Do Oligosaccharide-Supplemented Infant Formulas Improve Infant Gastrointestinal Health? A Systematic Review of Randomized Clinical Trials

Supplementing infant formulas (IFs) with oligosaccharides has gathered much attention over the years because of their purported disease-protecting and health-promoting properties. Despite various clinical trials evaluating the health efficacy of such formulas, many lacked rigor, producing conflicting results. This systematic review focuses on human intervention trials that have examined the purported effects of oligosaccharide-supplemented IFs on the gastrointestinal health in formula-fed infants There is strong evidence showing that supplementing IFs with fructooligosaccharides (FOS) or galactooligosaccharides (GOS) at 7-8 g/L, or other naturally-occurring oligosaccharides or synthetic human-milk oligosaccharides (HMOs) at up to 5.8 g/L, as per industry standards, is well-tolerated by infants, effective in increasing stool frequency and softening of stools, promoting the growth of Bifidobacterium spp. and moderate evidence for reducing the risk of enteric infections. However, the evidence related to the effectiveness of oligosaccharide supplementation in enhancing short-chain fatty acid production, improving gut barrier function, modulating immune function, and reducing the severity and incidence of allergic diseases remains weak and inconclusive and requires further investigation. Supplementation of IFs with oligosaccharides had no demonstrable effect on the growth rate of infants. Thus, further well-designed, randomized, placebo-controlled studies are needed to unequivocally demonstrate other health benefits of oligosaccharide-supplemented IFs.