Q:I have suffered from atrial fibrillation for the past 20 years. Recently, in addition to daily aspirin, my doctor suggested I take two 150 milligrams per day of magnesium and said there are no side-effects. I have been feeling just fine.
You did not mention magnesium in
a previous column about a heart problem. What are the functions of magnesium on the heart? I know four other people who are taking magnesium for the same reason as me, and they are all doing great.
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A:Magnesium is naturally present in our bodies. Half of the total body magnesium is in our bones.
It is a common mineral and is found in many foods we eat, including cereal, milk, green vegetables, avocados, nuts and fish. Unrefined grain such as brown rice and wheat bran and germ also contain magnesium. It is also present in most drinking water, unless it is too soft. Most people in North America get adequate amounts in their daily diet.
Magnesium is needed for many biochemical processes in the body and helps maintain healthy muscle and nerve functions. It can also help regulate blood sugar levels in diabetics and keeps bones strong.
Athletes often take magnesium to help alleviate muscle cramps, and pregnant women take vitamin supplements with added magnesium because the developing fetus takes it out of the mother’s body.
There has recently been increased interest in the role of magnesium in preventing and treating high blood pressure and other cardiovascular diseases. I didn’t mention magnesium as a treatment for heart rhythm problems in a previous column because it is not a mainstream recommended treatment.
However, you may need supplements if you have a medical condition that causes abnormally low blood magnesium levels.
Some medications and illnesses such as Crohn’s disease and colitis interfere with the absorption of minerals into the intestines, and chronic alcohol abuse can cause magnesium deficiency.
Low blood levels of magnesium may also be associated with low potassium, so this should be checked, especially if you are taking diuretics.
It is possible that the protective effect of magnesium on the heart is a result of the benefits that have been shown in diabetics and hypertension patients. Both diseases can lead to arteriosclerosis and heart problems.
There have been small studies on the effect of magnesium supplementation in heart patients, but more research involving much larger populations needs to be done before definite conclusions can be reached.
In the meantime, it is not harmful to take a couple of magnesium tablets a day. Too much may cause diarrhea and nausea because magnesium citrate and magnesium sulfate are used as laxatives.
Clare Rowson is a retired medical doctor in Belleville, Ont.