Lactose Intolerance

SUMMARY

  • A food intolerance is a metabolic disorder where the body lacks the ability to breakdown a specific substance and causes adverse reactions such as gas, bloating and abdominal pain. Lactose intolerance is a condition characterized by a deficiency of lactase, the enzyme responsible for breaking down lactose, a sugar found in milk and other dairy foods.
  • Approximately 40 to 60 million Americans suffer from lactose intolerance.
  • There is no cure for lactose intolerance, but symptoms can be controlled through diet and choosing dairy-free alternatives such as Turtle Mountain’s dairy-free frozen desserts.
  • For a person suffering from lactose intolerance it is important to make sure to balance the diet with other nutrient rich foods in place of dairy foods.

LACTOSE INTOLERANCE

Lactose intolerance is the body’s inability to breakdown lactose, the predominant sugar in milk. This inability results from a shortage of the enzyme lactase, which is produced by the cells that line the small intestine. Lactase breaks down lactose into simpler sugars that can then be absorbed into the bloodstream. When there is not enough lactase to digest the lactose, the results, although not usually dangerous, may be very distressing. 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.

Some causes of lactose intolerance are known. For instance, certain digestive diseases and injuries to the small intestine can reduce the amount of enzymes produced. In rare cases, children are born without the ability to produce lactase. For most people, though, lactase deficiency is a condition that develops naturally over time. After about 2 years of age, the body begins to produce less lactase. However, many people may not experience symptoms until they are much older.

Between 40 and 60 million Americans suffer from lactose intolerance. Certain ethnic and racial populations are more widely affected than others. Lactose intolerance affects approximately 75% of all African Americans and American Indians and 90% of Asian Americans. The condition is least common among persons of northern European descent. Researchers have identified a genetic variation associated with lactose intolerance; this discovery may be useful in developing a diagnostic test to identify people with this condition.

DIAGNOSIS

The most common tests used to measure the absorption of lactose in the digestive system are the lactose tolerance test, the hydrogen breath test, and the stool acidity test. These tests are performed on an outpatient basis at a hospital, clinic, or doctor's office. The lactose tolerance and hydrogen breath tests are not given to infants and very young children who are suspected of having lactose intolerance. Both these tests require the consumption of lactose which may be dangerous for the very young because they are more prone to dehydration that can result from diarrhea caused by lactose. If a baby or young child is experiencing symptoms of lactose intolerance, many pediatricians simply recommend changing from cow's milk to soy formula and waiting for symptoms to subside.

  • LACTOSE INTOLERANCE TEST: This test begins with the individual fasting (not eating) before the test and then drinking a liquid that contains lactose. Several blood samples are taken over a 2-hour period to measure the person's blood glucose (blood sugar) level, which indicates how well the body is able to digest lactose. Normally, when lactose reaches the digestive system, the lactase enzyme breaks it down into glucose and galactose. The liver then changes the galactose into glucose, which enters the bloodstream and raises the person's blood glucose level. If lactose is incompletely broken down, the blood glucose level does not rise and a diagnosis of lactose intolerance is confirmed.
  • HYDROGEN BREATH TEST: This test measures the amount of hydrogen in a person's breath. Normally, very little hydrogen is detectable. However, undigested lactose in the colon is fermented by bacteria producing various gases, including hydrogen. The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. In the test, the patient drinks a lactose-loaded beverage, and the breath is analyzed at regular intervals. Raised levels of hydrogen in the breath indicate improper digestion of lactose. Certain foods, medications, and cigarettes can affect the accuracy of the test and should be avoided before taking it. This test is available for children and adults.
  • STOOL ACIDITY TEST: If necessary, a stool acidity test, which measures the amount of acid in the stool, may be given to infants and young children. Undigested lactose fermented by bacteria in the colon creates lactic acid and other short-chain fatty acids that can be detected in a stool sample. In addition, glucose may be present in the sample as a result of unabsorbed lactose in the colon.

