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__NOTOC__
{{Infobox medical condition
{{Infobox Disease
| Name           = Selenium deficiency
| Name        = Rickets
| Image          = Se-TableImage.png
| ICD10       = {{ICD10|E|55| |e|50}}
| Caption       = [[Selenium]]
| ICD9       = {{ICD9|268}}
| DiseasesDB    = 11941
| Image      Rickets USNLM.gif
| ICD10         = {{ICD10|E|59||e|50}}
| Caption    A family with rickets. Paris, 1900.
| ICD9           = {{ICD9|269.3}}
| DiseasesDB    = 9351
| ICDO          =
| MedlinePlus    = 000344
  | OMIM          =
| MeshName      = Rickets
  | MedlinePlus    =
| MeshNumber    = D012279
| eMedicineSubj  =
| eMedicineTopic =
| MeshID        =
}}
}}
{{SI}}
'''[[Selenium]] deficiency''' is relatively rare in healthy well-nourished individuals. Few cases in humans have been reported.
{{CMG}}


==Overview==
==Causes==
It can occur in patients with severely compromised [[intestine|intestinal]] function, those undergoing [[total parenteral nutrition]], those who have had gastrointestinal bypass surgery, and also in persons of advanced age (i.e., over 90).<ref>{{cite journal |first1=Giovanni |last1=Ravaglia |first2=Paola |last2=Forti |first3=Fabiola |last3=Maioli |first4=Luciana |last4=Bastagli |first5=Andrea |last5=Facchini |first6=Erminia |last6=Mariani |first7=Lucia |last7=Savarino |first8=Simonetta |last8=Sassi |first9=Domenico |last10=Lenaz |first10=G |last9=Cucinotta |title=Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged ≥90 y |journal=American Journal of Clinical Nutrition |pmid=10648276 |url=http://www.ajcn.org/cgi/pmidlookup?view=long&pmid=10648276 |year=2000 |volume=71 |issue=2 |pages=590–8|display-authors=8 }}</ref>


'''Rickets''' is a softening of the bones in children potentially leading to fractures and deformity.  Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a [[vitamin D]] deficiency, but lack of adequate [[calcium]] in the diet may also lead to rickets. Although it can occur in adults, the majority of cases occur in children suffering from severe [[malnutrition]], usually resulting from [[famine]] or [[starvation]] during the early stages of childhood.
People dependent on food grown from selenium-deficient soil may be at risk for deficiency.
[[Osteomalacia]] is the term used to describe a similar condition occurring in adults, generally due to a deficiency of vitamin D.
The origin of the word "rickets" is unknown.  The Greek derived word "rachitis" (meaning "inflammation of the spine") was later adopted as the scientific term for rickets, due chiefly to the words' similarity in sound.


==Epidemiology==
For some time now, it has been reported in medical literature that a pattern of side-effects possibly associated with [[cholesterol]]-lowering drugs (e.g., [[statins]]) may resemble the pathology of selenium deficiency.<ref>{{cite journal |pmid=15031036 |year=2004 |last1=Moosmann |first1=B |last2=Behl |first2=C |title=Selenoprotein synthesis and side-effects of statins |volume=363 |issue=9412 |pages=892–4 |doi=10.1016/S0140-6736(04)15739-5 |journal=Lancet}}</ref><ref>{{cite journal |pmid=15542379 |year=2004 |last1=Moosmann |first1=B |last2=Behl |first2=C |title=Selenoproteins, cholesterol-lowering drugs, and the consequences: Revisiting of the mevalonate pathway |volume=14 |issue=7 |pages=273–81 |doi=10.1016/j.tcm.2004.08.003 |journal=Trends in Cardiovascular Medicine}}</ref>
[[Image:Rickets wrist.jpg|thumb|left|"rachitis" The "wrist widening" of rickets]]
Those at higher risk for developing rickets include:
*Breast-fed infants whose mothers are not exposed to sunlight
*Breast-fed infants who are not exposed to sunlight
*Individuals not consuming fortified milk, such as those who are [[lactose intolerant]]


