Efficacy of prebiotic, probiotic and synbiotic administration in improving growth in children aged 0-59 months living in low- and middle-income countries: a systematic review and meta-analysis.

Background: Poor growth is one of the major obstacles to human development, affecting millions of children under the age of 5 years, particularly those living in low- and middle-income countries (LMICs). The objective of this review was to evaluate the efficacy of administering pre-, pro- or synbiotics on the growth of children aged 0-59 months living in LMICs.

Methods: Google scholar, Pubmed, clinical trial.org and Science Direct databases were searched in April 2023 for randomised controlled trials of pre-, pro- or synbiotics that evaluated growth in under fives in LMICs. The primary outcome were weight and height gain. Secondary outcomes were head circumference, body mass index gain and Z score. Random-effects meta-analysis was used to calculate mean differences for continuous outcomes. Grading of Recommendations Assessment, Development and Evaluation criteria was used to assess certainty of the evidence.

Results: Eight trials involving 1375 children under 5 years of age were identified. Meta-analysis of 6 RCTs (n = 991 children) revealed a significant difference in favor of the experimental group (n = 579) compared the control group (n = 412) for weight gain: (MD = 0.33 kg, 95% CI 0.11 to 0.55); low-certainty evidence. Sub-group analysis revealed that pre-, pro, or synbiotics may be more effective in malnourished that healthy children (p = 0.003). Meta-analysis of height gain for 4 RCTs (n = 845) found that there was no significant difference between the experimental group (n = 496) and the control group (n = 349) (MD = 0.31 cm; 95% CI -0.36 to 0.98); low-certainty evidence. In sub-group analysis, prebiotics had a greater impact on height gain than synbiotics (p = 0.03). In the only study reporting an increase in head circumference (n = 32 children), this was not improved by the administration of synbiotics. However, administration of synbiotics to undernourished children significantly improved BMI gain.

Conclusion: The evidence for the administration of pre-, pro- or synbiotics on the growth of children in LMICs is weak. Administration of pre-, pro- or synbiotics may improve weight gain in both healthy and malnourished children. Prebiotics and synbiotics had a significant effect on weight gain. Further research is needed due to the small number of studies, short duration of administration and small sample size.