Alternate Names: Lactase deficiency; Milk intolerance; Disaccharidase deficiency; Dairy product intolerance
Causes and Risks:
Lactose is a substance found in milk and milk products. Inadequate production of the enzyme lactase in the small intestine results in the body’s inability to digest lactose. Patients with lactose intolerance who have ingested milk products may have symptoms such as abdominal bloating, excessive intestinal gas, nausea, diarrhea, and abdominal cramping.
Lactose intolerance is very common in adults and is not dangerous. Many adults, by the time they are 20 years old (approximately 30 million Americans), have some degree of lactose intolerance. This may be present at birth, develop in infancy when cow’s milk is introduced in the diet, or develop later in adulthood.
Lactose intolerance can be a serious condition in infants and small children because milk is the basis of the child’s diet. Eliminating milk from the diet can result in a deficiency of calcium, vitamin D, riboflavin, and protein. A milk substitute is a necessity. Commonly available soy formulas are adequate substitutes. Soy formulas need not be limited to infants. Toddlers to teens can drink soy formula if needed. Older children may also use lactase treated milk or find alternate dairy sources, such as cheese or yogurt.
A lactase deficiency may affect as many as 70 to 90% of Asian, African, African-American, Native American, and Mediterranean populations. In northern and western Europeans, the incidence is 10 to 15%.
Lactase deficiency may also occur as a result of intestinal diseases such as celiac sprue and gastroenteritis, or it may follow gastroduodenal surgery. Temporary lactase deficiency can result from viral and bacterial enteritis, especially in children, when the mucosal cells of the intestine are injured. Risk factors include being Asian, Black, Native American, or Mediterranean; previous gastroduodenal surgery; recent intestinal infection; and history of intestinal diseases. Overall incidence is 6 out of 10,000 people.
Prevention: There is no known way to prevent the development of lactose intolerance. However, avoiding or restricting the amount of milk products eaten can reduce or eliminate the symptoms.
Symptoms:
Note: Symptoms often follow ingestion of milk products and are often relieved by withdrawal of milk products.
Signs and Tests:
Treatment:
Removing milk products from the diet usually improves the symptoms. Lactase enzymes can be added to the milk (acidophilus milk) or taken in capsule or chewable tablet form.
Fermented milk products such as yogurt can usually be tolerated. Other sources of calcium should be added to the diet if milk products are eliminated. Goat’s milk can sometimes be tolerated. Drink it with meals, not alone. Buttermilk and cheeses have less lactose than milk.
Prognosis: Symptoms usually resolve when milk products are eliminated from the diet.
Complications: Weight loss and malnutrition are complications.
If you or your child has symptoms of lactose intolerance, consult with your physician regarding dietary substitutions.
Also call if symptoms worsen or do not improve with treatment, or if new symptoms develop.
