The effects of lactase deficiency on digestive symptoms and diet in patients with irritable bowel syndrome have not been well defined.
Dr Jianfeng Yang and colleagues from China assessed lactose absorption and tolerance and the intake of dairy products in healthy volunteers and patients with diarrhea-predominant irritable bowel syndrome.
The team reported that 60 patients diagnosed with irritable bowel syndrome, and 60 controls were given hydrogen breath tests to detect malabsorption and intolerance after administration of 10, 20, and 40 g lactose in random order 7–14 days apart.
Participants and researchers were blinded to the dose.
The team assessed associations between the results and self-reported lactose intolerance.
The research team assessed that malabsorption of 40 g lactose was observed in 93% of controls, and 92% of patients with irritable bowel syndrome .
|Self-reported lactose intolerance did not correlate with results from hydrogen breath tests|
|Clinical Gastroenterology & Hepatology|
Fewer controls than patients with irritable bowel syndrome were intolerant to 10 g lactose, 20 g lactose, and 40 g lactose
The doctors noted that H2 excretion was associated with symptom score.
Patients with irritable bowel syndrome self-reported lactose intolerance more frequently than controls, and ate fewer dairy products.
The researchers reported that self-reported lactose intolerance did not correlate with results from hydrogen breath tests.
Dr Yang's team concluded, "The risk of lactose intolerance is related to the dose of lactose ingested and intestinal gas production and is increased in patients with irritable bowel syndrome."
"Self-reported lactose intolerance, but not objective results from hydrogen breath tests, was associated with avoidance of dairy products."