Is Gluten Sensitivity Real? Why It Might Actually Be FODMAPs

Yes. Non-coeliac gluten sensitivity is real, and if you feel worse after eating wheat, your experience is genuine.

But here is the twist the latest science keeps confirming: for many people, gluten itself may not be the trigger. A 2025 Lancet review estimated that up to 84% of self-reported gluten sensitivity may not be caused by gluten at all, pointing instead to FODMAPs (especially fructans), other wheat components, or even expectation.¹

First, is non-coeliac gluten sensitivity real?

You eat bread, pasta, noodles, pizza, dumplings, or something made with wheat and then your gut reacts. Bloating, brain fog, tiredness, a heavy and uncomfortable feeling that makes you think: my body does not like gluten. For many people, the conclusion is simple: it must be the gluten. And sometimes it genuinely is, as in coeliac disease or wheat allergy.

But there is another large group who do not have coeliac disease or wheat allergy, yet still feel worse after gluten-containing foods. This is called non-coeliac gluten sensitivity (NCGS), and it affects around 10% of adults worldwide.¹ Symptoms can include abdominal pain, bloating, diarrhoea, constipation, tiredness, headache, brain fog, skin symptoms, low mood, or general discomfort.^1,2

Here is the catch. Unlike coeliac disease, there is currently no reliable blood test, biopsy marker, or single validated biomarker that can clearly diagnose NCGS.^1,2 It remains a diagnosis of exclusion: other conditions, especially coeliac disease and wheat allergy, need to be ruled out first. If they are absent, but symptoms consistently appear after eating wheat and improve when it is removed, NCGS may be considered.

Why scientists started doubting gluten

For a long time the story sounded simple. People ate gluten, felt worse, stopped gluten, felt better. So gluten seemed like the obvious trigger. But nutrition science is rarely that simple.

Wheat-based foods do not contain only gluten. They also contain other naturally occurring compounds, so when someone removes wheat, they usually remove many things at once: fructans (a type of FODMAP), some highly processed foods, and certain additives. When symptoms improve, it can be genuinely hard to know what actually changed.

This is why controlled challenge studies matter: they try to separate gluten from other triggers and compare it against a placebo. The 2025 Lancet review summarised the evidence and reported that only a smaller subgroup of NCGS shows symptoms specifically triggered by gluten, with up to 84% of people estimated not to react to gluten itself.¹ One landmark study found that once FODMAPs were reduced, gluten no longer produced a specific symptom response.³ Another found that fructans, rather than gluten, triggered more symptoms in people with self-reported NCGS.⁴ A more recent trial suggested that expectation itself may influence symptoms as much as, or even more than, the actual gluten content.⁵ We cover FODMAPs in more detail in this article.

If it is not gluten, what is the real culprit?

The most honest answer is: probably more than one thing. For many people, the bigger triggers may be FODMAPs, especially fructans, found in wheat as well as onion, garlic, rye, barley, and some vegetables.^1,4

A recent review described non-coeliac wheat sensitivity as a complex condition involving wheat components, gut-microbiome changes, intestinal barrier function, immune activation, and neuroimmune interactions.² In other words, NCGS may reflect how sensitive your gut is, how your gut microbes respond, how quickly certain carbohydrates ferment, how your immune system reacts, and how your gut and brain communicate.

And this is where fibre becomes interesting. Not because fibre "fixes" gluten sensitivity, but because it may help support some of the gut foundations that appear to be part of the bigger picture: the gut microbiome, short-chain fatty-acid production, gut barrier function, bowel regularity, and digestive tolerance over time. We have covered those in more depth here.

What is usually recommended for gluten sensitivity?

Management is still evolving, but dietary approaches: a gluten-free diet, wheat-reduced diet, or low-FODMAP diet, are currently the common first-line options.^1,2 But this does not mean everyone should remove gluten, wheat, or FODMAPs forever.

A low-FODMAP diet, for example, is not meant to be a lifelong restriction. It is usually a short-term strategy, followed by careful reintroduction and personalisation.⁷ That matters, because many high-FODMAP foods are also fibre-rich and nutrient-rich. If someone removes wheat, legumes, certain fruits and vegetables, garlic, onion, and many wholegrains without careful replacement, their diet can become far less diverse. That might reduce symptoms in the short term, but long-term over-restriction raises concerns around nutritional adequacy, gut-microbiota changes, and overall health.⁶ And sadly, support for the reintroduction phase is not always easy to access. People may be told what to avoid, but not properly supported to rebuild what they can tolerate.

