Selenium is important for the function of glutathione peroxidase, an enzyme that helps protect cells from lipid peroxides and free radicals. Selenium deficiency usually results from low dietary intake. The onset can be subtle and diagnosis usually requires recognition of a disease-associated risk state.


Biochemical role of selenium:

(1) glutathione peroxidase

(2) enzyme for converting T4 to T3 (type I iodothyronine 5'-deiodinase)


Clinical settings for selenium deficiency:

(1) deficiency in soil

(2) total parenteral nutrition without supplementation

(3) inflammatory bowel disease (Crohn's disease)

(4) chronic alcoholics

(5) HIV-positive patients

(6) protein malnutrition

(7) premature infants

(8) phenylketonuria and maple syrup urine disease (poor protein intake)

(9) dialysis


Clinical findings:

(1) cardiomyopathy (Keshan disease in China, peripartum cardiomyopathy in sub-Saharan Africa)

(2) muscle weakness

(3) osteoarthritis (Kashin-Beck disease)


It also has been implicated as contributory in endemic cretinism and Balkan nephropathy.


The presence of a clinical finding in a patient with an appropriate clinical setting should prompt measurement of a patient's selenium levels.


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