MAGNESIUMfor HEALTH and DISEASE PREVENTION*
Magnesium ions are essential to the basic nucleic acid chemistry of life, and thus are essential to all cells of all known living organisms. Magnesium is a vital component of a healthy human diet and deficiency has been implicated in a number of human diseases.
What is Magnesium?
Magnesium is a chemical element with the symbol Mg. It is one of the alkaline earth metals. The atomic number is 12, and it is the ninth most abundant element in the earth by mass.
The free element (metal) is not found in nature. It burns with a brilliant white light, and hence its use in fireworks.
The Biology of Magnesium
Magnesium is the fourth most abundant mineral in the human body and is essential to health. Approximately 50% of total body magnesium is found in bone. The other half is found predominantly inside cells of body tissues and organs. Only 1% is found in blood, but the body works very hard to keep blood levels of magnesium constant.
Magnesium is needed for more than 300 biochemical reactions in the body, since over 300 different enzymes require magnesium in order to function.
· helps maintain normal muscle and nerve function
· supports the immune system
· is essential for normal heart rhythm
· keeps bones strong
· regulates blood glucose levels
· promotes normal blood pressure
· is involved in energy metabolism, as well as the metabolism of proteins, carbohydrates and fats
· helps genes function properly.
To express this another way: magnesium is an important mineral in the body for the electrical stability of the cells, the maintenance of membrane integrity, muscle contraction, nerve conduction and the regulation of vascular tone, as well as being important in bone health.
The metabolic role of magnesium is so diverse that it is difficult to find a body system that is not affected by magnesium deficiency. Our cardiovascular system, nervous system, muscles, kidneys, hormone-secreting glands, liver and brain all rely upon magnesium for their metabolic function.
Magnesium regulates the body’s nerve and muscle tone. In many nerve cells, magnesium serves as a chemical gate-blocker – as long as there is enough magnesium around, calcium cannot rush into the nerve cell and activate the nerve. The nerve is kept relaxed. If our diet supplies too little magnesium, this gate-blocking can fail and the nerve cell can become over-activated. This can explain how magnesium deficiency can trigger muscle tension, muscle spasms, muscle craps and muscle fatigue.
Dietary magnesium is absorbed in the small intestine and is excreted through the kidneys.
Symptoms of severe magnesium deficiency are rare in western countries. However there is concern about the prevalence of sub-optimal magnesium stores in the body. For many people, dietary intake may not be high enough to promote optimal magnesium stores, which may be protective against disorders such as cardiovascular disease and immune dysfunction.
The health status of the digestive system and the kidneys significantly influences the magnesium levels in the body. Approximately one-third to one-half of dietary magnesium is absorbed. Disorders such as Chron’s disease and chronic or excessive vomiting and diarrhoea can result in magnesium depletion.
Healthy kidneys are able to limit urinary excretion of magnesium to compensate for low dietary intake. Excessive loss of magnesium in the urine can be a side-effect of some medications such as diuretics and some antibiotics like gentamycin. Excessive loss of magnesium in the urine can also occur in cases of poorly-controlled diabetes and alcohol abuse.
Signs and Symptoms of Magnesium Deficiency
Early signs of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue and weakness. Later, numbness, tingling, muscle contractions and cramps, seizures, personality changes and abnormal heart rhythms can occur. Many of these symptoms are general and can result from a variety of medical conditions other than magnesium deficiency.
Food Sources of Magnesium
Eating a wide variety of legumes, nuts, whole grains and vegetables, especially ‘greens’, will meet the daily dietary need for magnesium. Green vegetables, such as spinach and kale, are good sources because the centre of the chlorophyll molecule (which gives green vegetables their colour) is magnesium. Chlorophyll is almost identical to haemoglobin, the only difference is that chlorophyll has a central magnesium atom whereas, in haemoglobin, it is replaced with an iron atom.
Refined (white) flour is low in magnesium because the magnesium-rich bran has been removed.
Recommended Dietary Allowance
· Adult males 400 mg/day
· Adult females 310 mg/day
· During pregnancy and lactation 350-400 mg/day
Selected Food Sources of Magnesium
Different publications give different levels of magnesium. The amount of minerals and trace elements in a food is variable and depends greatly on the soil in which the food is grown. The following is simply a guide (from US Department of Agriculture, 2003) to the approximate content of magnesium in a small selected number of foods:
· Almonds (30gm) 80 mg
· Spinach (½ cup, cooked) 75 mg
· Soybeans (cooked, ½ cup) 75mg
· Peanuts (30gm) 50 mg
· Lentils (cooked, ½ cup) 35 mg
· Beans (eg kidney beans, cooked, ½ cup) 35 mg
· Banana (raw, 1 medium) 30 mg
· Bran flakes (½ cup) 30 mg
· Bread (whole wheat, 1 slice) 25 mg
When is Extra Magnesium Needed?
In general, as already stated, eating a variety of whole grains, legumes and vegetables (especially dark-green leafy vegetables) every day will help provide the recommended dietary intake of magnesium.
Magnesium supplementation may be indicated when a specific health problem causes an excessive loss of magnesium or limits magnesium absorption:
· Some medicines, as referred to above
· Poorly controlled diabetes
· Chronic mal-absorptive problems, eg Chron’s disease, coeliac disease
· Older people
If supplement of magnesium is indicated, the amount of magnesium in the compound and its bio-availability influence the effectiveness of the magnesium supplement.
