The review, a collaboration between Wageningen University & Unilever, proposes these strains are members of a group that contributes to overall beneficial effects in children living in Low- and Middle-Income Countries (LMIC).
This group also includes the species L. acidophilus, Bifidobacterium animalis subsp. lactis, and Bacillus coagulans along with prebiotics galacto-oligosaccharides (GOSs) and oligosaccharides (including oligofructose).
Whilst the study acknowledges the evidence is limited to draw firm conclusions about the effect of gut-targeted interventions on growth outcomes, the team draws attention to probiotics and synbiotics as having greater potential in this instance when compared to the prebiotics featured in the review.
“Our review effects of probiotics were primarily seen in undernourished children, whereas synbiotics had positive effects in both undernourished and healthy children,” the study comments.
“It would [therefore] be of interest to investigate the role of the initial health status of the children on the effects of the gut-targeted interventions.
“Moreover, attention should be paid to other community and societal factors such as health care, education, society and culture, and agriculture and food systems,” the team adds.
“These factors have an impact on growth and development of children and may influence the effectiveness of gut-targeted nutritional interventions.”
Methodology
In the review, a total of eleven probiotic, six prebiotic and four synbiotic studies met the inclusion criteria and quality assessed using the Cochrane Risk of Bias tool.
In addition, the certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.
By evaluating the risk of bias, imprecision, inconsistency, indirectness, and publication bias, the certainty of the evidence was judged as “very low,” “low,” “moderate,” or “high”.
Here, the certainty of the evidence for probiotics was judged as very low owing to methodological limitations of the studies, inconsistency of the results, and imprecision.
The certainty of the evidence for prebiotics was judged as low owing to methodological limitations of the studies and imprecision. The certainty of the evidence for synbiotics was judged as moderate owing to imprecision.
The review’s main findings identified five out of the 11 probiotic studies showed a beneficial effect of probiotics on more than one of the growth outcomes as compared with control.
Here, one out of the four studies were in healthy children and three out of four studies were in undernourished children.
Of the three studies in which the health status was not described, one showed beneficial effects. No significant effects of prebiotics on any of the growth outcomes were seen.
Synbiotics appeared more beneficial than probiotics and prebiotics alone in three out of four studies showing a beneficial effect of the synbiotics on the growth outcomes.
Combination benefits
Along with the benefits of the various strains and the prebiotics, the team also found the combination of linolenic acid, linoleic acid, arachidonic acid, DHA, inulin, and FOSs showed beneficial effects on the growth of children living in LMICs.
“Probiotics may be more effective in undernourished children than in healthy children, because they may restore their dysbiotic microbiota, affecting growth,” the paper speculates.
“Probiotics may ameliorate dysbiotic microbiota in undernourished children, thereby affecting growth.”
For the certainty of the prebiotic evidence that was judged as low, the team pointed to the small number of included trials.
Furthermore, the doses of 0.5–2 grams (g) of prebiotics used by some of the studies included may have been too low to induce an effect, since most prebiotics require an oral dosage of over three grams per day (g/d) to induce an effect.
The four included studies that showed overall a beneficial effect of synbiotics on growth outcomes, was attributed to its synergistic manner, in which the prebiotics are specifically and preferentially fermented by the probiotic.
“This increases the opportunity for the probiotic to adhere and grow in the gut,” the team writes. “In theory, this could especially be true for undernourished children who have dysbiotic gut microbiota and increased colonisation potential.”
Source: Curr Dev Nutr.
Published online: doi: 10.1093/cdn/nzab124
“Gut Microbiota–Targeted Nutritional Interventions Improving Child Growth in Low- and Middle-Income Countries: A Systematic Review.”
Authors: Lise Heuven et al.