Trace Elements

Key points

• • Trace elements are needed in tiny amounts and many work as cofactors that help enzymes function, so a lack of one can disable the reactions that depend on it.
• • Iron is central to haemoglobin and many enzymes, and its lack causes a microcytic anaemia (iron is covered in more detail as its own topic).
• • Iodine is needed to make thyroid hormones, so a lack causes goitre and, in a developing child, impaired growth and brain development.
• • Copper is a cofactor for several enzymes; its build-up in Wilson disease damages the liver and brain, while a rare inherited lack causes Menkes disease.
• • Zinc is needed for many enzymes and for wound healing and immunity, and a deficiency causes a skin and gut disorder called acrodermatitis enteropathica.
• • Selenium is part of an antioxidant enzyme, and fluoride strengthens teeth in small amounts but mottles them in excess.