Individuals with red hair  have a decreased risk for rickets due to their greater production of vitamin D in sunlight.<ref>[http://www.derm.med.ed.ac.uk/06_teaching/redhairgen.htm Red hair and genetics]</ref>
==Reference ranges==
In the USA, the [[Dietary Reference Intake]] for adults is 55&nbsp;µg/day. In the UK it is 75&nbsp;µg/day for adult males and 60&nbsp;µg/day for adult females. 55&nbsp;µg/day recommendation is based on full expression of plasma [[glutathione peroxidase]]. [[Selenoprotein P]]<ref name="pmid17508906">{{cite journal |doi=10.1089/ars.2007.1528 |title=From Selenium to Selenoproteins: Synthesis, Identity, and Their Role in Human Health |year=2007 |last1=Papp |first1=Laura Vanda |last2=Lu |first2=Jun |last3=Holmgren |first3=Arne |last4=Khanna |first4=Kum Kum |journal=Antioxidants & Redox Signaling |volume=9 |issue=7 |pages=775–806 |pmid=17508906}}</ref> is a better indicator of selenium nutritional status, and full expression of it would require more than 66&nbsp;µg/day.<ref name="pmid15817859">{{cite journal |pmid=15817859 |year=2005 |last1=Xia |first1=Y |last2=Hill |first2=KE |last3=Byrne |first3=DW |last4=Xu |first4=J |last5=Burk |first5=RF |title=Effectiveness of selenium supplements in a low-selenium area of China |volume=81 |issue=4 |pages=829–34 |journal=The American Journal of Clinical Nutrition}}</ref>


==Etiology==
==Signs and symptoms==
Vitamin D is required for proper calcium absorption from the gut. In the absence of vitamin D, dietary calcium is not properly absorbed, resulting in [[hypocalcemia]], leading to skeletal and dental deformities and [[neuromuscular]] symptoms, e.g. hyperexcitability.
Selenium deficiency in combination with [[Coxsackievirus]] infection can lead to [[Keshan disease]], which is potentially fatal. Selenium deficiency also contributes (along with [[iodine deficiency]]) to [[Kashin-Beck disease]].<ref name=":0">{{Cite web|url = http://www.atsdr.cdc.gov/toxprofiles/tp92-c3.pdf|title = Toxicological Profile for Selenium|date = September 2003|accessdate = 7 Sep 2015|website = Agency for Toxic Substances and Disease Registry|publisher = U.S. Department of Health and Human Services|last = |first = }}</ref> The primary symptom of Keshan disease is [[myocardium|myocardial]] [[necrosis]], leading to weakening of the heart. [[Kashin-Beck disease]] results in [[atrophy]], degeneration and [[necrosis]] of [[cartilage]] tissue.<ref>{{cite journal |doi=10.1056/NEJM199810153391604 |title=Kashin–Beck Osteoarthropathy in Rural Tibet in Relation to Selenium and Iodine Status |year=1998 |last1=Moreno-Reyes |first1=Rodrigo |last2=Suetens |first2=Carl |last3=Mathieu |first3=Françoise |last4=Begaux |first4=Françoise |last5=Zhu |first5=Dun |last6=Rivera |first6=Maria T. |last7=Boelaert |first7=Marleen |last8=Nève |first8=Jean |last9=Perlmutter |first9=Noémi |last10=Vanderpas |first10=Jean |journal=New England Journal of Medicine |volume=339 |issue=16 |pages=1112–20 |pmid=9770558|display-authors=8 }}</ref>  Keshan disease also makes the body more susceptible to illness caused by other nutritional, biochemical, or infectious diseases.


A rare [[X-linked dominant]] form exists called [[X-linked hypophosphatemia|Vitamin D resistant rickets]].
Selenium is also necessary for the conversion of the thyroid hormone [[thyroxine]] (T4) into its more active counterpart, [[triiodothyronine]],<ref name=":0" /> and as such a deficiency can cause symptoms of [[hypothyroidism]], including extreme [[Fatigue (medicine)|fatigue]], mental slowing, [[goiter]], [[cretinism]], and [[habitual abortion|recurrent miscarriage]].<ref>{{cite web|title = Selenium: Dietary Supplement Fact Sheet|url = http://ods.od.nih.gov/factsheets/Selenium-HealthProfessional/|publisher = National Institutes of Health|accessdate = July 4, 2013}}</ref>


