A macro-element with amazing properties, well known as anti-stress, magnesium is essential for the proper functioning of our body. Involved in more than 300 cellular reactions, it is at the heart of many processes: functioning of our organs, immune defense, fixation of minerals, including calcium, muscle contraction, metabolism, etc. The athlete consumes more than the sedentary. In case of deficiency, fatigue, and irritability set in, performance drops, and recovery is longer. Explanations and practical advice.
What is magnesium?
Magnesium is a chemical element whose symbol is Mg. It is also a metal present in large quantities on earth, coming in 5th position just after aluminum, iron, calcium, and sodium. It is finally a macro-element or mineral salt. Our body contains about 25 to 30 grams, two-thirds of which are in the bones and a third in the soft tissues (organs, muscles). Blood plasma contains only 1%, hence the difficulty in measuring its level and detecting a possible deficiency.
The name magnesium comes from Magnesia, a Greek city very rich in magnesia, a salt known since the Renaissance for its laxative properties.
What role does magnesium play in our body?
Magnesium is essential for the proper functioning of our body. It plays a catalytic role and is involved in more than 300 cellular biochemical reactions.
It participates in the transmission of nerve impulses
Magnesium is involved in the transmission of nerve impulses through protein synthesis, and therefore in muscle contraction. It intervenes during a sports activity, but also in activities such as intestinal transit, heart rate, etc.
It intervenes in the metabolism or energy production of our body
Magnesium participates in the transformation of carbohydrates (glycolysis) and lipids (lipolysis) into ATP, an energy that can be used by our muscle cells. Hence its importance in sports practice! But metabolism is also involved in all energy-consuming operations such as the reproduction and repair of our cells, the functioning of our organs (including the brain), stress management, thermoregulation, etc.
It helps in the fixation of calcium and potassium
Magnesium salts (hydroxide, citrate, carbonate) being alkaline in nature, neutralize the acidity of the tissues and thus participate in the acid-base balance, which allows, in particular, the fixation on the bones of macro-elements such as calcium and potassium. Magnesium thus plays an important role in growth (formation of bones and teeth).
It intervenes in the immune defense
Magnesium is involved in our body's immune defense mechanisms.
Many other virtues
In addition to its key role in our body, magnesium has many virtues. It is a muscle relaxant and a powerful anti-stress. It acts as a cardio-protector and a vascular-protector (it increases the resistance of blood vessels) which is why it is used by emergency hospital services in cases of infarction. It is used as a preventive cancer therapy. It has laxative properties. Because it increases the solubility of calcium, it is said to have preventive effects on kidney stones. According to recent studies (Enhancement of Learning and Memory by Elevating Brain Magnesium. Neuron, Jan. 28, 2010), it would allow the proper functioning of memory and promote cerebral plasticity (the ability of the brain to adapt with experience). It has anti-inflammatory, anti-allergic properties (it is an anti-histamine in the same way as drugs used in allergies). A lack of magnesium would accelerate the aging of our cells.
In the sportsman
At the sporting level, magnesium is essential for the proper functioning of the neuromuscular system. Any deficiency leads to a drop in performance and a decrease in the ability to recover. We address this point below.
Magnesium for the normal functioning of our body
However, magnesium should not be considered as a miracle product that must absolutely be consumed in quantity to be better off; but rather as a macro-element necessary for the normal functioning of our body which, if not taken in sufficient quantities, can cause disorders.
Our magnesium needs
Since magnesium is neither manufactured nor stored by our body, it is necessary to consume it through our diet or, in case of deficiency, by a punctual treatment.
