Magnesium in the Diet

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Magnesium in diet

Definition

Magnesium is an essential mineral for human nutrition.

Food Sources

Most dietary magnesium comes from vegetables, particularly dark-green,

leafy vegetables. Other foods that are good sources of magnesium are

soy products, such as soy flour and tofu; legumes and seeds; nuts (such

as almonds and cashews); whole grains (such as brown rice and millet);

and fruits or vegetables (such as bananas, dried apricots, and

avocados).

Functions

Magnesium has several important metabolic functions. It plays a role in

the production and transport of energy. It is also important for the

contraction and relaxation of muscles. Magnesium is involved in the

synthesis of protein and it assists in the functioning of certain

enzymes in the body.

Recommendations

These are the recommended daily requirements of magnesium:

Children

1-3 years old: 80 milligrams

4-8 years old: 130 milligrams

9-13 years old: 240 milligrams

14-18 years old (boys): 410 milligrams

14-18 years old (girls): 360 milligrams

Adult females: 310 milligrams

Pregnancy:

360-400 milligrams

Breast feeding women: 320-360 milligrams

Adult males: 400 milligrams

Side Effects

Toxic symptoms from increased magnesium intake are not common because

the body eliminates excess amounts. Magnesium excess almost always

occurs only when magnesium is supplemented as a medication.

Magnesium deficiency is rare.

The symptoms include muscle weakness, fatigue, hyperexcitability, and

sleepiness. Deficiency of magnesium can occur in alcoholics or people

whose magnesium absorption is decreased due to surgery, burns, or

problems with malabsorption (inadequate absorption of nutrients from

the intestinal tract). Certain medications or low blood levels of

calcium may be associated with magnesium deficiency.

Deficiency symptoms have three categories:

Early symptoms include irritability, anorexia, fatigue, insomnia,

and muscle twitching. Other symptoms include poor memory, apathy,

confusion, and reduced ability to learn.

Moderate deficiency symptoms consist of rapid heartbeat and other

cardiovascular changes.

Severe deficiency symptoms could lead to tingling, numbness, and

a sustained contraction of the muscles, along with hallucinations and

delirium.

Last Reviewed: 6/5/2002 by Donna R. , M.D., M.P.H., Department

of Medicine, Massachusetts General Hospital, Boston, MA.