Paging Dr. Frischer: Magnesium
I occasionally recommend magnesium supplements to patients. When might they be helpful?
Some half of all Americans routinely take dietary supplements. In this world of vitamin, mineral, and nutritional supplements, magnesium is having a popular moment. Magnesium is a mineral that our bodies must have in order to maintain proper blood pressure, strong bones, and a steady heart rhythm. It controls our blood sugar levels and makes protein and DNA. More than 300 chemical reactions in the body rely, in part, on magnesium.
The recommended daily dose of magnesium for most healthy people is 320 mg for women and 420 mg for men. A reasonably healthy diet should make this target easy. Foods rich in magnesium include leafy green vegetables, beans, nuts, whole grains, pumpkin seeds, soy milk, bananas…and even dark chocolate.
Extra magnesium is important for those with magnesium deficiency, or who have complications of pregnancy such as preeclampsia and eclampsia. Some evidence also suggests that extra may be helpful for people with cardiovascular disease, insomnia, high blood pressure, migraines, anxiety, diabetes and diabetic neuropathy, muscle soreness, and constipation, and could be useful for brain health and smoking cessation.
Magnesium levels can be measured with a simple blood test. Normally, our body does a great job regulating the amount of magnesium in the blood. When the level rises, our kidneys get rid of the excess in the urine. If the level falls, the intestines absorb more from the diet, the kidneys hold onto more, and the bones release it into the blood.
Symptoms of low magnesium include nausea, fatigue, and reduced appetite. Severely low levels can produce numbness in the arms and legs, muscle cramps, and an abnormal heart rhythm. Common causes of low magnesium include malnutrition, Crohn’s disease, parathyroid disease, kidney disease, other intestinal conditions that prevent absorption, medications like diuretics and proton pump inhibitors, and alcohol abuse. Magnesium deficiency becomes more common as we age.
High magnesium levels are extremely rare, but symptoms include nausea, headache, muscle weakness, and trouble breathing. It is usually seen in kidney failure, overdosing on supplements, and in those taking certain medications, such as a magnesium laxative.
Unless you have a proven reduced level of magnesium, or one of the conditions that clearly would benefit from more, there is no compelling reason to routinely take a magnesium supplement. For those who do need extra, magnesium supplements are available in several different forms, including magnesium citrate, magnesium glycinate, and magnesium oxide. 350 mg daily in a supplement is generally considered safe.
The bottom line? Most of us who eat a reasonably balanced diet have no need to be concerned with our magnesium levels. While magnesium supplements are recommended for those with certain health conditions or taking specific medications, too much of the mineral can be harmful. I urge you to discuss taking any supplement with your doctor.
Dr. Alan Frischer is former chief of staff and former chief of medicine at Downey Regional Medical Center. Write to him in care of this newspaper at 10927 Downey Ave., Suite C, Downey, CA 90241.