Review for 10.1186/s12876-025-03756-8 (2025)

Title: The Association between the Dietary Index for Gut Microbiota and Non- Alcoholic Fatty
Liver Disease: Evidence from NHANES 2017-2020
Version: 0 Date: 18 Feb 2025
Reviewer's report:
Dear Editor,
I appreciate the opportunity to review the manuscript titled "The Association between the
Dietary Index for Gut Microbiota and Non-Alcoholic Fatty Liver Disease: Evidence from
NHANES 2017-2020." The study provides important insights into the relationship between
the Gut Microbiota Dietary Index (DI-GM) and the risk of non-alcoholic fatty liver disease
(NAFLD), emphasizing the role of dietary patterns in shaping gut microbiota and influencing
liver health.
After reviewing the manuscript, I have a few comments and suggestions to further improve the
clarity and impact of the paper.
Clinical Comments:
Gut Microbiota and Metabolic Pathways: The authors discuss the relationship between DI-GM
and NAFLD but could provide a deeper understanding of how specific dietary components in
the DI-GM influence the gut microbiota's metabolic pathways. The dysbiosis of gut microbiota
and its role in liver metabolism, including the production of metabolites such as short-chain
fatty acids (SCFAs), bile acids, and trimethylamine-N-oxide (TMAO), should be explored more
thoroughly. Incorporating recent findings on how gut microbiota impacts metabolic dysfunction
and inflammation could enhance the manuscript's relevance. References to include:
doi.org/10.1186/s13643-023-02299-x
DOI: 10.1097/MS9.0000000000001740
doi.org/10.1016/j.dsx.2024.103110
doi.org/10.1016/j.dsx.2024.103110
DOI: 10.1007/s00018-019-03011-w
doi.org/10.3389/fnut.2021.700058
Gut-Liver Axis: As the gut microbiota plays a critical role in NAFLD progression, I encourage
the authors to discuss the gut-liver axis in greater detail. This includes how gut-derived
metabolites, such as SCFAs and bile acids, influence hepatic fat metabolism, insulin resistance,
and inflammation. Furthermore, exploring how improving gut microbiota diversity through diet
can enhance gut barrier function and prevent the entry of harmful endotoxins could provide new
insights into NAFLD management.
Dietary Modulation of Gut Microbiota: It would be helpful if the authors discuss how specific
dietary patterns, such as those promoting a high fiber intake or low in processed foods, may
help modify gut microbiota and potentially mitigate NAFLD progression. Practical dietary
interventions for patients based on DI-GM scores could be valuable for clinicians, focusing on
foods that favorably influence gut health, such as fermented products and plant-based foods.
Updated Prevalence of NAFLD: The manuscript would benefit from an update in the
introduction regarding the current global prevalence of NAFLD, which has been reported to be
as high as 30.2%. Citing the following recent paper will provide an updated perspective on this
growing issue and strengthen the manuscript's context:
DOI: 10.1016/j.arcmed.2024.103043
Statistical Comments:
Nonlinear Relationships and Clinical Significance: The manuscript presents a nonlinear
relationship between DI-GM and NAFLD risk. I recommend the authors provide further
explanation of the clinical significance of the inflection point identified in the restricted cubic
spline (RCS) analysis. Specifically, how should clinicians interpret DI-GM scores below and
above the threshold of 2? Clarifying this would allow for more practical applications of the
findings in clinical settings.
Subgroup Analyses and Generalizability: The subgroup analyses performed by the authors
suggest consistency in the association of DI-GM with NAFLD risk across various groups.
However, I recommend that the authors further explore how race, socio-economic status, and
other factors might affect the relationship between DI-GM and NAFLD in more detail. It would
be helpful to examine whether dietary interventions should be tailored based on these factors to
better predict and prevent NAFLD risk.
Sensitivity Analysis: The sensitivity analysis conducted in the study adds strength to the
findings. I suggest the authors consider discussing the impact of potential unmeasured
confounders, such as variations in the use of antibiotics, which could affect gut microbiota
composition and contribute to NAFLD risk.