Lactose intolerance overview: Difference between revisions
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==Overview== | ==Overview== | ||
Lactose intolerance is the term used to describe a decline in the level of [[lactase]], an [[enzyme]] needed for proper [[Metabolism|metabolization]] of [[lactose]] (a sugar that is a constituent of milk and other dairy products), in human beings. | Lactose intolerance is the term used to describe a decline in the level of [[lactase]], an [[enzyme]] needed for proper [[Metabolism|metabolization]] of [[lactose]] (a sugar that is a constituent of milk and other dairy products), in human beings. | ||
==Historical Perspective== | ==Historical Perspective== | ||
The ancient Greek physician [[Hippocrates]] (460-370 B.C.) first noted gastrointestinal upset and skin problems in some who consumed milk. The condition was first recognized in the 1950s and 1960s when various organizations like the United Nations began to engage in systematic famine-relief efforts in countries outside Europe for the first time. Holzel et al (1959) and Durand (1959) produced two of the earliest studies of lactose intolerance. | The ancient Greek physician [[Hippocrates]] (460-370 B.C.) first noted gastrointestinal upset and skin problems in some who consumed milk. The condition was first recognized in the 1950s and 1960s when various organizations like the United Nations began to engage in systematic famine-relief efforts in countries outside Europe for the first time. Holzel et al (1959) and Durand (1959) produced two of the earliest studies of lactose intolerance. | ||
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==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> They are primary lactose intolerance, secondary lactose intolerance and congenital lactase deficiency. | 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. | ||
==Pathophysiology== | |||
==Causes== | ==Causes== | ||
Some causes of lactose intolerance are well known. Primary [[lactase]] deficiency is a condition that develops over time. After about age 2 the body begins to produce less lactase, though most people will not notice symptoms until they are much older. Secondary lactase deficiency occurs when injury to the small intestine or certain digestive diseases reduce the amount of lactase a person produces. These diseases include [[celiac disease]], [[inflammatory bowel disease]], and [[Crohn’s disease]]. | Some causes of lactose intolerance are well known. Primary [[lactase]] deficiency is a condition that develops over time. After about age 2 the body begins to produce less lactase, though most people will not notice symptoms until they are much older. Secondary lactase deficiency occurs when injury to the small intestine or certain digestive diseases reduce the amount of lactase a person produces. These diseases include [[celiac disease]], [[inflammatory bowel disease]], and [[Crohn’s disease]]. | ||
==Differentiating Lactose Intolerance from other Diseases== | ==Differentiating Lactose Intolerance from other Diseases== | ||
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==Epidemiology and Demographics== | ==Epidemiology and Demographics== | ||
An estimated 70%<ref name="Kretchmer1"> Kretchmer N. ''Lactose and lactase: a historical perspective''. Gastroenterology, 1971;61, 805–813</ref> of adult humans are considered lactose intolerant, it is uncommon in healthy northern westerners and a few others groups. Between 30 and 50 million Americans are [[lactose]] intolerant and certain ethnic and [[race|racial]] populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent. | An estimated 70%<ref name="Kretchmer1"> Kretchmer N. ''Lactose and lactase: a historical perspective''. Gastroenterology, 1971;61, 805–813</ref> of adult humans are considered lactose intolerant, it is uncommon in healthy northern westerners and a few others groups. Between 30 and 50 million Americans are [[lactose]] intolerant and certain ethnic and [[race|racial]] populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent. | ||
==Risk Factors== | ==Risk Factors== | ||
Babies that are born [[prematurity|prematurely]] are also more likely to be lactose intolerant, because [[lactase]] levels do not increase until the [[third trimester]] of a woman’s [[pregnancy]]. | Babies that are born [[prematurity|prematurely]] are also more likely to be lactose intolerant, because [[lactase]] levels do not increase until the [[third trimester]] of a woman’s [[pregnancy]]. | ||
==Natural History, Complications and Prognosis== | ==Natural History, Complications and Prognosis== | ||
Lactose intolerance is common, it is not a threat to good health. | Lactose intolerance is common, it is not a threat to good health. | ||
==Diagnosis== | ==Diagnosis== | ||
===History and Symptoms=== | |||
===Physical Examination=== | |||
===Laboratory Findings=== | ===Laboratory Findings=== | ||
Laboratory tests include [[hydrogen breath test]], stool acidity test, and [[intestine|intestinal]] [[biopsy]]. Since lactose intolerance is the normal state for most adults on a worldwide scale, and not considered a disease condition, diagnosis is not necessarily required. | Laboratory tests include [[hydrogen breath test]], stool acidity test, and [[intestine|intestinal]] [[biopsy]]. Since lactose intolerance is the normal state for most adults on a worldwide scale, and not considered a disease condition, diagnosis is not necessarily required. | ||
