Magnesium
Magnesium is a silver-white light metal that oxidizes to silver-grey magnesium oxide when exposed to air. It has the atomic number 12, the chemical symbol Mg, and is assigned to the alkaline earth metals in the periodic table of elements. It was discovered and described as an element in 1755 by the English chemist Joseph Black (1728- 1799). The element was named after the Greek peninsula of Magnesia. It is found, for example, in the dolomite rock of the Dolomites as calcium magnesium carbonate. In seawater, around 15% of the salts are dissolved in the form of magnesium chloride. Magnesium is rarely used in technology due to its low hardness and high susceptibility to corrosion. In contrast, magnesium alloys, for example with aluminium, are characterized by a low density and therefore a low weight, as well as high strength and corrosion resistance. Such alloys are increasingly being used in the construction of motor vehicles, aircraft and ships. For example, NASA used a magnesium alloy containing around 85% magnesium, 14% lithium and 1% aluminum to build the Saturn V rocket. It is the eighth most common element in the earth's crust. However, due to its high chemical reactivity, it does not occur in its pure form, but only in various compounds.
In medicine, magnesium is considered a bulk element. An adult's body contains an average of 25 grams of magnesium. More than half of this magnesium is stored in the bones, most of the remainder in the cell interior, only about 1% is dissolved in the blood (1). Magnesium has physiological functions in bone formation and muscle metabolism.
Magnesium is also important in medicine and pharmacy as a component of some antacids, i.e. medicines to combat excessive stomach acid, and some laxatives.
Functions in the body
Alongside calcium, to which it has a physiological counterpart function, magnesium plays a decisive role in building and maintaining the skeletal system and teeth and stabilizes the inner cell skeleton of cells. It also regulates muscle and nerve functions by controlling muscle contraction, among other things, through the magnesium concentration. To date, around 300 enzymes are known that require the "cooperation" of magnesium for their activity. In energy metabolism in particular, the positively charged magnesium ion (Mg2+) is required to stabilize the negatively charged phosphate ions (PO43-) in the ATP (adenosine triphosphate) molecule. Together with ADP (adenosine diphosphate), ATP is a key substance in biological energy transfer.
What your body needs magnesium for:
- Energy: Magnesium contributes to normal energy-yielding metabolism and to the reduction of tiredness and fatigue.
- Protein: Magnesium contributes to normal protein synthesis.
- Cell division: Magnesium has a role in the process of cell division.
- Muscles: Magnesium contributes to normal muscle function.
- Nervous system: Magnesium contributes to normal functioning of the nervous system and to normal psychological function.
- Bones and teeth: Magnesium contributes to the maintenance of normal bones and teeth.
- Electrolytes: Magnesium contributes to electrolyte balance.
Foods containing magnesium
In general, it can be said that whole grain products, raw vegetables, nuts and chocolate are rich in magnesium. Examples of particularly magnesium-rich foods include sunflower seeds (420 mg/100 g), sesame seeds (370 mg/100 g), unhulled rice (160 mg/100 g), wheat germ (250 mg/100 g), chocolate (140 mg/100 g) and oatmeal (140 mg/100 g). You should also look for a high magnesium content when choosing mineral water. Good mineral waters can contain over 80 mg of magnesium per liter.
Magnesium supplements
People who suffer from a medical condition should discuss taking magnesium supplements with their doctor in advance. Although magnesium supplements are generally well tolerated, they may not be safe for people taking certain diuretics, heart medications or antibiotics.
Common forms in food supplements are citrate, bisglycinate, oxide and carbonate. What matters for comparison is the declared amount of elemental magnesium per serving.
Deficiency symptoms, hypomagnesemia
Normal values are given for magnesium. These are 0.8 to 1.1 mmol/l when magnesium is determined in plasma or serum. Hypomagnesemia is present below 0.8 mmol/l, with clear symptoms, such as increased excitability of the skeletal muscles and the central nervous system, only occurring above approx. 0.4 mmol/l. Hypomagnesemia is often accompanied by hypocalcemia, i.e. a calcium deficiency.
Dietary surveys show that part of the population does not reach the reference values for magnesium through their diet.
A magnesium deficiency can manifest itself in a number of ways:
- Muscle and calf cramps
- Restlessness, nervousness, dizziness, lack of concentration
- Headaches, migraines
- Heart disorders: tachycardia, cramps in the heart muscles, arrhythmia and heart pain.
- Gastrointestinal problems such as nausea, vomiting, diarrhea, cramps
These symptoms often have other causes too and do not allow self-diagnosis. Persistent complaints should be checked by a doctor.
Reasons for a magnesium deficiency:
- Chronic alcoholism
- Abuse of laxatives
- Chronic diarrhea or surgical removal of intestinal segments
- Increased renal (via the kidneys) excretion of magnesium (e.g. in hyperaldosteronism, diabetics or prolonged use of diuretics).
Overdose, hypermagnesemia and intoxication
In healthy people there are generally no overdoses, too much ingested magnesium is excreted. However, if kidney function is impaired, an excess of magnesium can occur, especially if magnesium-containing drugs such as antacids or laxatives are taken.
The normal values for magnesium in plasma or serum are between 0.8 and 1.1 mmol/l. The symptoms of an overdose develop depending on the magnesium concentration in the blood. For example, diarrhea and reduced excitability of the muscles and the central nervous system can occur from approx. 2 mmol/l. Magnesium concentrations above 5 mmol/l lead to symptoms of paralysis, impaired excitation formation and propagation in the heart and a drop in blood pressure. Respiratory depression, nausea and vomiting may also occur. An extreme overdose of magnesium can lead to respiratory and cardiac arrest.
