In this article: How much do you need? Good sources of magnesium 10 important ways magnesium helps Scientific sources Contact Jean Carper

Mighty magnesium
This overlooked nutrient fights against heart disease, pain and diabetes.

Readers constantly ask me, "Am I getting enough calcium?" They rarely ask, "Am I getting enough magnesium?"

Yet that may be the most critical nutritional question of the moment. Americans' intake of magnesium dropped 50% in the last century, and the consequences are alarming. A lack of magnesium underlies our epidemic of heart disease, high blood pressure, diabetes and osteoporosis, says Lawrence Resnick, M.D., a professor of medicine at Cornell Medical Center. Minus magnesium, hearts beat irregularly; arteries stiffen, constrict and clog; blood pressure rises; blood tends to clot; muscles spasm; insulin grows weaker and blood sugar jumps; bones lose strength; and pain signals intensify.

"Many people needlessly suffer pain -- including fibromyalgia, migraines and muscle cramps -- because they don't get enough magnesium," says Mildred Seelig, M.D., a leading magnesium researcher at the University of North Carolina.

Many people worsen the problem by loading up on calcium, which flushes magnesium out of cells, Resnick says. He urges getting at least 1 milligram of magnesium for each 2mg of calcium.

How much do you need?
The recommended daily allowance for magnesium is 320mg for women, 400mg for men. Many authorities take a 400mg magnesium supplement daily. Possible side effects: diarrhea or loose stools. "It's no big deal," Seelig says, because the body usually adapts, or you can cut back. Avoid magnesium supplements if you have kidney disease. You need extra magnesium if you drink alcohol or if you take diuretics or high doses of calcium. Those all deplete magnesium.

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Good sources of magnesium
Nuts and seeds	per 1 ounce
Pumpkin seeds	152mg
Sunflower kernels	100mg
Almonds	78mg
Cashews	73mg
Peanuts	50mg
Walnuts	45mg
Wheat bran cereals	per 1 ounce
100% Bran	134mg
All Bran	106mg
Wheat germ	90mg
Raisin Bran	48mg
Legumes	per 1/2 cup
Tofu	94mg
Baked beans	72mg
Chickpeas, cooked, canned	52mg
Lentils, cooked	43mg
Fruits and Vegetables
Potato, med. w/skin	56mg
Spinach, 1 cup raw	50mg
Spinach, 1/2 cup cooked	79mg
Avocado 1/2 Hass	35mg
Banana, med.	34mg
Seafood	per 3 ounces
Shrimp, cooked, peeled	43mg
Salmon	31mg

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10 important ways it helps

1. Heart arrhythmias. "People need to know magnesium deficiency predisposes them to serious, even deadly, heart arrhythmias" -- irregular and abnormally fast heartbeats or atrial fibrillation -- says cardiac specialist Michael Brodsky at the College of Medicine of the University of California, Irvine. In a British study, taking magnesium daily for six weeks reduced arrhythmias between 25% and 50%. In new U.S. Department of Agriculture tests, women skimping on magnesium developed irregular heartbeats within three months. Supplements corrected the abnormality.

2. Blocked arteries. High blood magnesium cuts your odds of dying from common "ischemic" heart disease (blocked or narrowed arteries) by one-third, say researchers at the Centers for Disease Control and Prevention. In other research, magnesium shortages lower good HDL cholesterol and accelerate hardening of the arteries.

3. Blood pressure. Cornell's Lawrence Resnick recently documented that the higher the magnesium inside your cells, the more apt you are to have lower blood pressure, more elastic blood vessels and a less enlarged heart. He calls magnesium a natural calcium-channel blocker (blood-pressure drug) and says supplements can help normalize blood pressure.

4. Diabetes. "Diabetes is a magnesium deficiency state," says Jerry Nadler, M.D., of the University of Virginia School of Medicine. He finds 80% of diabetics have low intracellular magnesium. Indeed, research suggests low magnesium boosts your risk of developing type 2 diabetes by one-third. He says supplements can improve insulin activity and may cut diabetes' risk and complications. Some specialists tell diabetics to take 400mg magnesium daily.

5. Strong bones. Magnesium is as vital as calcium in preventing osteoporosis, says the University of North Carolina's Mildred Seelig: It's essential for normal bone metabolism. In a Swedish study, magnesium, but not calcium, helped prevent hip fractures in older women. Tufts researchers found high magnesium intake predicted higher bone mass and less bone loss in older people.

6. Migraines. Half of migraine sufferers have low magnesium, and upping magnesium has reduced the duration, intensity and frequency of migraines. Headache frequency dropped 42% in German adults who took 600mg magnesium daily for a month. Italian children given 122mg to 366mg magnesium daily had two-thirds fewer migraines after a month.

7. Sound sleep. Several studies show a lack of magnesium can alter electrical activity in the brain, causing agitated sleep and frequent awakenings. "It looks like magnesium is important for a good night's sleep," says USDA researcher Forrest H. Nielsen.

8. Safer pregnancy. Extensive research shows that magnesium lessens pre-eclampsia, in which blood pressure soars in late pregnancy, upping the risk of spontaneous abortions and premature, low-birth-weight babies. A large new British study of 10,000 women in 33 countries confirms that taking magnesium sulphate supplements reduced the hazard by 50%.

9. Pain relief. If you have leg cramps or other muscle cramps, taking 100mg to 400mg magnesium daily may bring relief, Seelig says. Extra magnesium also may help prevent or relieve painful myalgias (including the syndrome known as fibromyalgia), chronic lower back pain, restless legs syndrome, erythromelalgia (a painful dilation of skin blood vessels) and chronic fatigue syndrome. Seelig says magnesium reduces a pain transmitter in the nervous system called substance P.

10. Extra benefits. Taking magnesium could counteract the heart attack and stroke hazards of hormone replacement therapy, Seelig says: "I still use HRT, because research shows magnesium counters estrogen's clot-producing abilities." Further, magnesium may help treat premature ejaculation and relieve certain symptoms of premenstrual syndrome.

Contributing Editor Jean Carper is an authority on food as medicine. Contact her at jeancarper.com.