Fluoride
Fluoride minimises bone loss and prevents dental caries (1mg of fluoride per litre of drinking water produces a 60-70% reduction in dental caries). Fluoride is also useful in the reduction of the development of osteoporosis as bone containing fluoride is more stable and resistant to degeneration.
Chloride
Chloride deficiency has been seen on children fed formula mixed with chloride free water.  This syndrome is characterized by loss of appetite, failure to thrive, muscle weakness, lethargy and severe hypokalaemic metabolic alkalosis.
Iron
Iron is essential for the production of haemoglobin and myoglobin.  These are essential in oxygen transport.  It is also present in serum transferring and certain enzymes.
Zinc
Zinc plays a role in a number of metabolic acivities such as synthesis and degradation of major metabolites (carbohydrates, lipids, proteins and nucleic acids).  Zinc deficiency has been associated with short stature, hypogonadism and mild anaemia – symptoms include hypogeusia (decreased taste acuity), delayed wound healing, alopecia, diverse forms of skin lesions and zinc responsive night blindness has also been documented.
Potassium
Potassium constitutes 5% of the total mineral content of the body.  It is the major cation of intracellular fluid.  It is involved in the maintenance of normal water balance, osmotic equilibrium and acid-base balance.  Along with calcium it aids in the regulation of neuromuscular activity.  Potassium also promotes cellular growth.  Deficiency of potassium may lead to muscle weakness and mental apathy.  Cardiac failure may also result.
Sodium
Sodium is a major cation for extracellular fluid.  Sodium helps regulate the size of extracellular compartment and the plasma fluid volume.  It is also involved in the conduction of nerve impulses and muscle contraction control.
Magnesium
Magnesium is second to potassium as an intracellular cation.  Magnesium is essential for the production and transfer for protein synthesis, and for contractility of muscle and excitable nerves.  It is also a co-factor in numerous enzyme systems.  Magnesium deficiency results in the loss of appetite, growth failure, ECG changes and neuromuscular changes.
Calcium
Calcium is essential to build and maintain teeth and bones.  It is important for the metabolism of some enzymes.  It is important in the initiation of the blood clotting process.  It is also influential in the transport function of the cell membranes.  It is required in nerve transmission and regulation of the heart beat and tone.  Deficiency leads to rickets, osteomalacia, osteoporosis, scurvy, leg cramps and hypertension.