Manganese in a nutshell:
Manganese is a a co-factor for many enzymes and is needed during respiration (production of energy) as it remove free radicals during the burning of oxygen. Manganese is also required to help the release of sugars from the muscles and liver when energy is needed.Best source of Manganese for Juicers
It is highly unlikely that you will suffer from a manganese deficiency. However, you can boost levels in your juices by including blueberries, spinach and pineapple.
Not to be confused with magnesium, manganese a trace mineral named for the Greek word for magic. It works its “magic” as a key component in an antioxidant that is used in every cell in the human body, but excesses of manganese can be toxic.
Alternative names:
Manganese; mangano; manganum.
What Is Manganese?
Manganese is a metal that functions as a co-factor for numerous enzymes in all living things, including green plants, animals, and people. Plants use manganese to make the oxygen evolving complex that releases oxygen into the atmosphere. Animals, including humans, use manganese to make manganese superoxide dismutase. This enzyme enables the mitochondria to use oxygen to make energy without free radicals of oxygen causing damage to the cell.
What Does Manganese Do in the Human Body?
About 90% of the oxygen we breathe winds up in the mitochondria of our cells to be used to make energy. Manganese superoxide dismutase acts as a catalyst to capture free radicals of oxygen. It uses the potentially damaging free radicals of oxygen to make hydrogen peroxide, which quickly breaks down into water.
Manganese is also a critical component of an enzyme called phosphoenolpyruvate carboxykinase, or PEPCK. This enzyme enables muscle cells and liver cells to release glucose sugar from its storage form, glycogen.
Manganese is essential for the body's manufacture of arginase. This enzyme enables the body to transform the amino acid arginine into citrulline and ornithine and then back into arginine as needed. In the brain, manganese activates the enzyme glutamine synthase. This enzyme converts the brain-damaging excitotoxin glutamate into the harmless amino acid glutamine.
What Happens When We Don't Get Enough Manganese?
The simple answer to the question of what happens when human beings don't receive enough manganese in their diets is that scientists don't really know because it never happens except in contrived situations.
Some nutritional scientists have conducted experiments with volunteers to see what happens when certain elements are intentionally left out of the diet. They observed tendencies for slow growth of bones, unusually low cholesterol levels, insulin resistance, and rashes on the skin when volunteers were intentionally deprived of manganese. These experiments were interrupted to ensure that the volunteers did not suffer permanent damage.
Are You at Risk for Manganese Deficiency?
The body absorbs calcium, iron, and magnesium through the same transport pathways as it uses to absorb manganese. If you were to take very large amounts of supplemental calcium, iron, or magnesium, then it is theoretically possible that you would develop manganese deficiency. This has never been reported in the medical literature.
It's also possible that if you have the hereditary disease hemochromatosis, which causes high iron levels in the bloodstream, you might also have trouble absorbing manganese. This also has not been reported in the medical literature.
A chemical called phytate, which is found in the fiber in whole grains, fruits, and vegetables, interferes with the ability of the small intestine to absorb manganese, as do high levels of vitamin C. There are no known cases of manganese deficiency caused by eating too many fruits and vegetables or fiber-rich whole grains, or taking too much vitamin C.
How to Make Sure You Get Enough Manganese
In the United States, the Food and Nutrition Board of the Institute of Medicine determined “adequate intake” (AI) levels for manganese based on average daily intake of manganese from food in healthy people. In infants during the first six months of life, the need for manganese is extremely small, just 0.003 mg (3 micrograms) per day. Babies aged 6 months to 1 year need 0.6 mg per day, toddlers aged 1 through 3 need 1.2 mg per day, and children aged 4 through 8 need 1.5 mg per day.
After the age of 8, males need ore manganese than females because of differences in body mass. Boys aged 9 to 13 need 1.9 mg a day while girls in the same age group need 1.6 mg. Teenage males up to the age of 19 need 2.2 mg a day while teenage females in the same age group need 1.9 mg per day.
Adult men need 2.3 mg of manganese per day and adult women need 1.9 mg per day. During pregnancy, women need 2.0 mg of manganese per day, and women who are breastfeeding need 2.6 mg per day.
It's actually hard not to get enough manganese, especially if you drink tea. A single cup of green tea made the Japanese way (adding hot water directly to powdered green tea without straining) may contain as much as 90 mg of manganese, more than a month's supply. A cup (100 g) of blueberries contains 11 mg of manganese, almost enough manganese for a week. A single serving of spinach, green beans, pineapple, blackeyed peas (cowpeas), or oat bran provides about 4 mg of manganese, enough for two days. 
Essentially no one suffers deficiency of manganese. In some cases, however, manganese supplements may support recovery from some disease conditions.
Using Manganese Supplements to Support Recovery from Disease
A study found that taking a daily supplement that contained 1,000 mg of calcium, 15 mg of zinc, 2.5 mg of copper, and 5 mg of manganese helped protect women who already had osteoporosis from additional fractures than just taking calcium by itself. Since the supplement contained three additional minerals, it is not certain that manganese was responsible for stronger bones.
Another study found that women who take a combination of calcium and manganese are less likely to suffer symptoms of PMS. It's not known whether the calcium or the manganese in the supplement was 
responsible for PMS relief.
Studies have also been conducted to see if manganese helps diabetes and seizure disorders, but the results have been inconclusive.
Manganese Toxicity
You are a lot more likely to run into problems with manganese toxicity than you are to benefit from taking manganese supplements. The most serious manifestation of manganese poisoning is Parkinson's disease. Excessive consumption of manganese can kill cells in the substantia nigra of the brain, preventing them from producing the neurochemical dopamine. This can cause the obvious symptoms of Parkinson's disease such as tremors and rigidity, but it can also cause mood disorders, loss of “executive function” (good judgment), and loss of pleasure in food, sex, personal success, and human interaction.
The upper limit (UL) for manganese supplements is 11 mg per day. If you are nearing an excessive dose of manganese, one of the first symptoms will be your feces turning black. Taking manganese supplements can interfere with blood testing for alkaline phosphatase (a chemical measure to test for bone and liver disorders), causing an inaccurately high reading.
All of these chemicals are manganese in a form your body can absorb: manganum, manganeso, manganese amino acid chelate, manganese asorbate, manganese aspartate complex, manganese chloridetetrahydrate, manganese citrate, manganese gluconate, manganese dioxide, manganese glycerophosphate, manganese sulfate, manganese sulfate monohydrate, and manganese manganese sulfate tetrahydrate. Any of these forms of manganese can cause toxic reactions when taken in excess.