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| Magnesium In Depth |
Magnesium, like calcium, is an earth alkali mineral. The word magnesium comes from the name of the Greek city, Magnesia, where large deposits of magnesium carbonate (MgCO3) were found. This "salt" was first used as a laxative; magnesium carbonate and magnesium sulfate are still used in this way. Magnesium is the "iron" of the plant world, as iron is to hemoglobin, magnesium is to chlorophyll, the "blood" pigment of plants. The central atom of the chlorophyll structure is magnesium.
About 65 percent of our magnesium is contained in the bones and teeth. As with calcium, the bones act as a reservoir for magnesium in times of need. The remaining 35 percent of magnesium is contained in the blood, fluids, and other tissues; there is a high concentration, actually higher than in the blood, in the brain. Magnesium is present in significant amounts in the heart. Most of it, like potassium, is inside the cells.
The process of digestion and absorption of magnesium is very similar to that of calcium. The suggested ratio of intake of these two vital nutrients is about 2:1, calcium to magnesium. Magnesium also requires an acidic stomach environment for best absorption, so taking it between meals or at bedtime is recommended. Meals high in protein or fat, a diet high in phosphorus or calcium (calcium and magnesium can compete), or alcohol use may decrease magnesium absorption. It is possible that some of the hangover symptoms related to alcohol are in part due to magnesium depletion. Taking this mineral with some thiamine (B1) and drinking extra water can help prevent hangover symptoms.
Usually, about 40-50 percent of the magnesium we consume is absorbed, though this may vary from 25-75 percent depending on stomach acid levels, body needs, and dietary habits. Stress may increase magnesium excretion, and the resulting temporary magnesium depletion may make the heart more sensitive to electrical abnormalities and vascular spasm that could lead to cardiac ischemia. The kidneys can excrete or conserve magnesium according to body needs. The intestines can also eliminate excess magnesium in the feces. Otherwise, magnesium absorption is generally affected by the factors shown in the table (see Calcium) entitled Factors Affecting Calcium Absorption.
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Many factors affect magnesium availability from foods. One is the amount of magnesium in the soil in which the food is grown. Much magnesium can be lost in the processing and refining of foods and in making oils from the magnesium-rich nuts and seeds. Nearly 85 percent of the magnesium in grains is lost during the milling of flours. Soaking and boiling foods can leach magnesium into the water, so the "pot liquor" from cooking vegetables may be high in magnesium and other minerals. Oxalic acid in vegetables such as spinach and chard and phytic acid in some grains may form insoluble salts with magnesium, causing it to be eliminated rather than absorbed. For these reasons and those previously discussed, many people get insufficient magnesium from their diets.
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Magnesium, like potassium, is primarily an intracellular nutrient. It activates enzymes that are important for protein and carbohydrate metabolism, and it is needed in DNA production and function. Magnesium also modulates the electrical potential across cell membranes, which allows nutrients to pass back and forth. It helps in the release of energy by transferring the key phosphate molecule to adenosine triphosphate (ATP), an energy source generated by the cytochrome system.
In summary, even though it is not as prevalent as the other macrominerals, magnesium has many essential metabolic functions in the body. It is important in the production and transfer of energy, in muscle contraction and relaxation, in nerve conduction, in protein synthesis, and in many biochemical reactions as a cofactor to enzymes. Magnesium is also thought to dilate the blood vessels.
