The important trace elements are iodine, fluoride and zinc, while the common minerals are sodium, potassium, calcium, magnesium phosphate and iron.

• Iodine deficiency causes thyroid enlargement (goitre) and hypothyroidism (with retarded mental development). This is uncommon in South Africa due to iodine being added to table salt. However, it is still seen in mountainous regions where rock salt or non-iodated salt is used.
• Fluoride deficiency is common in some regions of South Africa and results in dental caries. It is prevented by fluoridation of drinking water.
• Zinc deficiency may result in growth failure and an increased risk of infections. Weekly zinc supplements decrease the incidence and severity of both pneumonia and diarrhoea. Zinc fortification of food is an important method of providing adequate amounts of zinc in the diet.
• Calcium and phosphate deficiency may cause rickets and increase the risk of osteoporosis in adult life. It is prevented by including milk in the diet.

Trace element and mineral deficiency is best avoided by taking a well-balanced diet.