Although lactose-free dairy products for the clinical management of lactose intolerance (LI) are widely available, scientific evidence on their efficacy is still lacking. This study comparatively analyzed the efficacy of flavored lactose-free milk (LFM) and whole milk (WM) in reducing symptoms in South Korean adults with LI. This prospective study was conducted in adults suspected of LI. All screened participants underwent the hydrogen breath test (HBT) using 570 mL of chocolate-flavored WM (20 g of lactose) and responded to a symptom questionnaire. LI was confirmed when the ΔH2 peak exceeded 16 ppm above baseline values and with the occurrence of symptoms after WM consumption. The participants who were diagnosed with LI underwent the HBT again with 570 mL of chocolate-flavored LFM (0 g of lactose), followed by the symptom questionnaire survey after 1 week. After excluding 40 participants who did not meet the diagnostic criteria for LI and 2 who were lost to follow-up, a total of 28 lactose-intolerant individuals were enrolled in the study. The ΔH2 values in the first HBT were significantly higher than those in the second HBT (33.3 ± 21.6 ppm vs. 8.6 ± 6.3 ppm, P < .001). Similarly, there was a significant reduction in the total symptom score in the second HBT (4.18 ± 1.51 vs. 0.61 ± 0.98, P < .001). Flavored LFM is well tolerated in South Korean adults diagnosed with LI based on the HBT and symptom questionnaire results. Therefore, LFM may be a viable alternative to WM.
Keywords: breath test; hydrogen; lactose intolerance; milk.