Maternal High Fibre Fermented Diet Effect on Breastfed Infant Gut Microbiome

Not Applicable

Recruiting

• Conditions: Healthy; Mothers Who Have Babies Between 0-6 Months and Are Actively Breastfeeding

• Registration Number: NCT06977113
• Lead Sponsor: University of Glasgow

Brief Summary

Breastfeeding is recommended for babies from birth to 6 months old because breastmilk provides all the nutrients babies need for growth and development. Breast milk contains sugars called oligosaccharides which support the development of healthy gut in babies. The foods breastfeeding mothers eat might influence the sugars in their breast milk and the natural friendly bacteria inside their babies' gut called gut microbiota which are important for overall health. Fibre-rich foods like fruits, vegetables, whole grains, beans, and nuts, as well as fermented foods like yogurt and kefir, support a healthy gut.

The main aim of this study is to find out if eating foods rich in fibre and fermented foods by breastfeeding mothers can affect the bacteria residing in the gut of their breastfed babies. The study will also explore how this diet affects the mother's gut microbiota, breast milk composition and gastrointestinal (GI) symptoms for both mothers and babies. The main question of the study is:

• Does a 2-week diet high in fibre and fermented foods eaten by breastfeeding mothers affect the gut microbiota of their breastfed babies aged 2 to 5 months old compared to mothers' habitual diet?

Participants will:

* Be randomly assigned into one of the two groups: (1) one group eats a specific diet (that is high fibre fermented foods rich diet) (25 g of fibre/day) in addition to their habitual diet, or (2) the second group continues with their habitual diet (no specific foods will be provided) (16 g of fibre/day).

* Attend single study visit to the study location

* Provide body measurements (weight and height) of mothers and babies at study visit and provide weight only during each home visit

* Complete gut health questionnaires for both mothers and babies twice during the study

* Complete a 3-day 24-hour dietary recalls twice during the study

* Provide stool samples (3 from babies and 2 from mothers) and 2 breastmilk samples

Researchers will then compare stool samples of both mothers and babies to see if the specific diet makes any difference to the gut microbiota.

Detailed Description

Study Duration:

The study will span a total of 3 weeks, comprising a 1-week run-in period followed by a 2-week intervention period.

Recruitment:

Healthy exclusive breastfeeding women aged over 18 years old and their healthy new-borns aged between 2 to 5 months will be recruited from the general population residing in the Glasgow \& Clyde area of Scotland. The study will be advertised using posters distributed through different channels including word of mouth, breastfeeding support groups, schemes, venues and organisations and social media platforms. Researchers will screen potential participants for eligibility and only recruit healthy participants (i.e., healthy mothers and infants). Eligible participants will be invited to attend a 1h study visit at the researchers' metabolic facilities for further screening.

Study Visit:

Researchers will recheck participants' eligibility, reiterate the study purpose and requirements and answer any questions or concerns the participants may have. If the participants are still inclined to take part in the study, they will be asked to sign a consent but will be made aware that they can withdraw at any time. Participants will be assigned a unique study identification number for anonymisation of personal information and will be explained on data retention policy up to the point of study withdrawal. Sociodemographic information will be collected using a questionnaire and anthropometric measurements will be assessed for both mother and baby. Maternal body weight (in kg) in light clothes and barefoot will be measured using an electronic body weight scale (TANITA) and maternal height (in cm) will be measured using a stadiometer. Maternal BMI (in kg/m2) will be calculated. The baby's weight will be measured without the nappy (diaper). Infant body weight (in kg), and length (in cm) will be obtained as well, using a baby scale and infantometer (SECA) and with the involvement of the baby's mothers and or caregivers.

The specific procedures for the study protocol will be explained to the participants. The study researcher will provide participants with the necessary kits and instructions for sample collection (stool and breast milk). The study researcher will schedule home visits (three in total) to participant's home addresses. During each home visit, the study researcher will pick up stool and breast milk samples, provide new collection kits, collect gastrointetional (GI) paper questionnaires, and measure the baby's and mother's weights.

Post Study Visit:

After the study visit, mothers will start a run-in (baseline) period of 7 days where they will be following their normal habitual diet, provide first stool and breast milk samples, complete dietary assessment and gastrointestinal (GI) related questionnaires. The tools are a 3-day multiple pass 24-hour dietary recall, the Gastrointestinal Symptom Rating Scale (GSRS) for mothers, and the Infant Gastrointestinal Symptom Questionnaire (IGSQ) for infants.

After the completion of the study run-in period and the collection of baseline data, participants will be randomly assigned either to the high fibre fermented food rich diet in addition to their habitual diet (25 g of fibre/day) or to their habitual diet (16 g of fibre/day) for two weeks. The study intervention foods will be commercially available from local grocery shops and delivered to the participant's homes. The foods will be only administered to the mothers. No interventions will be administered to the infants.

Researchers will follow up with participants using mobile phone numbers to monitor for food deliveries, send reminders for home visits, complete the 3-day multiple pass 24-hour recall, and collect samples and questionnaires.

Data Collection:

1. Questionnaires

During the study visit, participants will complete a study visit questionnaire (including background, dietary and pregnancy and birth information).

After the study visit, participants will complete 3-day multiple-pass 24-hour dietary recalls at two time points - at baseline (study week 1) and at the last week of study intervention (study week 3)

Participants will complete GSRS and IGSQ at two time points - at baseline (study week 1) and after the last week of study intervention (study week 3).

