The Need for

Background: Preclinical and observational studies suggest that the gut microbiome plays a role in the pathogenesis of heart failure (HF); the gut microbiome may be modified by fermentable dietary fibre (FDF). The Need for Methods: Participants were randomly allocated 1:1:1 to either of the intervention arms (5 g/d or 10 g/d acacia) or to the control arm (10 g/d microcrystalline cellulose (MCC; nonfermentable active control). Adherence and tolerance were assessed, and clinical events were monitored for safety. All outcomes (NT-proBNP, ST2, New York Heart Association class, Kansas City Cardiomyopathy Questionnaire scores, 6-minute walk test score, gut microbiome) were measured at baseline, and at 6 and 12 weeks. Results: Between September 13, 2018 and December 16, 2021, 51 patients were randomly allocated to either MCC (n = 18), acacia 5 g daily (n = 13), or acacia 10 g daily (n = 18). No differences occurred between either dose of acacia and MCC in NT-proBNP level, ST2, New York Heart Association class, or questionnaire scores over 12 weeks. Dietary treatment arms had a negligible impact on microbial communities. No safety, tolerability, or adherence issues were observed. Conclusions: Dietary supplementation with acacia gum was both safe and well tolerated in ambulatory patients with HF; however, it did not change NT-proBNP level, ST2, or the composition of the gut microbiome.ClinicalTrials.gov: NCT03409926.