===Electrocardiogram=== | |||
===Chest X Ray=== | |||
===CT=== | |||
===MRI=== | |||
===Echocardiography or Ultrasound=== | |||
===Other Imaging Findings=== | |||
===Other Diagnostic Studies=== | |||
==Treatment== | ==Treatment== | ||
===Medical Therapy=== | ===Medical Therapy=== | ||
===Surgery=== | |||
Lactose intolerance is easy to treat. No treatment can improve the body’s ability to produce lactase, but symptoms can be controlled through [[diet]]. The basic principles involved in the management of lactose intolerance include avoiding dietary lactose, substitution of nutrients, using enzyme substitute and regulating calcium intake. | Lactose intolerance is easy to treat. No treatment can improve the body’s ability to produce lactase, but symptoms can be controlled through [[diet]]. The basic principles involved in the management of lactose intolerance include avoiding dietary lactose, substitution of nutrients, using enzyme substitute and regulating calcium intake. | ||
===Primary Prevention=== | |||
===Secondary Prevention=== | |||
===Cost-Effectiveness of Thearpy=== | |||
===Future or Investigational Therapies=== | |||
==Case Studies== | |||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
{{WS}} | |||
{{WH}} | |||
[[Category:Gastroenterology]] | [[Category:Gastroenterology]] | ||
[[Category: | [[Category:Endocrinology]] | ||
[[Category: | [[Category:Needs content]] | ||
Revision as of 20:05, 14 July 2016
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Lactose intolerance is the term used to describe a decline in the level of lactase, an enzyme needed for proper metabolization of lactose (a sugar that is a constituent of milk and other dairy products), in human beings.
Historical Perspective
The ancient Greek physician Hippocrates (460-370 B.C.) first noted gastrointestinal upset and skin problems in some who consumed milk. The condition was first recognized in the 1950s and 1960s when various organizations like the United Nations began to engage in systematic famine-relief efforts in countries outside Europe for the first time. Holzel et al (1959) and Durand (1959) produced two of the earliest studies of lactose intolerance.
Classification
There are three major types of lactose intolerance.[1] They are primary lactose intolerance, secondary lactose intolerance and congenital lactase deficiency.
Pathophysiology
Causes
Some causes of lactose intolerance are well known. Primary lactase deficiency is a condition that develops over time. After about age 2 the body begins to produce less lactase, though most people will not notice symptoms until they are much older. Secondary lactase deficiency occurs when injury to the small intestine or certain digestive diseases reduce the amount of lactase a person produces. These diseases include celiac disease, inflammatory bowel disease, and Crohn’s disease.
Differentiating Lactose Intolerance from other Diseases
The differential diagnosis must distinguish lactose intolerance from milk allergy, which is an abnormal immune response (usually) to milk proteins.
Epidemiology and Demographics
An estimated 70%[2] of adult humans are considered lactose intolerant, it is uncommon in healthy northern westerners and a few others groups. Between 30 and 50 million Americans are lactose intolerant and certain ethnic and racial populations are more affected than others. Up to 80 percent of African Americans, 80 to 100 percent of American Indians, and 90 to 100 percent of Asian Americans are lactose intolerant. The condition is least common among people of northern European descent.
Risk Factors
Babies that are born prematurely are also more likely to be lactose intolerant, because lactase levels do not increase until the third trimester of a woman’s pregnancy.
Natural History, Complications and Prognosis
Lactose intolerance is common, it is not a threat to good health.
Diagnosis
History and Symptoms
Physical Examination
Laboratory Findings
Laboratory tests include hydrogen breath test, stool acidity test, and intestinal biopsy. Since lactose intolerance is the normal state for most adults on a worldwide scale, and not considered a disease condition, diagnosis is not necessarily required.
Electrocardiogram
Chest X Ray
CT
MRI
Echocardiography or Ultrasound
Other Imaging Findings
Other Diagnostic Studies
Treatment
Medical Therapy
Surgery
Lactose intolerance is easy to treat. No treatment can improve the body’s ability to produce lactase, but symptoms can be controlled through diet. The basic principles involved in the management of lactose intolerance include avoiding dietary lactose, substitution of nutrients, using enzyme substitute and regulating calcium intake.
Primary Prevention
Secondary Prevention
Cost-Effectiveness of Thearpy
Future or Investigational Therapies
Case Studies
References
- ↑ 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)
- ↑ Kretchmer N. Lactose and lactase: a historical perspective. Gastroenterology, 1971;61, 805–813