Bioavailability refers to the amount of magnesium in food, medications and supplements that is absorbed in the intestines and ultimately available for biological activity in the cells and tissues.
The percentage of magnesium in compounds used in oral supplements is
· Magnesium oxide 60% magnesium
· Magnesium carbonate 45% magnesium
· Magnesium hydroxide 42 % magnesium
· Magnesium citrate 16% magnesium
· Magnesium chloride 12% magnesium
· Magnesium sulphate 10% magnesium
Although magnesium oxide contains more elemental magnesium than magnesium chloride, it has lower bio-availability. It is for this reason that many supplements are a “magnesium complex”, ie contain several salts: the total magnesium content is always listed.
Conditions that may Benefit from Magnesium Supplements
As already indicated, magnesium deficiency and associated symptoms are rare in western counties. However, sub-optimal levels of magnesium are relatively common. The following conditions may benefit from optimal levels of magnesium, obtained either by improving the diet or by supplementation.
Epidemiological evidence suggests that magnesium may play an important role in regulating blood pressure. Diets that provide plenty of fruits and vegetables, which are good sources of potassium and magnesium, are consistently associated with lower blood pressure. To cite but one study, the DASH study (Dietary Approaches to Stop Hypertension) was a clinical trial that showed that high blood pressure (hypertension) could be significantly lowered by a diet that emphasises fruits and vegetables. Such a diet will be high in magnesium, potassium and calcium and low in sodium and fat.
Diets high in magnesium are frequently high in potassium and dietary fibre and this makes it difficult to evaluate the independent effect of magnesium on blood pressure. The DASH diet is recommended as a beneficial eating plan for people with hypertension and for those with ‘pre-hypertension’ who desire to prevent high blood pressure.
Diabetes is a disease resulting from insufficient production of insulin and/or inefficient use of insulin. Insulin is a hormone, made by the pancreas, which helps convert sugar and starches in food into energy to sustain life.
Magnesium plays an important role in carbohydrate metabolism. It may influence the release and activity of insulin. Low levels of magnesium (hypomagnesaemia) are frequently seen in individuals with type 2 diabetes (adult onset diabetes, often linked to obesity). Hypomagnesaemia may worsen insulin resistance. The kidneys lose their ability to retain magnesium during periods of severe hyperglycaemia (elevated blood glucose, ie diabetes), resulting in low blood levels of magnesium.
Several epidemiological studies, involving hundreds of thousands of people, have shown that “over time, the risk of developing type 2 diabetes was greater in men and women with lower magnesium intake.”
Several clinical studies have examined the potential benefit of supplemental magnesium on metabolic control of type 2 diabetes. The results of one such study, where supplemental magnesium was compared to placebo, showed that those who received a magnesium supplement (300 mg magnesium per day) had higher blood levels of magnesium and improved metabolic control of diabetes.
These observed associations between magnesium metabolism, diabetes and high blood pressure increase the likelihood that magnesium metabolism my influence cardiovascular disease.
Some observational surveys have associated higher blood levels of magnesium with lower risk of coronary artery disease. In addition, some dietary surveys have suggested that higher magnesium intake may reduce the risk of having a stroke (cerebrovascular disease). There is also evidence that low body stores of magnesium increases the risk of abnormal heart rhythms, which may increase the risk of complications after a heart attack.
These studies suggest that consuming the recommended amounts of magnesium may be beneficial to the cardiovascular and cerebrovascular systems.
Magnesium is a mineral that plays an important role in maintaining healthy bones. It contributes to bone density and helps prevent the onset of osteoporosis.
Since magnesium works closely with calcium, it is important to have an appropriate ratio of both minerals in order for them to be effective. An ideal ratio of calcium:magnesium is 2:1. For example, in taking supplements, if you take 1000mg of calcium, you should also take 500 mg of magnesium. The importance of sunlight and vitamin D in the prevention of osteoporosis must not be forgotten (see my November 2007 newsletter ‘Sunlight and Health’).
The Risk of Too Much Magnesium?
Dietary magnesium does not pose a health risk.
Pharmacological doses of magnesium in supplements can promote adverse effects such as diarrhoea and abdominal cramping. The risk of magnesium toxicity increases with kidney failure. Very large doses of magnesium-containing laxatives and antacids have also been associated with magnesium toxicity. Signs of excess magnesium include changes in mental status, nausea, diarrhoea, anorexia and muscle weakness.
300-500mg of elemental magnesium from a ‘magnesium complex’ daily.
The theme of many of the Collison Newsletters, as well as my book ‘How to Live to 100+ Years free from Symptoms and Disease’(see home page), is that a plant-based low-fat diet is the foundation of health. This diet supplies adequate magnesium and hence the benefits as described above.
An interesting article ‘Magnesium Chloride for Health and Rejuvenation’, by Dr Walter Last, opens with the following
“Magnesium is nothing short of a miracle mineral in its healing effect on a wide range of diseases as well as in its ability to rejuvenate the aging body”.
See health-science-spirit.com for the full text.
*Copyright 2008: The Huntly Centre.
Disclaimer: All material on the huntlycentre.com.au website is provided for informational or educational purposes only. Consult a health professional regarding the applicability of any opinions or recommendations expressed herein, with respect to your symptoms or medical condition.
Back to the list Print friendly version