Magnesium

Magnesium is a vital mineral involved in more than 300 enzymatic reactions. What is a nutrient? Nutrients are substances we must eat for good health.

Health Claims

A mineral essential in a wide array of biological processes, magnesium may contribute to the prevention and treatment of many medical disorders.

What is It?

Magnesium is an alkaline earth metal. An adult body possesses about 25 grams of magnesium. About half resides in bone, and a large percentage is also found inside muscle cells. Only one per cent is found in blood.

How Does it Work?

Virtually all chemical processes in the body require enzymatic reactions to assist in normal physiology. Magnesium is a critical co-factor in more than 300 of these reactions. In particular, it is necessary in the manufacture of proteins, production of cellular energy, muscle contraction, blood vessel tone, cellular communications and nerve conduction. Additionally, magnesium is an essential component in the maintenance of healthy bones.

What Evidence Supports its Use?

We could easily devote hundreds of pages to discussing research on the value of magnesium. Studies indicate that magnesium may contribute to the prevention and treatment of many disorders, including, but not limited to:

• cardiovascular disease
• hypertension
• diabetes
• epilepsy
• fatigue
• migraine headaches
• premenstrual syndrome
• attention deficit hyperactivity disorder
• osteoporosis
• muscle cramps
• anxiety
• asthma

How Should I Take It?

Dietary intake of magnesium has declined dramatically over the last century, mostly a result of food processing and food choices. Today's refined foods have very little magnesium; white bread has half the magnesium of whole wheat bread. Meats, milk and foods high in simple starches such as white flour and white rice do not contain significant magnesium. However, dark green vegetables, nuts, legumes and whole grains are rich sources of magnesium. When you eat, think green, as magnesium is present in the green pigment (chlorophyll) of plants.

There are different types of magnesium supplements available: magnesium oxide, gluconate, sulphate, chloride, aspartate, malate and citrate forms. Generally, those forms with the lowest intestinal solubility (oxide, gluconate and sulphate) are not absorbed as well. Magnesium citrate may emerge as the supplement of choice, as a recent study in the American Journal of Cardiology showed significant increases in magnesium levels after daily administration of 365 mg magnesium citrate.

The recommended dietary allowance for magnesium is 400 mg for adult males and 310 mg for females. However, based on results of large dietary surveys, it is clear that most North Americans should consider increasing dietary intake and/or supplementation. Nutritionally oriented doctors often recommend up to 400 to 600 mg of supplemental magnesium in divided doses. However, the higher the dose, the less absorption takes place. Research indicates that only 12 percent of a 1,000 mg dose will be absorbed, compared to 70 percent of a 30 mg dose.

Caveats

Magnesium is a particularly safe mineral. Toxicity reports are rare. Those with impaired kidney function should see a doctor before supplementing. Doses higher than 800 mg can often cause loose stool and diarrhea.

The Bottom Line

Maximize your daily magnesium intake through dietary sources, particularly green foods. Supple-mentation may be useful for many North Americans. See your health-care provider if you're considering supplementing with magnesium to treat a medical condition.

Your body contains 25 grams of magnesium:

50% bones, 49% muscle cells, and 1% blood.