Manganese is a micromineral that activates a number of important enzymes in the body. In this article I will be discussing this nutrient in greater detail and providing you with a summary of its main functions, the best food sources, the recommended daily allowances (RDAs) and the potentially adverse effects of consuming too much or too little.
Awareness of manganese dates back to ancient times when early artists used pyrolusite (a compound of manganese and oxygen) to give glass a purple colour. In the 1700s chemists started to investigate the possibility of pyrolusite containing a new element. In 1770 the German chemist Ignatius Gottfried Kaim became the first person to successfully isolate this element from pyrolusite. However, his report was not read by many chemists and because of this he is not often credited with its discovery. In 1774 the Swedish mineralogist Johann Gottlieb Gahn also managed to isolate manganese from pyrolusite and in doing so was given the credit for discovering and isolating this element.
The main role of manganese is to activate a number of important enzymes including glycolsyltranserferases and xylosyltransferases (which both assist in the formation of healthy bones). It also activates the enzymes that are responsible for utilising choline, vitamin B1, vitamin B7 and vitamin C. On top of this it supports healthy metabolism, helps the body produce thyroxine (a thyroid hormone which helps regulate body heat and the use of oxygen in cells), controls blood glucose levels (which is particularly useful for people suffering from diabetes) and promotes reproductive health (by helping the body produce sex hormones).
The RDA for manganese increases with age. Children aged between 0 and 6 months are advised to consume just 0.003 milligrams (mg) of this nutrient each day but this requirement increases significantly to 1.5mg per day for children aged between 4 and 8 years. The RDA for fully grown men aged 19 years and older is 2.3mg per day whilst the RDA for women within the same age range is a slightly lower 1.8mg per day. The tolerable upper limit (TUL) for this nutrient is 11mg per day.
Tea is a particularly good source of manganese with black tea containing 0.77mg per cup and green tea containing 1.58mg per cup. Fruits and vegetables are also an excellent source of this nutrient with garlic (1.67mg per 100g), pineapple (1.18mg per 100g) and raspberries (0.67mg per 100g) all containing high levels.
Exceeding the TUL for manganese can have a number of negative side effects which include impotence, manganese madness (a syndrome which can lead to hallucinations, irritability and violence) and nervous system disorders (similar to those experienced by people suffering from Parkinson’s disease).
Manganese deficiency is extremely rare and has only been observed when this nutrient is deliberately eliminated from the diet. Even when this does happen magnesium can normally be used by the body as a substitute. In the rare instances where deficiency does occur it can lead to blindness, bone loss, high blood glucose levels, loss of hair colour, nausea and skin rashes.