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Lactose intolerance:
Lactose intolerance is the inability to digest significant
amounts of lactose, the predominant sugar of milk. This inability
results from a shortage of the enzyme lactase, which is normally
produced by the cells that line the small intestine. Lactase
breaks down the lactose, milk sugar, into glucose and galactose
that can then be absorbed into the bloodstream. When there is
not enough lactase to digest the amount of lactose consumed,
produce some uncomfortable symptoms. Some adults have low levels
of lactase. This leads to lactose intolerance. The ingested lactose
is not absorbed in the small intestine, but instead is fermented
by bacteria in the large intestine, producing uncomfortable volumes
of carbon dioxide gas. While not all persons deficient in lactase
have symptoms, those who do are considered to be lactose intolerant.
Common symptoms include nausea, cramps, bloating, gas, and
diarrhea, which begin about 30 minutes to 2 hours after eating
or drinking foods containing lactose. The severity of symptoms
varies depending on the amount of lactose each individual can
tolerate.
Fortunately, lactose intolerance is relatively easy to treat
by controlling the diet. No cure or treatment exists to improve
the body's ability to produce lactase. Young children with lactase
deficiency should not eat any foods containing lactose. Most
older children and adults need not avoid lactose completely,
but individuals differ in the amounts and types of foods they
can handle. Dietary control of lactose intolerance depends on
each person's learning through trial and error how much lactose
he or she can handle.
Adapted from: Lactose
Intolerance
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graphic of hydrolysis of lactose in a new window
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