The recommended daily intake of magnesium is 6 mg/kg body weight per day in adults with average activity, with a minimum of 360 mg in adults, or about 360 mg in women and 420 mg in men (Recommended Nutritional Intakes of the French population, Ambroise Martin, Tech*Doc, Masson 2001). This need is increased in athletes, adolescents, pregnant or lactating women (increased estrogen levels lead to a decrease in magnesium levels), and the elderly.
| Catégorie | Apport recommandé |
|---|---|
| Adolescent | 410 mg |
| Adulte sédentaire | 360 mg (60 kg) - 420 mg (70 kg) |
| Sportif | +10% à +20% supplémentaires |
| Femme enceinte ou allaitante | 25 à 40 mg supplémentaires |
| Personne âgée (> 65 ans) | 25 à 40 mg supplémentaires |
In developed countries, modern diet and lifestyle have fundamentally changed the amounts of magnesium ingested. So much so that this intake is lower than the recommended daily intake. According to SUVIMAX (*), a study conducted in France between 1994 and 2003, 72% of men and 77% of women who participated in the study have intakes below 2/3 of the recommended intake, a limit under which doctors and nutritionists warn against the consequences on health. This study reveals that French women have an average intake of 280 mg compared to 370 mg for men. Another study conducted in France by INRA in 2004 people over 15 years of age indicates more pessimistic figures with an average intake of 224 mg.
(*) SU.VI.MAX (SUpplementation in Vitamins and Anti-oxidant Minerals) is a study launched in France in October 1994 by Dr. S. Hercberg.
Causes of magnesium deficiency
Our diet should normally provide the amounts of magnesium we need. However, this is not the case due to several factors, such as changing eating habits and practices, anxiety, stress. Added to this is an increased need in adolescents, the elderly, pregnant women, and athletes.
Our food: refining, cooking with water, aboveground cultivation, enemies of magnesium
The magnesium content of our modern diet has become low due to raw material preparation techniques, food preservation, and culinary techniques. Thus, refining, blunting, and smoothing eliminates almost all the magnesium contained in sugar, wheat, and rice. Cooking with water causes up to 50% of the mineral salts contained in vegetables to be lost. Added to this is the depletion of soils, the use of phosphate-based fertilizers that reduce the assimilation of magnesium, and the increasing use of aboveground techniques. Foods that are supposed to provide us with magnesium therefore no longer contain or are not enough to meet our daily needs. In addition, eating habits have changed with an increased preference for refined products rather than complete products and a decrease in the consumption of magnesium-rich green vegetables. Another aggravating factor is that we eat less than we did 50 years ago, so we absorb fewer nutrients! So be careful in case of diet or fast food such as fast food!
Stress: a major consumer of magnesium
In a stressful situation, whether physical (pain, inappropriate temperature, noise for example) or psychic (emotions, tensions, overwork), our body, in response to this stress, consume more magnesium. The adrenal glands release hormones, including adrenaline, which cause vitamin K to be secreted within cells. Vitamin K drives, magnesium out of the cell. This excess magnesium in the blood is then evacuated by the kidneys in the urine.
Stress is not necessarily limited to the difficult trials of life, for example, tensions at work, illness, etc. It includes all the mundane events such as the sound of a door slam, a lively family meal, a task performed in difficult conditions, etc. All these events are magnesium consumers. Our body reacts all the better to stress when it has magnesium.
Metabolism, or the process of transforming energy reserves into energy that can be used by muscles, requires magnesium intake. The greater the effort, the more magnesium is consumed. In addition, sport is a physical stress that requires an adaptation of the cardiovascular system to the effort and an adaptation of the body to the constraints imposed on it (weather conditions, emotions, etc.). More magnesium will be consumed in case of high heat, cold, high humidity.
Foods that are enemies of magnesium
Coffee and alcohol promote the elimination of magnesium in the urine. Tea and red wine, by the tannin they contain, decrease its absorption.
Certain acids, such as oxalic acid found in rhubarb, sorrel or spinach, or phytic acid present in whole grains, legumes, or oleaginous fruits, would reduce the assimilation of magnesium by our body.
Between deficiency and excess. What effects on the body?
