Does alpha-galactosidase alleviate irritable bowel symptoms?

BACKGROUND:

More than 80 % of IBS patients report abdominal bloating. Excess colonic fermentation and gas production may attribute to gaseous symptoms. Several vegetable foodstuffs contain oligosaccharides with an alpha-galactosidic linkage resistant to mammalian hydrolases. Assisted hydrolysis with exogenous alpha-galactosidase enzyme (AG) reduces flatulence after a carbohydrate-rich meal in healthy volunteers. AG is a natural enzyme of fungal origin, derived from aspergillus niger.

AIM:

To assess the effect of AG on symptom severity and quality of life in IBS patients with abdominal bloating or flatulence as most disturbing symptoms.

METHODS:

A randomized, double-blind, placebo-controlled study. 125 subjects aged 18 to 65 years fulfilling Rome III IBS criteria received three capsules of AG (400 GaIU/caps), or placebo, three times a day with meals for 12 weeks. They completed a validated Irritable Bowel Syndrome - Symptom Severity Score (IBS-SSS) at the baseline, after 4, 8, and 12 weeks of treatment, and after a four-week follow-up period. The severity of flatulence was assessed with visual analog scale in an item added in the IBS-SSS questionnaire. Study subjects also filled the Irritable Bowel Syndrome - Quality of Life (IBS-QOL) questionnaire at the baseline, after 12 weeks of treatment, and after four-week follow-up. The primary outcome variable was the change of IBS-SSS from baseline during the treatment and follow-up periods. Severity of flatulence and abdominal bloating as well as the change in IBS-QOL overall score were the secondary outcome variables. Percentage of responders was compared between AG and placebo groups. A decline of >50 points in the SSS was defined as a clinical response. The primary and secondary outcome variables were analyzed by repeated measures ANOVA model. A two-sided p-value less than 0.05 was considered statistically significant.

RESULTS:

25 patients (18 in AG group and 7 in placebo group, p = 0.016) withdrew from the study. Abdominal pain (n=4) and diarrhea (n=2) were more often reported as reason for withdrawal in AG group. No statistically significant differences were detected in symptom profiles between AG and placebo groups, although AG showed a trend towards a more prominent decrease in SSS. The response rate at week 16 was higher in AG group (Table). At baseline, IBS-QoL scores were 61.0 and 70.2 in placebo and AG groups, and after treatment period, 69.6, and 74.2, respectively, p = 0.418.

CONCLUSIONS:

AG shows trend over placebo in alleviating IBS symptoms. Improvement of clinical response after 4 week follow-up suggests a long term effect of unknown mechanism, potentially related to alterations in gut microbiota. GI related side-effects may be a coincidence in this study, but irritation of GI tract can not be excluded. More research is needed to assess AG's position in IBS treatment (Table Presented).