Selenium deficiency
Encyclopedia
Selenium
deficiency is relatively rare in healthy well-nourished individuals. Few cases have been reported.
function, those undergoing total parenteral nutrition
, those who have had gastrointestinal bypass surgery, and also on advanced aged people (over 90).
Alternatively, people dependent on food grown from selenium-deficient soil are also at risk.
for adults is 55 µg/day. In the UK it is 75 µg/day for adult males and 60 µg/day for adult females. 55 µg/day recommendation is based on full expression of plasma glutathione peroxidase
. Selenoprotein
P is a better indicator of selenium nutritional status, and full expression of it would require more than 66 µg/day.
, which is potentially fatal. Selenium deficiency also contributes (along with iodine deficiency
) to Kashin-Beck disease
. The primary symptom of Keshan disease is myocardial necrosis
, leading to weakening of the heart. Kashin-Beck disease results in atrophy
, degeneration and necrosis
of cartilage
tissue. Keshan disease also makes the body more susceptible to illness caused by other nutritional, biochemical, or infectious diseases.
Selenium is also necessary for the conversion of the thyroid hormone thyroxine
(T4) into its more active counterpart, triiodothyronine
, and as such a deficiency can cause symptoms of hypothyroidism
, including extreme fatigue, mental slowing, goitre
, cretinism
and recurrent miscarriage
.
Selenium
Selenium is a chemical element with atomic number 34, chemical symbol Se, and an atomic mass of 78.96. It is a nonmetal, whose properties are intermediate between those of adjacent chalcogen elements sulfur and tellurium...
deficiency is relatively rare in healthy well-nourished individuals. Few cases have been reported.
Causes
It can occur in patients with severely compromised intestinalIntestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
function, those undergoing total parenteral nutrition
Total parenteral nutrition
Parenteral nutrition is feeding a person intravenously, bypassing the usual process of eating and digestion. The person receives nutritional formulae that contain nutrients such as glucose, amino acids, lipids and added vitamins and dietary minerals...
, those who have had gastrointestinal bypass surgery, and also on advanced aged people (over 90).
Alternatively, people dependent on food grown from selenium-deficient soil are also at risk.
Reference ranges
In the USA, the Dietary Reference IntakeDietary Reference Intake
The Dietary Reference Intake is a system of nutrition recommendations from the Institute of Medicine of the U.S. National Academy of Sciences. The DRI system is used by both the United States and Canada and is intended for the general public and health professionals...
for adults is 55 µg/day. In the UK it is 75 µg/day for adult males and 60 µg/day for adult females. 55 µg/day recommendation is based on full expression of plasma glutathione peroxidase
Glutathione peroxidase
Glutathione peroxidase is the general name of an enzyme family with peroxidase activity whose main biological role is to protect the organism from oxidative damage...
. Selenoprotein
Selenoprotein
In molecular biology a selenoprotein is any protein that includes a selenocysteine amino acid residue. Among functionally characterized selenoproteins are five glutathione peroxidases and three thioredoxin reductases, which both contain only one Se-Cys. Selenoprotein P is the most common...
P is a better indicator of selenium nutritional status, and full expression of it would require more than 66 µg/day.
Presentation
Selenium deficiency in combination with Coxsackievirus infection can lead to Keshan diseaseKeshan disease
Keshan disease is a congestive cardiomyopathy caused by a combination of dietary deficiency of selenium and the presence of a mutated strain of Coxsackievirus, named after Keshan County of Heilongjiang province, Northeast China, where symptoms were first noted. These symptoms were later found...
, which is potentially fatal. Selenium deficiency also contributes (along with iodine deficiency
Iodine deficiency
Iodine is an essential trace element; the thyroid hormones thyroxine and triiodotyronine contain iodine. In areas where there is little iodine in the diet—typically remote inlandareas where no marine foods are eaten—iodine deficiency gives rise to...
) to Kashin-Beck disease
Kashin-Beck Disease
Kashin-Beck disease is a chronic, endemic osteochondropathy , which is mainly distributed from northeastern to southwestern China involving 15 provinces . Tibet currently has the highest incidence rate of KBD in China . Southeast Siberia and North Korea are also other affected areas...
. The primary symptom of Keshan disease is myocardial necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
, leading to weakening of the heart. Kashin-Beck disease results in atrophy
Atrophy
Atrophy is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations , poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, disuse or lack of exercise or disease intrinsic to the tissue itself...
, degeneration and necrosis
Necrosis
Necrosis is the premature death of cells in living tissue. Necrosis is caused by factors external to the cell or tissue, such as infection, toxins, or trauma. This is in contrast to apoptosis, which is a naturally occurring cause of cellular death...
of cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
tissue. Keshan disease also makes the body more susceptible to illness caused by other nutritional, biochemical, or infectious diseases.
Selenium is also necessary for the conversion of the thyroid hormone thyroxine
Thyroxine
Thyroxine, or 3,5,3',5'-tetraiodothyronine , a form of thyroid hormones, is the major hormone secreted by the follicular cells of the thyroid gland.-Synthesis and regulation:...
(T4) into its more active counterpart, triiodothyronine
Triiodothyronine
Triiodothyronine, C15H12I3NO4, also known as T3, is a thyroid hormone. It affects almost every physiological process in the body, including growth and development, metabolism, body temperature, and heart rate....
, and as such a deficiency can cause symptoms of hypothyroidism
Hypothyroidism
Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone.Iodine deficiency is the most common cause of hypothyroidism worldwide but it can be caused by other causes such as several conditions of the thyroid gland or, less commonly, the pituitary gland or...
, including extreme fatigue, mental slowing, goitre
Goitre
A goitre or goiter , is a swelling in the thyroid gland, which can lead to a swelling of the neck or larynx...
, cretinism
Cretinism
Cretinism is a condition of severely stunted physical and mental growth due to untreated congenital deficiency of thyroid hormones usually due to maternal hypothyroidism.-Etymology and use of cretin:...
and recurrent miscarriage
Habitual abortion
Habitual abortion, recurrent miscarriage or recurrent pregnancy loss is the occurrence of three or more pregnancies that end in miscarriage of the fetus, usually before 20 weeks of gestation...
.