Effect of lactase supplementation on infant colic: Systematic review of randomized controlled trials

To systematically review evidence on the efficacy and safety of using a lactase supplementation for managing infant colic. The MEDLINE, EMBASE, and Cochrane Library databases were searched (up to September 2023) for randomized controlled trials (RCTs) comparing oral lactase supplementation with placebo or no intervention in infants younger than 6 months old with infant colic. The risk of bias was assessed using the revised version of the Cochrane risk-of-bias tool. Outcomes measured were selected according to a standardized core outcome set. Five RCTs involving a total of 391 infants were identified. Three RCTs reported reduced crying duration, but one showed effect only in a compliant group (40.4%, p = 0.0052). A meta-analysis of two RCTs found no difference in crying duration and fussing time during 1 week of lactase treatment compared with placebo (mean difference [MD] -17.66 min/day, 95% confidence interval [CI], -60.8 to 25.5; I² = 68% and MD 2.75, 95% CI, -58.2 to 57.2; I² = 80%, respectively). Other outcomes were assessed only in individual studies or not reported. The risk of bias was low in only one RCT, high in three, and raised some concerns in one. While individual trials have shown some promise, the overall evidence for the efficacy of lactase supplementation in treating infant colic remain inconclusive. Further well-designed RCTs are necessary to determine the effects of lactase on managing infant colic.