==Presentation==
==Epidemiology and prevention==
[[Image:XrayRicketsLegssmall.jpg|thumb|left|[[Radiograph]] of a two-year old rickets sufferer, with a marked [[genu varum]] (bowing of the [[femur]]s) and decreased bone [[opacity]], suggesting poor [[bone mineralization]].|right]]
These diseases are most common in certain parts of China where the intake is low<ref name="urlSelenium: Mineral Deficiency and Toxicity: Merck Manual Professional">{{cite web |url=http://www.merck.com/mmpe/sec01/ch005/ch005i.html |title=Selenium: Mineral Deficiency and Toxicity: Merck Manual Professional |work= |accessdate=2008-11-29}}</ref> because the soil is extremely deficient in selenium. Studies in [[Jiangsu Province]] of China have indicated a reduction in the prevalence of these diseases by taking selenium supplements.<ref>{{Cite web|title = Dietary Supplement Fact Sheet: Selenium — Health Professional Fact Sheet|url = http://ods.od.nih.gov/factsheets/selenium.asp|website = ods.od.nih.gov|accessdate = 2015-09-08}}</ref> In Finland, selenium salts are added to chemical fertilizers, as a way to increase selenium in soils.<ref>{{Cite journal|url = http://ajcn.nutrition.org/content/48/2/324.full.pdf|title = Selenium intake and serum selenium in Finland: effects of soil fertilization with selenium|date = 1988|accessdate = 8 September 2015|journal= American Journal of Clinical Nutrition|last = Varo|first = Pertti|last2 = Alfihan|first2 = Georg|last3 = Ekholm|first3 = Paivi|last4 = Aro|first4 = Antti|last5 = Koivistoinen|first5 = Pekka}}</ref>
Signs and symptoms of rickets include:
*Bone pain or tenderness
*[[tooth|dental]] problems
*[[muscle]] weakness (rickety myopathy or "floppy baby syndrome")
*increased tendency for [[fracture]]s (easily broken bones), especially [[greenstick fracture]]s
*Skeletal deformity
**Toddlers: Bowed legs ([[genu varum]])
**Older children: Knock-knees ([[genu valgum]]) or "windswept knees"
**Cranial, spinal, and pelvic deformities
*Growth disturbance
*[[Hypocalcemia]] (low level of calcium in the blood), and
*[[Tetany (medical sign)|Tetany]] (uncontrolled muscle spasms all over the body).
*[[Craniotabes]] (soft skull)
*[[Costochondral]] swelling (aka "[[rickety rosary]]" or "[[rachitic rosary]]")
*[[Harrison's groove]]
*Double malleoli sign due to metaphyseal hyperplasia [http://medicalpics.blogspot.com/2007/04/double-malleoli-sign-of-rickets.html]


