How To Boost Immunity In Infants: Role Of Prebiotics banner

How To Boost Immunity In Infants: Role Of Prebiotics


  • Infants are more susceptible to infection due to immature immune system.
  • Introduction of age-appropriate complementary foods is crucial for the proper development of an infant.
  • Prebiotics like GOS:FOS (9:1) support gut microbiome homeostasis, thereby improving immunity, thus supporting the development of the infant.

Infants are more susceptible to develop certain infections caused by bacteria, viruses, and parasites due to inadequately developed immune systems compared to older children and adults1. This article discusses the influence of prebiotic supplementation on an infant's immune system.

An infant's immune system is functionally immature at birth and transits from innate (type 1) to adaptive immunity (type 2) after birth1,2. Type 2 immunity is responsible for establishing tolerance against infections and differentiation between friendlygut microbiota and harmful pathogens2. In the early months of life, human milk supplies the necessary bioactive components, including human milk oligosaccharides (HMOs)- the prebiotics that protect the infant during the early months of life1.

Recent evidence suggests that HMOs play an important role in building an infant's health through the stimulation of immune development, support for intestinal development, develop gut microbiome, and promotion of the barrier function1. Galactooligosaccharides (GOS) and fructooligosaccharides (FOS) are two dietary oligosaccharides having prebiotic effects similar to HMOS3. Particularly, a 9:1 ratio of GOS:FOS is increasingly studied for its beneficial health effects in infants2. Broadly, the enhancing effects of GOS and FOS on an infant's health can be categorized as follows.

  • Enhance commensal-gut microbiota, that contribute immunomodulatory function and production of beneficial metabolites2.
  • Promote balanced concentrations of beneficial short-chain fatty acids (SCFAs) and vitamins2.
  • Assist in immunity development during early life2.

Effect of GOS and FOS on Commensal Flora

The role of gut microbiota in maintaining immune and metabolic homeostasis is well-established, and modulation of beneficial gut microbiota using prebiotics like GOS and FOS has remained an area of interest in recent years4. In this context, Table 1 depicts the clinical studies involving GOS:FOS and their effect on gut microbiota.

Table 1: Effect of GOS:FOS (9:1) on gut microbiota enhancement5-7 (Adapted from: Chi et al., 2019, Ivakhnenko and Nyankovskyy, 2013; Veereman-Wauters et al., 2011)

Study Infant population (GOS:FOS/Comparator) Treatment duration Key outcomes in GOS:FOS cohort
15 GOS:FOS (n=25);
Distilled water (n=25)
21 days
  • Led to the rapid growth of beneficial Lactobacillus colonies.
26 GOS:FOS (n=80);
Breast milk (n=80);
Standard Formula (n=80)
2 months
  • Bifidobacterium and Lactobacilli count similar to breast-fed infants as mentioned below.
  • Breast milkfed infants (9.047 ± 1.075 and 7.26 ± 0.65 CFU/g, accordingly).
  • GOS:FOS supplemented formula-fed infants (8.92 ± 1.011 and 7.22 ± 0.74 CFU/g, accordingly).
37 Standard formula (n=21);
GOS:FOS- 0.8 g/L (n=19);
Oligofructose:FOS- 0.4 g/L or 0.8 g/L (5:5)(n=21);
Breast milk (n=21)
28 days
  • Intestinal bacterial composition of infants supplemented with GOS:FOS (0.8 g/dL) formula was closer to the breast-fed pattern at days 14 and 28.

GOS:FOS- Galactooligosaccharides:fructoligosaccharides (9:1); CFU- Colony Forming Units

As evident from Table 1., GOS and FOS in the ratio of 9:1 have the potential to modulate intestinal flora in infants and can produce bifidogenic effects similar to breast milk8. Evidence suggests that GOS:FOS administered at 0.4 and 0.8 g/100 ml concentration produced bifidogenic properties. Interestingly, the higher concentration of GOS:FOS (0.8 g/100 ml) produced more beneficial effect on stool characteristics without any side effects7.

Promotion of beneficial short chain fatty acids (SCFAs) and vitamins

SCFAs like acetate, propionate, and butyrate are the primary metabolites produced by the gut bacteria2,4. They are implicated in intestinal epithelial cell integrity, host immunity, lipid metabolism, regulation of appetite, glucose homeostasis, and immune function4. Prebiotics like GOS and FOS serve as food for gut microbiota that produces these SCFAs4. Recently, a clinical study conducted on infants reported that GOS supplementation in infants was associated with increased numbers of Bifidobacteria, augmenting the total SCFAs percentage compared to baseline9.