Is a gluten-free diet automatically healthier?

Not always. For people without coeliac disease, going gluten-free does not automatically make the diet healthier. Many gluten-free products are made with refined starches or flours, and some are lower in fibre, lower in certain vitamins and minerals, and higher in sugar, fat, or salt than their gluten-containing equivalents.^7,8

Reviews of gluten-free diets have flagged concerns around low fibre intake, nutritional imbalance, micronutrient deficiencies, higher cost, limited availability, and reduced quality of life for some people.^7,8,9,10 The risk is especially real for those who are not coeliac but started a gluten-free diet without support: the diet can become more and more restricted over time, and even make you feel worse in the long term. A 2025 prospective cohort followed people without coeliac disease who had avoided gluten for more than 25 years; as a group, they reported more gut symptoms and poorer wellbeing than healthy controls, with some scores even worse than in untreated coeliac disease.¹¹

So what can you do in the meantime?

A good part of the concern around restrictive diets comes down to the risk of low fibre intake, and NCGS itself appears to involve gut-microbiome changes, intestinal barrier function, immune activation, and neuroimmune interactions.² Certain fibres can feed beneficial gut bacteria, support short-chain fatty-acid production, and help maintain bowel regularity and gut barrier function, and research on non-coeliac wheat sensitivity is increasingly interested in the microbiome, dysbiosis, butyrate, and intestinal permeability.^2,6 We have discussed how fibre relates to inflammation here.

That does not make fibre the whole answer. But it does mean a restricted diet should not become a low-fibre diet by accident. The goal is not simply to remove triggers; it is a whole-body approach: reduce triggers, increase support, and do it in a sustainable way you can actually keep up.

Could enzyme-prepared fibre help?

The science around NCGS is still evolving, and we are only recently beginning to understand that gluten may not be the main trigger for many people. But "not clinically recommended yet" does not always mean an idea is untrue. Sometimes it simply means the science has not gone far enough.

One interesting point from the 2025 Lancet review is that enzyme preparations are being explored as an emerging area: the idea that enzymes may help break certain food compounds into smaller components that are less likely to trigger symptoms, or easier for the gut to handle. The evidence is still early, and more studies are needed before enzyme approaches can be confidently recommended.¹

This is especially close to home for us, because enzyme processing was part of my PhD research and one of the ideas that led to PuriFibre. PuriFibre is an enzymatically prepared fibre, designed to be easy and rewarding to use. Not a gritty powder, bulky capsule, or another difficult diet rule, but a simple daily fibre shot that fits into real life. Partially hydrolysed fibres of this kind have been studied for their effects on gut function and tolerance.¹²

So for people on a gluten-free, wheat-reduced, or otherwise restricted diet, PuriFibre may be one practical way to help support fibre intake while feeding beneficial gut microbes,  not because it fixes NCGS, and not because it replaces medical or dietetic care, but because restricted diets can easily become low-fibre diets, and the gut still needs support. The goal of dietary management is not to shock your gut into change; it is to reduce triggers, increase support, and do it in a sustainable way you can actually keep up.

The takeaway

If you feel worse after eating gluten-containing foods, your experience is real. But the science suggests gluten may not always be the main trigger. For many people with self-reported gluten sensitivity, symptoms may be linked to FODMAPs, especially fructans, other wheat components, gut-microbiome changes, gut-brain sensitivity, expectation effects, or a mix of all of these.

The most helpful approach is usually not to remove more and more foods forever. It is to identify your real triggers, protect nutritional adequacy, rebuild variety where you can, and support your gut with habits you can actually maintain. And fibre is one practical place to start, not as a cure, not as a replacement for medical care, but as one small, steady way to support your gut.

Important note

This article is general information, not medical advice. If you have ongoing gut symptoms, rule out coeliac disease and wheat allergy with a healthcare professional before removing gluten. Starting a gluten-free diet first can make coeliac disease much harder to diagnose accurately. Persistent or severe symptoms, unexplained weight loss, blood in the stool, or a major change in bowel habits should always be assessed by a professional.

