Selenium deficiency

Selenium deficiency when severe may present with arthritic and cardiac-related symptoms. 

Epidemiology

Up to one billion people globally are thought to have some degree of selenium deficiency.

Phenylketonuria (PKU) patients are more likely to experience selenium deficiency as many of the foods containing phenylalanine are important dietary sources of selenium too. In addition hypovitaminosis E is often an associated finding.

Associations

Three conditions have been found to be linked to severe selenium deficiency:

• Keshan disease
• Kashin-Beck disease
• myxoedematous endemic cretinism

Clinical presentation

• psychiatric symptoms: low mood, anxiety, delirium
• reduced male fertility
• growth impairment in children
• severe deficiency:
  • cardiac dysfunction
  • arthropathy

Pathology

Elemental selenium is vital for the functioning of ~25 selenoproteins in the human body. Three of these are thyroid deiodinases (D1, D2 and D3), which have a key metabolic role in the thyroid, and are also important in normal functioning of the central nervous system, brown fat and the skeletal musculature. Several glutathione peroxidases, which are part of the oxidative defence of the body, are also selenoproteins. The normal functioning of the male reproductive system, including testosterone production, also relies on adequate dietary selenium.

Treatment and prognosis

Selenium supplementation is the cornerstone of successful treatment, with the objective of 90 μg per day in the adult patient ¹.