Magnesium deficiency, or hypomagnesia, has noticeable effects on health and well-being, such as muscles that function less well, poor stress management, disrupted vital functions. The most obvious cases are:
- At the physiological level: chronic fatigue, lack of enthusiasm, pump strokes, insomnia, migraines, dizziness, difficulty concentrating, constipation, palpitations, brittle hair, and nails. In extreme cases, diabetes, high blood pressure, osteoporosis.
- At the psychological level: anxiety, low morale, irritability, mood swings, and, in extreme cases, anxiety, depression.
- At the muscular level: cramps, muscle spasms, nervous tics, muscle pain, decreased sports, and recovery abilities. In extreme cases, attacks of tetany, infarction.
According to a study conducted in 2008 by American researchers (1), our cells age faster in the case of magnesium deficiency. Another study (2) indicates that magnesium would allow the maintenance of memory. At the sporting level, any impairment leads to a significant drop in performance and a longer recovery.
Taken in excess, magnesium can lead to intestinal disorders with diarrhoea because of its laxative properties. Hypermagnesemia can cause nausea and vomiting, low blood pressure, dry mouth, drowsiness, muscle weakness, in extreme cases, coma, or even cardiac arrest. Nevertheless, our kidneys are able to eliminate up to 6 grams of magnesium per day. It is therefore rare to witness an overdose. On the other hand, an excess can be dangerous in people with kidney failure.
(1) Magnesium deficiency accelerates cellular senescence in cultured human fibroblasts, D. Killilea, B. Ames
(2) Enhancement of Learning and Memory by Elevating Brain Magnesium. Neuron, Jan. 28, 2010
In the sportsman
Magnesium in the heart of metabolism and the neuromuscular system
Magnesium is a very important element in athletes since it is at the heart of metabolic reactions, intervening in the Krebs cycle and the transformation of carbohydrate and lipid reserves into energy for the muscle (glycolysis and lipolysis process). Without magnesium, no energy.
Magnesium is also essential for the proper functioning of muscles: it is involved in the synthesis of proteins that allow muscle contraction and good coordination.
Sports practice can lead to magnesium deficiencies
Various studies show that physical activity, depending on the conditions in which it is practiced, can lead to deficiencies (Callis et al 1987, Refsum et al 1973). The athlete, therefore, consumes more magnesium than a sedentary person and must take it into account in his diet to stay healthy and optimize his performance.
More magnesium removed in hot and humid weather
Experiments have shown that athletes lose magnesium in sweat when sports activity is practiced in hot and humid weather. Thus, more magnesium is spent running in summer by the sea than in dry weather at 20 degrees. However, these expenses remain limited thanks to a phenomenon of osmosis that minimizes losses.
Magnesium deficiency: what impact on performance?
In case of magnesium deficiency, we observe:
- A significant drop in performance and VO2max.
- Longer recovery after exercise.
- An increase in oxidative stress (see our box), magnesium acting as an anti-oxidant.
Studies show that magnesium intake in a deficient athlete can significantly increase his performance and general well-being. On the other hand, this contribution has no visible effect on a non-deficient athlete.
The magnesium needs of the athlete
The magnesium needs of the athlete depend of course on various parameters such as his level of training, the type of activity practiced, its frequency, its intensity, and the conditions in which it is carried out. An athlete must increase his magnesium intake by 10 to 20% of an adapted diet and, if necessary and on the advice of a doctor, by food supplements.
Where to find magnesium?
Foods containing magnesium
Did you know?
Dark chocolate is rich in magnesium. 1 large square (10 g) provides between 15 and 20 mg of magnesium! A good reason to have fun!
Foods particularly rich in magnesium are molluscs (periwinkles, bulots, mussels), oleaginous dried fruits (almonds, walnuts, pistachios, hazelnuts), pulses (white beans, red beans, lentils), whole grain products, cocoa, and dark chocolate. Some mineral waters are also rich in magnesium: Donat Mg, Rozana, Hépar, Quézac, Badoit, Contrex.