An [[X-ray]] or [[radiography|radiograph]] of an advanced sufferer from rickets tends to present in a classic way: bow legs (outward curve of long bone of the legs) and a deformed chest. Changes in the skull also occur causing a distinctive "square headed" appearance. These deformities persist into adult life if not treated.
==Selenium deficiency in non-human animals==
In some regions (e.g. much of the northeastern and northwestern US and adjacent Canada, and the southeastern US), selenium deficiency in some animal species is common unless supplementation is carried out.<ref name=NRCsheep1985>{{cite book | url = https://books.google.com/books?id=UMb4ZwEACAAJ | title = Nutrient Requirements of Sheep | author1 = Subcommittee On Sheep Nutrition. National Research Council | year = 1985}}</ref>  Selenium deficiency is responsible (either alone or together with vitamin E deficiency) for many of the cases of WMD ("white muscle disease"), evidenced at slaughter or during necropsy by whitish appearance of striated muscle tissue due to bleaching by peroxides and hydroperoxides.<ref>{{cite book |  url = https://books.google.com/books?id=yhgBwjoJ8WoC |  title = Jensen and Swift's diseases of sheep |  isbn = 9780812110999 |  author1 = Kimberling |  first1 = Cleon V |  year = 1988}}</ref> Although this degenerative disease can occur in foals, pigs and other animal species, ruminants are particularly susceptible.<ref>{{cite journal | url = https://books.google.com/books?id=epjiKYkgbIAC | title = The Mineral Nutrition of Livestock | isbn = 9780851991283 | author1 = Underwood | first1 = Eric John | last2 = Suttle | first2 = N. F | year = 1999}}</ref>  In general, absorption of dietary selenium is lower in ruminants than in non-ruminants, and is lower from forages than from grain.<ref name=NRCsr2007>National Research Council, Committee on Nutrient Requirements of Small Ruminants.  2007.  Nutrient requirements of small ruminants.  National Academies Press, Washington.  362 pp.</ref> Sheep are more susceptible than cattle to WMD, and goats are more susceptible than sheep.<ref name=NRCsr2007/> Because of selenium's role in certain peroxidases (converting hydroperoxides to alcohols) and because of the antioxidant role of vitamin E (preventing hydroperoxide formation), a low level of Se can be somewhat (but not wholly) compensated by a high level of vitamin E.  (In the animal, localization of peroxidases and vitamin E differs, partly because of the fat-solubility of vitamin E.)   Some studies have indicated that about 0.12 or 0.23&nbsp;mg Se per kg of dry matter intake may be sufficient for avoiding Se deficiency in sheep in some circumstances.<ref name=NRCsheep1985/>  However, somewhat higher Se intake may be required for avoidance of  WMD where certain legumes are consumed.<ref>Whanger, P. D., P. H. Weswig, J. E. Oldfield, P. R. Cheeke and O. H. Muth.  1972.  Factors influencing selenium and white muscle disease:  forage types, salts, amino acids and dimethyl sulfoxide. Nutr. Rep. Int. 6; 21-37.</ref>  The cyanogenic glycosides in some white clover ([[Trifolium repens]]) varieties may influence the Se requirement,<ref name=NRCsr2007/> presumably because of cyanide from the aglycone released by glucosidase activity in the rumen<ref>Coop, I. E. and R. L. Blakely.  1949. The metabolism and toxicity of cyanides and cyanogenic glycosides in sheep. N. Z. J. Sci. Technol. 30: 277-291.</ref> and inactivation of glutathione peroxidases by the effect of absorbed cyanide on the [[glutathione]] moiety.<ref>{{cite journal | pmid = 7426660 | year = 1980 | last1 = Kraus | first1 = RJ | last2 = Prohaska | first2 = JR | last3 = Ganther | first3 = HE | title = Oxidized forms of ovine erythrocyte glutathione peroxidase. Cyanide inhibition of a 4-glutathione:4-selenoenzyme | volume = 615 | issue = 1 | pages = 19–26 | journal = Biochimica et Biophysica Acta | doi=10.1016/0005-2744(80)90004-2}}</ref>


Long-term consequences include permanent bends or disfiguration of the long bones, and a [[Scoliosis|curved back]].
In areas where selenium deficiency in livestock is a concern, selenium (as selenite) may be supplemented in feed.  In  some countries, e.g. the US and Canada, such supplementation is regulated.  Neonate ruminants at risk of WMD may be administered both Se and vitamin E by injection; some of the WMD myopathies respond only to Se, some only to vitamin E, and some to either.<ref>Kahn, C. M. (ed.) 2005. Merck veterinary manual. 9th Ed. Merck & Co., Inc., Whitehouse Station.</ref>


==Diagnosis==
==References==
A doctor may diagnose rickets by:
 
*Blood tests:     
**Serum [[calcium]] may show low levels of calcium, serum [[phosphorus]] may be low, and serum [[alkaline phosphatase]] may be high.
*[[Arterial blood gas]]es may reveal [[metabolic acidosis]] 
*[[X-ray]]s of affected bones may show loss of calcium from bones or changes in the shape or structure of the bones.
*Bone biopsy is rarely performed but will confirm rickets.
 