Magnesium poisoning
Magnesium poisoning causes the symptoms already described for hypermagnesemia. Treatment of magnesium poisoning consists of gastric lavage and/or intravenous injection with 10% calcium gluconate solution or 0.5 to 1 mg neostigmine. In addition, respiratory support or stabilization of the circulation may be necessary.
Requirements
For adults aged 19 and over, the German Nutrition Society (DGE) gives estimated values of 350 mg of magnesium per day for men and 300 mg for women. For adolescents aged 15 to under 19, the values are 330 mg (male) and 260 mg (female); for children, depending on age, between 170 and 280 mg.
For pregnant and breastfeeding women, the DGE gives 300 mg per day each. The following groups of people may also have an additional need for magnesium: athletes with a high training volume whose diet does not offset sweat losses; diabetics, who excrete more magnesium through their urine; alcoholics; and older people, who often do not drink enough. Furthermore, the intake of some medicines can be a reason for an increased magnesium requirement. The following medicines are mentioned as examples: Aminoglycosides, Ciclosporin, oral contraceptives, laxatives, glucocorticoids, diuretics, etc. In addition, people with heart disease may have an increased need for magnesium, but people with heart disease should always discuss any additional intake of magnesium supplements with the doctor treating them. It is assumed that the daily requirement of magnesium should be roughly covered by a normal diet. In small comparative studies, magnesium from organic compounds such as citrate was absorbed better than from oxide; the declared amount of magnesium per serving remains decisive. Short-term shortages in magnesium intake are bridged by the magnesium reserves in the bones. However, deficiencies can occur in the event of illness, malnutrition or frequently in older people.
Requirements in sport
Magnesium is also lost through sweat during training. How much depends on duration, intensity and individual conditions; no fixed additional dose for athletes can be derived from this. If you train a lot and at the same time eat little or a one-sided diet, check your intake more closely. For food supplements, the German Federal Institute for Risk Assessment (BfR) recommends a maximum of 250 mg of magnesium per recommended daily serving, split into two or more portions. Read more in our guide Magnesium for athletes.
Safety and side effects
Magnesium is probably safe and harmless for most people when taken orally or through the correct use of prescription injectable products. In some people, magnesium can cause stomach upset, nausea, vomiting, diarrhea and other side effects.
For food supplements, the German Federal Institute for Risk Assessment (BfR) recommends a maximum of 250 mg of magnesium per recommended daily serving, split into two or more portions. Higher additional amounts mainly cause diarrhoea. If kidney function is impaired, magnesium can accumulate in the body and have serious consequences such as an irregular heartbeat or low blood pressure.
Precautions and warnings
Pregnancy and breastfeeding: Magnesium is probably safe for pregnant and breastfeeding women when taken in the recommended amounts. These amounts depend on the woman's age. Pregnant and breastfeeding women should consult their doctor to find out what amounts are right for them.
Heart block: High doses of magnesium, typically administered intravenously, should not be given to people suffering from heart block.
Kidney problems such as kidney failure: Kidneys that are not functioning well have problems excreting magnesium. Taking extra magnesium could result in a build-up of magnesium in the body that can reach dangerous levels. If you have kidney problems, only take magnesium after consulting your doctor.
Interactions of magnesium with the following medications should be taken with caution:
Antibiotics (aminoglycoside antibiotics)
Some antibiotics can affect the muscles. These antibiotics are known as aminoglycoside antibiotics. Magnesium can also affect the muscles. Taking aminoglycoside antibiotics and giving a magnesium injection could cause muscle problems.
Antibiotics (quinolone antibiotics)
Magnesium could reduce the amount of quinolone antibiotics that the body can absorb. Taking magnesium in combination with quinolone antibiotics could reduce the effectiveness of quinolone antibiotics. To avoid this interaction, quinolone antibiotics should be taken at least two hours before or four to six hours after taking magnesium supplements.
Antibiotics (tetracyline antibiotics)
Magnesium can bind to tetracyline antibiotics in the stomach. This reduces the amount of tetracyline antibiotics that the body can absorb. Taking magnesium in combination with tetracyline antibiotics could reduce the effectiveness of tetracyline antibiotics. To avoid this interaction, magnesium should be taken two hours before or four hours after taking tetracyline antibiotics.
Bisphosphonates
Magnesium can reduce the amount of bisphosphonates absorbed by the body. Taking magnesium in combination with bisphosphonates can reduce the effectiveness of bisphosphonates. To avoid this interaction, bisphosphonates should be taken at least two hours before magnesium or later in the day.
Medication for high blood pressure
Magnesium could lower blood pressure. Taking magnesium in combination with medication for high blood pressure could result in an excessive drop in blood pressure.
Muscle relaxants
Magnesium appears to help relax the muscles. Taking magnesium in combination with muscle relaxants could increase the risks and side effects of muscle relaxants.
Diuretics (potassium-sparing diuretics)
Some diuretics can increase magnesium levels in the body. Taking these diuretics in combination with magnesium could result in excessively high magnesium levels in the body.
Conclusion
A balanced diet can cover your magnesium requirement in many cases. A supplement makes sense if there is a real gap in your intake; in that case, compare the declared amount of elemental magnesium per serving.
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