Manganese is an essential trace mineral in animal nutrition and is also believed to be necessary in human nutrition. The total body content of manganese in humans is only 10-20 mg. "It activates numerous enzyme systems including those involved in glucose metabolism, energy production,  and superoxide dismutase. It is a major constituent of several metalloenzymes, hormones, and proteins of humans. It is also part of the developmental process and the structure of the fragile ear bones and joint cartilage."*

Functions	Manganese ions have been shown to scavenge hydroxyl and superoxideradicals. It is a crucial element of the metalloenzyme manganese superoxide dismutase (MnSOD). MnSOD is found in mitochondria and is the principle element of mitochondria oxidant defense system. Absorption takes place in the small intestine by both active-transport and passive diffusion mechanisms. Minute quantities are needed for protein and fat metabolism, healthy nerves, a healthy immune system, and blood sugar regulation. It is also necessary  for energy production and normal bone growth, as well as reproduction. It is essential for people with an iron deficiency and is needed for the utilization of vitamin B1 and vitamin E. Manganese and the B-complex vitamins work well together to give a feeling of well being.
Deficiencies can cause	Ataxia (a blocked ability to coordinate movement), atherosclerosis, dizziness, hearing loss, hypercholesterolemia, hypoglycemia, muscle therapy, pancreatic atrophy, and tinnitis.
Toxicity can cause	Anorexia, impaired judgment, Parkinsonism, memory loss.
Food Sources	Avocados, nuts, seeds, seaweed, and whole grains. Blueberries, egg yolks, legumes, dried peas, pineapples, and green leafy vegetables.
Herbal Sources	Alfalfa, burdock root, catnip, chamomile, chickweed, dandelion, eyebright, fennel seed, fenugreek, ginseng, hops, horsetail, lemongrass, mullein, parsley, peppermint, raspberry, red clover, rose hips, wild yam, yarrow, and yellow dock.
R.D.A.** ESSADI (Estimated Safe and Adequate Daily Dietary Intake)	Infants 0-0.5 year            0.3-0.6mg 0.5-1 year            0.6-1.0mg Children 1-3 years             1.0-1.5mg 4-6 years             1.5-2.0mg 7-10 years           2.0-3.0mg Young Adults and Adults 11+ years             2.0-5.0mg

Comments: Individuals with liver problems/failure should steer clear of manganese supplementation unless directed by their physician. Pregnant women, as well as nursing mothers should avoid manganese intakes above the ESSADI, which is 2.0mg to 5.0mg daily.

*Rare Earths, Forbidden Cures by Joel D. Wallach, BS, DVM. ND. and Ma Lan, MD, MS.; Double Happiness Publishing Company; Bonita, California; 1994
**The Nutrition Desk Reference by Robert Garrison, Jr., M.A., R.Ph. and Elizabeth Somer, M.A., R.D. (Keats Publishing Company, New Canaan, Connecticut) 1995, pp. 206-207.