Manganese is categorized as an essential trace nutrient (i.e. a mineral). It acts as a cofactor, providing function for specific enzyme-based activities. Its importance remains relatively ignored by the general population. This may be due to the lack of deficiency states associated with manganese, and the minute quantities needed for overall physiological health.
The majority of consumed manganese is deposited into our metabolic organs. This includes the bones, liver, pancreas, kidneys, pituitary, and adrenal glands. At any given moment, we store an estimated 15 - 20 milligrams of manganese in these differentiated areas of the body. Existing deposits give the body the ability to readily convert this mineral for accomplishing a variety of tasks, including; decarboxylation, hydrolysis, phosphorylation, and transamination.
Manganese exists as an important component of the direct enzyme manganese superoxide dismutase (MnSoD). This assists in the usance of vitamins such as Vitmain C, Vitamin B1, biotin, and choline. It may also prove to be a potent antioxidant, protecting us from external free radical damage upon cellular membranes located within the body. This may be especially relevant in the prevention of the aging process, its associated metabolic processes, and the development of certain irregular chronic health conditions. 
There are a number of forms of manganese which the body uses for biochemical processes. These include manganese salts (manganese gluconate and sulfate), and manganese chelates. Chelates of manganese include; aspartate, picolinate, fumarate, malate, succinate, and citrate.
Legumes, seeds, nuts, and whole grain products provide the best source of manganese in our diets. Vegetables and fruits assist us in achieving our daily dietary intake of manganese; however, these sources only contain moderate amounts of the mineral. Animal sources should not be counted on by individuals for fulfilling the daily requirements of manganese from diet. Dietary supplements containing manganese are considered highly effective.
|Food||Amount per serving||Milligrams (mg)|
|Wheat germ||2 Tbs.||2.8|
|Whole wheat pasta||1 cup||1.9|
|Soy nuts||¼ cup||.85|
|Pumpkin seeds||¼ cup||1.7|
|Cooked Oatmeal||1 cup||1.4|
|Sweet potatoes||½ cup||1.3|
|Pineapple (fresh, juiced)||½ cup||1.25|
|Oysters, cooked||3.5 oz.||1.2|
|Blackstrap Molasses||2 Tbs.||1.1|
|Tomato juice||1 cup||1.0|
|Grape juice||1 cup||0.9|
|Brown rice, cooked||½ cup||0.9|
|Soy nuts||¼ cup||0.9|
|Sunflower seeds||¼ cup||0.7|
It is estimated that our ability to consume manganese for biochemical processes lies within the range of 15 - 30%. Many factors may contribute to this absorption percentage, such as competing with other vital nutrients during the digestive process.
Manganese’s most important function may lie within the digestive process, allowing for the utilization of consumed nutrients from dietary sources. Manganese remains an important component in the assimilation of all nutrients, particularly proteins, as it readily activates peptidase activity. As mentioned, manganese is also an important cofactor in the synthesis of cholesterols, fatty acids, and glucose metabolism.
Manganese may also provide us aid in times of illness. The growth and maintenance of boney structures and joint membranes is also directly attributed to proper dietary intakes of manganese; also promoting healthy formations of mucopolysaccharides. In fact, persons with low levels of manganese (primarily the antioxidant MnSOD) are at an elevated risk for the onset of diseases such as arthritis and osteoporosis. [2, 3, 4]
The combination of manganese ascorbate with alternative herbal supplements, like glucosamine and chondroitin, has been thoroughly researched in providing for effective treatment options associated with the abovementioned conditions of the bone.  This combination of nutrients may alleviate some of the pain associated with degenerative joint/bone conditions, while preserving critical bone mineral density in affected persons.
Diabetics may also benefit from adequate levels of manganese in the body. It has been shown that individuals suffering from type I and type II diabetes have significantly lowered levels of manganese in their systems than those without this disease.  Through research, physicians have identified Low-Density Lipoproteins (LDLs), and their associated oxidative properties, as being the primary cause of the elevated risk factors for heart attack and stroke in diabetics. Studies also suggest that supplementary manganese in those suffering from either type I or type II diabetes, may effectively reduce these risks, by preventing the oxidation of low-density lipoproteins. 
Manganese levels may also impact individuals suffering from seizures; predominantly epileptics.  Sufficient levels of manganese in the body allow for the regulation of neurotransmitters in the brain. Lowered levels of manganese have been shown to adversely impact neurological functions of muscle such as convulsions, and lack of coordination. 
