Food Intolerance: Lactose Intolerance

Lactose intolerance (LI) is characterized by abdominal symptoms (e.g., nausea, bloating, and pain) after ingestion of dairy products. The genetic basis of lactose malabsorption is well established, and several tests for this condition are available including genetic, endoscopic, and hydrogen breath tests. In contrast, LI is less well understood. Recent studies show that the risk of symptoms after lactose ingestion depends on the dose of the lactose, lactase expression, intestinal flora, and the sensitivity of the gastrointestinal tract. LI has recently been defined as symptoms that develop after ingestion of lactose that do not develop after ingestion of a placebo by a person with lactose maldigestion.