Minerals - Magnesium (Mg)

Question 1

Magnesium (Mg)

Answer 1

• Magnesium (Mg) Is the third? most common cation found in the body, after potassium (K).
• The body contains approximately 25 g of Mg (with about 60% in bone; 39% in cells and muscle; 1% in serum/extracellular fluid.
• Mg serves many body functions, and is a cofactor in over 300 enzymatic reactions
• Haemoglobin and chlorophyll are almost identical in their structure, with haemoglobin having iron at its core, and chlorophyll (the green plant pigment), magnesium at its core

Question 2

Food sources

Answer 2

Magnesium is found mostly in plants (especially seeds, nuts, whole grains, legumes and dark green leafy vegetables).
Key food sources / Per 100 g:
Green leaves; e.g. swish chard, spinach / 86 mg
Nuts and seeds; e.g. pumpkin seeds, flax / 535 mg
Beans; e.g. soy beans, haricot, Pinto / 86 mg
Whole grains; e.g. amaranth, buckwheat / 266 mg
Cacao powder / 599 mg
Beef steak / 19 mg

Question 3

Functions: Energy production

Answer 3

Functions: Energy production
* Needed to convert ADP to ATP
* Essential for glucose metabolism and insulin sensitivity (Mg is a cofactor involved in the modulation of glucose transport– it is needed for the activity of tyrosine kinase)
Therapeutic uses:
* Fatigue
* Insulin resistance – diabetes, PCOS, atherosclerosis
* Supporting growth
Tyrosine = an amino acid, kin- = ‘kinesis’ (to move), -ase = enzyme

Question 4

Functions: Cell signalling

Answer 4

Functions: Cell signalling
* Ion transport across cell membranes, I.e. for K and Ca ions
* Conduction of nerve impulses
* Mg is used in the phosphorylation of proteins (important for DNA repair, as well as metabolism and cell signalling pathways)
Therapeutic uses:
* Migraines
* Heart arrhythmias
* Hypertension
* Bipolar disorder
* Mood disorders
* PMS (especially with B6)

Question 5

Functions: Blood clotting

Answer 5

Functions: Blood clotting
* Mg and Ca Work together: Ca Promotes Clotting, Mg Inhibits it
Therapeutic uses:
* Atherosclerosis
* Angina
* Strokes

Question 6

Functions: Structural

Answer 6

Functions: Structural
* Mg Needed in forming decay-resistant tooth enamel
* A key component of bone matrix
* Stabilises cell membranes
Therapeutic uses:
* Osteoporosis
* Osteomalacia, Ricketts
* Supports tooth enamel

Question 7

Functions: Muscle relaxation

Answer 7

Functions: Muscle relaxation
* Mg (and ATP) Are required to break the actin–myosin bond
* Vasodilator (Anti-hypertensive)
Therapeutic uses:
* Muscle pain/cramps
* Fibromyalgia
* Constipation

Question 8

Functions: Sleep and calming

Answer 8

Functions: Sleep and calming
* Mg Is used as a cofactor for GABA synthesis and in the serotonin melatonin pathway
Therapeutic uses:
* Insomnia
* Stress/anxiety

Question 9

Absorption and excretion

Answer 9

• In healthy adults, 30-50% of dietary magnesium is absorbed, mostly in the distal small intestine (ileum)
• Phosphate (especially from high phytate containing foods) and Ca may be inhibitors of Mg absorption, whilst protein and fructose may enhance Mg absorption
• Mg is excreted urine, faeces and, to a lesser extent, during intensive exercise and sweating
• Mg homoeostasis is regulated primarily by the kidneys
• 99% of our bodies magnesium resides inside our cells. Therefore, serum Mg levels do not accurately reflect Mg status

Question 10

Supplementation/salt baths

Answer 10

• When using magnesium supplements, Mg Glycinate, citrate and malate are favoured over Mg oxide due to its low bioavailability
• Different formulations may have different applications; e.g. Mg citrate can be more effective for constipation
• Epson salt baths (Mg sulphate) are an effective way of administering Mg (with a therapeutic dose of 500 g - 1 kg per bath)
• The ‘tolerable upper limit’ (TUL) for Mg supplementation is 400 mg
• Toxicity is generally not a concern but excessive intakes from supplements can lead to diarrhoea, as only so much can be absorbed at once
• Caution using high-dose Mg for someone with hypotension

Question 11

Deficiency and insufficiency causes

Answer 11

Mg Deficiency is a rare, but insufficiency is extremely common:
* Common causes of Mg insufficiency include;
o Poor nutrition (high in processed foods, low in dark green vegetables, legumes, nuts and seeds)
o Chronic stress increases (increases Mg excretion)
o Alcoholism
o Other malabsorption conditions

Question 12

Symptoms of insufficiency

Answer 12

• Fatigue, Insomnia
• Anxiety, depression, Irritability, panic attacks
• Muscle cramps/ spasms/ twitches
• Headaches (e.g. tension-type and migraines)
• Palpitations

Question 13

Magnesium functions and therapeutic uses

Answer 13

Energy production
Cell signalling
Blood clotting
Structural
Muscle relaxation
Sleep and calming