A prospective study carried out in the Netherlands has examined the effect of a lactose-restricted diet among patients with irritable bowel syndrome (IBS) and lactose malabsorption.
A positive hydrogen breath test and a positive blood-glucose test defined lactose malabsorption.
An analysis of symptoms was completed before, during, 6 weeks after, and 5 years after starting the diet.
In addition, the number of visits made by the patients to the outpatient clinic was scored during 6 years.
In 17 out of 70 IBS patients (24%), lactose malabsorption was detected.
There was no difference in the symptom score between patients with a positive lactose tolerance test and patients with a negative lactose tolerance test.
After 6 weeks of the lactose-restricted diet, symptoms were markedly improved in lactose-malabsorption-positive patients.
After 5 years, one patient was lost for follow-up, and 14 out of the remaining 16 lactose malabsorption patients (88%) still had no complaints during the lactose-restricted diet.
Two patients chose not to follow the diet continuously and accepted the discomfort caused by lactose intake.
|24% of IBS patients were lactose-malabsorbers.
|European Journal of Gastroenterology and Hepatology|
Only 2 out of 16 patients (13%) no longer experienced any benefit from lactose restriction.
In the 5 years before their diagnosis of lactose malabsorption, these 16 patients visited the outpatient clinic a total of 192 times (mean 2.4 visits per year per person; range 1-7 visits).
In the 5 years after diagnosis, they visited the outpatient clinic a total of 45 times (mean 0.6 visits per year per person; range 0-6 visits).
Clarisse J.M. Boyer and Hans A.R.E. Tuynman, who undertook the study, concluded from their findings that a lactose-restricted diet markedly improved symptoms both in the short term and the long term in a large majority of IBS patients with previously clinically unrecognized lactose malabsorption.
Furthermore, they found that visits by all patients to the outpatient clinic were reduced by 75%.
They end their report by strongly recommending that "since diet therapy is extremely cost- and time-saving, lactose malabsorption, which is easily treatable, should be excluded before diagnosing IBS."