Description Prebiotics are forms of dietary fibre which cannot be digested, but which can be fermented within the gut by specific colonies of gut bacteria that are recognised as being beneficial to health. The fermentation process feeds the bacterial species and produces chemical byproducts which are also thought to be beneficial.1

Different types of fibre support different species of bacteria.

Function/ Used for There are a number of different types of prebiotic recognised which support different types of gut bacteria; the two most researched forms are:

  • Fructo-oligosaccharides (FOS) which is fermented by the Lactobacillus forms of gut bacteria
  • Galacto-oligosaccharides (GOS) which is fermented by the Bifidobacterium colonies in the gut

The benefits of prebiotics are still being explored and may go beyond those conferred by probiotics (the colonies of beneficial bacteria that FOS and GOS support).

Current understanding of prebiotics indicates that they support the health of the gastrointestinal tract, may reduce blood lipid levels and may support the immune system.2

Intake N/A
As a supplement Both FOS and GOS are widely available in health food stores across the UK.

Dosage will vary between products; however it is a regulatory requirement that dosage is noted on the packaging of any food supplement.

Found in (dietary sources) N/A
Deficiency N/A
Precautions and contraindications None known.
Use in pregnancy and breastfeeding No known problems.
Interactions e.g. with other medications None reported.
Adverse effects Some reports of flatulence, bloating and diarrhoea which is reversed on stopping treatment.
  1. Schrezenmeir J, de Vrese M. Probiotics, prebiotics, and synbiotics – approaching a definition. The American Journal of Clinical Nutrition 2001; 73:2 361s-364s
  2. Gibson GR, Hutkin R, Sanders ME, Prescott SL, Reimer RA, Salminen SJ, Scott K, Stanton C, Swanson KS, Cani PD, Verbeke K, Reid G. Expert consensus document: The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of prebiotics. Nature Reviews GI & Hep 2017; 14:491–502