Magnesium is involved in the formation of bone, helps maintain normal muscle and nerve function, keeps heart rhythms normal and participates in more than 300 biochemical reactions in the body. Magnesium also helps the body produce energy and make proteins.
Green leafy vegetables, nuts, legumes and whole grains are rich food sources of magnesium. Refined foods generally contain low levels of magnesium. Water can be a source of magnesium—“hard” water contains more than “soft” water.
Magnesium deficiency is rare in healthy individuals. Magnesium depletion can occur in individuals with diabetes, osteoporosis, chronic alcoholism and malabsorption problems. Severe magnesium depletion can result in numbness, tingling, muscle contractions and cramps, seizures, abnormal heart rhythms, and low blood levels of calcium and potassium (which magnesium regulates at the cellular level).
Naturally occurring magnesium in food and water has not been shown to cause adverse effects. However, too much magnesium from nonfood sources, such as magnesium salts, has been shown to cause mild to severe toxicity. Symptoms can range from diarrhea, nausea and abdominal cramps to difficulty breathing, extremely low blood pressure and irregular heartbeat.
The following table lists the recommended intake for healthy people based on current scientific information.