Other areas of study concerning lower levels of manganese in the body include; Premenstrual Syndrome (PMS), thyroid function (via the production of thyroxine), tinnitus (ringing in the ears), and milk production in lactating women. 
There is not a specific Recommended Dietary Allowance (RDA) for manganese; estimated safe and adequate intakes for this mineral have been established by the Food and Nutrition Board of the National Research Council. All dosages and intakes are expressed in milligrams in the table below:
|Under 6 months||0.3 mg|
|7-12 months||0.6 mg|
|1-3 years||1.2 mg|
|4-8 years||1.5 mg|
|9-13 years||1.6 mg (females)-1.9 mg (males)|
|14-18 years||1.6 mg (females)- 2.2 mg (males)|
|19 years and older||1.8 mg (females)- 2.3 mg (males)|
|Pregnancy||2 mg||2 mg|
|Lactation||2.6 mg||2.6 mg|
Deficiencies of this trace mineral are unlikely to occur in humans. This is due, in part, to the minute amount needed to fulfill the daily requirements for various manganese-related tasks in the body. Manganese-induced deficiency has been extensively studied in other animals. Scientist suggests that if a deficiency were present in a human subject, signs and symptoms would possibly include; poor bone growth, birth defects, problems with blood glucose levels, and reduced fertility.
There have been no reported overdose toxicities regarding the excessive dietary intake of manganese. Toxicity has been observed in mine and steel mill workers around the world. However, in these individuals, toxicity was produced by the inhalation of manganese-containing dusts. Exposure to this metallic substance can cause what’s known as “manganese madness,” or adverse effects on the central nervous system. These symptoms include; loss of appetite, muscle rigidity, tremors, convulsions, and hallucinations. 
More research is necessary, but those receiving paternal nutrition with excessive amounts of manganese present in the solution, may be at risk for the development of an overdose as well.
1. Luk E, Carroll M, Baker M, Culotta VC. Manganese activation of superoxide dismutase 2 in Saccharomyces cerevisiae requires MTM1, a member of the mitochondrial carrier family. Proc Natl Acad Sci U.S.A. Sep 2003;100(18): 10353-7.
2. Gaby AR. Natural treatments for osteoarthritis. Alt Med Rev. 1999;4(5): 330-341.
3. Morselli B, Neuenschwander B, Perrelet R, Lippunter K. Osteoporosis diet [in German]. Ther Umsch. 2000;57(3):152-160.
4. Saltman PD, Strause LG. The role of trace minerals in osteoporosis. J Am Coll Nutr. 1993;12:384-389.
5. Leffler CT, Philippi AF, Leffler SG, Mosure JC, Kim PD. Glucosamine, chondroitin, and manganese ascorbate for degenerative joint disease of the knee or low back: a randomized, double-blind, placebo-controlled pilot study. Military Medicine. 1999:164(2):85-91.
6. Wimhurst JM, et al. Comparison of Ability of Mg and Mn to Activate the Key Enzymes of Glycolysis. FEBS Lett. Nov 1972;27(2):321-26.
7. Leonhartdt W, Hanefeld M, Muller G, et al. Impact of concentrations of glycated hemoglobin, alpha-tocopherol, copper, manganese on oxidation of low-density lipoproteins in patients with type I diabetes, type II diabetes, and control subjects. Clin Chim Acta. 1996;254(2): 173-186.
8. Papavasilious PS, et al. Seizure disorders and Trace Metals: Manganese Tissue Levels in Treated Epileptics. Neurology. Nov 1979;29(11):1466-73.
9. Dupont CL, Tanaka Y. Blood manganese levels in children with convulsive disorder. Biochem Med. 1985;33(2): 246-255.
10. Bendich A. The potential for dietary supplements to reduce premenstrual syndrome (PMS) symptoms. J Am Coll Nutr. 2000;19(1):3-11.
11. Food and Nutrition Board, Institute of Medicine. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. National Academies Press. 2002. http://www.pdrhealth.com/drug_info/nmdrugprofiles/herbaldrugs/101840.shtml (Chapters 1, 2, and 8)
12. Komaki H, Maisawa S, Sugai K, Kobayashi Y, Hashimoto T. Tremor and Seizures associated with chronic manganese intoxification. Brain Dev. 1999;21(2):122-124.