Magnesium is also present in green vegetables because it is one of the main constituents of chlorophyll. If its concentration is lower compared to that of the foods mentioned above, it remains interesting given the quantities of vegetables ingested during a meal.
Table of foods rich in magnesium:
| RANG | ALIMENT | TENEUR EN MAGNESIUM |
|---|---|---|
| 1 | meloukhia en poudre | 609,00 mg |
| 2 | sel marin gris non iodé non fluoré | 503,00 mg |
| 3 | sardine à l'huile d'olive | 467,00 mg |
| 4 | fleur de sel | 424,00 mg |
| 5 | chocolat en poudre non sucré | 376,00 mg |
| 6 | graine de cumin | 366,00 mg |
| 7 | noix du Brésil | 366,00 mg |
| 8 | graine de tournesol | 364,00 mg |
| 9 | café en poudre | 356,00 mg |
| 10 | graine de coriandre | 330,00 mg |
| 11 | graine de sésame | 324,00 mg |
| 12 | bigorneau | 310,00 mg |
| 13 | germe de blé | 256,00 mg |
| 14 | curry en poudre | 254,00 mg |
| 15 | escargot | 250,00 mg |
| 16 | noix de cajou | 247,00 mg |
| 17 | épice (aliment moyen) | 233,00 mg |
| 18 | amande | 232,00 mg |
| 19 | pignon de pin | 227,00 mg |
| 20 | gingembre moulu | 214,00 mg |
| 21 | chocolat noir (70% cacao minimum) en tablette | 206,00 mg |
| 22 | fromage à pâte pressée cuite (aliment moyen) | 202,00 mg |
| 23 | chicorée et café en poudre | 199,00 mg |
| 24 | biscuits secs à teneur enrichis en vitamines et minéraux | 195,00 mg |
| 25 | poivre noir moulu | 190,00 mg |
| 26 | baguette ou boule aux céréales et graines artisanal | 181,00 mg |
| 27 | levure alimentaire | 170,00 mg |
| 28 | beurre de cacahuète | 169,00 mg |
| 29 | cacahuète grillée et salée | 168,00 mg |
| 30 | pain de mie complet | 167,00 mg |
| 31 | poudre maltée, cacaotée et sucrée pour boisson | 162,00 mg |
| 32 | farine de sarrasin | 157,00 mg |
| 33 | pain de mie multicéréale | 156,00 mg |
| 34 | biscuits secs fourrés aux fruits | 152,00 mg |
| 35 | chocolat noir (70% cacao) sans sucres ajoutés en tablette | 149,00 mg |
| 36 | cacahuètes enrobées de chocolat | 146,00 mg |
| 37 | filets d'anchois à l'huile (conserve) | 144,00 mg |
| 38 | mélange apéritif de graines salées et raisins secs | 143,00 mg |
| 39 | chocolat noir aux fruits secs en tablette | 140,00 mg |
| 40 | bulot cuit | 135,00 mg |
| 41 | tofu | 134,00 mg |
| 42 | céréales pour petit déjeuner riches en fibres enrichies en vitamines et minéraux | 132,00 mg |
| 43 | pop-corn | 132,00 mg |
| 44 | noix de macadamia | 130,00 mg |
| 45 | riz rouge sec | 130,00 mg |
| 46 | noix | 126,00 mg |
| 47 | noix de pécan | 125,00 mg |
| 48 | lait en poudre écrémé | 115,00 mg |
| 49 | frik sec | 114,00 mg |
| 50 | chocolat en poudre (ou granulés) sucré | 111,00 mg |
Should I take magnesium supplements?
Many magnesium products in tablets or ampoules in various forms (citrates, lactates, gluconates, etc.) can be found in pharmacies or specialized stores. A cure is only useful if the need is justified (see the symptoms listed above) and preferably following the diagnosis of a doctor. In case of doubt, it is advisable to do the test for a month and see if the effects are visible (decrease in fatigue, irritability, etc.). If no effect is observed at the end of the month, it is very likely that taking magnesium was unnecessary. Otherwise, the cure must remain short (2 months maximum) because the body could get used to an excessive intake of magnesium and no longer fix it. In any case, the magnesium supplement should not replace a natural intake through the diet, but be used punctually to respond to a temporary deficiency related to an exceptional event (stress, intensive sports practice, etc.). The advice of a doctor is recommended.
