Fiber2026-05

Nutritional Interventions Targeting the Gut Microbiome in MASLD: From Prebiotics and Probiotics to Postbiotics and Fecal Microbiota Transplantation.

Acierno Carlo, Caturano Alfredo, Barletta Fannia, Rinaldi Luca et al. — Nutrients

Summary

This review examines how various nutritional strategies, including dietary changes and supplements like prebiotics and probiotics, might influence gut bacteria to help manage metabolic dysfunction-associated steatotic liver disease (MASLD). While a balanced, healthy diet remains the most effective approach, current evidence suggests that specific gut microbiome-targeting interventions haven't yet definitively proven to significantly improve liver health outcomes in MASLD. More robust research is still needed to confirm their benefits.

AI-generated summary — read the original

Key points

For metabolic dysfunction-associated steatotic liver disease (MASLD), a healthy overall diet is currently the most effective approach.
While prebiotics and probiotics show some promise in influencing gut bacteria, their direct benefits for MASLD liver health are not yet clearly established.
No specific gut microbiome-targeting nutritional intervention has definitively shown improvement in liver tissue damage in MASLD.
Future studies need to focus on clear liver health outcomes, not just indirect markers.

What the study looked at

This review explored how different nutritional approaches that affect the gut microbiome might influence metabolic dysfunction-associated steatotic liver disease (MASLD). **How it was studied:** This was a narrative review, meaning the authors synthesized and critically evaluated existing research on the topic. They focused on human studies, prioritizing those with clinically meaningful outcomes, adequate duration, and sample size, to assess the effectiveness and safety of these interventions. **What it found:** The review concluded that general dietary optimization remains the most well-supported intervention for MASLD. While prebiotics and probiotics showed some inconsistent effects on indirect markers like blood tests, they haven't consistently demonstrated significant improvements in liver health itself. Newer interventions like postbiotics and fecal microbiota transplantation are still in very early stages of research. Crucially, no microbiome-targeted nutritional strategy has yet proven to improve liver tissue damage in MASLD, highlighting the need for future studies to focus on direct liver outcomes rather than just surrogate markers.

Dietary takeaway

While specific supplements targeting the gut microbiome are still under investigation for MASLD, this review reinforces the importance of a generally healthy diet. Eating a variety of fiber-rich foods like fruits, vegetables, whole grains, and legumes provides natural prebiotics that support a healthy gut, which in turn may benefit overall metabolic health. Remember that this is a review of existing studies, and no single study or review provides definitive answers for individual health.

Abstract

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a highly prevalent liver-centred manifestation of systemic metabolic dysfunction. The gut-liver axis provides a biologically credible therapeutic rationale because intestinal dysbiosis, impaired barrier integrity, microbial metabolites, bile acid signalling, short-chain fatty acids, and trimethylamine N-oxide may influence hepatic steatosis, inflammation, and fibrogenesis. This narrative review critically evaluates dietary patterns, prebiotics, probiotics, synbiotics, postbiotics, and fecal microbiota transplantation (FMT) as microbiome-directed strategies in MASLD. The comparative framework prioritises disease-specific human evidence, clinically meaningful endpoints, trial duration and sample size, reproducibility, safety, and feasibility. Dietary optimisation remains the most clinically grounded intervention, whereas probiotics and synbiotics show modest and heterogeneous signals on biochemical or metabolic surrogate endpoints. Prebiotics are mechanistically coherent but supported by limited liver-centred trials. Postbiotics and microbiome-mediated bioactives remain early-stage and require stricter definitional boundaries. FMT is investigational and should not be extrapolated from its established role in recurrent infection. Most available evidence across all intervention categories relies principally on surrogate endpoints-including aminotransferases, insulin resistance indices, lipid parameters, and microbiome compositional shifts-rather than on validated liver-centred outcomes such as histological improvement or quantitative liver fat assessment; this constrains the strength of conclusions that can currently be drawn. Across all categories, microbiome modulation does not by itself establish liver disease modification, and no microbiome-targeted nutritional intervention has yet demonstrated histological benefit in MASLD. Future trials in this field should prioritise validated hepatic endpoints, phenotype-stratified patient enrolment, adequate follow-up duration, and direct comparisons between intervention categories to determine which microbiome-directed strategies, if any, deliver measurable and reproducible hepatic benefit beyond surrogate markers.

View on PubMed →DOI: 10.3390/nu18111765