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Magnesium sulfate has been used specifically to lower blood pressure in pregnant women with preeclampsia, which is characterized by edema, hypertension, and hyperreflexint in this case. Through its nerve- and muscle-relaxing effect, magnesium may be helpful in reducing epileptic seizures caused by nerve excitability. By increasing calcium solubility, especially in the urine, magnesium can help prevent kidney stones, especially calcium oxalate stones. Research has shown this effect in a high percentage of people who form kidney stones regularly. Actually, it is thought that calcium oxalate stones are most likely to form in people who are magnesium deficient, so we may just be correcting that deficiency. Through this same effect, magnesium is helpful in preventing other tissue and blood vessel calcification (and thereby atherosclerosis), as well as some problems of the teeth, including cavities. For these purposes, a daily dose of 50 mg. of vitamin B6 and 200-300 mg. of magnesium oxide is often given. Supplementing magnesium has been shown to be very helpful in alleviating many symptoms related to the menstrual period. Menstrual cramps, irritibility, fatigue, depression, and water retention have been lessened with magnesium, usually given along with calcium and often with vitamin B6. Magnesium is often at its lowest level during menstruation, and many symptoms of premenstrual syndrome (PMS) are relieved when this mineral is replenished. Supplementing magnesium in the same amount (or more) as calcium (about 500-1,000 mg. daily) is currently recommended for premenstrual problems. Fatigue is often reduced with magnesium (and potassium) supplementation. The many enzyme systems that require magnesium help restore normal energy levels. Because of this function and its nerve and muscle support, magnesium may also be helpful for nervousness, anxiety, insomnia, depression, and muscle cramps. Magnesium is also given as part of a treatment for autism or hyperactivity in kids, usually along with vitamin B6. Getting children and fatigued adults to eat more green vegetables and chlorophyll is often helpful for supplying additional naturally-occurring magnesium. People tend to sleep better after taking magnesium before bed. Alcoholics tend to have low magnesium levels, and this mineral can be helpful during withdrawal and to prevent or reduce hangover symptoms. |
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When given orally, magnesium sulfate (Epsom salts) is not absorbed but attracts water into the colon and thus acts as an effective laxative. Epsom salts in a bath are absorbed slightly and are known to be relaxing. For injuries, a concentrated solution is used as a compress to help drain toxins. Magnesium is also thought to reduce lead toxicity and its buildup, possibly through competing for absorption. Since magnesium is an alkaline mineral, it is used in several over-the-counter antacids.
| Deficiency and toxicity |
Magnesium deficiency is actually fairly common; however, it is usually not looked for, and therefore, not found or corrected. Deficiency is more likely in those who eat a processed-food diet; in people who cook or boil all foods, especially vegetables; in those who drink soft water; in alcoholics; and in people who eat food grown in magnesium-deficient soil, where synthetic fertilizers containing no magnesium are often used. Deficiency is also more common when magnesium absorption is decreased, such as after burns, serious injuries, or surgery and in patients with diabetes, liver disease, or malabsorption problems; and when magnesium elimination is increased, as in people who use alcohol, caffeine, or excess sugar, or who take diuretics or birth control pills.
Early symptoms of magnesium deficiency can include fatigue, anorexia, irritability, insomnia, and muscle tremors or twitching. Psychological changes, such as apathy, apprehension, decreased learning ability, confusion, and poor memory may occur. Tachycardia (rapid heartbeat) and other cardiovascular changes are likely with moderate deficiency, while severe magnesium deficiency may lead to numbness, tingling, and tetany (sustained contraction) of the muscles as well as delirium and hallucinations.
Arterial spasm, specifically of the coronary arteries, is a significant recent concern with magnesium deficiency. This could lead to angina symptoms or even a heart attack. Blood pressure can rise with magnesium deficiency, while an increased likelihood of kidney stones and other tissue calcification is possible.
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Magnesium chelated with amino acids is probably the most absorbable form. Less absorbable forms include magnesium bicarbonate, magnesium oxide, and magnesium carbonate. Magnesium oxide is probably somewhat better than magnesium carbonate (dolomite). The newly available salts of magnesium aspartate or citrate, both known as mineral transporters, have a better percentage of absorption. ZMA ( zinc and magnesium aspartate) for men is a great product
| Calcium-magnesium balance is important. It is usually suggested that when we supplement calcium we take about half that amount in magnesium. If we increase calcium intake, we should likewise increase magnesium. We should also increase magnesium intake when we consume more phosphorus, vitamin D, or protein or when we have higher blood cholesterol. Those on birth control pills or diuretics, postmenopausal women, and those who drink alcohol need more magnesium. |
The levels of magnesium used by physicians are commonly in the range of 600-1,000 mg.; however, the researchers in the kidney stone studies used only 200-300 mg. of supplemental magnesium oxide. Calcium and magnesium are both alkaline minerals, so they are not taken with or after meals, as they can reduce stomach acid as well as being absorbed poorly when taken with food. They are absorbed better when taken between meals or on an empty stomach, especially with a little vitamin C as ascorbic acid. Many calcium-magnesium combinations are formulated with hydrochloric acid and vitamin D to aid the mineral absorption. And taking them before bedtime may be very helpful in increasing utilization of both these important minerals and lead to a sleep-filled night.
| Water & Health | Health Nutrients | Magnesium & Heart Attacks | Vitamin Health |
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