Vitamins, Minerals and Dietary Supplements
What is magnesium?
An essential trace element, magnesium is found in every cell in the body.
It is silver-white in color and metallic in nature.
Why do we need it?
Magnesium is responsible for a variety of bodily functions. It is needed
for bone, protein and fatty acid formation; the creation of new cells;
the activation of B vitamins; relaxing muscles; clotting blood; proper
function of the immune system; and the formation of ATP. Insulin secretion
and function also require magnesium.
Because magnesium has so many different actions in the body, the exact
reasons for some of its effects remain unknown. Preliminary research,
however, has shown it to improve vision in people with glaucoma, lower
blood pressure, reduce hyperactivity in children, and reduce symptoms
in people suffering from chronic fatigue syndrome.
How much magnesium should I take?
According to the National Academy of Sciences, the recommended daily
allowance (RDA) of magnesium is as follows:
- Adult men: 400 milligrams/day
- Adult women: 310 milligrams/day
- Children aged 7-10: 130 milligrams/day
- Infants: 75 milligrams/day
- Pregnant/lactating women: between 310-350 milligrams/day
In addition, it is recommended that people with kidney disease should
not take magnesium supplements without first consulting a doctor.
What are some good sources of magnesium?
Chocolate is an excellent source of magnesium. Moderate amounts can be
found in legumes, nuts, whole grain foods, soy flour, tofu, green vegetables,
brown rice, raisins and seafood.
What can happen if I don't get enough magnesium?
While magnesium deficiency is rare, diabetics, people who routinely take
laxatives or diuretics, and alcoholics are at greater risk for becoming
deficient. Symptoms of magnesium deficiency include fatigue, insomnia,
abnormal heart rhythms, muscle weakness and spasm, depression, listlessness
and loss of appetite.
What can happen if I take too much?
Toxicity from increased magnesium intake is rare, because the body usually
eliminates excess amounts. The most common symptom of magnesium of toxicity
is diarrhea, a condition which may occur with amounts as low as 500 milligrams
per day. Excess intake of magnesium may also result in decreased calcium
- Recommended Dietary Allowances, 10th ed. Washington,
D.C.: National Academy Press, 1989.
- Murray M. Encyclopedia of Nutritional Supplements.
Rocklin, CA: Prima Publishing, 1996.
- Gaspar AZ, Gasser P, Flammer J. The influence of magnesium
on visual field and peripheral vasospasm in glaucoma. Ophthalmologica
- Kawano Y, Matsuoka H, Takishita S, Omae T. Effects
of magnesium supplementation in hypertensive patients. Hypertension
- Starobrat-Hermelin B, Kozielec T. The effects of magnesium
physiological supplementation on hyperactivity in children with attention
deficit hyperactivity disorder (ADHD): Positive response to magnesium
oral loading test. Magnesium Res 1997;10:149-56.
- Cox IM, Campbell MJ, Dowson D. Red blood cell magnesium
and chronic fatigue syndrome. Lancet 1991;337:757-60.