Background: Despite rapidly increasing global burden of metabolic-associated fatty liver disease (MAFLD), therapeutic options remain limited. Dietary modulation is a key component of MAFLD management, with reduced energy intake for weight loss considered first line therapy. The relationship between gut microbiota and MAFLD shows potential for microbiota-modulating dietary therapy to improve disease outcomes. This study aimed to explore dietary variables relevant to gut microbiota in MAFLD, informing translational dietary intervention-based research.
Methods: A retrospective case-control design involved recruitment via public hospital clinics and an existing biobank. Outcome measures included 3-day dietary intake, MAFLD clinical markers, and shotgun metagenomic sequencing. Data were transformed for normality and compared using Levenes t-test and Pearson correlation with SPSS.
Results: Twenty-nine adults with MAFLD and 29 healthy controls were recruited (Table 1). Dietary fibre (22.0±11.1g/day vs. 29.2g±9.2g/day, p<0.01) and omega-3 fatty acid intakes (0.23±0.19g/day vs. 0.76±1.12g/day, p<0.02) were significantly less in the MAFLD group compared with controls. Food group analysis indicated the MAFLD cohort consumed less high fibre foods such as whole grains (20.2±19.5g/day vs. 34.4±27.4g/day, p<0.03), nuts and seeds (0.35±0.52 vs. 1.01±1.48, p<0.03). Energy and macronutrient intakes did not differ between groups. Microbiota differences were evident between groups across 162 different taxa, of which 75% were Firmicutes. Taxa that were significantly less abundant in MAFLD are positively associated with dietary fibre, nuts, seeds, and whole grain intake (p<0.05). Functional pathways (>1200) significantly differed between groups, indicating different metabolic processes between groups. Significantly increased functional pathways in healthy controls were associated with dietary fibre and high fibre food intakes and negatively associated with ultra-processed foods and free fructose intake (p<0.05). Inflammatory markers (high sensitivity C-reactive protein and cytokeratin 18) were higher in the MAFLD group (p<0.03). Increased inflammation was negatively associated with total dietary fibre intake and positively associated with Blautia spp., all of which were higher in abundance in MAFLD compared to controls (p<0.05).
Conclusions: Microbiota differences between people with MAFLD compared to controls were associated with dietary intake and clinical outcomes The finding that diet quality was associated with taxonomic and functional pathway differences is clinically relevant for MAFLD dietary management. Future translation-focussed research investigating whole food effects on microbiota and subsequent metabolic outcomes is warranted.

<b>Table 1: </b>Demographic, clinical and dietary data of participants with metabolic-associated fatty liver disease (MAFLD) and healthy controls.

Table 1: Demographic, clinical and dietary data of participants with metabolic-associated fatty liver disease (MAFLD) and healthy controls.

Eleanor Beck

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