Lactose intolerance
Lactose intolerance is a condition caused by a lack of an enzyme called
lactase. Inadequate amounts of lactase cause the body to be unable to digest
lactose, a sugar found in milk products. Lactase is normally produced in the
small intestine where it breaks lactose down into a form that can be absorbed by
the blood. A lack of lactase can cause uncomfortable symptoms for some people.
Those who do exhibit the symptoms are said to be lactose intolerant.
Thirty to 50 million Americans (adults and children) are lactose intolerant.
The disorder affects some populations more than others:
- Seventy-five percent of all African-Americans and Native Americans are
lactose intolerant.
- Ninety percent of Asian-Americans are lactose intolerant.
- Lactose intolerance is least common among people with a northern European
heritage.
Digestive diseases or injuries to the small intestine can reduce the amount
of enzymes produced and is the usual cause of lactose intolerance in young
children. However, most cases of lactose intolerance develop over a period of
many years in adolescents and adults.
The following are the most common symptoms for lactose intolerance. However,
each individual may experience symptoms differently. Common symptoms, which
begin about 30 minutes to two hours after consuming foods or beverages
containing lactose, may include:
- Nausea
- Cramps
- Bloating
- Gas
- Diarrhea
The severity of symptoms varies depending on the amount of lactose consumed
and the amount each individual can tolerate. The symptoms of lactose intolerance
may resemble other conditions or medical problems. Always consult your child's
physician for a diagnosis.
The most common diagnostic tests (performed on an outpatient basis at the
hospital, clinic, or physician's office) used to measure the absorption of
lactose in the digestive system include the following:
- Lactose tolerance test
This test measures the absorption of lactose in
the digestive system. After fasting, the patient drinks a liquid that contains
lactose. The diarrheal stools are then tested for lactose for the next 24
hours.
Undigested lactose fermented by bacteria in the colon creates lactic acid and
other fatty acids, which can be detected in a stool sample, along with glucose
as a result of unabsorbed lactose.
- Hydrogen breath test
The patient drinks a lactose-heavy beverage. The
breath is then analyzed at regular intervals to measure the amount of
hydrogen. Undigested lactose in the colon is fermented by bacteria, resulting
in the production of various gases, including hydrogen. When high levels of
hydrogen are present in the breath, improper digestion of lactose is
diagnosed.
Specific treatment for lactose intolerance will be determined by your child's
physician based on:
- Your child's age, overall health, and medical history
- The extent of the disease
- Your child's tolerance for specific medications, procedures, or therapies
- The expectations for the course of the disease · your opinion or
preference
Although, there is not a treatment to improve the body's ability to produce
lactase, symptoms caused by lactose intolerance can often be controlled with a
proper diet. In addition, lactase enzymes may be suggested by your child's
physician.
Calcium is essential for the growth and repair of bones throughout life and
has been suggested as a preventive measure for other diseases. Because milk and
other dairy products are a major source of calcium, parents must be concerned
with lactose intolerant children and teenagers getting enough calcium in a diet
that includes little or no milk.
The recommended daily dietary allowance (RDA) for calcium, released in 1997
by the National Institutes of Medicine, varies by age group.
- 0 to 6 months, 210 mg
- 6 months to 1 year, 270 mg
- 1 to 3 years, 500 mg · 4 to 8 years, 800 mg
- 9 to 18 years, 1,300 mg
Many nondairy foods are high in calcium, including:
- Green vegetables, such as broccoli and kale (Swiss chard, spinach, and
rhubarb are not listed because the body cannot use their calcium content -
they contain substances called oxalates, which inhibit calcium absorption)
- Fish with soft, edible bones, such as salmon and sardines
- Yogurt with active cultures may be a good source of calcium for many
people with lactose intolerance - evidence shows that the bacterial cultures
used in making yogurt produce some of the lactase enzyme required for proper
digestion.
Your child's physician may prescribe a calcium supplement if your child is
unable to get enough calcium from his/her diet.
Vitamin D is necessary for the body to absorb calcium, therefore, your
child's diet should provide an adequate supply of vitamin D. Sources of vitamin
D include eggs and liver. Sunlight is also a good source of vitamin
D.