Common Fibre Types Linked to Gut Inflammation

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Published on July 23, 2025

Key Points:

Not all dietary fibres are beneficial—some may trigger inflammation in sensitive guts.
Prebiotic fibres like inulin and FOS can worsen symptoms in users with inflammatory gut issues or irritable gut.
Research shows fibres type, microbiome diversity, and user profiles determine individual response.
Understanding your fibres tolerance may ease bloating, discomfort, and long-term gut health issues.

In a culture obsessed with gut health, fibre has long been considered universally beneficial. It’s prescribed for regularity, praised for feeding good bacteria, and promoted across everything from cereal boxes to probiotic gummies. But emerging science tells a more complex story—one where not all fibres are created equal, and in some users, certain types may actually worsen gut inflammation.

For millions dealing with bloating, cramping, or unpredictable digestion, the trigger may not be gluten or dairy—but the very fibres they were told to eat more of.

Why This Matters

Digestive discomfort affects more than half of U.S. adults. The American Gastroenterological Association reports that over 60 million Americans experience persistent gut symptoms. For users with irritable gut, inflammatory gut issues, or small intestinal bacterial overgrowth (SIBO),common dietary fibres – especially isolated or processed additives – can irritate rather than soothe the gut lining.

As the wellness market floods with fibre-enriched foods, prebiotics, and powders, it’s critical to know which types of fibre help – and which may hurt.

The Fibre Paradox: When “Healthy” Isn’t Helpful

Fibre falls into two main categories:

Soluble fibre dissolves in water, forming a gel-like substance. It feeds beneficial bacteria and slows digestion. Sources include oats, legumes, and psyllium.
Insoluble fibre does not dissolve; instead, it adds bulk to stool and speeds up transit. Found in wheat bran, whole grains, and many vegetables.

A third group, prebiotic fibres—such as inulin and fructooligosaccharides (FOS)—are often added to “gut-friendly” foods. While they stimulate growth of beneficial bacteria, they can also cause bloating and trigger immune responses in users with disrupted gut environments. Lab studies show that these fibres, when fermented, can activate the immune system. A study found that these fibres increased immune signals (TNF-α, IL-1β, and IL-10) in human blood cells by triggering specific immune receptors called TLRs.

What Is Gut Inflammation?

Gut inflammation can be overt—seen in bloodwork or biopsies—or subtle and subclinical. It may present through elevated biomarkers such as faecal calprotectin or C-reactive protein (CRP), but in everyday life, it shows up as bloating, urgency, pain, and irregular bowel movements.

Certain fibres can contribute to this inflammatory response by:

Altering gut microbiota in ways that promote dysbiosis².
Disrupting the mucosal barrier, increasing permeability (“leaky gut”)³.
Triggering the immune system in sensitive or predisposed individuals⁴.

What the Research Shows

Inulin

Derived from chicory root, inulin is commonly added to bars, yoghurts, and supplements. Emerging research suggests inulin isn’t always gentle. A 2024 study in the Journal of Experimental Medicine found it worsened symptoms in animals with irritable gut⁵.

Wheat Bran

Wheat bran is a classic insoluble fibre, but not ideal for sensitive guts. A 2002 study in Digestive Diseases & Sciences found that people with irritable gut issues tolerated wheat bran poorly – it often increased bloating and discomfort compared to gentler fibre. Its coarse texture and fermentation by gas-producing bacteria may irritate the gut lining, making symptoms worse in some people⁶.

Resistant Starch

Found in green bananas and cooked-then-cooled potatoes, resistant starch can improve gut function in some users. However, in those with SIBO, its fermentation in the small intestine may lead to significant bloating and mucosal stress⁷.

Psyllium

Psyllium husk is often recommended for regularity. A 2023 study showed that while psyllium can reduce urgency, it caused bloating and fermentation-related symptoms at higher doses⁸.

Why Individual Response Varies

The gut is not one-size-fits-all. Genetics, microbiome diversity, and immune history fibre tolerance. A 2021 study found that individual microbiome profiles predicted whether users benefited from or reacted negatively to fibre intake.

Users with post-viral fatigue, trauma-related digestive dysregulation, or inflammatory gut issues often experience heightened reactivity to fermentable fibres—especially those classified as FODMAPs (fermentable oligo-, di-, mono-saccharides and polyols).

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What Experts Recommend

The American Gastroenterological Association now emphasises personalised nutrition over generic fibre guidelines. The World Gastroenterology Organisation’s 2023 update advises against prebiotic fibre supplementation in users with active gut inflammation, recommending a study-based reintroduction approach instead.

Functional nutrition experts also support elimination protocols, such as the low-FODMAP diet, to help identify which fibres trigger symptoms in each individual.

Hidden Sources of Fibre Additives

Many “high-fibre” processed foods include synthetic or isolated fibres like:

Polydextrose
Resistant maltodextrin
Chicory root extract

These additives, while increasing total fibre on labels, can disrupt microbial balance and irritate the mucosal lining in vulnerable users.

Practical Guidelines: Choose Wisely

Generally Well-Tolerated Fibres

Cooked oats
Steamed vegetables (e.g., carrots, zucchini)
Flaxseed (ground)
Psyllium (low-dose)
Berries

Fibres That May Trigger Symptoms in Sensitive Guts

Inulin and FOS (especially as additives)
Wheat bran
Chicory root fibre
Resistant starch (especially in SIBO)
Polydextrose and maltodextrin

Self-Check: Are You Fibre Sensitive?

Try this 4-step fibre tolerance test:

Track your symptoms daily after eating high-fibre foods.
Eliminate added fibres like inulin or polydextrose for two weeks.
Reintroduce one fibre type at a time while monitoring symptoms.
Consult a health professional if discomfort persists or escalates.

This self-check is not diagnostic but can help guide discussion with a healthcare professional.

Final Thoughts

Fibre isn’t the enemy. But it’s not a universal remedy either. For users with inflamed or sensitive guts, smarter—not more—may be the key. When fibre fits your biology, it can build a stronger gut. When it doesn’t, it may quietly undermine it.

Understanding how your body responds to different fibre types can reduce symptoms, calm inflammation, and put you back in control of your digestive health.

The goal isn’t to eliminate fibre – but to identify which forms best support your gut’s current state.

If you experience bloating or discomfort after eating high-fibre foods, consider tracking your intake and discussing it with a healthcare professional. Personalised guidance can help identify the fibres that best support your gut health and overall well-being.

This blog post aims to be informational and should not replace professional health advice. Always consult with a health professional for personalised advice.