During my dietary assessment, a notable pattern emerged regarding bread products. The patient consistently reported symptoms after consuming small portions of sourdough bread, including traditional wheat sourdough and 100% spelt sourdough varieties. Symptoms typically developed within an hour of consumption and included abdominal bloating, headache, flushing, and fatigue. This finding was of particular interest as sourdough spelt bread is often recommended during IBS management due to its reduced fructan content.

In contrast, she reported significantly better tolerance to gluten-free bread products, particularly non-yeasted options such as flatbreads and wraps. This suggested that her symptoms may not be solely attributable to fructan sensitivity. The rapid onset and systemic nature of her symptoms raised the possibility of an adverse response to fermented foods, histamine-containing foods, and/or non-coeliac gluten sensitivity.

My dietetic management focused on an individualised approach rather than further restriction of FODMAP-containing foods. Gluten-free alternatives were incorporated to support dietary adequacy and symptom management. A pragmatic trial of reducing fermented and histamine-rich foods was undertaken, including limiting sourdough bread, aged cheeses, cured meats, and other higher histamine foods. I encouraged fresh food preparation and monitored symptom response while aiming to maintain the least restrictive diet possible.

Over subsequent follow-up appointments, the patient reported a reduction in both gastrointestinal and extra-intestinal symptoms. Dietary variety was gradually expanded while retaining foods that were well tolerated, including selected gluten-free products. She also reported improved confidence with food choices and a reduction in symptom-related anxiety.

This case highlights the complexity often encountered in individuals with IBS who continue to experience symptoms despite appropriate implementation of first-line dietary advice and a low FODMAP diet. It demonstrates the importance of recognising potential overlap between IBS, fructan sensitivity, non-coeliac gluten sensitivity, and possible histamine-related food reactions. It also reinforces the value of a flexible, patient-centred approach that prioritises symptom management and quality of life while avoiding unnecessary dietary restriction. Further research is needed to clarify the role of histamine intolerance and non-coeliac gluten sensitivity in patients presenting with persistent gastrointestinal and systemic symptoms.