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Gut Health

The gut is the foundation of whole-body health — from immunity to mood. Here is what the evidence says about healing and maintaining it.

This page is for educational purposes only and does not replace medical advice. If you have a diagnosed gut condition (IBS, IBD, Crohn's, coeliac), work with your gastroenterologist.

Key nutrients for gut health

The compounds with the strongest evidence for microbiome support and gut lining repair.

Lactobacillus & Bifidobacterium

Grade A

10–50 billion CFU/day

The most-studied probiotic genera. Reduce IBS symptoms, antibiotic-associated diarrhoea, and improve microbiome diversity. Strain matters — L. rhamnosus GG and B. longum BB536 have the strongest evidence.

Prebiotic fibre (inulin/FOS)

Grade A

5–10g/day

Feeds beneficial bacteria, increases Bifidobacterium counts, and improves stool consistency. Found in chicory, garlic, onion, leeks, and Jerusalem artichoke.

L-Glutamine

Grade B

5–10g/day

Primary fuel for enterocytes (gut lining cells). Reduces intestinal permeability ("leaky gut") in RCTs. Particularly useful after illness, antibiotics, or high-stress periods.

Zinc carnosine

Grade B

75mg/day

Stabilises the gut lining and reduces mucosal inflammation. Used clinically for gastric ulcers and leaky gut. Better absorbed than standard zinc.

Butyrate (or tributyrin)

Grade B

300–600mg/day

Short-chain fatty acid that fuels colonocytes, reduces gut inflammation, and supports the gut-brain axis. Produced naturally by fermenting fibre — or supplemented directly.

Saccharomyces boulardii

Grade A

250–500mg/day

A probiotic yeast with strong evidence for preventing and treating diarrhoea, including traveller's diarrhoea and C. difficile recurrence. Survives antibiotics.

6 natural strategies with strong evidence

Ranked by effect size and quality of evidence.

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#1

Eat 30+ different plant foods per week

The American Gut Project found that people eating 30+ plant varieties per week had significantly more diverse microbiomes than those eating 10 or fewer. Diversity is the single strongest predictor of gut health.

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#2

Eat fermented foods daily

A Stanford RCT (2021) found that a high-fermented-food diet increased microbiome diversity and reduced inflammatory markers more than a high-fibre diet alone. Yogurt, kefir, kimchi, sauerkraut, and miso are the most evidence-backed sources.

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#3

Minimise ultra-processed foods

Ultra-processed foods (emulsifiers, artificial sweeteners, refined carbohydrates) reduce microbiome diversity, increase intestinal permeability, and promote dysbiosis. Polysorbate 80 and carboxymethylcellulose have direct evidence for gut lining disruption.

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#4

Manage stress actively

The gut-brain axis is bidirectional — chronic stress alters gut motility, increases permeability, and shifts the microbiome toward dysbiosis. Mindfulness-based stress reduction (MBSR) improves IBS symptoms in RCTs.

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#5

Exercise regularly

Regular aerobic exercise increases microbiome diversity and short-chain fatty acid production independently of diet. Even 150 min/week of moderate activity produces measurable microbiome improvements.

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#6

Use antibiotics only when necessary

A single course of broad-spectrum antibiotics can reduce microbiome diversity by 25–50%, with some species not recovering for 6–12 months. When antibiotics are necessary, take S. boulardii concurrently and follow with a probiotic course.

Best foods for gut health

Whole foods with the strongest evidence for microbiome diversity and gut lining integrity.

KefirContains 30+ probiotic strains. Strongest evidence for microbiome diversity of any single food.
Sauerkraut & kimchiFermented vegetables rich in Lactobacillus. Reduce inflammatory markers and improve gut barrier function.
Garlic & onionRich in inulin and FOS — potent prebiotics that selectively feed Bifidobacterium.
OatsBeta-glucan fibre feeds beneficial bacteria and produces butyrate. Also reduces LDL cholesterol.
Jerusalem artichokeThe highest inulin content of any food. Powerful prebiotic — start with small amounts to avoid gas.
Bone brothRich in glycine, proline, and collagen precursors that support gut lining integrity.
BlueberriesPolyphenols act as prebiotics, selectively increasing Bifidobacterium and Akkermansia muciniphila.
LegumesHigh in resistant starch and soluble fibre — the primary fuel for butyrate-producing bacteria.

Ready to heal your gut?

The Gut Health Plan gives you a structured 7-day protocol with nutrition, probiotic, and lifestyle guidance.

Start the Gut Health Plan