The recommended dosage for a magnesium supplement is 5 mg per kilogram of body weight or 300 mg/day for a 60-kilogram person. In some people, taking magnesium as a supplement accelerates transit, or even can cause diarrhea. It is then advisable to reduce the dose and/or try the product in another form.
We recommend this supplement in the form of soluble organic salts (gluconate, pidolate, citrate, glycerophosphate, aspartate, malate for example) for their good bioavailability and optimal assimilation in the intestine. For better penetration at the cell level, these salts are often accompanied by vitamin B6 or taurine. They can also be taken as a soluble organic complex, such as bisglycinate, which also offers excellent bioavailability and is highly assimilable by the body.
If you do not know which product to buy, we offer the 3 references below which are magnesium salts, highly assimilable, and well tolerated by the body. You will find them at Nutri*Co or on the Onatera website:
- Highly assimilable magnesium (Nutri*Co) (1 bottle offered from 60 € of purchases with the code SPORTPASSION). This quality product with high magnesium content contains vitamin B6 and does not disturb digestive comfort.
- MBE's 6-in-1 Magnesium (Onatera) is a formula offering 6 high-quality bioavailable magnesium sources combined with vitamin B6 and taurine.
- Magnesium Bisglycinate (Onatera), a highly assimilable product as well.
Careful! The magnesium cure is contraindicated in case of renal failure. Magnesium taken in the form of a drug makes it difficult to absorb certain drugs (treatment of osteoporosis in particular) and antibiotics. Better to shift their intake by 2 to 3 hours. Check with your pharmacist or doctor.
Magnesium in practice
Some basic rules
- Eat balanced, vary your diet.
- Avoid refined products. Replace white bread with wholemeal bread. Consume brown grains and rice.
- Consume vegetables, preferably green because they are richer in magnesium.
- Consume dried fruits, especially after sports, in the recovery phase.
- Eat pulses (beans, lentils) at least once a week.
- Give a small place to dark chocolate, rich in magnesium.
- Drink mineral waters, concentrated in magnesium (Hépar, Badoit, Quézac, Contrex).
- Replace cooking with water with steaming or smothering. Cook your vegetable al dente preferably.
- Avoid tannic drinks during meals (tea, red wine), alcohol in general, and coffee: tannin reduces the absorption of magnesium, alcohol, and coffee promotes its elimination in the urine.
- Beware of diets: by eating less, you absorb fewer mineral salts, therefore less magnesium. Choose your food accordingly.
Properly assimilate magnesium
Our body assimilates only 25 to 50% of the magnesium contained in food. It is, therefore, necessary to consume quantities greater than the recommended daily intake to meet our needs.
Magnesium is all the more easily assimilated as it is soluble. Thus, mineral waters would allow optimal absorption. However, this principle is controversial.
Vitamins D and B6 promote magnesium fixation. Vitamin D is found in oily fish and some oils. It is also produced by skin exposed to the sun. Vitamin B6 is present in fresh vegetables and fruits, especially in garlic, spinach, beef liver.
Magnesium does not mix well with certain minerals, dietary fiber, and acids (phytic and oxalic) but would be better assimilated in the presence of fermented sugars.
- The phytic acid present in whole grains, legumes, or oleaginous fruits, would decrease the absorption of magnesium from our body. To lessen this effect, it is advisable to grill cereals and oleaginous fruits and soaks pulses and cereals before cooking.
- Sorrel and rhubarb contain oxalic acid. Consume them outside of meals.
- Excess calcium inhibits the assimilation of magnesium. Decal any calcium supplement intake for 2 to 3 hours.
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