'''Patient #1: Radiographs of the knee in a patient with rickets'''
<gallery>
Image:Rickets-001.jpg
Image:Rickets-002.jpg
</gallery>
 
'''Patient #2:  Radiographs of the knee in a patient with rickets'''
<gallery>
Image:
 
Rickets-201.jpg
 
Image:
 
Rickets-202.jpg
 
</gallery>
 
'''Patient #3:  Radiograph of the chest in a patient with rickets'''
<gallery>
Image:
 
Rickets-301.jpg
 
</gallery>
 
==Ricketts: Microscopical Findings==
{{#ev:youtube|y7iA0_jkOTI}}
==Treatment and prevention==
===Diet and sunlight===
[[Image:Cholecalciferol.png|thumb|left|[[Cholecalciferol]] (D3)]]
[[Image:Ergocalciferol.png|thumb|left|[[Ergocalciferol]] (D2)]]
Treatment involves increasing dietary intake of calcium, phosphates and vitamin D. Exposure to ultraviolet light (sunshine), [[cod liver oil]], halibut-liver oil, and [[Ergosterol|viosterol]] are all sources of vitamin D.
 
A sufficient amount of ultraviolet in sunlight each day and adequate supplies of calcium and phosphorus in the diet can prevent rickets. Darker-skinned babies need to be exposed longer to the [[ultraviolet|ultraviolet rays]].  The replacement of vitamin D has been proven to correct rickets using these methods of [http://pediatrics.aappublications.org/cgi/content/full/112/2/e132 ultraviolet light therapy]and medicine.
 
Recommendations are for 200 [[international unit]]s (IU) of vitamin D a day for infants and children. Children who do not get adequate amounts of vitamin D are at increased risk of rickets.  Vitamin D is essential for allowing the body to uptake calcium for use in proper bone calcification and maintenance.
 
===Supplementation===
Sufficient vitamin D levels can also be achieved through dietary supplementation.  Vitamin D3 ([[cholecalciferol]]) is the preferred form since it is more readily absorbed than vitamin D2.  Most [[dermatology|dermatologists]] recommend vitamin D supplementation as an alternative to unprotected ultraviolet exposure due to the increased risk of skin cancer associated with sun exposure.
 
According to the [[American Academy of Pediatrics]] (AAP), infants who are breast-fed may not get enough vitamin D from breast milk alone. For this reason, the AAP recommends that infants who are exclusively breast-fed receive daily supplements of vitamin D from age 2 months until they start drinking at least 17 ounces of vitamin D-fortified milk or formula a day [http://aappolicy.aappublications.org/cgi/content/full/pediatrics;111/4/908]. This requirement for supplemental vitamin D is not a defect in the evolution of human breastmilk but is instead a result of the modern-day infant's decreased exposure to sunlight.
 
== References ==
{{reflist|2}}
{{reflist|2}}
<references/>
== External links ==
*[http://aappolicy.aappublications.org/cgi/content/full/pediatrics;111/4/908 AAP Recommendations on Vitamin D Supplementation]
*[http://courses.washington.edu/bonephys/hypercalU/opmal2.html Dr. Susan Ott's website on osteomalacia]
*[http://www.healthvitaminsguide.com/deficiencies/rickets.htm Rickets - Symptoms, Causes, Treatment]
*[http://dictionary.reference.com/search?q=osteomalacia Dictionary.com - Osteomalacia]
*[http://www.fluoridealert.org/health/bone/fluorosis/osteomalacia.html Fluoride & Osteomalacia]
*[http://www.beyonddiscovery.org/content/view.txt.asp?a=414 History of Vitamin D and the battle against Rickets]
* {{Chorus|00906}}


{{Nutritional pathology}}
{{Nutritional pathology}}


[[Category:Malnutrition]]
[[Category:Mineral deficiencies]]
[[Category:Pediatrics]]
[[Category:Selenium]]
[[Category:Skeletal disorders]]
[[Category:Gastroenterology]]
 
[[de:Rachitis]]
[[es:Raquitismo]]
[[fi:Riisitauti]]
[[fr:Rachitisme]]
[[ko:구루병]]
[[it:Rachitismo]]
[[ja:くる病]]
[[nl:Rachitis]]
[[no:Rakitt]]
[[pl:Krzywica]]
[[pt:Raquitismo]]
[[ru:Рахит]]
[[simple:Rickets]]
[[sv:Rakitis]]
[[tr:Raşitizm]]
[[zh:佝僂病]]
 
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Revision as of 15:10, 3 June 2016

Template:Infobox medical condition Selenium deficiency is relatively rare in healthy well-nourished individuals. Few cases in humans have been reported.

