Alexander G. Schauss, PhD
AIBR Life Sciences Division
The word "manganese" comes from the Latin word, "magnes", meaning magnet. For many years manganese fueled the industrial revolution because it was found to increase the resistance of steel to impact. Railroad tracks, for instance, contain 1.2% maganese. Only recently has it been discovered that manganese is vital to human health, hence it is considered by many an essential trace element.
Among many of its most important functions, manganese:
- activates numerous enzymes
- helps in the utilization of thiamin
- helps in the utilization of vitamin E (tocopherol)
- helps in the utilization of iron, and
- increases the level of the antioxidant, superoxide dismutase (SOD)
Too much manganese may cause problems. For example, excessive manganese interferes with iron absorption. (Excessive iron can also interfere with manganese absorption.) It is believed that taking a calcium supplement may interfere with manganese absorption. For this reason, many health practitioners recommend that if manganese supplements is needed, it be taken at a time other than when a calcium supplement is taken.
Recent studies are suggesting that infants under 24 months of age should not consume excessive amounts of manganese in the diet or via infant formula, since it may increase the risk of interfering in the brain’s chemistry, leading to negative behavioral effects.Yet manganese is vitally important to our health. Insufficient manganese concentrations in the tissue and cells of the body can lead to a variety of problems, including:
- heart disease
- lower levels of the good cholesterol fraction, HDL-cholesterol
- accelerated bone loss
- reduced fertility
- retarded growth in children
- low blood sugar
- middle ear problems, including difficulty maintaining balance
Unrefined whole grains and cereal products are the richest dietary sources of manganese. Unfortunately, the refined of grains has lead to widespread inadequacies in the daily intake of manganese from our diet. Fruits and vegetables to a more limited degree can provide manganese in the diet. Black teas are a rich source of manganese, especially for populations not consuming enough unrefined grains as cereal products.
There is no current recommended dietary allowance (RDA) for manganese for healthy individuals consuming a mixed North American diet. The provisional recommended daily dietary intake is:
- Infants > 0.3 mg.
- Children 0.6 mg.
- Males (11-18) 1.0 mg.
- Males (adults) 1.0 mg.
- Females 1.0 mg.
- Pregnant unknown
- Lactating (1st 6 mos.) unknown
(1) Shils, M.E. and Young, V.R. Modern Nutrition in Health and Disease, 7th Edition. Lea & Febiger: Philadelphia, 1988.
(2) Schauss, A.G. Minerals, Trace Elements and Human Health. Life Sciences Press: Tacoma (WA), 1996.
(3) Recommended Dietary Allowances, 10th Edition. National Research Council. National Academy Press: Washington, D.C. 1989.