Mechanisms of Food-Induced Symptom Induction and Dietary Management in Functional Dyspepsia

Abstract

Functional dyspepsia (FD) is a common disorder of gut-brain interaction, characterised by upper gastrointestinal symptom profiles that differentiate FD from the irritable bowel syndrome (IBS), although the two conditions often co-exist. Despite food and eating being implicated in FD symptom induction, evidence-based guidance for dietetic management of FD is limited. The aim of this narrative review is to collate the possible mechanisms for eating-induced and food-related symptoms of FD for stratification of dietetic management. Specific carbohydrates, proteins and fats, or foods high in these macronutrients have all been reported as influencing FD symptom induction, with removal of ‘trigger’ foods or nutrients shown to alleviate symptoms. Food additives and natural food chemicals have also been implicated, but there is a lack of convincing evidence. Emerging evidence suggests the gastrointestinal microbiota is the primary interface between food and symptom induction in FD, and is therefore a research direction that warrants substantial attention. Objective markers of FD, along with more sensitive and specific dietary assessment tools will contribute to progressing towards evidence-based dietetic management of FD.

Prevalence, symptoms and risk factor profile of rumination syndrome and functional dyspepsia: a population‐based study

“…91,92 Plausible mechanisms of benefit of restrictive diets include altering luminal osmotic contents, 93,94 but emerging evidence suggests a possible link to mucosal inflammation through microbiome-mediated mast cell activation or directly through atypical food sensitivities. [95][96][97][98] Both rumination syndrome and FD were more likely to avoid one or more components of the 6-food elimination diets (fish, eggs, nuts, soy, wheat and milk) than controls, even when this was assessed independent of wheat and dairy (Figure 6). 69 This diet has been studied in eosinophilic oesophagitis, a non-IgE T helper-2-mediated inflammatory condition 99 that overlaps with eosinophilic duodenitis in up to half of the cases when extra-oesophageal symptoms are present.…”

Physiological mechanisms of unexplained (functional) gastrointestinal disorders

“…With this in mind and given that FGID patients report food intolerances and meal‐associated symptom onset (Duncanson et al . 2021), metabolism of dietary components by the microbiota probably contributes to symptoms.…”

Functional dyspepsia: A critical appraisal of the European consensus from a global perspective

“…Dietary factors were not endorsed as a key pathogenic factor in the European consensus 1 . Although evidence exists that patients with FD have meal‐related symptoms, robust dietary recommendations are lacking other than trying small, frequent meals comprising low fiber content 37–40 . Across the globe, specific carbohydrates with or without gluten, fats, proteins, and in some Asian countries, notably India, spicy foods have been implicated in development of FD symptoms 40–50 .…”

“…Although evidence exists that patients with FD have meal‐related symptoms, robust dietary recommendations are lacking other than trying small, frequent meals comprising low fiber content 37–40 . Across the globe, specific carbohydrates with or without gluten, fats, proteins, and in some Asian countries, notably India, spicy foods have been implicated in development of FD symptoms 40–50 . Although a low fermentable, oligosaccharides, disaccharides, monosaccharides, and polyol (FODMAP) diet is recognized and recommended for patients with IBS with symptom relief in 50–80% of patients short term, such a diet has not been explored widely in FD trials 42–44 …”

“…In addition, food additives were implicated to have a deleterious effects on the gut in the European Food Standards Authority's 2015 publication as an emerging risk in urgent need for research 51 . In our experience, given the complexities of food triggers connected to FD symptoms, a tailored approach targeting a patient's individual needs may be best met in the hands of a well‐educated dietician in a multidisciplinary setting who understands the multifactorial nature of the patient symptoms 40 . Smoking was also not considered a risk factor for FD but a recent pooled analysis of three population‐based endoscopic studies observed a strong dose‐response effect of smoking in postprandial distress syndrome but not epigastric pain syndrome 52…”