Magnesium Functions

Magnesium is involved in more than 300 essential metabolic reactions, some of which are discussed below.

Energy production

The metabolism of carbohydrates and fats to produce energy requires numerous magnesium-dependent chemical reactions. Magnesium is required by the adenosine triphosphate (ATP) synthesizing protein in mitochondria. ATP, the molecule that provides energy for almost all metabolic processes, exists primarily as a complex with magnesium (MgATP).

Synthesis of essential molecules

Magnesium is required at a number of steps during the synthesis of nucleic acids (DNA and RNA) and proteins. A number of enzymes participating in the synthesis of carbohydrates and lipids require magnesium for their activity. Glutathione, an important antioxidant, requires magnesium for its synthesis.

Structural roles

Magnesium plays a structural role in bone, cell membranes, and chromosomes.

Ion transport across cell membranes

Magnesium is required for the active transport of ions like potassium and calcium across cell membranes. Through its role in ion transport systems, magnesium affects the conduction of nerve impulses, muscle contraction, and the normal rhythm of the heart.

Cell signaling

Cell signaling requires MgATP for the phosphorylation of proteins and the formation of the cell signaling molecule, cyclic adenosine monophosphate (cAMP). cAMP is involved in many processes, including the secretion of parathyroid hormone (PTH) from the parathyroid glands (see Vitamin D and Calcium for additional discussions of the role of PTH).

Cell migration

Calcium and magnesium levels in the fluid surrounding cells affect the migration of a number of different cell types. Such affects on cell migration may be important in wound healing.

Nutrient Interactions

Zinc: High doses of zinc in supplement form appear to interfere with the absorption of magnesium. A zinc supplement of 142 mg/day in healthy adult males significantly decreased magnesium absorption and magnesium balance (the difference between magnesium intake and magnesium loss).

Fiber: Large increases in the intake of dietary fiber have been found to decrease magnesium utilization in experimental studies. However, the extent to which dietary fiber affects magnesium nutritional status in individuals with a varied diet outside the laboratory is not clear.

Protein: Dietary protein may affect magnesium absorption. One study found that magnesium absorption was lower when protein intake was less than 30 grams/day, and higher protein intakes (93 grams/day vs. 42 grams/day) were associated with improved magnesium absorption in adolescents.

Vitamin D and calcium: The active form of vitamin D (calcitriol) may increase the intestinal absorption of magnesium to a small extent. However, magnesium absorption does not seem to be calcitriol-dependent as is the absorption of calcium and phosphate. High calcium intake has not been found to affect magnesium balance in most studies. Inadequate blood magnesium levels are known to result in low blood calcium levels, resistance to parathyroid hormone (PTH), and resistance to some of the effects of vitamin D.

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