Authors: Bohmer CJ, Tuynman HA.

Institution: Department of Gastroenterology, Academical Hospital Free University, Amsterdam, The Netherlands.

Objective: The prevalence of lactose malabsorption (LM) in the Caucasian population of northern Europe is estimated to be low. Irritable bowel syndrome (IBS) is a very common diagnosis, and its symptoms are nearly identical to those of LM. Therefore we investigated the prevalence of LM among IBS patients in comparison with healthy volunteers.

Results: In 17 out of 70 (24.3%) IBS patients LM was detected, in comparison with 2 out of 35 (5.7%) controls (P < 0.009). There was no difference in the pre-entry mean lactose intake and symptom score between the LM positive and negative IBS patients. The mean symptom score of the LM positive group showed a marked decrease after 6 weeks of dietary therapy (P < 0.001).

Conclusion: A substantial number of IBS patients showed a clinically unrecognized lactose malabsorption, which could not be discriminated by symptoms and dietary history, and which can be treated with a lactose-restricted diet. Therefore LM has to be excluded before the diagnosis IBS is made.

Study link: http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=pubmed&dopt=Abstract&list_uids=8930569&query_hl=23

• The Clinical Relevance of Lactose Malabsorption in Irritable Bowel Syndrome
• Normalization of Lactulose Breath Testing Correlates with Symptom Improvement in Irritable Bowel Syndrome. a Double-Blind, Randomized, Placebo-Controlled Study
• The Effect of a Lactose-Restricted Diet in Patients with a Positive Lactose Tolerance Test, Earlier Diagnosed as Irritable Bowel Syndrome: a 5-year Follow-Up Study
• Lactose Intolerance in Different Types of Irritable Bowel Syndrome in North Indians