Formula Medical Group
Apple Valley, CA

James Krider, MD

   any search words
   all search words


What is magnesium?

Magnesium is one of the essential dietary minerals, an inorganic (nonplant) substance that comes from the earth. The body requires only small amounts of magnesium; even so, magnesium is included among the macrominerals (along with calcium, sodium, phosphorus, chloride, and potassium) because it is required in larger amounts than the trace, or microminerals, which are needed only in minute amounts.

Why is magnesium important to nutrition?

Magnesium plays a crucial role in several vital processes. For example, it is needed to build strong bones and to manufacture essential amino acids. It also activates some of the enzymes that transfer and release energy in the muscles. Other vital functions include the conduction

Good sources of magnesium

  • Salad greens.
  • Nuts.
  • Soybeans and tofu.
  • Seeds.
  • Whole grains, such as those found in whole-grain breads and cereals.
  • Green, leafy vegetables, such as spinach, broccoli, and cabbage.

of nerve impulses to the muscles and adjustment to different environmental temperatures, especially cold.

How much magnesium do I need?

The Recommended Dietary Allowances (RDAs) for magnesium (in milligrams per day) are as follows:

  • 40 for infants.
  • 60 to 170 for children ages 1 to 10.
  • 270 for males ages 11 to 14.
  • 400 for males ages 15 to 18.
  • 350 for males over the age of 19.
  • 280 for females over the age of 11.
  • 320 to 355 during pregnancy and lactation.

Salad greens and fresh green, leafy vegetables are high in magnesium

Salad greens and fresh green, leafy vegetables are high in magnesium

The best way to consume the daily requirement of magnesium is by eating a varied diet that includes green vegetables and whole grains. A balanced diet provides all the magnesium that is normally needed for good health without distorting its proper balance with other essential minerals.

What happens if I don't get enough magnesium?
In the United States, magnesium deficiency is rare, occurring mostly among people with severe kidney disease or in alcoholics. Use of diuretics (water pills) also can deplete the body's stores of magnesium. Signs of magnesium deficiency include:

  • Loss of appetite.
  • Leg cramps.
  • Muscle tremors and twitching.
  • Irregular heartbeats.
  • Weakness and lethargy.
  • Personality changes.
  • Nausea and vomiting.
  • Seizures, especially in children.
  • Difficulty in adjusting to changes in temperature, especially when going from warm to cold.
  • A variety of complex metabolic disturbances.

What happens if I get too much magnesium?
Excessive consumption of magnesium can lead to a serious condition called hypermagnesia. It would be difficult, if not impossible, to develop hypermagnesia from diet alone, but taking high-dose supplements of the mineral can be dangerous. Overloading the body with magnesium

can affect the way nerve impulses are transmitted to the muscles. This results in an inability to properly contract and relax muscle fibers. In severe cases, low blood pressure and even cardiac arrest may occur. Kidney patients are at particular risk of serious complications from excessive magnesium.

Should I take magnesium supplements?
No. A proper diet provides all the magnesium a person needs. Even pregnant women and nursing mothers can easily increase the amount of magnesium in their daily diets without supplements.

Recent studies indicate magnesium supplements given during a heart attack may lower mortality. However, this use is considered experimental.

Advice about magnesium

  • It is almost always unnecessary and undesirable to take a magnesium supplement.
  • During pregnancy or breast­feeding, a woman should consult her doctor about adapting the diet to increase her daily intake of magnesium. Depending upon her normal dietary habits, she may or may not need to add foods that are good sources of magnesium.
  • Athletes who engage in regular, vigorous workouts may also need to increase magnesium in their diets. A doctor who specializes in sports medicine or a registered dietitian can recommend dietary changes.
  • In general, fresh foods are a better source of magnesium and other important nutrients than processed foods. A varied diet rather than one made up of only a few favorite foods, is more likely to provide adequate magnesium, as well as other essential nutrients.
  • A person who has been diagnosed as having kidney disease must be especially careful to avoid consuming too much magnesium. Do not take vitamin or mineral pills that contain magnesium, and ask the doctor about cutting back on dietary sources of it.

Foods made with whole grains, nuts, and seeds are also good sources of magnesium.

Foods made with whole grains, nuts, and seeds are also good sources of magnesium.
This article was last reviewed December 12, 2005 by Dr. James Krider.
Reproduced in part with permission of Home Health Handbook.

Printer Friendly Page

Return to Nutrition