You are here:

Ask the doctor: Should I have my magnesium level checked?

Q. Should I have my magnesium level checked regularly to make sure I’m getting enough for my bones?

A. You need adequate magnesium, and not just for bone health. It’s central to hundreds of biochemical reactions throughout the body and essential for proper nerve, muscle, heart rhythm, and immune function. It also helps regulate blood sugar levels and promotes healthy blood pressure. We get most of the magnesium we need in food (good sources are whole grains, legumes, and dark-green leafy vegetables). Most multivitamins also contain some magnesium.

Magnesium is absorbed in the intestine and travels through the blood to cells and tissues; any excess is excreted through the kidneys. About half of the magnesium we absorb is stored in bone; the other half, in cells throughout the body. Only a little is found in blood. As a result, the blood level of magnesium doesn’t tell us much about the body’s total store of the mineral.

Magnesium deficiency, which is rare in this country, can cause muscle weakness, cramping, or cardiac arrhythmias. Conditions that impair absorption, such as chronic vomiting, Crohn’s disease (an inflammatory condition of the intestine), celiac disease, and gastric bypass surgery, can lead to magnesium deficiency.

For women ages 31 and over, the recommended dietary allowance of magnesium is 320 milligrams (mg) per day (360 mg/day for pregnant women). Surveys suggest that many Americans don’t get enough magnesium in their diets. But if you’re otherwise healthy, your magnesium level is probably normal and you don’t need to check it regularly. It’s much more important to make sure that you’re including whole grains, dark-green leafy vegetables, and legumes in your diet. (For a list of foods and their magnesium content, go to

— Celeste Robb-Nicholson, M.D.
Editor in Chief, Harvard Women’s Health Watch

Posted by: Dr.Health

Back to Top