magnesium - the role, absorption, and uptake in the body
Recommended Daily Intake (RDI):
Woman 19-30yrs 310mg/day; >30yrs 320mg/day
Men 19-30yrs 400mg/day; >30yrs 420mg/day
The majority of magnesium in the body occurs in the bones, muscles, and tissues.
Magnesium has many metabolic and structural functions it is required for the mitochondria to carry out oxidative phosphorylation.
It is involved in both aerobic & anaerobic energy generation plus glycolysis.
Maintenance of bone health & optimal bone growth.
Co-factor for more than 300 enzymes.
Plays a role in regulating potassium fluxes & the metabolism of calcium
Muscle & nervous system function.
Magnesium is absorbed in the intestines by both active and passive processes. Kidneys play a central role in magnesium homeostasis through active reabsorption which is influenced by sodium load and the acid-base balance.
What affects magnesium uptake?
High fibre intakes of >40-50g per day lowers magnesium absorption
High zinc intakes ≥142mg per day reduces absorption
Protein intake <30g per day decreases magnesium absorption.
When Protein intake is exceptionally high renal magnesium excretion increases.
High dietary calcium intakes (~2600mg per day) combined with high sodium intake contributes to a shift to negative magnesium balance.
Depletion of magnesium maybe observed mainly among athletes in endurance type sports.
Deficiency symptoms include muscle weakness, irritability, nausea, and depression.
In females: Sub-optimal intake of magnesium may cause or increase pre-menstrual tension and discomfort.
Excess: large intakes (3-5g) may have a laxative effect.
Individuals with abnormal renal function can be subject to hyper magnesium; symptoms include depression, nausea, vomiting & hypotension.
Magnesium in supplement form should be present with calcium in a 1 to 2 ratio of magnesium to calcium.
food sources include:
Rice Bran - Oat Bran - Wheat Bran – Buckwheat Rye - Pumpkin seeds - Edamame Beans – Dates Kale – Banana – Spirulina – Quinoa - Brown Rice - Brazil Nuts