Minerals are inorganic molecules, derived from soil and rock, that are required by humans for correct metabolic function. Minerals constitute just under 5% of the total body weight in humans, and of these the macrominerals are quantitatively the largest contributors. The classification of macromineral is not fixed and varies slightly with differing classification systems. Generally, macrominerals are those which comprise over 5 grams in a typical 60 kg human (0.001%) or those required in intakes over 100 mg per day. However, in general intakes of the macrominerals are in gram amounts per day. The macrominerals in human nutrition are sodium, sulphur, potassium, chloride, calcium, magnesium and phosphorus. Chloride, potassium and sodium are important electrolytes and help maintain osmotic potential. Calcium, magnesium and phosphorus, are required for the correct structural integrity of the skeleton. Sulphur is unusual in that it is not used by humans in isolation, but is generally present associated with the amino acids taurine, methionine and cysteine.
In some cases the essential macrominerals are required in gram amounts per day. This makes it difficult for adequate intakes to be achieved easily from foods. Consuming the Western diet makes it particularly likely that macromineral deficiencies with develop in magnesium, potassium and calcium, because these minerals are absent from most processed foods. However, in contrast the Western diet oversupplies chloride and sodium, because of the ubiquitous addition of table salt to the same processed foods. This creates a situation where mineral imbalances can develop in those consuming the Western diet. This is problematic because the macrominerals are used as intracellular and extracellular ions. Imbalances in their intake can cause plasma membrane charge differentials to become stressed and this can lead to nervous system dysfunction. Over the long term this can develop into cramps, twitches and in serious cases myocardial infarction. Generally the macrominerals are safe and supplementation with minerals likely to be deficient from the diet can redress any imbalances with little chance of toxicity.