2. Biological samples

Participants will collect biological samples, including mother's stool and breast milk, at two time points - before and after study intervention (at study week 1 and after study week 3)

Infant's stool will be collected from nappies at three time points: before and after study intervention (at study week 1 and after study week 3) and halfway through the study (between study week 2 and week3, on day 8th of study intervention).

Participants will be provided with the special kits and instructions required for the collection of samples at homes. Once samples are produced, participants will be advised to immediately contact the researchers for prompt sample pick up and handle.

3. Body measurements

During the study visit, mother's weight, height and body composition, and baby's weight and length will be measured. The study researcher will take the baby's measurements with the assistance of the mother or caregiver and without the nappies.

After the study visit, the study researcher will obtain the mother's and the baby's body weight at each sampling visit (or home visit), meaning at baseline (study week 1) and halfway through the study (between study week 2 and week 3), and after the last week of study intervention (study week 3).

Dietary Compliance:

Fibre contents in maternal stools will be measured to monitor for their dietary compliance to the study intervention.

Sample Size:

The sample size was caluclated based on the primary outcome, infant faecal acetate, the predominant short chain fatty acid (SCFA) and the one expected to be affected by an increase in bifidobacteria. Based on previous randomly controlled trials, recruiting 52 mother-infant pairs would provide a power of 80% (P=0.05) to detect a significant mean change in faecal acetate of 60 μmol/g in infant's stool (SD: 75 μmol/g). Accounting for an approximate 10% drop-out rate, recruiting 56 mother-infant pairs (28 per study group) would ensure adequate power for this study.

Reimbursement:

After the completion of the study, participants will receive gift voucher as a gesture of appreciation for their time and effort in the study. Also, participants will be compensated for public transport to the NLB (i.e. New Lister Building, Glasgow Royal Infirmary, the study location).

Study Timeline

• Study Start: 2025-03-11
• Status Verified: 2025-05
• Study First Submitted: 2025-05-08
• Study First Submitted QC: 2025-05-08
• Last Update Submitted: 2025-05-08
• Study First Posted: 2025-05-18
• Last Update Posted: 2025-05-18
• Primary Completion: 2026-12
• Study Completion: 2028-05

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 56

Inclusion Criteria

• Healthy breastfeeding women aged 18 years old and older.
• Healthy singleton full-term infants (girls and boys) aged between 2 and 5 months old and who are exclusively breastfed.
• Participants who do not use lifelong medications, or antibiotic in the past 12 weeks to the study.
• Participants who do not use prebiotic or probiotic supplements in the last 4 weeks prior to the study.
• Participants who do not have serious problems stopping them from breastfeeding their babies.
• Participants who do not have food allergies or intolerances.
• Participants who do not have any chronic conditions like diabetes, cancer, heart disease, bowel disorders, eating disorders, or any illness requiring regular medical care or lifelong medication.
• Participants who do not have a history of complications during pregnancy (e.g., preeclampsia and gestational diabetes).

Exclusion Criteria

• Participants who are expecting two or more children (i.e., multiple births; twins, triplets).
• Participants who do not exclusively breastfed their infants (i.e., introduced formula or foods) or who have medical conditions known to contradict breastfeeding (e.g., classic galactosemia, human immunodeficiency virus (HIV-virus) infection, untreated tuberculosis (TB)).
• Preterm birth delivery.
• Participants with clinical diagnosis of chronic medical conditions (e.g., type 1 and type 2 diabetes mellitus, cancer, cardiovascular diseases, and mental illnesses, etc).
• Participants with medical conditions affecting gastric digestion or absorption (e.g., bowel disorders, such as inflammatory bowel diseases (IBD), irritable bowel disease (IBD), irritable bowel syndrome (IBS)).
• Participants with medical conditions affecting intervention intake (e.g., celiac disease, gluten hypersensitivity or lactose intolerance).
• Participants with a history of gestational complications.
• Participants who used antibiotics in the past 12 weeks prior to the study.
• Participants who used prebiotic or probiotic supplements in the past 4 weeks prior to the study.
• Participants who follow exclusion or restrictive diet (gluten-free, or weight loss).

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Primary Outcome Measures

Name	Time	Method
Gut Microbiota and Short Chain Fatty Acids of Breastfed Infants after 2-week Dietary Intervention	From enrollment to the end of intervention at 3 weeks	The primary objective is to evaluate whether the maternal 2-week diet rich in fibre and fermented foods alters the composition of microbiota and short chain fatty acid (SCFA) level in the gut of breastfed infants. Microbiota composition will be assessed, following stool DNA extraction, through 16S rRNA amplicon sequencing and quantitative polymerase chain reaction (qPCR). SCFA will be quantified using gas chromatography (GC) and potentially other microbial derived metabolites will be measured using other analytical techniques.

Secondary Outcome Measures

Name	Time	Method
Maternal Gut Microbiota and Microbial Metabolites and Breast Milk Composition	From enrollment to the end of intervention at 3 weeks	Microbiota composition will be assessed, following stool DNA extraction, through 16S rRNA amplicon sequencing and quantitative polymerase chain reaction (qPCR). Microbial activity will be assessed by quantifying short chain fatty acids (SCFA) using gas chromatography (GC) and other microbial derived metabolites will be measured using other analytical techniques. Breastmilk samples will be analysed for human milk oligosccharides (HMOs) profiles using high performance liquid chromatography (HPLC). Measurement of excreted fibre in stools will be also measured using the Association of Official Analytical Chemists method.

Trial Locations

Locations (1)

Human Nutrition, School of Medicine, University of Glasgow; 🇬🇧 Glasgow, Scotland, United Kingdom