For many people living with irritable bowel syndrome (IBS), gluten has become the default culprit for digestive symptoms. If bread, pasta, or pizza leave you bloated, uncomfortable, or running to the bathroom, it’s easy to assume gluten is the problem and your instinct may be to cut it out entirely. But a robust body of research suggests the real trigger isn’t gluten itself, but fructans: fermentable carbohydrates found in wheat, garlic, onion, and other nutritious foods that can be difficult to digest.
To help unpack what’s really going on, we spoke with Jessica R. Biesiekierski, a leading researcher in IBS, gluten, and FODMAPs. Her work reshapes how the clinical field thinks about food triggers, gut sensitivity, and why so many people feel better on a gluten-free diet (even when gluten isn’t the true cause for symptoms).
In this conversation, she explains why wheat is more complex than it may seem, why fructans intolerance is far more common than gluten intolerance, and how a more personalized approach, including tools like digestive enzymes, can help people manage symptoms without unnecessary long-term restriction.
We’re honored to sit down with you today. To get started, we’d love to learn about the focus of your work. What questions drive your research on gluten, FODMAPs and IBS?
I study why certain foods trigger symptoms in some people but not others, and how diet interacts with the gut and the brain to shape symptom experience. My goal is to help people with IBS feel better without unnecessary food rules or long-term restriction, using evidence-based, personalized approaches.
Gluten sensitivity is commonly discussed. Based on your research, what are we learning about non-celiac gluten sensitivity?
For most people without celiac disease, gluten itself is not the main cause of symptoms. When tested carefully, gluten rarely triggers symptoms on its own. Instead, symptoms often relate to how the gut processes certain foods and how the brain interprets signals from the gut.
How does the prevalence of gluten sensitivity compare to fructan or overall FODMAP sensitivity?
Fructans — a type of fermentable carbohydrate found in foods like wheat, onion, and garlic — are much more common triggers for people with IBS than gluten. This helps explain why many people feel better on a gluten-free diet even when gluten is not the true problem.
Tell us about the latest findings of your research on non-celiac gluten sensitivity and fructan intolerances. What are we learning about the role gluten and fructans play in IBS symptoms?
Carefully controlled studies show that symptoms are often driven by a combination of gut sensitivity and gut–brain interaction rather than a single food ingredient. In many cases, people experience symptoms even when gluten is absent, highlighting the importance of looking beyond gluten alone.
We know wheat is complicated. What do you wish the public better understood about wheat and its role in IBS symptoms?
Wheat is a complex food made up of many components. Removing gluten usually removes other things at the same time, so feeling better after cutting wheat does not automatically mean gluten was the cause. Understanding this can help avoid unnecessary long-term restriction.
For someone with IBS or food-related digestive symptoms, what are the clearest ways to differentiate gluten sensitivity from fructan intolerance?
The clearest way is a step-by-step, guided approach rather than guessing. This usually involves ruling out celiac disease first, then using short-term dietary trials and gradual re-introduction with professional support to identify personal triggers safely.
Why do you think gluten has become the main “culprit” in the public narrative around symptoms? Are there any misconceptions you’d like to set straight?
Gluten has become a simple and visible explanation for complex symptoms. While it’s an important trigger for people with celiac disease, for many others the story is more about gut sensitivity and gut–brain communication than gluten itself.
What are the risks of self-diagnosing non-celiac gluten sensitivity or restricting gluten when it’s not necessary?
Cutting out foods unnecessarily can reduce diet quality, increase anxiety around eating, and make symptoms harder to manage over time. Many people benefit more from understanding their individual tolerance than from strict avoidance.
What’s your perspective on the low FODMAP diet? What are its strengths, limitations, and what do people often get wrong about it?
The low FODMAP diet can be very effective when used properly, but it is not meant to be permanent. Its purpose is to help people identify which foods they tolerate, not to avoid a wide range of foods forever.
What strategies do you recommend for managing FODMAP and fructan-related symptoms without excessive diet restriction?
Managing FODMAP and fructan-related symptoms is best approached as a learning process, ideally with support from a dietitian. Many people can tolerate these foods in smaller amounts or specific forms, and gradual reintroduction helps identify personal thresholds rather than defaulting to long-term avoidance. It’s also important to recognize that symptoms are not driven by food alone — gut sensitivity, stress, and gut–brain interaction can amplify responses — so for some people, combining dietary guidance with gut–brain therapies such as cognitive behavioral therapy can support a more flexible and sustainable relationship with food.
For people who do experience gluten-specific symptoms, what are ways to manage symptoms without unnecessary diet restriction?
For the small number of people who appear to have gluten-specific symptoms outside celiac disease, the goal is targeted reduction rather than complete exclusion. This may involve limiting larger or more concentrated gluten exposures, choosing forms of wheat that are better tolerated, and regularly reassessing tolerance over time. Total avoidance is rarely necessary, and maintaining flexibility helps protect diet quality and reduce the burden of restriction.
What role can enzymes play in supporting people with fructan or other FODMAP intolerances? What about those with gluten sensitivity?
Digestive enzymes may help some people reduce symptoms and feel more confident eating a wider range of foods, particularly in everyday or social situations. This can be relevant for people who believe they are sensitive to gluten but may actually be reacting to fructans or other fermentable carbohydrates that often occur alongside gluten-containing foods. In these cases, enzymes that target carbohydrate digestion can reduce symptom burden, supporting dietary flexibility when used as part of a broader, personalized management approach rather than as a standalone solution.
Where do you see the field heading next? What research questions still need answers when it comes to gluten, fructans, and IBS?
IBS research is increasingly focused on personalized and integrated care, recognizing that symptoms arise from different drivers in different people. Ongoing research, including trials of exposure-based cognitive behavioral therapy alongside dietary interventions, is helping clarify how targeting both diet and the brain’s interpretation of gut signals can improve long-term outcomes. We are currently recruiting for an international study open to adults with IBS in Australia and the USA, where participants are randomized to either a dietary intervention or exposure-based CBT, with 12 weeks of free, personalized treatment delivered online. Learn more at www.gutresearchstudy.com
If you could offer advice to those struggling to identify their food triggers, what would it be?
Try not to assume that the first food you blame is the true cause. Symptoms often reflect a combination of food type, portion size, gut sensitivity, and context rather than a single ingredient. Taking a structured, curious approach with professional guidance (ideally from a dietitian) helps most people better understand their personal triggers, reduce unnecessary restriction, and gradually expand their diet while still feeling well.