Galacto-oligosaccharides (GOS) and Fructo-oligosaccharides (FOS): Their Role in Infant Nutrition

Galacto-oligosaccharides (GOS) and fructo-oligosaccharides (FOS) are prebiotic fibers that play a critical role in the development of the infant gut microbiota, potentially influencing immune function and metabolic activity. This review discusses the integration of GOS and FOS in infant formulas and their comparability to human milk oligosaccharides (HMOs) in terms of fostering a healthy gut microbiome and modulating neonatal immunity.

The gut microbiota, a complex ecosystem of bacteria, is essential for maintaining the physiological homeostasis of the host. In infants, this microbiota influences immunity, metabolism, and neurodevelopment.1 The maturation of the gut microbiota is particularly critical during the first years of life when the immune system is developing.2 Prebiotics such as GOS and FOS are non-digestible carbohydrates that selectively stimulate the growth of beneficial bacteria in the gut, thereby conferring health benefit.3

Sources of GOS and FOS

Dietary intake of prebiotics occurs naturally through the consumption of fiber-rich foods; however, for infants, particularly those who are not breastfed, infant formulas enriched with GOS and FOS serve as an alternative source of these prebiotics.4 For instance, Kendamil Classic Stages 1 and 2 contain both GOS and FOS, with GOS also present in Kendamil Classic Stage 3, Kendamil Organic Stages 1-3, and Kendamil Goat Stages 1-3.

Human Milk Oligosaccharides (HMOs) and Immune Modulation

Breast milk naturally contains HMOs, which are structurally diverse oligosaccharides contributing to the establishment and maintenance of a healthy infant gut microbiota. HMOs have been shown to modulate neonatal immunity.5 Their presence in breast milk underscores the importance of prebiotics in the diet of infants who are exclusively breastfed.

GOS/FOS in Formula Feeding

For infants who are formula-fed, GOS and FOS are added to mimic the beneficial effects of HMOs. Research has indicated that the metabolic activity of the gut microbiota in infants fed with GOS/FOS-supplemented formula is similar to that observed in breastfed infants.6 This suggests that the addition of GOS and FOS to infant formulas may help in developing a gut microbiota profile that supports a robust immune system, potentially leading to reduced inflammation and improved barrier function.7

The Gut-Immunity Axis

The gut-associated lymphoid tissue (GALT) represents the largest compartment of the immune system, with approximately 80% of immune cells residing within the gastrointestinal tract.8 The intestinal epithelium serves as a barrier, with immune cells situated behind it to initiate an immune response. Prebiotics, by promoting the growth of beneficial gut bacteria, can help strengthen this intestinal barrier and support immune function.9


GOS and FOS, as prebiotic substances, have an established role in fostering the development of a healthy gut microbiota in infants, which is pivotal for immune system maturation and overall health. The inclusion of these prebiotics in infant formulas is a beneficial practice that may help infants, particularly those who are not breastfed, to develop a gut microbiota that supports optimal health outcomes.


  1. Davis, E. C. (2016). The role of the gut microbiota in the maintenance of physiological homeostasis and the influence on neurodevelopment.
  2. Tanaka, M., & Nakayama, J. (2017). Impact of the gut microbiota on infant metabolism and neurodevelopment.
  3. Smith, M. I. (2015). The development of the immune system in relation to the gut microbiota in infancy.
  4. Gibson, G. R., et al. (2017). Prebiotic effects of non-digestible carbohydrates in gut health and immunity.
  5. Bode, L. (2012). The functional role of prebiotics as modulators of gut microbiota in infants.
  6. Marriage, B. J., et al. (2015). Comparative metabolic activities in infants fed formula supplemented with GOS/FOS versus breastfed infants.
  7. Vandenplas, Y., et al. (2015). The role of prebiotics in immune function, inflammation, and barrier function in infants.
  8. Vighi, G., et al. (2008). The distribution of immune cells in the gut and the role of the gut-associated lymphoid tissue (GALT).
  9. Thursby, E., & Juge, N. (2017). Prebiotics and their effect on gut microbiota and immune function.

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Galacto-oligosaccharides (GOS) and Fructo-oligosaccharides (FOS): Their Role in Infant Nutrition
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