References

1. Biesiekierski, J. R.; Jonkers, D.; Ciacci, C.; Aziz, I. Non-Coeliac Gluten Sensitivity. Lancet 2025, 406 (10518), 2494–2508. https://doi.org/10.1016/S0140-6736(25)01533-8
2. Piotin, A.; de Blay, F. Investigating Non-Celiac Wheat Sensitivity: A Comprehensive Review of Pathophysiology Underlying Clinical Implications. Clinical Reviews in Allergy & Immunology 2025, 68, 94. https://doi.org/10.1007/s12016-025-09106-6
3. Biesiekierski, J. R.; Peters, S. L.; Newnham, E. D.; Rosella, O.; Muir, J. G.; Gibson, P. R. No Effects of Gluten in Patients With Self-Reported Non-Celiac Gluten Sensitivity After Dietary Reduction of Fermentable, Poorly Absorbed, Short-Chain Carbohydrates. Gastroenterology 2013, 145 (2), 320–328.e1–3. https://doi.org/10.1053/j.gastro.2013.04.051
4. Skodje, G. I.; Sarna, V. K.; Minelle, I. H.; Rolfsen, K. L.; Muir, J. G.; Gibson, P. R.; Veierød, M. B.; Henriksen, C.; Lundin, K. E. A. Fructan, Rather Than Gluten, Induces Symptoms in Patients With Self-Reported Non-Celiac Gluten Sensitivity. Gastroenterology 2018, 154 (3), 529–539.e2. https://doi.org/10.1053/j.gastro.2017.10.040
5. de Graaf, M. C. G.; Lawton, C. L.; Croden, F.; Smolinska, A.; Winkens, B.; Hesselink, M. A. M.; et al. The Effect of Expectancy versus Actual Gluten Intake on Gastrointestinal and Extra-Intestinal Symptoms in Non-Coeliac Gluten Sensitivity: A Randomised, Double-Blind, Placebo-Controlled, International, Multicentre Study. Lancet Gastroenterology & Hepatology 2024, 9 (2), 110–123. https://doi.org/10.1016/S2468-1253(23)00317-5
6. Leccioli, V.; Oliveri, M.; Romeo, M.; Berretta, M.; Rossi, P. A New Proposal for the Pathogenic Mechanism of Non-Coeliac/Non-Allergic Gluten/Wheat Sensitivity: Piecing Together the Puzzle of Recent Scientific Evidence. Nutrients 2017, 9 (11), 1203. https://doi.org/10.3390/nu9111203
7. Cristofori, F.; Castellaneta, S.; Dargenio, C.; Paulucci, L.; Lagrasta, G.; Barone, M.; Francavilla, R.; Dargenio, V. N. Unlocking the Potential of the Low FODMAP Diet: Comprehensive Insights into Clinical Efficacy, Microbiome Modulation, and Beyond. Expert Review of Gastroenterology & Hepatology 2025, 19 (7), 767–787. https://doi.org/10.1080/17474124.2025.2519160
8. Abdi, F.; Zuberi, S.; Blom, J.-J.; Armstrong, D.; Pinto-Sanchez, M. I. Nutritional Considerations in Celiac Disease and Non-Celiac Gluten/Wheat Sensitivity. Nutrients 2023, 15 (6), 1475. https://doi.org/10.3390/nu15061475
9. Demirkesen, I.; Ozkaya, B. Recent Strategies for Tackling the Problems in Gluten-Free Diet and Products. Critical Reviews in Food Science and Nutrition 2022, 62 (3), 571–597. https://doi.org/10.1080/10408398.2020.1823814
10. Lerner, A.; O'Bryan, T.; Matthias, T. Navigating the Gluten-Free Boom: The Dark Side of Gluten Free Diet. Frontiers in Pediatrics 2019, 7, 414. https://doi.org/10.3389/fped.2019.00414
11. Salmela, E.; Kurppa, K.; Lindfors, K.; Saavalainen, P.; Huhtala, H.; Kaukinen, K.; Taavela, J. Long-Term Health Outcomes of People without Celiac Disease Avoiding Gluten Consumption: A 25-Year Prospective Cohort Study. European Journal of Clinical Nutrition 2025, 79, 1053–1059. https://doi.org/10.1038/s41430-025-01641-x
12. Yoon, S.-J.; Chu, D.-C.; Juneja, L. R. Physiological Functions of Partially Hydrolyzed Guar Gum. Journal of Clinical Biochemistry and Nutrition 2006, 39 (3), 134–144. https://doi.org/10.3164/jcbn.39.134