Subjective perception of lactose intolerance does not always indicate lactose malabsorption

Area of Science:

• Gastroenterology
• Clinical Nutrition
• Diagnostic Medicine

Background:

• Symptomatic lactose intolerance is prevalent, but abdominal symptoms after lactose ingestion may stem from causes other than lactose malabsorption.
• Distinguishing true lactose intolerance from other causes of gastrointestinal distress is clinically significant.

Purpose of the Study:

• To compare symptoms experienced by patients attributed to lactose intolerance with those provoked by a controlled lactose challenge.
• To investigate the relationship between perceived symptoms and actual lactose absorption capacity.

Main Methods:

• An observational, prospective study involving 353 patients undergoing a lactose hydrogen breath test (HBT).
• Patients completed validated questionnaires detailing home symptoms and symptoms post-lactose challenge.
• Classification into absorbers/malabsorbers (HBT) and tolerants/intolerants (questionnaire).

Main Results:

• Total symptom scores were significantly higher for self-reported home symptoms compared to lactose challenge symptoms (16 vs 8, P < .01).
• Lactose absorbers reported more intense home symptoms than malabsorbers (16 vs 4, P < .01).
• Symptom overperception at home was similar in men and women and occurred in both lactose tolerants and intolerants.

Conclusions:

• Symptoms patients associate with lactose intolerance in daily life are frequently not linked to lactose malabsorption.
• Even in individuals with confirmed lactose malabsorption, symptom recall can be exaggerated.
• Conventional patient history-taking is an unreliable method for diagnosing symptomatic lactose malabsorption.