Magnesium doesn’t get the kind of celebrity endorsements that calcium does, but it should. What other nutrient can claim chocolate as one of its better sources? A real workhorse in the body, magnesium is essential for some 325-plus biochemical reactions, more than any other nutrient. Many of those tasks are basic and indispensable.
"Its function is so broad that it touches on almost all physiological systems, all the way from energy generation inside cells to the interaction of nerve impulses and muscles in the heart," says Henry Lukaski, Ph.D., research leader for mineral nutrient functions at the U.S. Department of Agriculture Human Nutrition Research Center in Grand Forks, North Dakota.
Getting enough magnesium has been hailed as an all-around protective measure. In research discussions, this mineral has been tentatively linked with protection from heart arrhythmia (irregular heartbeat), high blood pressure, migraine headaches, and heart attacks.
Energy Everywhere
Magnesium is needed so that the body can produce energy from any food we eat—carbohydrate, protein, or fat. It works in the energy-generating powerhouses inside cells, called mitochondria. There it plays an essential role in producing the body’s basic energy currency. "Magnesium is needed for a cell to make ATP, the molecules that contain the energy, and then to break these molecules down to release the energy," explains Dr. Lukaski.
That’s important, because our bodies produce a large number of ongoing chemical reactions, none of which can take place without ATP. We need ATP all the time to move nutrients and other substances in and out of cells to digest food; to break down molecules and rearrange them into new molecules, such as protein or hormones; and to make muscles and nerves work. Without magnesium helping to make ATP, that energetic activity would be reduced to zero.
SUPPLEMENTSNAPSHOT
| Magnesium Supplement forms: Magnesium lactate, orotate, glycinate, gluconate, oxide, and hydroxide. May help: Heart arrhythmia, migraine headaches, angina, restless legs syndrome, Raynaud’s disease, asthma, binge-eating disorder, osteoporosis, and pregnancy-induced high blood pressure; also used for chronic fatigue syndrome, intermittent claudication, celiac disease, menstrual cramps, PMS, tinnitus, mitral valve prolapse, kidney stones, diabetes, insomnia, endometriosis, leg cramps, and high blood pressure. Daily Value: 400 milligrams. Special instructions: Take a form of magnesium, such as magnesium lactate, orotate, glycinate, or gluconate, that is easily absorbed and least likely to cause diarrhea. Magnesium oxide and hydroxide are more likely to cause diarrhea at higher dosages. Do not take at the same time as calcium, which competes with magnesium for the same absorption sites. Who’s at risk for deficiency: People with uncontrolled diabetes, who lose magnesium through their urine; alcoholics; people taking “loop” or non-potassium-sparing diuretics; people who seldom eat magnesium-rich foods; and those under severe stress. Good food sources: Wheat germ; unmilled grains such as whole wheat and brown rice; pumpkin, sunflower, and other seeds; cocoa; chocolate; unblanched almonds and filberts; rice bran; beans; lentils; tofu; spinach; Swiss chard; halibut; and mackerel. Cautions and possible side effects: Do not take more than 350 milligrams a day as a supplement without medical supervision. Consult your doctor before taking if you have heart disease or arrhythmia, impaired kidney function, high blood pressure, or migraine headaches or if you are taking diuretics. May cause diarrhea. |
In fact, Dr. Lukaski found that female volunteers who consumed 150 milligrams of magnesium a day—which is less than half the Daily Value but is the amount consumed by most women age 50 and older—soon began to slow down. After only two months on a low-magnesium diet, they were asked to ride a stationary bicycle at a moderate pace. On the low-magnesium regimen, volunteers used 15 percent more oxygen and had heart rates an average of 10 beats a minute faster than when they were getting higher doses of 350 milligrams a day.
"This means that people who are low in magnesium use more energy and have a greater strain on their hearts," Dr Lukaski says. "They can’t exercise as long or as hard and they get tired faster. It may even limit their ability to work or to do daily activities."
There’s more besides magnesium involved in energy production, but one thing’s for sure: If magnesium is in short supply, your tail will soon be dragging.
Making Muscles Work
Together with calcium, magnesium is involved in making sure that muscles work properly. "It’s the ratio of calcium to magnesium that’s important," explains Burton M. Altura, Ph.D., professor of physiology and medicine at the State University of New York (SUNY) Health Science Center in Brooklyn.
Magnesium is important for muscles to be able to relax, while calcium helps them contract. Too little magnesium in relation to calcium (or low levels of both) can make muscles cramp more easily and may make some muscles, like the smooth muscles that wrap around big blood vessels, stay somewhat contracted, Dr. Altura explains. Magnesium deficiency can make muscles go into spasms easily. When you’re short on magnesium, the waste products of metabolism, such as lactic acid, are harder to flush out, so you may get tired, burning, sore muscles.
Supplemental magnesium often helps people with migraine headaches or high blood pressure if they’re low in magnesium, Dr. Altura says. Since magnesium can also relax muscles in airways in the lungs, it sometimes helps people with asthma breathe easier, he adds. Magnesium even helps some forms of angina—spasms of the coronary arteries that can cause chest pain.
