Carl R. Darnall Army Medical Center - Health Library

Magnesium

Image for magnesium Magnesium is an essential mineral that has a hand in many vital body functions, for example releasing energy, building protein, and stabilizing bone. It is also one of several nutrients that helps keep blood pressure within a healthy range. And since magnesium is plentiful in vegetables, legumes, and whole grains, it is easy to consume enough if you are eating healthy food.

Functions  ^

Magnesium's functions include:

Recommended Intake  ^

Age Group Recommended Dietary Allowance
(mg/d)
Male Female
0-6 months Adequate intake
(AI) = 30
AI = 30
7-12 months AI = 75 AI = 75
1-3 years 80 80
4-8 years 130 130
9-13 years 240 240
14-18 years 410 360
19-30 years 400 310
31-50 years 420 320
>51 years 420 320
Pregnancy (18 years or younger) n/a 400
Pregnancy 19-30 years n/a 350
Pregnancy 31-50 years n/a 360
Lactation (18 years or younger) n/a 360
Lactation 19-30 years n/a 310
Lactation 31-50 years n/a 320

Magnesium Deficiency  ^

Magnesium deficiency is rare because most people have large stores of this mineral in their body. However, it can be caused by diseases or medications that interfere with the body's ability to absorb magnesium. Symptoms of a magnesium deficiency include: irregular heartbeat, nausea, confusion, depression, tingling, weakness, loss of appetite, and muscle contractions and cramps.

Conditions and medications that may lead to a magnesium deficiency include:

Tolerable Upper Intake  ^

It's also possible to get too much magnesium. The Office of Dietary Supplements publishes tolerable upper intake levels for magnesium.

Age Group Tolerable Upper Intake Levels
(mg/d)
Male Female
1-3 years 65 65
4-8 years 110 110
9-18 years 350 350
19+ years 350 350
Pregnancy (18 years or younger) n/a 350
Pregnancy 19+ n/a 350

Magnesium Toxicity  ^

Magnesium toxicity through food intake is not a concern for most healthy people. However, people with kidney disease may develop toxicity because the kidneys are responsible for regulating the level of magnesium in the blood. Also it is possible to take too much magnesium in supplements. Symptoms of magnesium toxicity include:

Major Food Sources  ^

Magnesium is found in a variety of foods. The best sources are legumes, nuts, whole grains, and certain vegetables. "Hard" water (which is high in dissolved minerals, specifically calcium and magnesium) is also a source of magnesium.

Foods that provide high levels of magnesium include:

Health Implications  ^

Blood Pressure

Greater magnesium intake is associated with a lower incidence of high blood pressure. This is the finding of a few large clinical studies. One of these, the DASH (Dietary Approaches to Stop Hypertension) study found that a diet high in magnesium, potassium, and calcium and low in sodium and fat can significantly lower blood pressure. You can get these nutrients by eating a diet rich in fresh fruits and vegetables, legumes, whole grains, and low-fat dairy foods.

Based on the growing number of studies showing a positive role for magnesium in managing blood pressure, the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends maintaining an adequate magnesium intake to prevent and manage high blood pressure.

Heart Disease

Several studies have found links between magnesium status and heart health. Many of these suggest that an adequate intake of magnesium is protective of the heart. However, further study needs to be done to clarify magnesium's role.

Osteoporosis

Since a significant amount of magnesium is stored in the bones and one of magnesium's roles is to help keep bones healthy, it would make sense that magnesium would help protect bones from the thinning of osteoporosis. Several studies have suggested just that—magnesium supplementation may improve bone mineral density. However it is still not clear, and more study needs to be done.

Tips For Increasing Your Magnesium Intake  ^

It is easy to meet your magnesium needs through foods. To increase your intake, try some of the following:

RESOURCES:

Eat Right—Academy of Nutrition and Dietetics
http://www.eatright.org

International Food Information Council Foundation
http://www.foodinsight.org

CANADIAN RESOURCES:

Dietitians of Canada
http://www.dietitians.ca

Health Canada
http://www.hc-sc.gc.ca

REFERENCES:

Appel L, Moore T, Obarzanek E, et al. A clinical trial of the effects of dietary patterns on blood pressure. N Engl J Med. 1997;336(16):1117-1124.

Magnesium. Office of Dietary Supplements website. Available at: https://ods.od.nih.gov/factsheets/Magnesium-HealthProfessional. Updated February 11, 2016. Accessed April 29, 2016.

Osteoporosis. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated April 29, 2016. Accessed April 29, 2016.

The seventh report of the Joint National Committee on Prevention, Detection, and Treatment of High Blood Pressure. Hypertension. 2003;42(6):1206-1252.

Last reviewed April 2016 by Michael Woods, MD  Last Updated: 4/29/2016