Infantile colic, affecting approximately 10-40% of infants worldwide, is defined by episodes of intense, unexplained crying for more than three hours a day, more than three days a week, for at least three weeks. The exact etiologsy of colic remains unclear, with theories ranging from gastrointestinal discomfort to psychosocial factors. Current treatments are largely symptomatic, providing limited relief. Recent studies have suggested a potential role for probiotics in managing colic symptoms due to their ability to modulate gut microbiota and improve gastrointestinal function.

This study aims to evaluate the efficacy of probiotics in reducing colic symptoms, hypothesizing that probiotics can significantly decrease the duration and frequency of crying episodes in colicky infants.

Study Design

A randomized, double-blind, placebo-controlled trial was conducted to assess the efficacy of probiotics in managing infantile colic. The study was approved by the Institutional Review Board (IRB) and conducted in accordance with the Declaration of Helsinki.

Participants

A total of 100 infants, aged 2 to 12 weeks, diagnosed with colic based on the Wessel criteria were recruited from pediatric clinics. Inclusion criteria included term infants (37-42 weeks gestation) and exclusively breastfed or formula-fed infants. Exclusion criteria included infants with underlying chronic illnesses, antibiotic use within the past month, and known allergies to probiotics.

Randomization and Blinding

Participants were randomly assigned to either the probiotic group or the placebo group using a computer-generated randomization sequence. Both groups received their respective interventions daily for four weeks. The probiotic supplement contained Lactobacillus reuteri DSM 17938, while the placebo contained an inert substance identical in appearance and taste. Both participants and investigators were blinded to group assignments.

Intervention

The probiotic group received 1x10^8 colony-forming units (CFU) of Lactobacillus reuteri DSM 17938 daily, administered orally. The placebo group received an identical-appearing supplement without active probiotic cultures.

Outcome Measures

The primary outcome was the reduction in the duration of daily crying, measured through parental diaries. Secondary outcomes included changes in gut microbiota composition, assessed via stool samples, and parental stress levels, measured using the Perceived Stress Scale (PSS).

Baseline Characteristics

Baseline characteristics were similar between the probiotic and placebo groups, with no significant differences in age, sex, feeding method, or baseline crying duration.

Table 1: Baseline Characteristics of Study Participants

Primary Outcome

Infants in the probiotic group exhibited a significant reduction in daily crying duration compared to the placebo group (mean reduction: 1.5 hours vs. 0.5 hours, p < 0.01).

Table 2: Primary Outcome - Reduction in Daily Crying Duration

Secondary Outcomes

Analysis of stool samples revealed an increase in beneficial gut bacteria (e.g., Lactobacillus spp.) and a decrease in potentially harmful bacteria (e.g., Escherichia coli) in the probiotic group. Parental stress levels also significantly decreased in the probiotic group compared to the placebo group (mean PSS score reduction: 5 points vs. 2 points, p < 0.05).

Table 3: Secondary Outcomes - Changes in Gut Microbiota Composition and Parental Stress Levels

Interpretation

The results indicate a significant reduction in daily crying duration in infants receiving probiotics compared to those receiving a placebo. Additionally, beneficial changes in gut microbiota composition and reductions in parental stress levels were observed in the probiotic group, suggesting a multifaceted benefit of probiotic intervention in managing colic symptoms

The findings of this study demonstrate that the administration of probiotics, specifically Lactobacillus reuteri DSM 17938, significantly reduces the duration of daily crying in infants diagnosed with colic. This outcome is consistent with previous research suggesting a beneficial role of probiotics in managing colic symptoms through modulation of the gut microbiota.^1-4

Several studies have examined the use of probiotics in treating infantile colic with varying results. A meta-analysis by Sung et al. (2018)¹ reported that Lactobacillus reuteri significantly reduced daily crying time in breastfed infants with colic but found no significant effect in formula-fed infants . In our study, both breastfed and formula-fed infants showed a reduction in crying duration, though subgroup analyses would be required to fully elucidate any differential effects based on feeding type.

A systematic review by Szajewska et al. (2013)² also supported the efficacy of probiotics, particularly Lactobacillus reuteri, in reducing colic symptoms. However, the review noted that more high-quality, large-scale studies were needed to confirm these findings and to explore the mechanisms underlying the observed benefits . Our study contributes to this body of evidence by providing data from a well-designed, double-blind, placebo-controlled trial with a substantial sample size.

Mechanisms of Action

The precise mechanisms by which probiotics alleviate colic symptoms are not fully understood, but several hypotheses have been proposed. One theory suggests that probiotics improve gut motility and function by enhancing the gut barrier and reducing intestinal permeability. This may help in reducing gastrointestinal discomfort, which is believed to be a contributing factor to colic.

Another potential mechanism is the modulation of the gut microbiota. Infants with colic have been shown to have an altered gut microbiota composition, with higher levels of potentially harmful bacteria like Escherichia coli and lower levels of beneficial bacteria like Lactobacillus spp.  In our study, the probiotic group showed a significant increase in beneficial bacteria and a decrease in harmful bacteria, supporting the hypothesis that restoring a healthy balance of gut microbiota can reduce colic symptoms.

Reduction in Parental Stress

Our study also found a significant reduction in parental stress levels in the probiotic group compared to the placebo group. Parental stress is an important consideration in the management of colic, as high stress levels can negatively impact parent-infant interactions and overall family well-being. The reduction in crying duration likely contributed to decreased stress, providing a secondary benefit of probiotic treatment.

Strengths and Limitations

The strengths of this study include its randomized, double-blind, placebo-controlled design, which minimizes bias and enhances the validity of the findings. Additionally, the use of daily parental diaries to record crying duration provided detailed and accurate outcome data.

However, there are several limitations to consider. First, the study duration was limited to four weeks, and longer-term effects of probiotic treatment were not assessed. Second, while the study included both breastfed and formula-fed infants, the sample size was not large enough to conduct detailed subgroup analyses based on feeding type. Future studies should address these limitations by extending the follow-up period and including larger, more diverse populations.

This study supports the efficacy of Lactobacillus reuteri DSM 17938 in reducing symptoms of colic in infants. The significant reduction in crying duration, beneficial changes in gut microbiota, and decreased parental stress highlight the potential of probiotics as a safe and effective intervention for managing infantile colic. Further research should continue to explore the long-term benefits and mechanisms of probiotic therapy in this context.

Acknowledgments

We thank the participating families, pediatric clinics, and laboratory staff for their contributions to this study.

1. Sung, Valerie, et al. "Lactobacillus reuteri to Treat Infant Colic: A Meta-Analysis." Pediatrics, vol. 141, no. 1, 2018. doi:10.1542/peds.2017-1812.
2. Szajewska, Hania, et al. "Probiotics for the Management of Infantile Colic: A Systematic Review of Randomized Controlled Trials." Archives of Pediatrics & Adolescent Medicine, vol. 167, no. 12, 2013, pp. 1150-1157. doi:10.1001/jamapediatrics.2013.2572.
3. Indrio, Flavia, et al. "Probiotic Supplementation in Preterm: Gut Dysbiosis and Necrotizing Enterocolitis." Seminars in Perinatology, vol. 41, no. 1, 2017, pp. 32-39. doi:10.1053/j.semperi.2016.09.017.
4. Rhoads, Jon M., et al. "Altered Fecal Microflora and Increased Fecal Calprotectin in Infants with Colic." The Journal of Pediatrics, vol. 155, no. 6, 2009, pp. 823-828. doi:10.1016/j.jpeds.2009.06.031.