Recommended dietary allowance (RDA) for magnesium
The official recommended daily dietary allowance for magnesium is around 300 to 400 mg. The RDA guidelines are based on values that are absolutely essential for preventing a deficiency.
However, according to scientific research, these recommended quantities may beinsufficient for maintaining optimal health and performance, particularly in the case of athletes.
Many experts therefore call for an increase of the RDA for magnesium to 6 to 8 mg per kilogram body weight, which corresponds to a daily dose of 400 to 1,000 mg of pure magnesium, according to body weight.
Magnesium is offered as magnesium salts in the form of magnesium chloride, magnesium citrate, magnesium orotate, magnesium sulfate and the like. For the dosage it is to be ensured, that the daily recommended quantity refers to the pure magnesium content and not the weight of the magnesium salts.
Who needs additional magnesium?
Everyone – because we all have too little magnesium. In 2006 the World Health Organisation (WHO) established that most people worldwide suffer from a magnesium deficiency.
How does a magnesium deficiency arise?
How does it happen that people in wealthy countries, where they lack nothing, also suffer from magnesium deficiencies? On the one hand our food contains less and less magnesium; and on the other, our bodies require more and more magnesium due to our stressed lifestyles and unhealthy eating habits.
This results in chronic magnesium deficiency that affects the entire world’s population. A number of complaints and illnesses are directly related to a deficiency of magnesium. Acute magnesium deficiency manifests itself in muscle twitches, cramps and cardiac irregularities.
Reasons for magnesium deficiency
- Increased stress
In stress situations the need for magnesium increases and additional adrenaline and noradrenaline, the stress hormones, are released, which simultaneously constrict the vessels. This results in increased blood pressure and cardiac pulse frequency. Since magnesium impacts on the release of stress hormones, a magnesium deficiency can aggravate the stress symptoms even more.
- Increased magnesium need during sport
Physical activities cause the body to require significantly more magnesium due to increased muscle actions. In addition, increased perspiration means that more magnesium is exuded. Sufficient magnesium prevents muscle cramps, a build-up of lactic acid, which is also responsible for sore muscles, and at the same time increases endurance.
- Poor diet
Our ancestors ingested foodstuffs rich in magnesium for thousands of years. Their main source of food comprised nuts, whole grain and vegetables, all of which are rich in magnesium. As a result there was no need for the body to store magnesium, which means that the body never learned how to store magnesium, which in turn means that we still have to take magnesium as a supplement today. So, what type of diet do we have today? White bread, fast food and sweet treats practically contain no more magnesium.
- Depleted soil
Even people who make a conscious effort to eat a healthy diet do not receive the required amount of magnesium from the food they consume, the reason being that our soil is depleted. Monocultures and the use of pesticides prevent the soil from regenerating naturally. Sour rain containing nitric acid reacts with magnesium, reducing the freely available magnesium. And even if magnesium is present in the soil, it cannot be absorbed by the plants, as the farming sector makes use of cheap, potassium-based fertilisers. Potassium is much more easily absorbed by plants than magnesium or calcium, resulting in only a low magnesium content in plants.
- Poor absorption
Absorption of magnesium in the gastro-intestinal system is problematic, as magnesium is an extremely reactive substance and always loses out compared to other minerals. Magnesium absorption is inhibited by a high absorption of calcium, phosphorus, fat, protein and alcohol, as well by a deficiency in the vitamins B1 and B6. Even under the most optimal conditions, a maximum of 50% of the magnesium content of food is absorbed.
Taking magnesium orally in the form of tablets or liquid results in an absorption of only approx. 20 percent.
Tannin in tea, oxalic acid in spinach or phytic acid in bran or soya beans block the absorption of magnesium in the intestines. The magnesium is excreted again without having unfolded its effect in the cell. If the stomach does not produce sufficient hydrochloric acid, as is often the case in older people, the magnesium salt cannot even split into its absorbable form.
