Effect of pre-, pro- and synbiotics on biomarkers of systemic inflammation in children: a scoping review

Systemic inflammation plays a central role in many diseases and is, therefore, an important therapeutic target. In a scoping review, we assessed the evidence base for anti-inflammatory effects of pre-, pro- and synbiotics in children. Of 1254 clinical trials published in English in Ovid Medline and Cochrane Library PubMed from January 2003 through September 2022, 29 were included in the review. In 6 studies of healthy children (n=1552), one reported that fructo-oligosaccharides added to infant formula significantly reduced pro-inflammatory biomarkers and one study of a single strain probiotic reported both anti- and pro-inflammatory effects. No effects were seen in the remaining two single-strain and one multi-strain probiotic and one synbiotic study. In 23 studies of children with diseases (n=1550), prebiotics were tested in 3, single-strain in 16 and multi-strain probiotics in 6 and synbiotics in 2 studies. Significantly reduced inflammatory biomarkers were reported in 7/10 studies of atopic/allergic conditions, 3/5 studies of auto-immune diseases, 1/2 studies of preterm infants, 1 study of overweight/obesity, 2/2 studies of severe illness and 2/3 studies of other diseases. However, often only one or two of several biomarkers were improved, increased pro-inflammatory biomarkers occurred in 5 of these studies and a probiotic increased inflammatory biomarkers in a study of newborns with congenital heart disease. The evidence base for the effects of pre-, pro- and synbiotics on systemic inflammation in children is weak. Further research is needed to determine if anti-inflammatory effects depend on the specific pre-, pro- and synbiotic preparations, health status and biomarkers studied.