The Macro Minerals

The Macro Minerals


Calcium is an essential mineral for all organisms as the movement of calcium ions (Ca 2+) into and out of cells functions as a biological signal for most cell processes, particularly neurotransmitter release, muscle contraction and electrical conduction in heart muscle and brain cells. Calcium is also essential to bone mineralisation and enamel production in teeth, and over 90% of body calcium resides in the skeleton.

High levels of calcium are naturally present in dairy foods, milk, yoghurt & cheese, approximating 250-300mg per serve, whilst tinned sardines and salmon contain about 250mg of well absorbed bioavailable calcium. Many vegetarian food sources also have significant calcium content, particularly tofu, seaweeds such as kelp, nuts & seeds, beans, figs, broccoli, kale and quinoa. Dietary calcium absorption is generally somewhat limited, being about 30-35% for dairy foods, about the same for sardines & salmon, and generally less for vegetable sources.

Calcium supplements are also widely available in pharmacies, health food shops and supermarkets. Calcium carbonate is the commonest supplement, is often sold in conjunction with Vit D, and calcium absorption approximates that of dairy foods, as do most other supplements. However, calcium carbonate does require gastric acid production for adequate absorption, and for people with impaired acid production, calcium citrate is a better choice as it does not require gastric acid for absorption.

Calcium insufficiency:
Calcium insufficiency may manifest with the following symptoms and signs:
Irritability, anxiety, agitation, insomnia, poor memory, dizziness, palpitations, numbness, muscle-twitching, muscle cramps, convulsions, mental confusion, osteoporosis, rickets, tooth-decay and loss.

Supplemental dosage:
Require 800 – 1000 mg/day of elemental calcium.  1500mg/day required in pregnancy and breastfeeding.

Rich Natural Sources:
Milk, other dairy foods, sardines & salmon, tofu, seeds (sesame, sunflower), soymilk, almonds, chickpea, carob, yeast, , parsley, broccoli, kale, bone meal, mineral water, dolomite.

Signs of Toxicity:
Anorexia, ataxia, depression, calcium deposits in tissues.
Recent research suggests that calcium intake above 1000mg may promote development of heart disease.


Magnesium is an essential mineral in all living organisms, with 99% of the mineral residing within the tissue cells. In humans, magnesium is a cofactor in over 300 enzyme pathways that regulate a wide and varied range of biochemical reactions involved in protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. Magnesium is also required for energy production, oxidative phosphorylation, and glycolysis. It contributes to the structural development of bone and is required for the synthesis of DNA, RNA, and the antioxidant glutathione. Magnesium also plays a role in the active transport of calcium and potassium ions across cell membranes, a process that is important to nerve impulse conduction, muscle contraction, and normal heart rhythm.

Magnesium is distributed widely in plant and animal foods, particularly in green leafy vegetables such as spinach, nuts & seeds, legumes & whole grains. Most animal foods such as seafood, poultry & lean meat are much lower in magnesium content than plant foods. Insufficient magnesium status may occur due to habitually low vegetable intake or excessive magnesium loss related to disease or medications.

Magnesium deficiency:
Magnesium insufficiency may manifest clinically with the following symptoms and signs:
Irritability, anxiety, agitation, restlessness, hyperactivity, insomnia,
noise intolerance, dizziness, palpitations & heart arrhythmia, high blood pressure,
poor circulation with cold hands and feet, muscle twitching and cramps, muscle soreness and tremors,
headache, anorexia, fatigue and  depression.

As magnesium deficiency worsens, numbness, tingling, muscle contractions and cramps, seizures, personality changes, abnormal heart rhythms, and coronary spasms can occur and severe deficiency can result in signs of hypocalcemia or hypokalemia (low serum calcium or potassium levels, respectively) because mineral homeostasis is disrupted

Supplemental dosage:
Require 300 – 450 mg/day of magnesium.  600 – 800 mg/day of magnesium may be given as a supplement and should always be balanced with potassium and calcium.

Rich Natural Sources:
Whole grains, legumes, milk, soymilk, almonds, cashews, seeds, green vegetables, and seafood.

Signs of Toxicity:
Nausea, diarrhoea, drowsiness, lethargy, sluggishness, bradycardia, low blood pressure, confusion and coma.


Zinc is an essential mineral that is involved in wide range of cellular metabolic processes. It is a catalytic factor for approximately 100 enzymes, and is essential for normal immune function, protein synthesis, wound healing, nuclear & mitochondrial DNA synthesis and maintenance and is vital to cell division, growth and development. Zinc is also required for proper sense of taste and smell.

Zinc is widely distributed in many foods, particularly in oysters, while red meat and poultry also provide substantial levels of zinc and supply the majority of zinc in the normal diet. Significant zinc levels are also found in other food sources such as beans, nuts, shellfish (crab and lobster), whole grains, fortified breakfast cereals, and dairy products, though high phytate levels in grains and legumes and nuts may bind to zinc and reduce bioavailability.

Zinc deficiency:

Zinc deficiency has been associated with the following symptoms and signs:

Acne, anorexia, loss of taste, eczema, glucose intolerance, diabetes, apathy, fatigue, depression, hyperactivity in children, impaired protein synthesis: hair loss, poor wound healing, skin stretch marks, soft or brittle nails, growing pains, recurrent infections, white-spots in nails, growth impairment: shortened stature, delayed sexual maturity, impotence, irregular menstruation.

Supplemental dosage:
10 – 30 mg daily.  NOTE: prolonged high dose use may cause copper and iron deficiency.

Rich Natural Sources:
Oysters, fish (sardines, herring), meat, liver, milk, seeds, wheat germ, onions, mushrooms, yeast, whole grains, nuts, peas, carrots, vegetables.