Further, evidence suggests that gut microbiota can produce vitamins like vitamin K2, retinol, folate, vitamin B6, and vitamin B7, which are an integral part of bone, vision, teeth, and glucose homeostasis2. Thus, it is suggested that the oligosaccharides that promote the gut microbiota which are involved in the synthesis of essential vitamins and SCFAs may have indirect beneficial health effects in the host2.

Assistance in Immunity Development During Early Years of Life

An infant’s nutritional exposure plays a pivotal role in the development and health of the majority of organ systems10. Further, evidence suggests that supplementation of prebiotics, GOS:FOS (9:1), has resulted in beneficial health outcomes in infants, as given below.

  • GOS:FOS (9:1) supplementation showed improved gut immunity, thereby proving to be beneficial to the immune system, as evident by enhanced secretory IgA in infant's fecal matter3.
  • GOS:FOS supplementation, n=342 healthy infants, for six months, reduced the incidence of gastroenteritis (0·12±0·04 vs. 0·29±0·05 episodes/infant/1 year; p=0·015), and lowered antibiotic courses (24/60 vs. 43/65; p=0·004) per year, compared to standard infant formula-fed infants8.
  • During the GOS:FOS supplementation period in infants up to the age of two years, fewer episodes of upper respiratory tract infection (p<0·01), and fever (p<0·00001), and reduced antibiotic prescriptions (p<0·05) appreared8.


Supplementation of prebiotics like GOS:FOS (9:1) in the diet of infants during the initiation of complementary feeding could benefit gut microbiome homeostasis, thereby improving overall health and supporting the development of the infant2.


  1. Donovan SM, Comstock SS. Human milk oligosaccharides influence neonatal mucosal and systemic immunity. Ann NutrMetab. 2016;69(Suppl. 2):41-51.
  2. McKeen S, Young W, Mullaney J, Fraser K, McNabb WC, Roy NC. Infant complementary feeding of prebiotics for the microbiome and immunity. Nutrients. 2019 Feb;11(2):364.
  3. Jeurink PV, van Esch BC, Rijnierse A, Garssen J, Knippels LM. Mechanisms underlying immune effects of dietary oligosaccharides. Am JClinNutr. 2013 Aug 1;98(2):572S-7S.
  4. Tandon D, Haque MM, Gote M, Jain M, Bhaduri A, Dubey AK, Mande SS. A prospective randomized, double-blind, placebo-controlled, dose-response relationship study to investigate efficacy of fructo-oligosaccharides (FOS) on human gut microflora. Sci Rep. 2019 Apr 2;9(1):1-5.
  5. Chi C, Buys N, Li C, Sun J, Yin C. Effects of prebiotics on sepsis, necrotizing enterocolitis, mortality, feeding intolerance, time to full enteral feeding, length of hospital stay, and stool frequency in preterm infants: a meta-analysis. EurJClinNutr. 2019 May;73(5):657-70.
  6. Ivakhnenko OS, Nyankovskyy SL. Effect of the specific infant formula mixture of oligosaccharides on local immunity and development of allergic and infectious disease in young children: Randomized study. PediatriaPolska. 2013 Sep 1;88(5):398-404.
  7. Veereman-Wauters G, Staelens S, Van de Broek H, Plaskie K, Wesling F, Roger LC, McCartney AL, Assam P. Physiological and bifidogenic effects of prebiotic supplements in infant formulae. J PediatrGastrNutr. 2011 Jun 1;52(6):763-71.
  8. Vandenplas Y, Zakharova I, Dmitrieva Y. Oligosaccharides in infant formula: more evidence to validate the role of prebiotics. Br J Nutr. 2015 May;113(9):1339-44.
  9. Sierra C, Bernal MJ, Blasco J, Martínez R, Dalmau J, Ortuno I, Espín B, Vasallo MI, Gil D, Vidal ML, Infante D. Prebiotic effect during the first year of life in healthy infants fed formula containing GOS as the only prebiotic: a multicentre, randomised, double-blind and placebo-controlled trial. EurJNutr. 2015 Feb 1;54(1):89-99.
  10. Amarasekera M, Prescott SL, Palmer DJ. Nutrition in early life, immune-programming and allergies: the role of epigenetics. Asian Pac J Allergy Immunol. 2013 Sep 1;31(3):175-8.