Causes

It can occur in patients with severely compromised intestinal function, those undergoing total parenteral nutrition, those who have had gastrointestinal bypass surgery, and also in persons of advanced age (i.e., over 90).[1]

People dependent on food grown from selenium-deficient soil may be at risk for deficiency.

For some time now, it has been reported in medical literature that a pattern of side-effects possibly associated with cholesterol-lowering drugs (e.g., statins) may resemble the pathology of selenium deficiency.[2][3]

Reference ranges

In the USA, the Dietary Reference Intake 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[4] is a better indicator of selenium nutritional status, and full expression of it would require more than 66 µg/day.[5]

Signs and symptoms

Selenium deficiency in combination with Coxsackievirus infection can lead to Keshan disease, which is potentially fatal. Selenium deficiency also contributes (along with iodine deficiency) to Kashin-Beck disease.[6] 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.[7] 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,[6] and as such a deficiency can cause symptoms of hypothyroidism, including extreme fatigue, mental slowing, goiter, cretinism, and recurrent miscarriage.[8]

Epidemiology and prevention

These diseases are most common in certain parts of China where the intake is low[9] because the soil is extremely deficient in selenium. Studies in Jiangsu Province of China have indicated a reduction in the prevalence of these diseases by taking selenium supplements.[10] In Finland, selenium salts are added to chemical fertilizers, as a way to increase selenium in soils.[11]

Selenium deficiency in non-human animals

In some regions (e.g. much of the northeastern and northwestern US and adjacent Canada, and the southeastern US), selenium deficiency in some animal species is common unless supplementation is carried out.[12] Selenium deficiency is responsible (either alone or together with vitamin E deficiency) for many of the cases of WMD ("white muscle disease"), evidenced at slaughter or during necropsy by whitish appearance of striated muscle tissue due to bleaching by peroxides and hydroperoxides.[13] Although this degenerative disease can occur in foals, pigs and other animal species, ruminants are particularly susceptible.[14] In general, absorption of dietary selenium is lower in ruminants than in non-ruminants, and is lower from forages than from grain.[15] Sheep are more susceptible than cattle to WMD, and goats are more susceptible than sheep.[15] Because of selenium's role in certain peroxidases (converting hydroperoxides to alcohols) and because of the antioxidant role of vitamin E (preventing hydroperoxide formation), a low level of Se can be somewhat (but not wholly) compensated by a high level of vitamin E. (In the animal, localization of peroxidases and vitamin E differs, partly because of the fat-solubility of vitamin E.) Some studies have indicated that about 0.12 or 0.23 mg Se per kg of dry matter intake may be sufficient for avoiding Se deficiency in sheep in some circumstances.[12] However, somewhat higher Se intake may be required for avoidance of WMD where certain legumes are consumed.[16] The cyanogenic glycosides in some white clover (Trifolium repens) varieties may influence the Se requirement,[15] presumably because of cyanide from the aglycone released by glucosidase activity in the rumen[17] and inactivation of glutathione peroxidases by the effect of absorbed cyanide on the glutathione moiety.[18]

In areas where selenium deficiency in livestock is a concern, selenium (as selenite) may be supplemented in feed. In some countries, e.g. the US and Canada, such supplementation is regulated. Neonate ruminants at risk of WMD may be administered both Se and vitamin E by injection; some of the WMD myopathies respond only to Se, some only to vitamin E, and some to either.[19]

