What are prebiotics? - Little Étoile

What are prebiotics?

What is dietary fibre?

To understand what prebiotics are, it helps to understand what dietary fiber is. Dietary fiber is a sub-category of macronutrients that helps with gut health and motility. In children, there are multiple health benefits of dietary fibre, including preventing obesity and constipation[1].
When children consume food, the bulk food is broken down in the stomach, and sent to the intestine where the nutrients and water are absorbed from it, across the intestine’s wall and into the body. What is left over is non-digested material and waste, which eventually becomes the feces.
In infants, milk oligosaccharides are older infants on solids, and older children, a lot of the non-digested fibre comes from complex carbohydrates broken down from fruits, vegetables and cereal grains, or from what is added to nutrient formulas. These stay in the gut and help to provide bulk to move the waste out, but also feed the good bacteria (gut microbiome) that live within the gut.

How are prebiotics related to dietary fibre?

Prebiotics are a form of dietary fibre, presented as purified, non-digestible carbohydrates in food products that feed the good bacteria in the gut. This includes those added to nutrient formulas for infants and children as oligosaccharides. These naturally occur in breastmilk and dairy foods, and are the preferred food for lactic acid bacteria that populate the microbiome[2].

Actually, many of the contents in the non-digested materials in the toddler and early childhood gut can feed the microbiome. This also contributes to have a prebiotic effect.

What are the health effects of prebiotics in children?

In protecting the microbiome, prebiotics indirectly help to guard the function of the intestine and immune system. The microbiome protects the part of the intestine where infections commonly happen, causing problems such as diarrhea and gas. Furthermore, treatment with antibiotics doesn’t just kill bad bacteria – it has been reported to kill the good ones, causing problems such as antibiotic associated diarrhea (AAD) [3].

The intestine also becomes prone to damage and nutrient losses. These, in turn, slow down growth and make the immune system more prone to infections.

In a research review of clinical reports involving children 0-24 months of age, the investigators demonstrated a 68% decrease in the number of infectious episodes needing antibiotic therapy following prebiotic use, compared to a placebo (blank) group [4].

Another research study has demonstrated that prebiotic supplementation to toddler milk led to a moderately reduced the risk of getting at least one respiratory infection, with lower rates of infection (8%) and total number of infectious episodes (12%), compared to control milk [5].

There is also evidence of a reduction in allergic conditions, as outlined in a review of 22 research studies[6]. Children given prebiotics, typically as a formula, and usually including the prebiotic oligosaccharide, GOS, showed a reduction in the risk of asthma (11%), eczema (6%) and food allergies (12%) compared to placebo (blank) groups.

Summing up

Prebiotics are a kind of dietary fibre that helps support the gut microbiome. All foods contain a certain amount of fibre, as non-digestible carbohydrates from plants and cereals. Prebiotics are more purified, and used to support digestive and immune system health in children.


  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262613/
  2. https://pubmed.ncbi.nlm.nih.gov/12215177/
  3. https://pubmed.ncbi.nlm.nih.gov/11118872/
  4. https://pubmed.ncbi.nlm.nih.gov/24903007/
  5. https://pubmed.ncbi.nlm.nih.gov/24614142/
  6. https://pubmed.ncbi.nlm.nih.gov/29035013/