Lactose intolerance classification: Difference between revisions
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==Overview== | ==Overview== | ||
There are three major types of lactose intolerance.<ref name="Melvin"> [http://aappolicy.aappublications.org/cgi/content/full/pediatrics;118/3/1279|Melvin B. Heyman. ''Lactose Intolerance in Infants, Children, and Adolescents''. PEDIATRICS Vol. 118 No. 3 September 2006, pp. 1279-1286 (doi:10.1542/peds.2006-1721)]</ref> They are primary lactose intolerance, secondary lactose intolerance and congenital lactase deficiency. | |||
==Classification== | ==Classification== | ||
There are three major types of lactose intolerance:<ref name="Melvin"> [http://aappolicy.aappublications.org/cgi/content/full/pediatrics;118/3/1279|Melvin B. Heyman. ''Lactose Intolerance in Infants, Children, and Adolescents''. PEDIATRICS Vol. 118 No. 3 September 2006, pp. 1279-1286 (doi:10.1542/peds.2006-1721)]</ref> | There are three major types of lactose intolerance:<ref name="Melvin"> [http://aappolicy.aappublications.org/cgi/content/full/pediatrics;118/3/1279|Melvin B. Heyman. ''Lactose Intolerance in Infants, Children, and Adolescents''. PEDIATRICS Vol. 118 No. 3 September 2006, pp. 1279-1286 (doi:10.1542/peds.2006-1721)]</ref> | ||
#Primary lactose intolerance | #Primary lactose intolerance: Environmentally induced by weaning in non dairy consuming societies. In most Asian and African cultures, mother's milk is the only commonly available milk and so milk consumption beyond infancy is not commonplace, therefore children become weaned, which is the same weaning process for all mammals (domesticated and wild). However societies such as the japanese where milk consumption has been on the increase, demonstrate that notwithstanding the genetic predisposition to lactose intolerance, they now present lower prevalence of lactose intolerance.<ref name="Yoshida">[http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1234085&dopt=Abstract ''Studies on the etiology of milk intolerance in Japanese adults'', Yoshida Y, Sasaki G, Goto S, Yanagiya S, Takashina K, Gastroenterol Jpn.;10(1):29–34, 1975]</ref> For any given individual the degree of weaning is probably genetically influenced. | ||
#Secondary lactose intolerance | #Secondary lactose intolerance: Environmentally induced, resulting from certain [[gastrointestinal diseases]], including exposure to [[intestinal parasites]] such as [[giardia]].<ref> [http://www.tulane.edu/~wiser/protozoology/notes/intes.html "Intestinal Protozoa" Mark Wiser 2000] </ref><ref>[http://www.emedicine.com/emerg/topic215.htm "Giardiasis" Andre Pennardt February 22, 2006] </ref> In such cases the production of lactase may be permanently disrupted.[http://www.aafp.org/afp/20020501/1845.html] | ||
#Congenital lactase deficiency present at birth and diagnosed in early infancy. | #Congenital lactase deficiency present at birth and diagnosed in early infancy. | ||
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
There are three major types of lactose intolerance.[1] They are primary lactose intolerance, secondary lactose intolerance and congenital lactase deficiency.
Classification
There are three major types of lactose intolerance:[1]
- Primary lactose intolerance: Environmentally induced by weaning in non dairy consuming societies. In most Asian and African cultures, mother's milk is the only commonly available milk and so milk consumption beyond infancy is not commonplace, therefore children become weaned, which is the same weaning process for all mammals (domesticated and wild). However societies such as the japanese where milk consumption has been on the increase, demonstrate that notwithstanding the genetic predisposition to lactose intolerance, they now present lower prevalence of lactose intolerance.[2] For any given individual the degree of weaning is probably genetically influenced.
- Secondary lactose intolerance: Environmentally induced, resulting from certain gastrointestinal diseases, including exposure to intestinal parasites such as giardia.[3][4] In such cases the production of lactase may be permanently disrupted.[2]
- Congenital lactase deficiency present at birth and diagnosed in early infancy.
Without lactase, the lactose disaccharide in many dairy products remains uncleaved and can not be absorbed through the intestinal wall into the bloodstream, so remains in the intestines. Enteral bacteria adapt to the relative abundance of this undigested sugar and their operons quickly switch over to lactose metabolism, which produces copious amounts of gas by fermentation.
This also causes a range of unpleasant abdominal symptoms, including stomach cramps, bloating, flatulence and diarrhea. As with other unabsorbed sugars (mannitol), the lactose raises the osmotic pressure of the colon contents, preventing the colon from reabsorbing water and hence causing a laxative effect to add to the excessive gas production.
References
- ↑ 1.0 1.1 B. Heyman. Lactose Intolerance in Infants, Children, and Adolescents. PEDIATRICS Vol. 118 No. 3 September 2006, pp. 1279-1286 (doi:10.1542/peds.2006-1721)
- ↑ Studies on the etiology of milk intolerance in Japanese adults, Yoshida Y, Sasaki G, Goto S, Yanagiya S, Takashina K, Gastroenterol Jpn.;10(1):29–34, 1975
- ↑ "Intestinal Protozoa" Mark Wiser 2000
- ↑ "Giardiasis" Andre Pennardt February 22, 2006