foodconsumer.org: Lactose Intolerance: What you need to know

Lactose Intolerance: What you need to know
================================================================================
admin on 02/26/2010 23:04:00
 
What is lactose intolerance?
Lactose intolerance is the condition in which a person can't digest lactose, a
disaccharide found in milk and milk products. The condition is caused by a
deficiency of the enzyme known as lactase which is supposed to be produced by
the cells lining the small intestine and break down lactose into two simple
sugar called glucose and galactose, which are then absorbed into the
bloodstream.
Note that lactose intolerance differs from milk allergy. The former does not
involve any immune response while the latter does.  Allergy can trigger a
life-threatening response while milk intolerance does not. Milk allergy occurs
commonly in the first year of life while lactose intolerance occurs mostly in
adulthood.
What causes lactose intolerance?
Lactose intolerance is caused by lactase deficiency. There are two types of
lactose deficiency.
Primary lactase deficiency begins after about the age of 2 years when the body
starts to produce less lactase. However, children are less likely to experience
symptoms of lactose intolerance. The condition will become severe after a person
gets into his late adolescence or adulthood.
Secondary lactase deficiency is caused by some injury to the small intestine
that occurs with severe diarrheal illness, celiac disease, Crohn’s disease, or
chemotherapy. This type of lactase deficiency can occur at any age but is more
commonly encountered in infancy.
Who is at risk for lactose intolerance?
Lactose intolerance is a condition commonly found among some ethnic and racial
populations including African Americans, Hispanic Americans, American Indians,
and Asian Americans and less commonly found among Americans of northern European
descent.
Infants who are born prematurely are more likely to have lactose intolerance
because lactase does not increase until the third trimester of pregnancy.
What are the symptoms of lactose intolerance?
Common symptoms including abdominal pain, abdominal bloating, gas, diarrhea,
nausea among others may occur 30 minutes to 2 hours after ingesting of milk and
milk products.  The severity varies with the individual and the amount of
lactose ingested.
How is lactose intolerance diagnosed?
Because other conditions like irritable bowel syndrome can also cause similar
symptoms, lactose intolerance is not easy to diagnose based on its symptoms.
One simple test is to eliminate milk and milk products from one's diet and see
what happens.
Two other tests include hydrogen breath test, which detects high amounts of
hydrogen in a patient who has lactose intolerance when he drinks milk, and stool
acidity test which detects high amounts of acid in the stool as undigested
lactose leads to lactic acid and other fatty acids.  The stool acidity test is
intended for children, but because lactose intolerance is uncommon among
children, doctors need consider other medical conditions in young children.
How is lactose intolerance managed?
One way to manage lactose intolerance is to avoid ingesting of milk and milk
products.  Those who love milk or other dairy products may consider training
their system to adapt to high doses of lactose. Start with small amounts and
then gradually increase the amount of milk.   Of course those who don't like
milk can simply avoid milk and other milk products to completely eliminate
lactose intolerance.
Lactose intolerance and calcium intake
Milk and milk products are a major source of calcium, which is found high also
in many vegetables or plant-based foods including white beans, tofu, Chinese
cabbage, spinach and rhubarb. Those who have lactose intolerance may consider
eating more plant-based foods that contain high amounts of calcium to make sure
they have a high intake of the mineral.
What other products contain lactose?
Many foods may contain lactose.  The following list is not complete, but gives
out the common ones:
bread and other baked goods
waffles, pancakes, biscuits, cookies, and mixes to make them
processed breakfast foods such as doughnuts, frozen waffles and pancakes,
toaster pastries, and sweet rolls
processed breakfast cereals
instant potatoes, soups, and breakfast drinks
potato chips, corn chips, and other processed snacks
processed meats, such as bacon, sausage, hot dogs, and lunch meats
margarine
salad dressings
liquid and powdered milk-based meal replacements
protein powders and bars
candies
non-dairy liquid and powdered coffee creamers
non-dairy whipped toppings
Those who want to avoid lactose need to pay attention to keywords on the label
including
milk
lactose
whey
curds
milk by-products
dry milk solids
non-fat dry milk powder
Lactose may also be present in some prescription medicines, including birth
control pills, and over-the-counter medicines like products to treat stomach
acid and gas. These medicines most often cause symptoms in people with severe
lactose intolerance, but may not cause any problem in those who have certain
tolerance.
This article contain content from NIH Publication No. 09–2751 updated June
2009