Effect of exogenous beta-galactosidase in patients with lactose malabsorption and intolerance: a crossover double-blind placebo-controlled study.

Abstract OBJECTIVE: To evaluate the efficacy of the addition to milk, 5 min and 10 h before its consumption, of a lactase obtained from Kluyveromyces lactis in lactose malabsorbers with intolerance. DESIGN: Double-blind, placebo-controlled, crossover study. SETTING: University Hospital. SUBJECTS: In total, 11 male and 19 female (aged from 18 to 65 y, mean age 43.3 y) lactose malabsorbers with intolerance participated. INTERVENTIONS: Each patient underwent three H(2) breath tests, in a random order. We used 400 ml of cow's semiskimmed milk as substrate and a beta-galactosidase obtained from K. lactis. The test A was carried out adding to the milk the enzyme (3000 UI), 10 h before its consumption; the test B was performed adding the beta-galactosidase (6000 UI) 5 min before milk ingestion and the test C was made using placebo. We evaluated the maximum breath H(2) concentration, the cumulative H(2) excretion and a clinical score based on intolerance symptoms (bloating, abdominal pain, flatulence and diarrhoea). RESULTS: Our study showed a significant reduction of the mean maximum H(2) concentration after both test A (12.07 +/- 7.8 p.p.m.) and test B (13.97 +/- 7.99 p.p.m.) compared with test C (51.46 +/- 16.12 p.p.m.) (ANOVA F = 54.33, P < 0.001). Similarly, there was a significant reduction of the mean cumulative H(2) excretion after both test A (1428 +/- 1156 p.p.m.) and test B (1761 +/- 966 p.p.m.) compared with test C (5795 +/- 2707 p.p.m.) (ANOVA F = 31.46, P < 0.001). We also observed a significant reduction of the mean clinical score after both test A (0.36 +/- 0.55) and test B (0.96 +/- 0.85) compared with test C (3.7 +/- 0.79) (ANOVA F = 106.81, P < 0.001). Moreover, with regard to the mean clinical score, there was a significant reduction after test A with respect to test B (Bonferroni's P = 0.03). CONCLUSIONS: Our study shows that in lactose malabsorbers with intolerance, the lactase obtained from K. lactis can represent a valid therapeutic strategy, with objective and subjective efficacy and without side effects.