Magnesium may help lower blood pressure

Magnesium is sometimes called “nature’s calcium channel blocker” because, like that class of heart drugs, the mineral blocks calcium from entering cells, relaxing blood vessels and lowering blood pressure. The body uses the essential mineral to maintain healthy bones and muscles, to manufacture proteins and fatty acids and to help the blood clot. Low intake has been linked to allergies, asthma, migraines, heart disease, chronic fatigue and hyperactivity. The mineral is abundant in dark leafy greens, such as spinach, and in nuts, whole grains and beans. But excessive laxative use, heart failure and alcoholism can cause magnesium deficiency.

Uses: People often take magnesium to help prevent heart disease and diabetes and to maintain strong bones.

Dose: Most doctors -- and the government -- recommend about 400 milligrams a day. But many people in the U.S., especially those who consume lots of processed foods, don’t get more than 200 milligrams a day. Magnesium supplements come in several forms (including magnesium aspartate, magnesium oxide and magnesium sulfate), which the body absorbs to different degrees.

Precautions: The most common side effects of high magnesium intake are diarrhea, nausea and cramps.

Research: Clinical trials have investigated myriad uses for magnesium. In a few studies the mineral helped improve vision in people with glaucoma. In others, it appeared to keep hyperactivity and ADHD in check in children and improve bladder control in women. Studies on heart disease and magnesium have produced a mixed bag of evidence so far, but the mineral does appear to lower blood pressure and cure some heart arrhythmias, and magnesium-rich diets have been shown to decrease the likelihood of heart attack and stroke. Studies have also linked low magnesium intake with increased risk of diabetes and osteoporosis. Last year, researchers at MIT showed that, on top of everything else, magnesium plays a critical role in learning ability and memory.

Dietary supplement makers are not required by the U.S. government to demonstrate that their products are safe or effective. Ask your healthcare provider for advice on selecting a brand.

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-- Elena Conis