Manganese
Overview
While the average person spends little time thinking about manganese, this mineral is an essential component to many of the enzyme systems in the human body. About 15 to 20 mg of manganese is found in the body, with half of it in the bones and the remainder located in the active metabolic organs: namely, the pancreas, the liver, the pituitary gland, the adrenal glands and the kidneys.
Sources of Manganese
The best sources of manganese are whole grains and nuts. Many of the animal foods have small amounts of this mineral, with egg yolks being a good source of manganese. Alfalfa is known to have high amounts of manganese, and leafy greens such as spinach, mustard greens and kale are also good sources of this mineral.
Black teas and coffee beans have small amounts of manganese, as well as pineapples and romaine lettuce.
However, in a similar way to our absorption of iron, the body’s utilization of manganese from dietary sources has only 15% to 30% efficiency. In fact, manganese and iron have a seesaw effect on each other. Too much absorption of one leads to a deficiency of the other.
If the soil in which the plants or vegetables are grown is deficient in manganese, the food products themselves will also have lower amounts of the mineral. The act of processing foods can also remove a vast amount of the manganese, with approximately 90% of the manganese being lost during the refinement of wheat to white flour. As is the case with many other food items, everyone should consume whole or unprocessed foods the vast majority of the time.
Functions of Manganese
While the best-known role of this mineral is its involvement with enzyme systems within the body, it is definitely an important one, facilitating the processes which include protein, fat and carbohydrate metabolism.
As manganese is closely tied to enzyme activity, this mineral is very important for proper digestion and utilization of food, particularly proteins.
Normal growth and development is also dependent on manganese, as well as for the repair of connective tissue and bones.
Postmenopausal women also seem to need more manganese to maintain their decreasing bone density.
Manganese is also a component of the enzyme known as superoxide dismutase, or SOD. This enzyme is a powerful free radical agent which helps to prevent cellular damage which occurs with the aging process or from the effects of asthma and cancer. Because of these properties, manganese is thought to function as a “protective” antioxidant.
Manganese is also being studied to see how large a role it plays in the production of thyroxine, which is an essential component for proper thyroid function.
Some research suggests that manganese is biochemically close to magnesium, and that magnesium may be an adequate substitute for manganese in the human body.
Uses of Manganese
While manganese has been used therapeutically as a nutrient, more research is needed to confirm its positive influence on certain diseases. Manganese does seem to have an anti-inflammatory effect on the body. Studies have also shown that manganese can help in cases of extreme fatigue by enhancing enzymes which seem to regulate nervousness, irritability and dizziness. Poor memory has also been shown to have a positive effect with manganese supplements.
One study concluded that manganese and zinc help to reduce high amounts of copper in the body, which may contribute to unwanted psychological states or even schizophrenia.
Some scientists believe that manganese may be useful in treating diabetes by helping to control the metabolism of glucose in elderly people with osteoarthritis. Research has also been conducted to study the effects of manganese on patients with multiple sclerosis and myasthenia gravis. Used in conjunction with the family of B vitamins, manganese may be able to alleviate some weakness or fatigue by stimulating nerve impulses.
Other research suggests that cancerous cells and tumors are very low in manganese, which suggests this mineral may someday have a role in combating the growth of cancer cells.
Manganese Deficiency
Studies have shown a direct correlation between low levels of manganese in infants with birth defects, including cleft palates and bone deformities.
Recent research also suggests manganese deficiencies may lead to abnormalities in the immune system. The activity of cells which protect the body from bacteria and other invaders are activated by manganese.
Studies have shown that manganese could very well be the least toxic of the minerals in the human body from a nutritional standpoint. When consuming manganese from food or supplements, there seems to be no toxic levels. However, when manganese is consumed through a water supply with abnormally high levels of the mineral, neuromuscular problems similar to Parkinson’s disease may result.
Extensive studies of animals have shown that manganese deficiencies can lead to sterility or poor growth in the offspring.
In human children, deficiencies in manganese can lead to convulsions, blindness or paralysis.
Adults with low levels of manganese may experience such symptoms as weakness, dizziness and hearing strange noises. It is thought these problems in children may be the result of underdevelopment of structures in the inner ear that help to regulate balance. Unstable gait and decreased strength, weight loss, skin problems and an irregular heartbeat have also been recorded.
Required Daily Amount
The Institute of Medicine at the National Academy of Sciences set recommendations for manganese in the year 2000. Men generally consume from diet alone about 2.2 mg of manganese and women consume around 1.7 mg. Recommended intake is between 4 to 5 mg per day. It is believed that individuals who are taking extra doses of calcium and/or phosphorous should also be taking more manganese.
It is believed that alcohol and lecithin can cause slight increases in manganese absorption.
Because manganese supplements may decrease utilization of iron, it is important to keep iron levels high as well.
Manganese is best absorbed when consumed between meals and without other minerals, as this may reduce the body’s ability to absorb manganese. Soy protein, cobalt and zinc may also interfere with absorption of manganese into the blood.
Supplements are available in chelated form or as manganese sulfate or gluconate. Safe amounts of manganese could go as high as 5 to 10 mg per day.
References
- Alan H. Pressman and Sheila Buff. The Complete Idiot's guide to vitamins and minerals, Alpha A member of Penguin Group (USA) Inc (2007)
- Brewer, S. The essential guide to vitamins, minerals and herbal supplements, Right Way (2010)
- Elson M. Haas, Md & Buck Levin, Phd, Rd. Staying Healthy with Nutrition: The Complete Guide to diet and nutritional medicine, Celestial Arts (2006)
- Holford, P. The optimum nutrition bible, Little Brown Group (2004)
- Holford, P & Lawson, S. Optimum Nutrition Made Easy How to achieve optimum health, Piatkus Books (2008)
- Lieberman, S. & Bruning, N. The Real Vitamin & Mineral Book, Avery, a Member of Penguin Group (USA) Inc (2003)
- Rodale Health Books. Healing with vitamins : the best nutrients to slow, stop, and reverse disease, Rodale, (2009)
- Royston, A. Vitamins and minerals for a healthy body, Heinemann Library, (2003)
- The National Research Council. Recommended Dietary Allowances, 10th ed, National Academy of Sciences (1989)
- Werbach, M. Nutritional Influences on Illness, 2nd ed, Third Line Press (1993)
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