Magnesium is also needed for the body to be able to construct its basic building materials, including protein, carbohydrates, fat, and nucleic acids, a cell’s genetic material. In some cases, magnesium simply provides the energy needed for the body to link together the molecules of amino acids that make up a protein or the fatty acids that make up fat and cell membranes. At other times, it helps change the shapes of molecules so that they can bind together. In the case of genetic material, magnesium molecules bind to the "backbone" of the famous double-stranded DNA helix, helping to stabilize its structure and maintain order. This is important since each cell uses DNA as the blueprint for reproducing itself or parts of itself. Body maintenance and repair depend on accurate DNA blueprints.
Healthy Heartthrobs
Certain minerals play important roles in maintaining your heart’s proper rhythm. These include potassium, magnesium, sodium, chloride, and calcium. Here again, a proper ratio is important.
When magnesium levels in the heart are low, people can develop certain types of heart arrhythmias, some of them potentially very dangerous, says Carla Sueta, M.D., Ph.D., assistant professor of medicine and cardiology at the University of North Carolina at Chapel Hill School of Medicine.
One type of potential arrhythmia problem affects the upper chamber, or atrium, of the heart. Another type, called ventricular arrhythmia, involves the lower heart chambers. In studies, intravenous magnesium reduced the incidence of death from several types of ventricular arrhythmia. "In fact, intravenous therapy with magnesium is now con-sidered standard therapy for two types of ventricular arrhythmia," Dr. Sueta says.
Too little magnesium can also induce something called refractory potassium deficiency. Unfortunately, you can’t correct a refractory deficiency simply by taking more potassium. But by getting more magnesium, you may ensure that this kind of deficiency never occurs in the first place.
Heart patients—and their doctors—need to pay heed to magnesium. Studies have shown that 65 to 75 percent of all people in intensive care units and 5 to 11 percent of people in general care sections of hospitals are deficient in magnesium. Also, magnesium deficiency can be caused by the very drugs meant to help heart problems. Some types of diuretics cause the body to excrete both magnesium and potassium, as does the heart-stimulating drug digitalis.
Overreactive Rodents
Years ago, German researchers dubbed magnesium a natural tranquilizer because it seemed to soothe jangled nerves. In people who are low in magnesium, it may do exactly that.
Magnesium is essential in the regulation of central nervous system functions, explains James Penland, Ph.D., head research psychologist at the USDA research center in North Dakota. Animals—and humans—low in magnesium have more "excitable" nervous systems that make them tend to overreact to stimulation. Rats, for instance, will jump in their cages at the sound of a closing door.
The human equivalent of the jumpy rat may experience symptoms of shakiness, insomnia, irritability, and anxiety, Dr. Penland says. He’s found changes in brain waves in women who get a low dose of 115 milligrams a day of magnesium. "Even when they have their eyes closed, their brain waves indicate a state of enhanced vigilance, or hyperreactivity," he explains. In other words, their brains just can’t relax completely.
Certainly, if you wake up several times during the night, if you’re irritable or seem jumpy during the day, or if you are experiencing tremors or shakiness and you know you’re not getting much magnesium, it’s worth discussing with your doctor, Dr. Penland says. Taking 200 to 300 milligrams a day as a supplement is safe for most people. If you’re severely deficient, though, you may need more than that amount, or injections. In that case, you need medical supervision.
Free-Radical Chaser
The less magnesium you consume, the greater your chances of developing atherosclerosis—clogged, inflamed arteries that cause heart disease and heart attacks. A magnesium deficiency promotes the generation of free radicals, the free-roaming, unstable molecules that can harm cells, including those lining arteries. When the arteries are roughed up by these renegades, it sets the stage for cholesterol deposits, explains Dr. Altura.
Magnesium deficiency also promotes heart disease by making it easier for harmful LDL cholesterol to be oxidized and for hearts to be overloaded with calcium. Both are steps in the development of heart disease, Dr. Altura says
Today, we get less magnesium in our diets than people were getting about a century ago. Back in 1910, the average was about 450 milligrams a day of magnesium, mostly provided by unprocessed foods and especially by whole grains. Nowadays, most people get less than 300 milligrams a day. Men average 185 to 250; women average 172 to 235. "This raises a real concern that people may be predisposed to chronic latent magnesium deficiencies that could have important health risks such as migraine headaches, heart disease, or high blood pressure," Dr. Altura says.
DV Delivery
If you’re otherwise healthy but have reason to believe that you’ve been shortchanging yourself on magnesium, you can reach the Daily Value of 400 milligrams a day fairly easily by eating magnesium-rich foods. Alternatively, you can figure out about how much you normally get in your diet and then supplement to get yourself up into the 400-milligram range, Dr. Altura says.
If you’re ill, however—if you have heart arrhythmia, kidney problems, high blood pressure, or migraine headaches—you should discuss magnesium supplementation with your doctor, Dr. Altura says. You may be so low in magnesium that you need quite a bit to get you back to normal. You may need extended treatment with oral supplements, and some people require injections.
To help determine true magnesium status, Dr. Altura and his wife, Bella T. Altura, Ph.D., research professor of physiology at the SUNY health center, developed a blood test that measures ionized magnesium, the active form of magnesium in the blood. Some specialists are now able to perform the test, according to Dr. Altura. If you’re concerned about a possible magnesium deficiency, ask your doctor about this test.