TREATMENT

Fortunately, lactose intolerance is relatively easy to treat. No treatment can improve the body's ability to produce lactase, but symptoms can be controlled through diet. Dietary control of lactose intolerance depends on people learning through trial and error how much lactose they can handle. Young children with lactose intolerance should not eat any foods containing lactose. Some older children and adults may not have to avoid lactose completely, but people differ in the amounts and types of foods they can handle.

BALANCED NUTRITION WITHOUT DAIRY PRODUCTS

Milk and other dairy products are a major source of nutrients in the American diet. The most important of these nutrients is calcium. Calcium is essential for the growth and repair of bones throughout life. In the middle and later years, a shortage of calcium may lead to thin, fragile bones that break easily, a condition called osteoporosis. A concern for both children and adults with lactose intolerance is getting enough calcium in a diet that includes little or no milk.
In 1997, the Institute of Medicine released a report recommending new requirements for daily calcium intake. How much calcium a person needs to maintain good health varies by age group. Recommendations from the report are shown in the following table (Table 1). Also, younger women and those pregnant or nursing require more calcium than the recommended daily values.

Table 1. Recommended Calcium Levels Per Age Group*
Age group Recommended daily intake of calcium (mg)
0–6 months 210 mg
7–12 months 270 mg
1–3 years 500 mg
4–8 years 800 mg
9–18 years 1,300 mg
19–50 years 1,000 mg
51–70+ years 1,200 mg
*Table Extracted From: National Digestive Diseases Information
Clearinghouse (NDDIC). Lactose Intolerance [Internet].
National Institutes of Health (NIH) Publication No. 03-2751 March 2003

In planning meals, it is important to make sure that each day's diet includes enough calcium even if the diet does not contain dairy products. Many non-dairy foods are high in calcium. Green vegetables such as broccoli and kale, and fish with soft, edible bones, such as salmon and sardines, are excellent sources of calcium. To help in planning a high-calcium and low-lactose diet, the table that follows (Table 2) lists some common foods that are good sources of dietary calcium and shows how much lactose they contain.

Table 2. Calcium and Lactose in Common Foods*
Vegetables Calcium Content Lactose Content
Calcium-fortified orange juice, 1 cup 308–344 mg 0
Sardines, with edible bones, 3 oz. 270 mg 0
Salmon, canned, with edible bones, 3 oz. 205 mg 0
Soymilk, fortified, 1 cup 200 mg 0
Broccoli (raw), 1 cup 90 mg 0
Orange, 1 medium 50 mg 0
Pinto beans, 1/2 cup 40 mg 0
Tuna, canned, 3 oz. 10 mg 0
Lettuce greens, 1/2 cup 10 mg 0
Dairy Products Calcium Content Lactose Content
Yogurt, plain, low-fat, 1 cup 415 mg 5 g
Milk, reduced fat, 1 cup 295 mg 11 g
Swiss cheese, 1 oz. 270 mg 1 g
Ice cream, 1/2 cup 85 mg 6 g
Cottage cheese, 1/2 cup 75 mg 2–3 g
*Table Extracted From: National Digestive Diseases Information Clearinghouse (NDDIC). Lactose Intolerance [Internet]. National Institutes of Health (NIH) Publication No. 03-2751 March 2003
Dairy Alternatives Calcium Content Lactose Content
So Delicious Dairy Free Sugar Free Fudge Bars 100 mg 0

Even though lactose intolerance is widespread, it need not pose a serious threat to good health. People who have trouble digesting lactose can find quality dairy-free alternatives readily available that replace their dairy counterparts. Older women at risk for osteoporosis and growing children who must avoid milk and foods made with milk can meet most of their special dietary needs by eating greens, fish, and other calcium-rich foods that are free of lactose. A carefully chosen diet, with calcium supplements if the doctor or dietitian recommends them, is the key to reducing symptoms and protecting future health.

REFERENCES

1. “Lactose Intolerance.” National Digestive Diseases Information Clearinghouse (NDDIC). 28 Feb 2005. National Institutes of Health (NIH).

2. “Lactose Intolerance.” The American Gastroenterological Association. 22 Feb. 2005.