Naturally Occurring Food Chemical Components and Extraintestinal and Gastrointestinal Symptoms in Adults: A Systematic Review

Objective: This systematic review aims to synthesise existing literature to examine the relationship between natural food chemical components and reported symptoms. 

Design: A systematic literature review was completed. Databases CINAHL (Ebscohost), Medline (Ovid), Scopus, Informit Health and Google Scholar were searched to identify relevant articles. The population included human studies of adults (≥17 years) and excluded those with IgE-mediate food allergies. Studies examining food chemical components or ‘food chemical elimination diets’ and symptoms were included. Data was synthesised based on clinical conditions and specific food chemical components examined. The risk of bias was assessed using the Academy of Nutrition and Dietetics ‘Quality Criteria Checklist: Primary Research’. 

Results: Of the 1659 articles retrieved, 21 met inclusion criteria. This included eight randomised controlled trials, four non-randomised controlled trials, four cohort studies with placebo-controlled challenge, one prospective cohort study, three cross sectional cohort studies, one case–controlled study. Available studies support the role of a low-histamine diet for symptoms in chronic urticaria and low-salicylate diet for reducing sino-nasal symptoms in aspirin exacerbated respiratory disease and chronic rhinosinusitis and/or asthma. While further evidence is needed to verify the role of glutamate in respiratory, pain, asthma and gastrointestinal symptoms. 

Conclusions: Food chemical elimination diets may improve condition-specific symptoms across the adult cohorts outlined within this review, with the strongest evidence to support the role of a low-histamine diet for management of symptoms in chronic urticaria and a low-salicylate diet in aspirin exacerbated respiratory disease and/or asthma. Further well-designed trials are needed to elucidate the effect of specific natural food chemical components on symptoms. 

Trial Registration: Systematic review number: CRD42022322511.