- Magnesium deficiency due to alcohol intake
Alcohol promotes excretion of magnesium via the kidneys. In the case of chronic alcoholism or a higher consumption of alcohol, magnesium is lost through increased elimination via the liver and kidneys.
- Magnesium deficiency due to medication
The intake of certain medication can lead to a magnesium deficiency. Diuretic tablets, medication for lowering blood pressure such as ACE inhibitors, laxatives, or cardiotonics such as Digitalis significantly reduce the magnesium level in the body. Other medications such as the contraceptive pill, insulin, antibiotics or cortisone are also linked to magnesium deficiency.
- Increased requirement for magnesium during pregnancy
Nausea, cramps, high blood pressure or early onset of contractions: These are all linked to a deficiency of magnesium and the resultant tensioning of the smooth musculature.
Magnesium deficiency diagnosis
Magnesium is mainly required in the cells. Only one percent of the magnesium content is found in the blood plasma. Consequently, a normal blood test is unsuitable for determining a magnesium deficiency.
In the event of a magnesium deficiency, the body counterbalances this primarily by activating magnesium from body structures that are rich in magnesium; the bones in particular. As a result, magnesium deficiency is not directly detected by means of lowered blood serum levels. Only once these magnesium depots are exhausted does the magnesium concentration in the blood serum drop.
Low serum levels are therefore a sure sign of magnesium deficiency. However, a reduction in the overall magnesium in the body may result in symptoms and complaints much earlier. For this reason the following test can provide a valuable indication of magnesium deficiency.
Magnesium deficiency test
- Are you often stressed?
- Do you frequently drink alcohol?
- Do you often wake up at night due to cramps?
- Are your muscles stiff after physical activities or sports?
- Do you suffer from muscle tension, especially in the neck and shoulder area?
- Do you suffer from migraines?
- Are you diabetic?
- Do you often have a sensation of tingling or numbness in your arms or legs?
- Do you primarily live off fast foods?
- Do you frequently drink fizzy soft drinks?
- Do you regularly take medication such as diuretic tablets, ACE inhibitors, laxatives or cardiotonics (e.g. Digitalis)?
- Do you sometimes experience twitching of your eyelids?
- Do you suffer from menstrual cramps?
If you have answered at least two of these questions with “yes”, this could be an indication of a magnesium deficiency.
Blood and urine values
Normal magnesium concentration values in the plasma are between 0.75 and 1.1 mmol/l and in the erythrocytes between 1.95 and 2.65 mmol/l. A plasma value over 0.75 mmol/l is, however, no guarantee that no deficiency of magnesium exists. The normal excretion of magnesium via the urine varies between 2.5 and 5.5 mmol/day.
Determination of magnesium in erythrocytes and blood plasma
More informative than the mere determination of magnesium in blood plasma is the additional determination in the erythrocytes, since indeed 99 % of the magnesium is found in the cells. However, this investigation also has a catch, as the erythrocyte can only absorb magnesium during its development phase in the bone marrow. The mature erythrocytes lack the transport mechanisms for this. Apart from that, the mature erythrocyte no longer has any cell nucleus. However the magnesium in the cell concentrates precisely here.
Intracellular magnesium determination
The intracellular magnesium determination is therefore the only laboratory-related determination method with significance. This is possible, for example, by means of scanning electron microscopic X-ray emission spectral analysis. In several investigations it could be shown, that there is a significant correlation between the intracellular magnesium content of oral mucous membrane cells and the magnesium content of heart tissue.
Likewise, a correlation between the magnesium content of oral mucous membrane cells and clinical indications of a magnesium deficiency could also be proven. The cells of the oral mucous membrane can be obtained simply and without major intervention by means of a smear. After fixation the cells can be stored practically indefinitely and can be measured repeatedly. This method enables the early determination of an intracellular magnesium deficiency. However, at present corresponding analysis units only exist in the USA. At present this method is therefore too time-consuming and costly for routine investigations.