Prebiotics (Inulin / FOS / GOS)

Also known as: Inulin · FOS (fructooligosaccharides) · GOS (galactooligosaccharides) · Chicory root fibre

●●●Strong Evidence

Non-digestible fibres that selectively feed beneficial gut bacteria (Bifidobacterium, Lactobacillus), increasing SCFA production (butyrate, propionate, acetate). More sustainable microbiome support than probiotics alone.

Effective Dose

5–15g / day

per clinical evidence

Evidence Level

Strong

Gut Health & Digestive

Mechanism

Selective fermentation substrate for beneficial gut bacteria

primary action

Best For

Microbiome diversity

Immune health, Bowel regularity, SCFA production

This profile is for informational purposes only and does not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications.

What Is Prebiotics (Inulin / FOS / GOS)?

Prebiotics are selectively fermented fibres that support growth of beneficial bacteria without directly introducing new strains. Unlike probiotics (transient colonisers), prebiotics feed the existing resident microbiome, producing short-chain fatty acids (SCFAs) and improving microbiome diversity more sustainably. Combining prebiotics with probiotics (synbiotics) produces additive effects.

How It Works: The Science

Inulin and FOS are cleaved by beta-fructosidase in Bifidobacterium species, generating acetate, propionate, and butyrate. Butyrate is the primary fuel for colonocytes and is essential for gut barrier integrity (upregulating tight junction proteins via histone deacetylase inhibition). Propionate travels to the liver and reduces gluconeogenesis and fat synthesis. GOS specifically promotes Bifidobacterium growth in infants and adults.

Primary Mechanism

Selective fermentation substrate for beneficial gut bacteria

Evidence-Based Benefits

Increases Bifidobacterium and Lactobacillus populations

strong

Multiple RCTs — consistent bifidogenic and lactogenic effects at 5–15g/day

Improves bowel regularity and stool frequency

moderate

Niness (1999) — inulin and FOS significantly improved transit time and frequency

Enhances calcium and magnesium absorption

moderate

Coudray et al. (2003) — inulin supplementation increased calcium absorption

Dosage Guide

Effective Dose

5–15g / day

5–15g/day. Start at 3–5g to allow gut bacteria to adapt (bloating and flatulence are common at higher starting doses — titrate up over 2–3 weeks). Chicory-derived inulin and FOS are the most widely available.

Safety Profile & Side Effects

Flatulence and bloating are common, especially early on — a normal fermentation response, not a sign of harm. Symptoms reduce after microbiome adapts. Not suitable for SIBO (small intestinal bacterial overgrowth) without medical guidance.

Who Should (and Shouldn't) Take It

Best for

Microbiome diversityImmune healthBowel regularitySCFA production

Who it's for

Broadly beneficial — everyone can improve microbiome diversity with prebiotic fibre. Most impactful for those eating a low-fibre diet. Combine with probiotics for synbiotic effect.

Frequently Asked Questions

What is the recommended dose of Prebiotics (Inulin / FOS / GOS)?

Is Prebiotics (Inulin / FOS / GOS) safe?

How does Prebiotics (Inulin / FOS / GOS) work?

Who should take Prebiotics (Inulin / FOS / GOS)?

Broadly beneficial — everyone can improve microbiome diversity with prebiotic fibre. Most impactful for those eating a low-fibre diet. Combine with probiotics for synbiotic effect.

Related Ingredients

Probiotics (Lactobacillus / Bifidobacterium)Psyllium Husk L-Glutamine Beta-Glucan (Oat / Yeast)

Medical Disclaimer

Ingredient profiles are for informational purposes only and do not constitute medical advice. Consult a qualified healthcare professional before starting any supplementation, especially if you have pre-existing conditions or take medications. Full disclaimer →