Karen Harris

Karen Harris is a professional writer and editor with more than two decades of experience in research-driven nonfiction writing. With a background in journalism and a Master's degree in English, she brings a meticulous approach to fact-finding, source evaluation, and clear communication of complex topics. Her work spans health, lifestyle, and consumer education, always with a focus on accuracy and readability.

Context

Prebiotics are added to infant formula to mimic human milk oligosaccharides (HMOs) and promote beneficial gut bacteria. This systematic review examined whether prebiotic supplementation in cow’s milk-based infant formula influences gut microbiota composition, gut environment markers, growth outcomes, and safety in infants aged ≤6 months.

Study Overview

Design 

Systematic review and meta-analysis of randomized controlled trials
Registered at PROSPERO (CRD42021253589)


Included studies
30 trials
5,290 infants


Comparators
Standard cow’s milk formula
Human milk


Outcomes assessed
Gut microbiota composition (including Bifidobacterium and Lactobacillus)
Fecal pH
Secretory IgA
Fecal calprotectin
Growth parameters
Safety and tolerance

Key Findings

Compared with standard formula:

  • Increased Bifidobacterium abundance
    MD: 0.49
    95% CI: 0.27–0.71

  • Decreased fecal pH
    MD: –0.39
    95% CI: –0.57 to –0.20

  • No adverse impact on growth parameters

Compared with human milk:

  • Increased total bacteria counts

  • Similar overall growth outcomes

  • No consistent differences in Lactobacillus abundance

Weight-for-age z-scores slightly favored prebiotic formula in two studies.


Limitations

  • Substantial heterogeneity across studies, including differences in prebiotic type (GOS, FOS, inulin, oligofructose, mixtures), dosage, intervention duration, and microbiome assessment methods.

  • Short follow-up periods in many trials, limiting conclusions about long-term microbiome development and clinical outcomes.

  • Variability in microbiome measurement techniques, including differences in taxonomic resolution and laboratory methods, which may affect pooled estimates.

  • Relatively small sample sizes in several trials, and incomplete reporting of statistical power calculations for growth and microbiome outcomes.

  • Potential publication bias, as studies reporting positive findings may be more likely to be published.

  • Limited reporting of full formula composition, beyond prebiotic supplementation, making it difficult to assess the influence of other nutritional differences between products.

Neutral Interpretation

Prebiotic supplementation in infant formula appears to:

  • Promote Bifidobacterium growth

  • Reduce fecal pH

  • Maintain normal growth patterns

However, heterogeneity between studies was substantial due to differences in prebiotic types (GOS, FOS, inulin, oligofructose), dosages, and microbiome measurement techniques.

Long-term clinical significance remains uncertain.

Full Citation

Kebbe M, Leung K, Perrett B, Reimer RA, Adamo K, Redman LM.
Effects of Infant Formula Supplemented With Prebiotics on the Gut Microbiome, Gut Environment, Growth Parameters, and Safety and Tolerance: A Systematic Review and Meta-Analysis.
Nutrition Reviews. 2024.
PMID: 39832301
Available via PubMed: https://pubmed.ncbi.nlm.nih.gov/39832301/

Disclosure

This summary is based on the published systematic review and meta-analysis.
It is provided for informational purposes only and does not constitute medical advice.
Infant feeding decisions should be discussed with a qualified healthcare professional, especially in the presence of medical conditions or growth concerns.