Walnuts as a first solid food for breastfed infants

Walnut as a First Food During Complementary Feeding on Gut Microbiota and Immunity Development in Breastfed Infants

Not applicable Interventional Colorado State University · NCT07081698

This trial will test whether introducing small amounts of walnuts during early complementary feeding changes the gut microbiome, inflammation, eczema, and growth in healthy breastfed infants.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment90 (estimated)
Ages5 Months to 5 Months
SexAll
SponsorColorado State University Academic / other
Locations1 site (Fort Collins, Colorado)
Trial IDNCT07081698 on ClinicalTrials.gov

What this trial studies

Researchers will give controlled amounts of walnut to full-term, predominantly breastfed infants starting early in complementary feeding and follow changes in gut microbiota, inflammatory markers, atopic dermatitis status, allergy indices, and growth over time. The main aims are to track microbiome structure and function, inflammation and allergy-related outcomes, and growth trajectories, while an exploratory nutri-metabolomics analysis will look for walnut-specific food signatures linked to immunity markers. Eligible infants are generally healthy, born at term, and have minimal prior solid-food or formula exposure. The study is conducted at a clinical nutrition laboratory in Fort Collins, Colorado, and some procedural details are withheld until study completion.

Who should consider this trial

Good fit: Full-term, generally healthy breastfed infants with minimal prior solid-food or formula exposure are the intended participants.

Not a fit: Infants who were born preterm, have health conditions affecting normal growth, have significant prior formula or solid-food intake, or already regularly consume nuts are unlikely to benefit from participation.

Why it matters

Potential benefit: If successful, introducing walnuts early could reduce allergy or eczema risk and favorably shape the infant gut microbiome and growth patterns.

How similar studies have performed: Early introduction of peanut has shown allergy-prevention benefits, but trials specifically testing walnuts and their effects on the infant microbiome and inflammation are limited, so this approach is relatively novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Full term: gestational age ≥ 37 weeks
* Generally healthy without conditions that would affect normal growth
* No significant consumption of complementary food (e.g., no more than 1 oz of solid foods per week)
* Exclusively breastfed (\< 2 weeks of cumulative formula exposure)

Exclusion Criteria:

* Adults unable to consent
* Pregnant women
* Prisoners

Where this trial is running

Fort Collins, Colorado

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Gut -MicrobiotaInflammatory MarkersInfant DevelopmentWalnutMicrobiomeInfantPediatricNutrition
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.