Effect of Breastfeeding Mothers Drinking Fennel Seed Infusion on Infants With Colic (BabyGut)

Impact of Mothers Consuming a Fennel Infusion on Infantile Colic in Exclusively Breastfed Infants

The goal of this clinical trial is to determine whether a fennel-water infusion taken by mothers reduces colic in breastfed infants. The study will also assess the effect of the fennel infusion on the mothers' milk and the gut microbiota of the infants. The main questions it aims to answer are:

• Does a fennel-water infusion taken by mothers reduce colic in breastfed infants?
• What changes occur in the gut microbiota of responders (participants whose infants show reduced colic symptoms after the intervention)? Researchers will evaluate changes in the microbiota of breast milk and the stool of breastfed infants after the mothers consume a fennel infusion.

Participants-mothers of infants-will:

• Take 1 L of fennel infusion daily for 7 days.
• Keep a diary of infant colic symptoms, including time spent crying, and periods of fussiness or irritability without a definite explanation.
• Provide breast milk and infant stool samples before treatment (day 0) and at the end of treatment (day 7) for analysis of microbial communities.

Study Overview

• Status: Completed
• Conditions: Colic, Infantile
• Intervention / Treatment: Dietary supplement: Fennel infusion

Detailed Description

The project will investigate the effect of maternal ingestion of fennel infusion and the associated microbial changes in milk and the infant gut. A beneficial effect has been reported by mothers as part of popular medicine, but this has not been studied in controlled trials.

The trial aims to elucidate the mechanisms by which fennel compounds exert a colic-reducing effect in babies via breast milk. The investigators will determine whether an orally administered fennel seed infusion affects monitored symptoms or microbial parameters, and whether the composition of the fecal microbiota differs between colicky and non-colicky infants. Mothers will be asked to drink an infusion of fennel seeds (Foeniculum vulgare var. dulce) (20 g/L, 1 L per day) for one week. Samples of milk and feces will be collected at the beginning of treatment (day 0) and at the end of treatment (day 7) for microbiome analysis.

Samples will be prepared for Illumina sequencing by 16S rRNA gene amplification of the bacterial community. Raw reads will be extracted from the Illumina MiSeq System in fastq format and processed in the QIIME2 package using DADA2 to infer amplicon sequence variants (ASVs) and their relative abundances across samples. Taxonomy will be assigned to ASVs with the q2 feature-classifier using a pre-trained Naïve Bayes classifier of the Silva database. For species assignment, sequences will be further analyzed using the GenBank DNA database with the Basic Local Alignment Search Tool (BLAST) algorithm.

Alpha diversity will be determined using the number of taxa, individuals - amplicon sequence variants (ASVs), dominance (1-Simpson index), Margalef's richness index, evenness, and Chao1. Alpha diversity results will be compared before and after the intervention using the Wilcoxon signed-rank test. Beta diversity will be measured using principal coordinate analysis (PCoA) based on Bray-Curtis distance matrices for ASVs and PERMANOVA. The Wilcoxon signed-rank test will be used to compare normalized ASVs at the genus and species levels before the intervention (day 0) and after (day 7).

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Portugal
  • Angra do Heroísmo, Portugal
    • Universidade dos Açores, FCAA
  • Azores
    • Angra do Heroísmo, Azores, Portugal, 9700-042
      • Universidade dos Açores, IITAA

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Breastfed infants aged 1 to 5 months, full-term (gestational age between 38 and 42 weeks) of both sexes, diagnosed with infantile colic. The ROME IV criteria for diagnosed infant colic were used in this study.

Exclusion Criteria:

• Infants fed with artificial infant formula, use of antibiotics in the last 3 months by mothers or infants.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Mother - Infant; Breastfeeding women and their infants	Dietary supplement: Fennel infusion; The mothers were asked to drink an infusion of fennel seeds (1 L per day) for one week .

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of participants with a ≥50% reduction in daily crying duration as measured by a parent-reported 24-hour diary.	Response is defined as a reduction of at least 50% from baseline in mean daily crying duration. The baseline value is the mean daily crying duration recorded by parents in a 24-hour diary for the two days before treatment initiation, as reported in a questionnaire. The post-treatment value is the mean daily crying duration recorded in the 24-hour diary on the final two days of the one-week treatment period.	One week
Changes in bacterial community of infant stool samples	The bacterial community, assessed by changes in biodiversity indices and the relative proportions of bacterial genera in infant stool samples, will be evaluated before the intervention (day 0) and at the end of the trial (day 7).	One week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in bacterial community of breast milk	The bacterial community, assessed by changes in biodiversity indices and the relative proportions of bacterial genera in breast milk samples, will be evaluated before the intervention (day 0) and at the end of the trial (day 7).	One week

Collaborators and Investigators

• Sponsor: IITAA, Universidade dos Açores
• Investigators: Principal Investigator: Célia C. Silva, IITAA, Universidade dos Açores

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2021
• Primary Completion (Actual): April 30, 2024
• Study Completion (Actual): December 31, 2024

Study Registration Dates

• First Submitted: September 26, 2025
• First Submitted That Met QC Criteria: November 15, 2025
• First Posted (Actual): November 19, 2025

Study Record Updates

• Last Update Posted (Actual): November 19, 2025
• Last Update Submitted That Met QC Criteria: November 15, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Fennel
• Additional Relevant MeSH Terms: Infant, Newborn, Diseases; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Colic
• Other Study ID Numbers: M1.1.C/C.S./050/2021/01

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD used in the results publication.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No