Synbiotics, probiotics or prebiotics in infant formula for full term infants: a systematic review

Nutrition Journal

Oct 2012

DOI: 10.1186/1475-2891-11-81

Citations:158

Influential Citations:8

Systematic Reviews / Meta-Analyses

Enhanced Details

Methods

Design: randomized controlled trials; participants: healthy full-term infants (>37 weeks gestation or birth weight ≥2.5 kg), age 0–12 months, formula-fed only; no disease, congenital abnormality or eczema; settings include multi-centre and single-centre trials; blinding described in some trials.

Intervention

Synbiotics: three regimens in term infant formulas. Regimen 1: Bifidobacterium longum BL999 + Lactobacillus rhamnosus; 90% galactooligosaccharide (GOS) + 10% short-chain fructooligosaccharide (scFOS); 0.4 g/100 mL; B. longum BL999 dose 1.29×10^8 to 2.58×10^8 CFU/100 mL; L. rhamnosus 6.45×10^8 CFU/100 mL; duration 4–6 months. Regimen 2: Bifidobacterium longum BL999 + Lactobacillus paracasei; 90% GOS + 10% scFOS; 0.4 g/100 mL; BL999 dose similar; duration 4–6 months. Regimen 3: Bifidobacterium longum BL999 alone; 90% GOS + 10% scFOS; 0.4 g/100 mL; duration 4–6 months. Probiotics: regimens used various strains (e.g., Bifidobacterium lactis Bb12; Lactobacillus GG; Lactobacillus reuteri; Bifidobacterium bifidum); dosages ranged from 1.5×10^6 to 3.85×10^8 CFU/g powder for Bifidobacteria and 1×10^6 to 1×10^8 CFU/g powder for Lactobacilli; durations from 14 days to 7 months; some formulas were acidified or reduced-protein.

Results

Synbiotics did not significantly improve growth (weight, length, head circumference). Probiotics did not significantly improve growth or (consistently) reduce infections; stool frequency may increase with some regimens, but results are inconsistent. Prebiotics increased weight gain modestly (approx. 0.97 g/day in meta-analysis) and stool frequency, but did not consistently affect length, head circumference, infections, or hospitalization. No evidence that synbiotics are superior to probiotics or prebiotics. Overall, evidence quality is low due to imprecision, inconsistency, varied preparations, and potential publication bias. Routine supplementation of term infant formula with synbiotics, probiotics or prebiotics is not supported.

Limitations

Small sample sizes in several studies; heterogeneity in strains/doses/durations; varied formulas and outcome reporting; risk of bias and potential publication bias; overall low certainty of evidence.

Abstract

BackgroundSynbiotics, probiotics or prebiotics are being added to infant formula to promote growth and development in infants. Previous reviews (2007 to 2011) on term infants given probiotics or prebiotics focused on prevention of allergic disease and food hypersensitivity. This review focused on growth and clinical outcomes in term infants fed only infant formula containing synbiotics, probiotics or prebiotics.MethodsCochrane methodology was followed using randomized controlled trials (RCTs) which compared term infant formula containing probiotics, prebiotics or synbiotics to conventional infant formula with / without placebo among healthy full term infants. The mean difference (MD) and corresponding 95% confidence intervals (CI) were reported for continuous outcomes, risk ratio (RR) and corresponding 95% CI for dichotomous outcomes. Where appropriate, meta-analysis was performed; heterogeneity was explored using subgroup and sensitivity analyses. If studies were too diverse a narrative synthesis was provided.ResultsThree synbiotic studies (N = 475), 10 probiotics studies (N = 933) and 12 prebiotics studies (N = 1563) were included. Synbiotics failed to significantly increase growth in boys and girls. Use of synbiotics increased stool frequency, had no impact on stool consistency, colic, spitting up / regurgitation, crying, restlessness or vomiting. Probiotics in formula also failed to have any significant effect on growth, stool frequency or consistency. Probiotics did not lower the incidence of diarrhoea, colic, spitting up / regurgitation, crying, restlessness or vomiting. Prebiotics in formula did increase weight gain but had no impact on length or head circumference gain. Prebiotics increased stool frequency but had no impact on stool consistency, the incidence of colic, spitting up / regurgitation, crying, restlessness or vomiting. There was no impact of prebiotics on the volume of formula tolerated, infections and gastrointestinal microflora. The quality of evidence was compromised by imprecision, inconsistency of results, use of different study preparations and publication bias.Authors’ conclusionsThere is not enough evidence to state that supplementation of term infant formula with synbiotics, probiotics or prebiotics does result in improved growth or clinical outcomes in term infants. There is no data available to establish if synbiotics are superior to probiotics or prebiotics. show less