The mineral magnesium is important for your heart, muscles, and kidneys. It is part of what makes up your teeth and bones. Most important, it activates enzymes, giving you energy and helping your body work properly. It can help reduce stress, depression, and insomnia. Vitamin B₆ helps you get the magnesium you need and works with magnesium in many ways.

Magnesium is available in many foods. However, most people in the United States probably do not get as much magnesium as they should from their diet. Nutrition tables can give you only a rough idea of how much magnesium you are getting. Scientists have found that different ways of determining the amount of magnesium in foods produce different results. Also, many foods have not been thoroughly analyzed.

Certain medical conditions can upset your body's magnesium balance. For example, intestinal flu with vomiting or diarrhea can cause temporary deficiencies. Stomach and bowel diseases, diabetes, pancreatitis, kidney malfunction, and diuretics can cause long-term deficiencies. Talk with your health care provider about your magnesium needs if you have any of these conditions.

Getting enough magnesium can help facilitate the results of conventional treatment for the corresponding conditions in the following ways:

• Reduce blood pressure
• Correct heart arrhythmias
• Help control acute asthma attacks
• Decrease insulin needs in the case of diabetes
• Prevent kidney stones
• Reduce cramps, irritability, fatigue, and water retention associated with menstruation
• Prevent serious complications of pregnancy, such as preeclampsia and eclampsia
• Restore normal energy level
• Reduce anxiety and the effects of stress 
• Maintain healthy bones 
• Improve concentration in attention deficit/hyperactivity disorder 
• Relieve pain and fatigue associated with fibromyalgia 

The richest sources of magnesium are tofu, nuts (Brazil nuts, almonds, cashews, black walnuts, pine nuts), pumpkin and squash seeds, peanuts, green leafy vegetables, legumes, wheat bran, whole grains, soybean flour, blackstrap molasses.

Other good sources are whole wheat flour, oat flour, beet greens, spinach, shredded wheat, bran cereals, oatmeal, bananas, baked potatoes (with the skin), pistachio nuts.

You can also get magnesium from many herbs, spices, and seaweeds (for example, agar seaweed, coriander, dill weed, celery seed, sage, dried mustard, basil, cocoa powder, fennel seed, savory, cumin seed, tarragon, marjoram, and poppy seed).

Magnesium is available in many forms. The best supplements are labeled "soluble," which means it's easier for your body to absorb the magnesium it needs. These come in gelatin capsules. Recommended types include magnesium citrate, magnesium gluconate, and magnesium lactate.

Other familiar sources of magnesium are magnesium hydroxide, often used as a laxative or antacid, and magnesium sulfate used as a laxative or tonic, or added to a bath. Some magnesium can be absorbed through the skin.

When used therapeutically under the guidance of a healthcare provider, small doses of magnesium are taken 3 to 6 times throughout the day, with a full glass of water with each dose to avoid diarrhea. Be sure to check with your heathcare provider before taking magnesium supplements and before considering them for a child.

Below is a list of recommendations for adequate daily magnesium intake from the diet established by the Food and Nutrition Board of the Institute of Medicine in 1997.

Pediatric

• Infants birth to 6 months: 30 mg
• Infants 6 months to 1 year: 75 mg
• Children 1 to 3 years: 80 mg
• Children 4 to 8 years: 130 mg
• Children 9 to 13 years: 240 mg
• Adolescent males 14 to 18 years: 410 mg
• Adolescent females 14 to 18 years: 360 mg

Adult

• Males 19 to 30 years: 400 mg
• Females 19 to 30 years: 310 mg
• Males 31+ years: 420 mg
• Females 31+ years: 320 mg
• Pregnant females under 18 years: 400 mg
• Pregnant females 19 to 30 years: 350 mg
• Pregnant females 31 to 50 years: 360 mg
• Breastfeeding females under 18 years: 360 mg
• Breastfeeding females 19 to 30 years: 310 mg
• Breastfeeding females 31 to 50 years: 320 mg

Do not take magnesium supplements if you have severe heart disease or kidney disease without talking with your health care provider.

Overuse of milk of magnesia (as a laxative or antacid) or Epsom salts (as a laxative or tonic) can cause you to ingest too much magnesium, especially if you have kidney problems. Too much magnesium can cause serious health problems and even death.

Magnesium may increase the likelihood of negative side effects (such as dizziness, nausea, and leg swelling) from calcium channel blockers, particularly nifedipine, that are used to control blood pressure. Pregnancy increases the likelihood of this interaction.

Magnesium may interfere with absorption of tiludronate, a medication similar to alendronate that is used for the treatment of osteoporosis. This interaction has not been reported with alendronate specifically. Magnesium supplements or magnesium-containing antacids should be taken at least two hours before or after taking these medications to minimize potential interference with absorption.

Magnesium tends to decrease during menopause; studies suggest, though, that hormone replacement therapy may lessen the loss of magnesium. If you are postmenopausal, on hormone replacement or not, talk to your healthcare provider about whether magnesium supplementation would be beneficial.

Magnesium hydroxide, commonly found in antacids, may increase the absorption of glipizide and glyburide, medications used to control blood sugar levels. Similarly, magnesium supplements improved the secretion of and sensitivity to insulin. Consult your healthcare provider to determine whether magnesium supplements are appropriate for you if you have diabetes and are currently taking any of these medications.

The absorption of quinolone and tetracycline antibiotics as well as nitrofurantoin is diminished when taken with magnesium supplements. Therefore, magnesium should be taken two to four hours before or after taking these medications to avoid interference with absorption.

Penicillamine, a medication used for the treatment of Wilson's disease and rheumatoid arthritis, can inactivate magnesium, particularly when high doses are used over a long period of time. However, supplementation with magnesium and other nutrients in patients on penicillamine therapy reduced the occurrence of side effects. Consult your healthcare practitioner to determine whether magnesium supplements may be appropriate for you.

Aminoglycoside antibiotics (such as gentamicin and tobramycin), thiazide diuretics (such as hydrochlorothiazide), loop diuretics (such as furosemide and bumetanide), amphotericin B, corticosteroids, antacids, insulin, and digoxin may lower magnesium levels. Although adequate levels of magnesium can increase the effectiveness of both insulin and digoxin specifically, consult your healthcare provider before taking magnesium supplements. Please refer to the depletions monographs on some of these medications for more information.

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