syndrome
- Rheumatoid arthritis
- Sprains and strains
- Form in Dietary Supplements
Food Sources of Manganese
Excellent food sources of manganese include mustard greens, kale, chard, raspberries, pineapple, romaine lettuce, collard greens and maple syrup, molasses, garlic, grapes, summer squash, strawberries, oats, spelt, green beans, brown rice, garbanzo beans, ground cloves, cinnamon, thyme, peppermint, and turmeric.
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