References

  1. Ravaglia, Giovanni; Forti, Paola; Maioli, Fabiola; Bastagli, Luciana; Facchini, Andrea; Mariani, Erminia; Savarino, Lucia; Sassi, Simonetta; et al. (2000). "Effect of micronutrient status on natural killer cell immune function in healthy free-living subjects aged ≥90 y". American Journal of Clinical Nutrition. 71 (2): 590–8. PMID 10648276.
  2. Moosmann, B; Behl, C (2004). "Selenoprotein synthesis and side-effects of statins". Lancet. 363 (9412): 892–4. doi:10.1016/S0140-6736(04)15739-5. PMID 15031036.
  3. Moosmann, B; Behl, C (2004). "Selenoproteins, cholesterol-lowering drugs, and the consequences: Revisiting of the mevalonate pathway". Trends in Cardiovascular Medicine. 14 (7): 273–81. doi:10.1016/j.tcm.2004.08.003. PMID 15542379.
  4. Papp, Laura Vanda; Lu, Jun; Holmgren, Arne; Khanna, Kum Kum (2007). "From Selenium to Selenoproteins: Synthesis, Identity, and Their Role in Human Health". Antioxidants & Redox Signaling. 9 (7): 775–806. doi:10.1089/ars.2007.1528. PMID 17508906.
  5. Xia, Y; Hill, KE; Byrne, DW; Xu, J; Burk, RF (2005). "Effectiveness of selenium supplements in a low-selenium area of China". The American Journal of Clinical Nutrition. 81 (4): 829–34. PMID 15817859.
  6. 6.0 6.1 "Toxicological Profile for Selenium" (PDF). Agency for Toxic Substances and Disease Registry. U.S. Department of Health and Human Services. September 2003. Retrieved 7 Sep 2015.
  7. Moreno-Reyes, Rodrigo; Suetens, Carl; Mathieu, Françoise; Begaux, Françoise; Zhu, Dun; Rivera, Maria T.; Boelaert, Marleen; Nève, Jean; et al. (1998). "Kashin–Beck Osteoarthropathy in Rural Tibet in Relation to Selenium and Iodine Status". New England Journal of Medicine. 339 (16): 1112–20. doi:10.1056/NEJM199810153391604. PMID 9770558.
  8. "Selenium: Dietary Supplement Fact Sheet". National Institutes of Health. Retrieved July 4, 2013.
  9. "Selenium: Mineral Deficiency and Toxicity: Merck Manual Professional". Retrieved 2008-11-29.
  10. "Dietary Supplement Fact Sheet: Selenium — Health Professional Fact Sheet". ods.od.nih.gov. Retrieved 2015-09-08.
  11. Varo, Pertti; Alfihan, Georg; Ekholm, Paivi; Aro, Antti; Koivistoinen, Pekka (1988). "Selenium intake and serum selenium in Finland: effects of soil fertilization with selenium" (PDF). American Journal of Clinical Nutrition. Retrieved 8 September 2015.
  12. 12.0 12.1 Subcommittee On Sheep Nutrition. National Research Council (1985). Nutrient Requirements of Sheep.
  13. Kimberling, Cleon V (1988). Jensen and Swift's diseases of sheep. ISBN 9780812110999.
  14. Underwood, Eric John; Suttle, N. F (1999). "The Mineral Nutrition of Livestock". ISBN 9780851991283.
  15. 15.0 15.1 15.2 National Research Council, Committee on Nutrient Requirements of Small Ruminants. 2007. Nutrient requirements of small ruminants. National Academies Press, Washington. 362 pp.
  16. Whanger, P. D., P. H. Weswig, J. E. Oldfield, P. R. Cheeke and O. H. Muth. 1972. Factors influencing selenium and white muscle disease: forage types, salts, amino acids and dimethyl sulfoxide. Nutr. Rep. Int. 6; 21-37.
  17. Coop, I. E. and R. L. Blakely. 1949. The metabolism and toxicity of cyanides and cyanogenic glycosides in sheep. N. Z. J. Sci. Technol. 30: 277-291.
  18. Kraus, RJ; Prohaska, JR; Ganther, HE (1980). "Oxidized forms of ovine erythrocyte glutathione peroxidase. Cyanide inhibition of a 4-glutathione:4-selenoenzyme". Biochimica et Biophysica Acta. 615 (1): 19–26. doi:10.1016/0005-2744(80)90004-2. PMID 7426660.
  19. Kahn, C. M. (ed.) 2005. Merck veterinary manual. 9th Ed. Merck & Co., Inc., Whitehouse Station.

Template:Nutritional pathology