Manganese

Manganese is a gray, very hard but brittle base heavy metal. It has the atomic number 25 in the periodic table of elements and the chemical symbol Mn. Manganese was already used in cave paintings in the form of brownstone. It was first extracted from manganese dioxide and coal in 1774 by the Swedish chemist Johann Gottlieb Gahn (1745-1818). It is the 14th most common element in the earth's crust. Pure manganese does not occur on earth, it is mainly found as manganese dioxide (MnO2) or as manganese sulfide (MnS). Manganese is of particular technical importance as an additive in steel production. Due to their hardness, durability and heat resistance, such manganese steels are used, for example, in rail construction, tapping or forging tools. Manganese is an essential, i.e. vital, trace element for humans. The body needs it for bone growth and it is also involved in the formation of various enzymes. The human body contains around 10 to 40 mg of manganese. Around 40 percent of this is found in the bones. Manganese is also found in the liver, kidneys, pancreas, muscles and hair pigments.

Functions in the body

Manganese is significantly involved in a number of important processes in the human body, as the trace element is essential for the function of various enzymes. For example, manganese is involved in the formation of cartilage and bone tissue. It activates the enzyme glycosyltransferase, which is involved in proteoglycan synthesis (chondroitin sulphate) in cartilage and bone. By activating pyruvate carboxylase, manganese is also involved in gluconeogenesis, i.e. the formation of new glucose. Furthermore, manganese activates the enzyme arginase, which plays a role in the urea cycle, and pancreatic enzymes, which are involved in the breakdown of protein building blocks (amino acids). Manganese is also required for the synthesis and release of insulin. It is involved in blood clotting through the production of prothrombin. Manganese can form an Mn-ATP complex with ATP (adenosine triphosphate) and act as a cofactor instead of magnesium. ATP is the key substance in biological energy transfer. Manganese is also involved in the production of melanin (pigment) and dopamine (neurotransmitter). It also activates a number of enzymes that act as antioxidants (Mn superoxide dismutase) and are important for the utilization of vitamin B1 (phosphatase).

Manganese in food

Apart from a few exceptions, such as snails and offal, animal foods generally contain less manganese than plant foods.

Some cereal products are particularly rich in manganese, e.g. oat flakes, wheat germ and soy flour. Among vegetables, soybeans, garlic and white beans are characterized by a higher manganese content. Of the fruits, pineapple, blueberries and raspberry juice are particularly high in manganese. Nuts, chocolate and some spices, such as cinnamon, ginger, black pepper and ground cloves, also contain high amounts of manganese.

Manganese-rich foods contain per 100 g approx:

• Rice 1.1 mg
• Millet 1.9 mg
• Wholemeal wheat bread 2.5 mg
• Hazelnuts 3 mg
• Whole wheat flour 3.5 mg
• Wheat bran 3.7 mg
• Soy flour 4 mg
• Oat flakes 4.5 mg

3.5 mg manganese (average daily requirement) is contained in:

• 75 g rolled oats
• 95 g wheat bran
• 115 g cereals
• 140 g wholemeal wheat bread
• 175 g pulses
• 320 g rice or rye bread
• 1200 g fish, meat, cheese or quark

Deficiency symptoms

The concentration of manganese can be determined in the blood, which is normally between 7.0-10.5 µg/l in whole blood and 0.3-1.1 µg/l in blood serum. Manganese deficiencies are not particularly common, which is why some symptoms of manganese deficiency have only been observed in animals. In ruminants, for example, manganese deficiency leads to lipid metabolism disorders, which manifest themselves in the form of hypocholesterolemia, i.e. a reduced cholesterol concentration. Furthermore, weight loss, growth disorders, osteoporosis and dysfunction of the reproductive organs have been observed in animals. Furthermore, coagulation disorders due to a prolonged prothrombin time and disorders of carbohydrate metabolism occur. Cartilage or bone deformations may also occur.

Overdose and poisoning

Overdoses with manganese are extremely rare. However, poisoning with manganese oxide (manganese dioxide) is known to have occurred in mining workers. Furthermore, workers in the manganese processing industry and steel workers can suffer from manganese poisoning. For this reason, manganese poisoning is also an occupational disease requiring compensation for those occupational groups particularly at risk.

Acute poisoning leads to severe pneumonia. Chronic poisoning leads to encephalitis (meningitis), which manifests itself in Parkinson's-like symptoms. Tremor, muscle stiffness as well as concentration and memory disorders occur. Particularly characteristic of Parkinson's symptoms is a tremor in which writing becomes smaller and smaller. The treatment of manganese poisoning is usually only symptomatic, i.e. only the symptoms and not the causes are treated. In the case of chronic poisoning, the Parkinson's drug levodopa can be given.

Requirements

According to the recommendation of the German Nutrition Society, children under the age of 7 need 1 to 2 mg of manganese per day, while older children, adolescents and adults need 2 to 5 mg per day. It can normally be assumed that the manganese requirement is covered by a balanced diet. However, various factors can lead to a manganese deficiency:

An increased need for manganese can be caused by a poor diet, for example if large amounts of simple carbohydrates (sugar) are consumed. The manganese requirement can also be increased by prolonged artificial (parenteral) nutrition. Alcoholics also often have an increased requirement. Furthermore, the increased intake of other minerals, such as calcium, iron, phosphate and zinc, can lead to a manganese deficiency. The reason for this is that the minerals interfere with each other's absorption. Increased oxidative stress (increased production of highly reactive oxidants, i.e. free radicals) can also possibly lead to an increased manganese requirement.

Requirements in sport

3-5mg a day with meals.

Safety and side effects

Manganese is probably safe and harmless for most adults in quantities of up to 11 mg per day. Excessive manganese intake can cause serious side effects including Parkinson's-like symptoms such as tremors. People who have problems excreting manganese, such as those with liver disease, may experience side effects from taking less than 11 mg of manganese per day. The amount of manganese that is safe for children depends on their age. Before giving manganese to children, you should talk to your doctor.

Precautions and warnings

Pregnancy and lactation: Manganese is probably safe and safe for pregnant and lactating women over 19 years of age at doses below 11 mg per day. Pregnant and lactating women under 19 years of age should limit the dosage of manganese used to less than 9 mg per day. Manganese may not be safe if used in higher amounts during pregnancy and lactation.

Chronic liver disease: People who suffer from chronic liver disease have trouble excreting manganese. In these people, manganese can accumulate in the body and cause tremors, mental problems such as psychosis and other side effects. For this reason, people who suffer from liver disease should be careful not to consume too much manganese.

Iron deficiency anemia: People who suffer from iron deficiency anemia seem to absorb more manganese than other people. If you suffer from this condition, you should be careful not to consume too much manganese.

Interactions with medication

Care should be taken when combining manganese with the following medications:

Antibiotics (quinolone antibiotics)

Manganese could reduce the amount of quinolone antibiotics that the body can absorb. Taking manganese in combination with quinolone antibiotics could reduce the effectiveness of quinolone antibiotics. To avoid this interaction, manganese supplements should be taken at least one hour after quinolone antibiotics.

Antibiotics (tetracyline antibiotics)

Manganese can bind to tetracyline antibiotics in the stomach. This reduces the amount of tetracyline antibiotics that the body can absorb. Taking manganese in combination with tetracyline antibiotics could reduce the effectiveness of tetracyline antibiotics. To avoid this interaction, manganese should be taken two hours before or four hours after taking tetracyline antibiotics.