Gluten vs FODMAPs: What the Research Actually Shows
Wheat contains two distinct types of compounds that can cause digestive discomfort. The first is gluten, the protein that causes genuine immune damage in people with coeliac disease. The second is fructans, a type of FODMAP (fermentable oligosaccharide) that feeds gut bacteria and produces gas in the process. Most bread-related bloating in people without coeliac disease is driven by the fructans, not the gluten.
A 2025 review in The Lancet found that gluten-specific effects largely disappear once FODMAPs are controlled for, with meta-analyses indicating only a small subgroup of people show genuine gluten-specific responses in controlled trials.
Gluten gets the blame. Fructans are usually the cause. And the reason fructans cause problems for some people but not others comes down to the bacteria in the gut.
Why Some People Bloat From Bread and Others Don't
FODMAPs are fermented by gut bacteria in the colon. In a diverse, well-balanced microbiome, this fermentation is efficient and produces minimal gas. In a microbiome with reduced diversity or depleted SCFA-producing bacteria, fermentation becomes dysregulated, producing excess gas, altering gut motility, and causing the bloating and discomfort associated with bread consumption.
A 2023 double-blind, randomised crossover study published in Nutrients, examining the effects of FODMAPs and gluten on gut microbiota in IBS patients, found that FODMAPs, not gluten, altered microbiota composition and correlated with changes in phenolic-derived metabolites. Gluten showed no significant effect on gut microbiome composition. FODMAPs did. The implication is direct: the digestive response to bread is shaped by the gut microbiome, not the gluten content.
The Low-FODMAP Diet: Useful but Incomplete
A low-FODMAP diet is the standard clinical recommendation for bread-related bloating. It works by reducing the fermentable substrate that bacteria produce gas from. But it has a structural limitation: low-FODMAP diets also reduce prebiotic fibre intake, which over time depletes the beneficial bacteria that would otherwise process FODMAPs efficiently. The diet manages the symptom while potentially worsening the underlying microbiome problem.
A 2024 study in Frontiers in Microbiology examining low-FODMAP sourdough bread found that sourdough fermentation reduces FODMAP content while maintaining gut microbiome benefits. The lactic acid bacteria used in sourdough fermentation break down fructans during the long fermentation process, making the bread more tolerable for FODMAP-sensitive individuals without removing the prebiotic value. This is why many people who bloat from commercial bread tolerate sourdough better.
The goal is not to avoid all fermentable foods. The goal is a gut microbiome diverse enough to ferment them without producing excessive discomfort. That is a microbiome goal, not a dietary restriction goal.
What Actually Helps
Cutting bread provides short-term symptom relief but does not address the microbiome disruption that makes bread problematic in the first place. A more durable approach is building microbiome diversity through consistent prebiotic fibre from non-FODMAP sources, reducing the fermentation dysregulation that drives the bloating response.
DULCI provides 7g of clinically studied prebiotic fibre per scoop, an excellent source of fibre by the regulated standard. It ferments slowly and tolerably, supporting microbiome diversity without the gas-producing rapid fermentation associated with high-FODMAP foods. It dissolves in hot or cold liquid and can be stirred through food. It's heat stable, so you can cook and bake with it. Over time, a more diverse microbiome processes all foods more efficiently. Including bread.
If bread makes you bloated, you probably do not have a gluten problem. You likely have a gut bacteria problem that expresses itself when you eat fermentable carbohydrates.
Treat the bacteria and the bread becomes manageable again.
