Lactose intolerance is caused by the absence of the enzyme lactase that is produced by the cells lining the small intestine. This deficiency leaves the body unable to digest lactose, a sugar found in milk and milk products. Lactose intolerance is rare in babies and becomes more prevalent with age.
Statistics
According to a clinical report by the American Academy of Pediatrics, lactose intolerance is uncommon before 2 to 3 years of age in all populations. Approximately 20 percent of Hispanic, Asian and black children younger than 5 years old have symptoms of lactase deficiency. In contrast, Caucasian children typically do not develop symptoms of lactose intolerance until after 4 or 5 years of age. Among northern Europeans, only 2 percent of the total adult and child population is lactose intolerant.
Risk Factors
Lactose intolerance is more common among certain populations including African, Hispanic and Asian individuals. Celiac disease or wheat allergy and Crohn's disease predispose individuals to lactose intolerance. Premature infants born prior to 34 weeks of gestation may show developmental lactase deficiency due to immature intestine function. In this case, symptoms may be improved by an infant formula that contains lactase to aid in breaking down the lactose sugar.
Symptoms
An infant with lactose intolerance typically experiences severe diarrhea from birth and is not able to digest lactose in breast milk or formula based on cow's milk. Symptoms in older children and adults include abdominal distention, flatulence, abdominal cramping and ultimately diarrhea following ingestion of milk products. Many individuals can tolerate small quantities of dairy products and their symptoms appear only with larger quantities.
Alternatives
An intestinal illness with diarrhea can cause temporary lactose intolerance in a child. The symptoms should disappear within one to two weeks. Lactose intolerance should not be confused with milk allergy. In the latter, the infant or child reacts to the milk protein, casein, and not to the lactose sugar. A milk allergy may cause gas, bloating, irritability as well as rash and swelling. Consult your doctor about allergy testing if your infant appears sensitive to milk products.
