$Unique_ID{BRK03914}
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$Title{Lactose Intolerance}
$Subject{Lactose Intolerance Lactase Deficiency Disaccharidase Deficiency
Alactasia}
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Copyright (C) 1986, 1987, 1988 National Organization for Rare Disorders,
Inc.

117:
Lactose Intolerance

** IMPORTANT **
It is possible that the main title of the article (Lactose Intolerance)
is not the name you expected.  Please check the SYNONYMS listing to find
alternate names and disorder subdivisions covered by this article.

Synonyms

     Lactase Deficiency
     Disaccharidase Deficiency
     Alactasia

General Discussion

** REMINDER **
The information contained in the Rare Disease Database is provided for
educational purposes only.  It should not be used for diagnostic or treatment
purposes.  If you wish to obtain more information about this disorder, please
contact your personal physician and/or the agencies listed in the "Resources"
section.


Malabsorption syndromes result from impaired absorption of nutrients from
the small bowel.  Lactose Intolerance is characterized by diarrhea and
abdominal distention.  A lack of one or more intestinal enzymes results in an
inability to digest certain carbohydrates.

Lactase, maltase, isomaltase, and sucrase usually split disaccharides (a
class of sugars containing two or more simple sugars) into monosaccharides
(simple sugars) in the small intestine.  Lactase is an intestinal enzyme
which splits lactose (a disaccharide commonly called milk sugar) into glucose
and galactose.  Glucose and galactose are then absorbed by an active
transport system in the small bowel.  In patients with an intolerance for
carbohydrates, the enzymes which digest these disaccharides in the small
bowel are lacking.  Symptoms generally develop after eating or drinking many
kinds of carbohydrates.

Symptoms

Characteristically, children with an Lactose Intolerance, and thus the
inability to tolerate types of sugar, have diarrhea and may be unable to gain
weight.  Symptoms in a adult may include rumbling noises in the intestines
(borborygmi), bloating, and flatus.  Nausea, diarrhea, and abdominal cramps
may also be present.  Diarrhea may be severe enough to even purge other
nutrients before they can be absorbed.

Patients with lactose intolerance may indicate a history of milk
intolerance.  Some individuals recognize the intolerance early in life and
either consciously or sometimes unconsciously make an effort to avoid eating
or drinking foods containing dairy products.  Tests are available for
diagnosis of lactose intolerance, which is a hereditary disorder usually
getting worse with age.

Causes

The inability to digest carbohydrates caused by a lack of one or more
intestinal enzymes results in Lactose Intolerance.  Lactase deficiency is a
genetic condition occuring fairly commonly among adults in all ethnic groups.
Asians, Blacks and people of Jewish decent may have a higher than normal
incidence of lactose intolerance.

An extremely rare congenital disorder is known as glucose-galactose
intolerance.  Sucrase and isomaltase deficiencies are also rare.

Therapies:  Standard

Lactose Intolerance is easily controlled by a lactose-free diet.  The
disorder is often managed simply by abstaining from dairy products.  (For
more information, please the article "Dietary Strategies for Lactose
Intolerance" in the Prevalent Health Conditions/Concerns area of NORD
Services.

Several lactose reduced dairy products are available in grocery stores
(including milk, ice cream, cottage cheese, etc.  The enzyme that breaks down
lactose is also available in tablets or drops that can be added to foods.
Lactaid liquid can be added to milk to break down the lactose and make it
digestible to people with this disorder.  Lactaid tablets can be taken within
one-half hour of eating dairy products which replaces the missing enzyme,
enabling patients to eat a normal diet.  For more information about
availability of this enzyme (or free samples), please contact:

     Lactaid, Inc.
     P.O. Box 111
     Pleasantville, NJ  08232
     1-800-257-8650

Therapies:  Investigational

This disease entry is based upon medical information available through
September 1988.  Since NORD's resources are limited, it is not possible to
keep every entry in the Rare Disease Database completely current and
accurate.  Please check with the agencies listed in the Resources section for
the most current information about this disorder.

Resources

For more information on Lactose Intolerance, please contact:

     National Organization for Rare Disorders (NORD)
     P.O. Box 8923
     New Fairfield, CT  06812-1783
     (203) 746-6518

     National Digestive Diseases Information Clearinghouse
     Box NDIC
     Bethesda, MD  20892
     (301) 468-2162

For free information on Lactose Intolerance, contact:

     Lactose Intolerance/HL
     National Institutes of Health
     Bldg. 31, Rm. 2B23
     9000 Rockville Pike
     Bethesda, MD  20892

References

THE MERCK MANUAL 15th ed:  R. Berkow, et al: eds; Merck, Sharp & Dohme
Research Laboratories, 1987.  P. 796.

CECIL TEXTBOOK OF MEDICINE, 18th ed.:  James B. Wyngaarden, and Lloyd H.
Smith, Jr., Eds.:  W. B. Saunders Co., 1988.  P. 751.