What is the efficacy of dietary, nutraceutical, and probiotic interventions for the management of gastroesophageal reflux disease symptoms? A systematic literature review and meta-analysis.

BACKGROUND: Treatments for Gastroesophageal Reflux Disease (GERD) symptoms include pharmaceutical, surgical, dietary, and lifestyle behaviors; however, dietary interventions lack evidence synthesis. RESEARCH QUESTION: What is the effect of dietary, probiotic, and nutraceutical interventions on GERD symptoms, with or without pharmaceutical therapy, in adults with a history of GERD or functional dyspepsia compared to no intervention, placebo, or usual care? METHOD: A systematic review and meta-analysis was performed according to PRISMA. The search strategy was implemented in MEDLINE, CINAHL, CENTRAL, and Embase on the 28th October 2020 and updated to 27th July 2021. Intervention studies were eligible if they evaluated the effect of a dietary, nutraceutical, or probiotic intervention on GERD symptoms in adults with a history of GERD or functional dyspepsia. The internal validity of studies was assessed using the Academy Quality Criteria Checklist; Review Manager software was used to perform meta-analysis; and certainty in the body of evidence was assessed using GRADE. RESULTS: 6,608 study records were retrieved from the search, with 21 studies (n = 24 highly heterogenous intervention groups) included (n = 10 restrictive dietary interventions; n = 3 non-restrictive dietary interventions; n = 8 nutraceutical interventions; and n = 3 probiotic interventions). GERD symptoms were clinically and statistically improved by a test-based elimination diet (n = 1 study), low nickel diet (n = 1 study), probiotic yoghurt (n = 1 study), psyllium husk (n = 1 study), prickly pear and olive leaf extract supplement (n = 1 study), and melatonin, amino acid and b-group vitamin supplement (n = 1 study) according to qualitative synthesis. Ginger-containing supplements could be meta-analyzed, and improved incidence of GERD symptom alleviation (n = 2 studies, OR: 7.50 [95%CI: 3.62-15.54], GRADE: high). No clinically and/or statistically significant effects were found for the remaining n = 16 highly heterogenous interventions. CONCLUSION: Evidence to guide the dietary management of GERD symptoms is limited in scope, quality, and feasibility. Based on the limited evidence available, dietary GERD management should be long-term, individualized, and consider both dietary restrictions and/or additions. PROSPERO ID: CRD42021224082.