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Section Links
Magnesium
- magnesium intake
- magnesium functions in the body
- magnesium regulation
- magnesium deficiency
- hypermagnesemia
Magnesium Intake
- dairy products
- soy
- clams and other seafoods
- whole grains and wheat germ
- almonds and other nuts
Magnesium's Functions in the Body
Of the body's magnesium, 54% is in the bone, 45% in the soft tissues and 1% in extracellular fluid.
Magnesium Regulation
All Mg2+ that is not protein-bound is filtered through the kidney's glomerulus. Following filtration, 30% is reabsorbed in the proximal tubule. Another 65% is paracellularly reabsorbed in the thick ascending loop of Henle, controlled by the voltage differential generated by active Na/Cl/K absorption. A further 5% is reabsorbed in the distal tubules. Magnesium handling is directly influenced by sensors which measure plasma magnesium ions.
PTH and calcitonin increase paracellular reabsorption, possibly by influencing tight junction permeability.
Booth loop diuretics and thiazides increase magnesium excretion.
Magnesium Deficiency
- weakness
- convulsions
- neuromuscular irritability
- failure to thrive
Hypermagnesemia
Signs of magnesium toxicity include:
- depressed deep tendon reflexes
- decreased respiratory rate, respiratory failure
- anuria
- hypotonia
- hypotension
- cardiac disturbances
Calcium IV is the antidote.