Signs of Toxicity:
Nausea, vomiting, diarrhoea, drowsiness, increased sweating, alcohol intolerance.  May induce copper and/or iron deficiency.   May induce seizures in people with epilepsy.


Iron is an essential mineral that is widely distributed in foods, as it is a requirement for all life forms, bacterial, plant and animal, due to its ability to easily accept and donate electrons in biochemical processes. In humans, iron is widely contained within protein structures that limit its reactivity and prevent undue free radical genesis. Iron is most commonly bound to heme molecules within tissues, where it contributes to cell redox reactions. Heme iron is vital to haemoglobin synthesis in red blood cells, oxidative phosphorylation and ATP genesis in the Electron Transport Chain. Iron is also an essential component of a variety of enzymes involved in synthesis of monoamine neurotransmitters, carnitine (the mitochondrial shuttle for TCA cycle activity, collagen and nitric oxide. Iron is also essential to the phagocytic activity of the white blood cells, via the enzymes catalyse and myeloperoxidase, which result in bactericidal free radical production.

Iron is generally well absorbed in its heme form from animal foods but non-heme iron is less well-absorbed and requires concomitant consumption of Vit C to enhance absorption. Animal meats and seafood generally have high iron content, and many plant-based foods also contain appreciable amounts of non-heme iron. However, despite the availability of iron in a wide range of foods, iron deficiency may occur due to i) intestinal malabsorption secondary to disease, ii) inadequate dietary intake, as in famine, poverty and those on vegan diets, iii) excess iron loss due to haemorrhage and undue menstrual blood loss.

Iron deficiency:

Iron deficiency has been associated with the following symptoms and signs:

Tiredness, easy fatigue, weakness, impaired memory, poor concentration,
impaired cognitive ability, poor learning, depression, dizziness,
brittle nails, lustreless nails, flattened or spoon-shaped nails, hair loss, difficulty in swallowing
anaemia, shortness of breath, cardiac failure,

Supplemental dosage:
The RDA for iron approximates 15mg in menstruating females and 10mg in other adults.
In iron deficiency supplemental therapy is required, usually as oral iron sulfate or gluconate.

Rich Natural Sources:
Meats, liver and organ meats, eggs, leafy green vegetables.

Signs of Toxicity:
Liver damage, induced vitamin C deficiency, bronzing of skin, anorexia, dizziness, headache, constipation, excessive iron storage can cause cirrhosis, diabetes and accelerate the development of arteriosclerosis, arthritis and Altzheimer’s.


Potassium is the primary positively charged ion (cation) within cells, whilst sodium is the principal cation outside the cells. The potassium concentration is about 30 times higher inside than outside cells, whilst sodium concentrations are about ten times lower inside than outside cells. This concentration difference in potassium and sodium across cell membranes creates an electrical gradient across the membrane, called the membrane potential, which determines the cell’s reactivity to stimuli. The membrane potential is maintained by ion pumps in the cell membrane, especially the sodium/potassium-ATPase pumps, which use energy (ATP) to pump sodium out of the cell in exchange for potassium. With electrochemical stimulation, sodium influx and potassium efflux reduces the electrical potential during cell depolarisation, thereby altering membrane permeability and triggering nerve and muscle cell activity. The Na/K-ATPase pump then reverses the altered sodium & potassium flux during repolarisation, promoting cell membrane stabilisation. Tight control of cell membrane potential is critical for nerve impulse transmission, muscle contraction, and heart function.

Potassium occurs naturally in many foods, particularly leafy green vegetables, vine fruit such as tomatoes, cucumbers, zucchini, eggplant and pumpkin, and root vegetables. It is also moderately abundant in beans and peas, tree fruits such as apples, oranges and bananas, milks and yoghurts and meats.

Inadequate potassium intake or excess loss secondary to diuretic medications can lead to intracellular potassium metabolism, and contribute to high blood pressure, muscle dysfunction, cardiac arrhythmias and brain cell dysfunction.

Potassium deficiency:
The recommended potassium dietary intake approximates 3000mg per day ~ though there is incomplete evidence that this recommended intake is insufficient for optimal potassium health benefits.

Potassium deficiency may manifest clinically with the following signs and symptoms: Associated with Deficiency:
Fatigue, anorexia, constipation, muscle weakness, muscle cramps, palpitations, heart arrhythmias, agitation, nervousness, depression.

Supplemental dosage:
Use salt substitutes or fruit and vegetable juice daily.  Magnesium-Potassium Aspartate supplements are often useful if muscle cramping or cardiac arrhythmias are present.

Rich Natural Sources:
Fruits, vegetables, fruit juices, vegetable soups.

Signs of Toxicity:
High dose potassium therapy, particularly when given intravenously, is quite toxic and can cause slowing of the heartbeat and cardiac asystole. Excess oral dosing may result in depressed appetite, apathy, muscle-fatigue, mental confusion and slurred speech.


Signs and symptoms associated with deficiency:
Lassitude, muscle weakness, hot-weather fatigue, dizziness, low blood pressure, weak thready pulse, anorexia, abdominal cramps, nausea and vomiting, flatulence, headache, impaired memory, confusion, convulsions.

Supplemental dosage:
Generally unnecessary except in cases of adrenal gland insufficiency, severe hypoglycaemia, sunstroke, exercise dehydration, or in cases of extreme perspiration.  Also useful in Chronic Fatigue Syndrome.  NB: in QLD summers,  may need added salt or salt tablets.

Rich Natural Sources:
Table salt, sea salt, rock salt, ham, bacon, cheese, sausages, dried fish, dried seafood, meats, poultry, butter, nuts.

Signs of Toxicity:
Anorexia, irritability, tension, confusion, fluid-retention, high blood pressure, excessive thirst and drinking, frequent urination, renal failure, premenstrual tension symptoms.

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