GOS/FOS prebiotics in formula milk
Get the GOS/FOS.
Learn more about the benefits of these vital prebiotics
Glossary at a glance
To keep the science simple, here’s a handy glossary of terms we’ll be using when we’re talking all things GOS/FOS:
- Prebiotics: help to feed and nourish the beneficial bacteria in the gut1
- GOS and FOS: types of prebiotics that act as nutrients and feed the good bacteria in the gut2
- The gut microbiome: a complex community of good and beneficial bacteria that live in the gut3
What are GOS and FOS prebiotics?
FOS (which stands for fructooligosaccharides) and GOS (referring to galactooligosaccharides) are types of prebiotics4.
Prebiotics feed the good bacteria in our gut and support our overall health5, and your baby can get them from either breast milk or baby formula.
The gut microbiome: your baby's gut garden
There are billions of bacteria living in your baby’s gut, and these make up their ‘gut microbiome’. These bacteria play a really important role in digesting food, supporting your baby’s immune system, and providing lots of other health benefits6 .
Just picture your baby’s gut microbiome as a garden full of plants and prebiotics like GOS and FOS as the sunlight and water that help them grow.
Prebiotics in breast milk
Breastmilk is recognised as the gold standard nutrition for babies and is rich in powerful prebiotics called human milk oligosaccharides (HMOs)4. HMOs play an essential role in the development of your baby’s nervous system and immune system to support them as they grow7.
When your baby drinks your breast milk, HMOs make their way to their intestine undigested. Once there, they are used by good bacteria and help them to grow, fueling your baby’s gut microbiome.
GOS and FOS in infant formula
In 1994, Nutricia Research (the research centre behind Aptamil) developed a unique prebiotic blend of 90% GOS and 10% FOS (9:1 GOS/FOS), closely resembling the structure of HMOs found in breastmilk.
Some infant formulas are fortified with 9:1 GOS/FOS prebiotics that can act in a similar way to HMOs, feeding your baby’s good gut bacteria8. This means that if you decide to exclusively formula feed your baby with formula fortified with prebiotics or combination feed with breast milk, your little one can still get some of the benefits of prebiotic effects.
Benefits of GOS and FOS for your baby
The special 9:1 GOS/FOS blend in some baby formulas can provide a number of benefits for your little one, like supporting their digestive system and laying important foundations for their immune system from the moment they’re born.
Supporting their digestion
Prebiotics like GOS/FOS can help your baby to digest and absorb nutrients by increasing the amount of good gut bacteria like bifidobacteria - a good bacteria that’s plentiful in the guts of breastfed babies9.
GOS/FOS can also have an impact on how they poo, as based on research, babies who drink infant formula enriched with a specific ratio and amount of prebiotics tend to have softer poos, similar to those babies who are breastfed10.
All in all, GOS and FOS play their part in supporting your baby’s digestive system.
Supporting their immune system
GOS and FOS do more than feed the good bacteria in the gut microbiota; they can also support your baby’s developing immune system. That’s because they can strengthen the gut wall barrier and reduce inflammation to improve your baby’s natural defences4.
Did you know?
Up to 80% of your immune system cells live in your gut11
Research shows that having a healthy gut as a baby can prevent some diseases later in life too, so getting the right nutrition from day one can set your little one up with a strong, healthy immune system for life12.
Supporting the building blocks of your baby’s future health
There's a lot of information out there on what and how to feed your baby, and it's easy to feel overwhelmed or anxious about making the right choice. That’s why we’re here to give you all the information you need on prebiotics, HMOs, and GOS/FOS, meaning you can make informed nutritional choices that work for you and your little one.
There’s no doubt that breastfeeding is best for your baby, but if you do choose to formula feed or combi feed, for whatever reason, selecting a baby formula that contains a special 9:1 blend of GOS/FOS can help to support your baby’s developing digestive system and support their immune system for a healthy start.
- Guts UK. Prebiotics & Probiotics [online]. Available at https://gutscharity.org.uk/advice-and-information/health-and-lifestyle/prebiotics-probiotics/. [Accessed January 2025]
- Bode L. Human milk oligosaccharides: every baby needs a sugar mama. Glycobiology 2012; 22(9): 1147–62.
- Imperial College Healthcare NHS Trust. (n.d.). James Kinross Q&A [online]. Available at: https://www.imperial.nhs.uk/about-us/blog/james-kinross-q-and-a. [Accessed January 2025]
- Selvamani S, Kapoor N, Ajmera A, El Enshasy HA, Dailin DJ, Sukmawati D, Abomoelak M, Nurjayadi M, Abomoelak B. Prebiotics in New-Born and Children's Health. Microorganisms. 2023 Sep 29;11(10):2453. doi: 10.3390/microorganisms11102453. PMID: 37894112; PMCID: PMC10608801.
- Davani-Davari D, Negahdaripour M, Karimzadeh I, Seifan M, Mohkam M, Masoumi SJ, Berenjian A, Ghasemi Y. Prebiotics: Definition, Types, Sources, Mechanisms, and Clinical Applications. Foods. 2019 Mar 9;8(3):92. doi: 10.3390/foods8030092. PMID: 30857316; PMCID: PMC6463098.
- NHS Genomics Education Programme (2019). The microbiome and childhood health [online] Available at http://www.genomicseducation.hee.nhs.uk/blog/the-microbiome-and-childhood-health/ [Accessed January 2025]
- Okburan G, Kızıler S. Human milk oligosaccharides as prebiotics. Pediatr Neonatol. 2023 May;64(3):231-238. doi: 10.1016/j.pedneo.2022.09.017. Epub 2023 Jan 2. PMID: 36642576.
- Vandenplas Y, De Greef E, Veereman G. Prebiotics in infant formula. Gut Microbes. 2014;5(6):681-7. doi: 10.4161/19490976.2014.972237. PMID: 25535999; PMCID: PMC4615227.
- Liu, F., Li, P., Chen, M. et al. Fructooligosaccharide (FOS) and Galactooligosaccharide (GOS) Increase Bifidobacterium but Reduce Butyrate Producing Bacteria with Adverse Glycemic Metabolism in healthy young population. Sci Rep 7, 11789 (2017). https://doi.org/10.1038/s41598-017-10722-2
- 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 Pediatr Gastroenterol Nutr. 2011 Jun;52(6):763-71. doi: 10.1097/MPG.0b013e3182139f39. PMID: 21593649.
- Wiertsema SP, van Bergenhenegouwen J, Garssen J, Knippels LMJ. The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients. 2021 Mar 9;13(3):886. doi: 10.3390/nu13030886. PMID: 33803407; PMCID: PMC8001875.
- Sarkar A, Yoo JY, Valeria Ozorio Dutra S, Morgan KH, Groer M. The Association between Early-Life Gut Microbiota and Long-Term Health and Diseases. J Clin Med. 2021 Jan 25;10(3):459. doi: 10.3390/jcm10030459. PMID: 33504109; PMCID: PMC7865818.
Last reviewed 7th July 2025
Authored by Bahee Van de Bor
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