Objective: Kefir is a fermented milk beverage that contains different cultures than yogurt. The objective of this study was to determine whether kefir improves lactose digestion and tolerance in adults with lactose maldigestion.
Design: Randomized block design.
Subjects: Fifteen healthy, free-living adults with lactose maldigestion.
Main outcome measures: Breath hydrogen excretion and lactose intolerance symptoms were monitored hourly for 8 hours after each test meal.
Intervention: Subjects were fed test meals consisting of 20 g lactose portions of milk (2% reduced fat), plain and raspberry flavored kefir, and plain and raspberry flavored yogurt, each following an overnight (12 hour) fast.
Statistical analysis: Mixed model ANOVA was performed on raw or transformed data, followed by Tukey HSD post hoc tests (when appropriate). Significance was defined as P<.05.
Results: The breath hydrogen area under the curve (AUC) for milk (224+/-39 ppm x h) was significantly greater than for the plain yogurt (76+/-14 ppm x h, P<.001), the plain kefir (87+/-37 ppm x h, P<.001), and the flavored yogurt (76+/-14 ppm x h, P=.005). The flavored kefir had an intermediate response (156+/-26 ppm x h). The yogurts and kefirs all similarly reduced the perceived severity of flatulence by 54% to 71% relative to milk. Abdominal pain and diarrhea symptoms were negligible among the five treatments.
Applications/conclusion: Because kefir improved lactose digestion and tolerance in this study, its use may be another potential strategy for overcoming lactose intolerance. Further studies of other types of kefir for improving lactose digestion are warranted.