Lactose intolerance occurs when the small intestine does not produce enough of the enzyme lactase. When people with lactose intolerance consume milk products, they 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.

Lactose intolerance is common in premature babies, but in term birth babies, it generally does not show up until they are at least 3 years old.

Eliminating milk from the diet can result in a deficiency of calcium, Vitamin D, riboflavin, and protein. Therefore, a milk substitute is a necessity. For infants under 2 years old, soy formulas are adequate substitutes. Good alternatives for toddlers and teens are soymilk or rice milk. Older children may also use lactase treated milk or find alternate dairy sources, such as cheese or yogurt.

Lactose intolerance is more common in Asian, African, African-American, Native American, and Mediterranean populations than in northern and western Europeans.

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.

• abdominal cramps
• bloating
• flatulence
• weight loss
• malnutrition(growth, slow (child 0-5 years)
• abdominal distention
• abdominal fullness, gaseous
• diarrhea
• stools - floating
• stools - foul smelling

Symptoms often follow ingestion of milk products and are often relieved by withdrawal of milk products.

• lactose tolerance test
• lactose-hydrogen breath test
• small bowel biopsy that shows a negative mucosal lactase assay

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.