Original article—alimentary tractSubjective Perception of Lactose Intolerance Does Not Always Indicate Lactose Malabsorption
Section snippets
Experimental Design
Three hundred fifty-three white patients (113 men, 240 women; median age, 41 years) referred to our Digestive System Research Unit for evaluation of suspected lactose maldigestion by a hydrogen breath test (HBT) with lactose were prospectively studied after providing informed consent. None declined to participate in the study, had history of gastrointestinal surgery, or had taken antibiotics or been prepared for radiologic or endoscopic examinations for at least 2 weeks before entering the
Lactose Breath Test Assessment
Lactose HBT result was abnormal, delta increase over 25 ppm, in 164 of the 353 patients (46.4%). These patients were classified as lactose malabsorbers. Age and female predominance were similar in lactose absorber and malabsorber groups.
Perception of Lactose Tolerance
Results of each individual item and total score on the home and lactose symptoms questionnaire are shown in Figure 1. All items except vomiting scored significantly higher in the home questionnaire than in the lactose challenge questionnaire. Consequently, the
Discussion
There is extended belief among patients with abdominal symptoms that these are caused by lactose in dairy products. Indeed, lactose-free milk and related food products have become quite successful commercially. Lactase deficiency in adults is indeed relatively common among the Western population, but enzyme deficiency and symptomatic lactose intolerance are not tightly correlated. When individuals think that they are intolerant to lactose, they tend to avoid dairy products.18 However, when
Acknowledgments
The authors thank Miss Christine O'Hara for her valuable contributions to the English revision of this manuscript.
References (25)
- et al.
Small intestinal lactase status, frequency distribution of enzyme activity and milk intake in a multi-ethnic population
Clin Nutr
(1996) - et al.
Lactose malabsorption and the genesis of irritable bowel syndrome symptoms
Gastroenterology
(2001) - et al.
Reduced intolerance symptoms from lactose consumed during a meal
Am J Clin Nutr
(1988) - et al.
Colonic fermentation may play a role in lactose intolerance in humans
J Nutr
(2006) - et al.
Tolerance to small amounts of lactose in lactose maldigesters
Am J Clin Nutr
(1996) - et al.
Self-reported milk intolerance in irritable bowel syndrome: what should we believe?
Clin Nutr
(2004) - et al.
Poor predictability of lactose malabsorption from clinical symptoms for Chilean populations
Am J Clin Nutr
(1978) - et al.
Abdominal symptoms and lactose: the discrepancy between patients' claims and the results of blinded trials
Am J Clin Nutr
(1996) - et al.
Lactose malabsorption in ulcerative colitis: a case-control study
Gastroenterol Hepatol
(2003) - et al.
Lactose intolerance symptoms assessed by meta-analysis: a grain of truth that leads to exaggeration
J Nutr
(2006)
Lactose intolerance in infants, children and adolescents
Pediatrics
Disaccharidase activities in children: normal values and comparison based on symptoms and histologic changes
J Pediatr Gastroenterol Nutr
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Conflicts of interest The authors disclose no conflicts.
Funding This work was supported in part by grants from the Generalitat de Catalunya (RE: 2001SGR00389) and Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (Ciberehd, Spain). Ciberehd is funded by the Instituto de Salud Carlos III, Spain.