Magnesium

General Info

Absorbtion

Magnesium is absorbed primarily from the middle and lowest divisions of the small intestine per two methods. One is a carrier-mediated process that operates when magnesium levels are low. The other is a simple diffusion process that occurs when magnesium levels are high.

Dietary Origins

The magnesium content in foods varies widely, as does the soil content of magnesium. Good food sources include cereal grains, dark green leafy vegetables, legumes, and nuts. Food processing is a major cause of magnesium depletion. Up to 85 percent of magnesium is lost when whole wheat is refined to produce white flour. Poor food choices, alcohol abuse, excess calcium intake, intestinal malabsorption (mal-əb-ˈsȯrp-shən), liver and kidney disease, and diabetes can also cause deficiencies.

Overview

Magnesium is a cofactor in over 300 enzymatic reactions in the body. It is essential for the transmission of nerve impulses, detoxification reactions, and for the formation of healthy bones and teeth, muscular activity, and temperature regulation. It is involved in energy production and the synthesis of DNA and RNA. The U.S. Department of Agriculture states that approximately 75 percent of Americans do not ingest the recommended dietary allowance of magnesium. Magnesium influences many of the activities associated with a wide variety of cardiac medications. For example, magnesium inhibits platelet aggregation, thins the blood, blocks calcium uptake, and relaxes blood vessels. Magnesium also oxygenates the blood of the heart muscle by improving cardiac contractility.

Toxicities & Precautions

General

The kidneys eliminate excess magnesium preventing toxicity.

Health Conditions

Individuals with kidney disease should consult with their physician before using a magnesium dietary supplement.

Side Effects

Excess ingestion of inorganic magnesium salts can cause diarrhea.

Functions in the Body

Blood Pressure:

Helps to lower elevated blood pressure. However, the effect is usually only moderate, and thus magnesium should not be viewed as a primary treatment for hypertension.

Bone:

Involved in calcium metabolism, the integrity of skeletal bone-crystal formation, and the synthesis of vitamin D.

Cardiovascular Function:

Magnesium influences multiple aspects of cardiovascular health. It blocks calcium uptake, decreases platelet stickiness, helps thin the blood, and relaxes blood vessels.

Heart Disease:

Adequate magnesium intake reduces the risk of cardiovascular disease and increases the survival rate following a heart attack. If intravenous magnesium is given during the early stages of a heart attack, it results in a 70 percent decline in deaths within one month following the event.

Metabolism:

Required for the metabolism of carbohydrates, proteins and fats, as well as activity related to calcium, phosphorus, and vitamin C. It is vital for the health of nervous and muscular tissues everywhere in the body.

Teeth:

Magnesium helps to bind calcium to tooth enamel, creating a barrier to tooth decay.

Symptoms & Causes of Deficiency

Although clinical deficiency is rare in the U.S., marginal deficiency appears to be widespread it has been shown that approximately 75 percent of Americans ingest less than the recommended daily allowance. Deficiency symptoms include: anxiety, confusion, depression, fatigue, fear, gastrointestinal disorders, high blood pressure, insomnia, irritability, kidney stones, loss of appetite, muscle cramps, nervousness, osteoporosis, restlessness, and weakness. It is now known that many heart attacks occur in people with healthy hearts. Magnesium deficiency increases calcium/magnesium ratio, which can cause a cardiac muscle spasm resulting in a heart attack, and death. Magnesium is important for prevention of cardiovascular disease. Magnesium deficiency is associated with increased incidence of atherosclerosis, heart attacks, hypertension, and stroke. Low levels of magnesium can cause stiffness in the blood vessels throughout the body, which elevates blood pressure and can cause a contraction or spasm in the heart muscle, which can result in sudden death.