Functional dyspepsia redefined: evidence supporting inflammatory dyspepsia - a systematic review.

Aim: With growing evidence linking food antigens to inflammation and symptoms, our objective was to review the evidence for the impact of dietary factors on functional dyspepsia (FD) pathogenesis. Background: FD is a common gastrointestinal disorder characterised by postprandial fullness, early satiety, epigastric pain, and burning. Methods: A systematic search of MEDLINE, EMBASE, PsycINFO, Scopus, and Cochrane databases was conducted for studies published between January 2000 and December 2024. Eligible studies included adults (≥18 years) with FD diagnosed using the Rome criteria. Data were synthesised narratively, and the risk of bias was assessed using ROBIS, RoB 2.0, and ROBINS-I tools. Results: Fourteen studies met inclusion criteria, evaluating seven key dietary categories: FODMAPs/wheat, prebiotics/probiotics, capsaicin, peppermint-caraway and cinnamon oils, herbal therapies, medications, and ginger-based interventions. High-FODMAP foods, gluten, and capsaicin were linked to symptom exacerbation, with some studies noting impaired epithelial barrier function, immune activation, or microbiota alterations. Interventions with anti-inflammatory or microbiota-modulating effects, including probiotics, peppermint-caraway oil, herbal formulations, and ginger-based supplements, were found to mitigate symptoms. Conclusion: Our findings show that specific dietary components can be implicated in inducing inflammation and symptoms in FD. Stress and anxiety might be another triggering factor for FD; hence, we see the utility of antidepressants in some cases. Since the symptoms are related to inflammation in most cases, we propose using 'inflammatory dyspepsia' to represent the true presentation for those patients with inflammation detected in their gastrointestinal mucosa. Large-scale randomised trials are needed to confirm findings and refine dietary guidelines.