Skip to main content
NCBI home page
Medicine logoLink to Medicine
. 2025 Apr 11;104(15):e42101. doi: 10.1097/MD.0000000000042101

Efficacy of sodium butyrate in improving nonalcoholic fatty liver disease: A meta-analysis of preclinical studies

Hongxin Xu a, Xia Wang b, Shoujun Song c, Lingyun Zhang c,*
PMCID: PMC11999427  PMID: 40228267

Abstract

Background:

To evaluate the efficacy of sodium butyrate (NaB) in ameliorating nonalcoholic fatty liver disease (NAFLD) in animals.

Methods:

Chinese and English databases (including PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wangfang Data, CQVIP, and SinoMed) were searched for literature related to NaB to improve the animal model of NAFLD from the establishment of each database to 2023-02. 2 researchers independently screened the literature and extracted the data. The SYRCLE tool was used to assess risk of bias. The extracted data were analyzed using Revman 5.3 and Stata 17.0.

Results:

A total of 1008 relevant references were reviewed, and 12 animal experiments involving 192 animals were included in the analysis: 96 in the NaB group and 96 in the model group. The results showed that animals in the NaB group had significantly lower levels of alanine aminotransferase (standardized mean difference (SMD) = −1.29, 95% confidence interval (CI) (−2.08, −0.49), P = .002], aspartate aminotransferase [SMD = −1.13, 95% CI (−1.75, −0.50), P = .0004], NAFLD activity scores [SMD = −3.19, 95%CI(−4.80, −1.58), P = .0001], triglyceride [SMD = −1.28, 95%CI(−1.66, −0.90), P < .00001] and total cholesterol levels [SMD = −1.39, 95%CI(−2.11, −0.67), P = .0002], interleukin-1β [SMD = −1.40, 95%CI (−1.87, −0.92), P < .00001], interleukin-6 [SMD = −1.38, 95%CI (−1.87, −0.90), P < .00001], tumor necrosis factor-alpha [SMD = −1.69, 95% CI (−2.10, −1.28), P < .00001], and other pro-inflammatory factors, and significantly higher tight junction protein-1 expression [SMD = 1.06, 95% CI (0.43,1.69), P = .0009].

Conclusion:

NaB treatment improves liver function in animals with NAFLD, protected the liver tissue, reduced triglyceride and total cholesterol levels, inhibited inflammation, and protected intestinal barrier function.

Keywords: animal model, meta-analysis, nonalcoholic fatty liver disease, sodium butyrate

1. Introduction

Nonalcoholic fatty liver disease (NAFLD) includes a wide range of disorders, such as nonalcoholic fatty liver, nonalcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular carcinoma.[1] The main characteristic of NAFLD is hepatic steatosis, which is currently defined in the U.S. Guidelines for the Management of NAFLD as having ≥ 5% fat infiltration on imaging or histology, without alcohol, drug, or viral-induced steatosis, and sometimes elevated liver enzymes.[2,3] Several hypotheses have been proposed for the development of NAFLD, including the “two-hit” and “multiple-hit” models, which involve factors such as lipotoxicity, oxidative stress, endoplasmic reticulum stress, chronic inflammatory stress, and mitochondrial dysfunction.[4,5] It is estimated that approximately 25% to 45% of the world’s population has NAFLD, which makes NAFLD one of the most important global health challenges.[6,7] However, there are currently no approved drugs for the treatment of NAFLD.

Short-chain fatty acids are volatile fatty acids produced by intestinal bacteria that metabolize dietary fiber, of which butyric acid is one of the most abundant.[8] Butyrate is thought to be the main energy supply for mammalian and human colon cells.[9] Studies have shown that the dietary addition of sodium butyrate (NaB), the major metabolite of Clostridium butyricum, can exert metabolic benefits in mice and humans by regulating intestinal flora, modulating lipid metabolism, and ameliorating inflammation, with metabolic benefits for metastatic colorectal cancer liver, diabetic nephropathy, and diabetic endotoxemia, among other diseases.[10–13] NaB supplementation has recently shown some effect in improving NAFLD.[14] Interest has gradually increased in animal studies on NaB for the treatment of NAFLD, but the validity of the evidence is not yet sufficient, the sample size is limited, no relevant clinical trial has been filed or article published on the effect of the dose of NaB, and the duration of the intervention on the efficacy of NAFLD is unclear. Therefore, a meta-analysis was conducted to evaluate the efficacy of NaB in the treatment of NAFLD in animals and to provide evidence for the clinical translation of NaB.

2. Materials and methods

2.1. Search strategy

This meta-analysis was conducted according to PRISMA 2020 guideline.[15] This meta-analysis is based on existing published literature and did not require ethical approval. 8 Chinese and English databases were searched, including PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wangfang Data, CQVIP, and SinoMed, and subject words + free words were used to search. The search terms included “nonalcoholic Fatty Liver Disease” and “ButyricAcid” as the subject words, and “NAFLD,” “Non alcoholic Fatty Liver Disease,” “Sodium Butyrate,” and “Butyrates” as the free words. Subject terms were searched in the subject field, and subject and free words were searched in the keyword field. Relevant literature was collected from the construction of each database until 2023-02.

2.2. Inclusion and exclusion criteria

The inclusion criteria for the present study were as follows: (1) Animal experiment; (2) NAFLD model; and (3) Experimental group treated with a therapeutic dose of NaB.

Studies meeting the following criteria were excluded: (1) Reviews, letters, conference abstracts, dissertations, and duplicate publications; (2) Nonanimal in vivo experiments; (3) Irrelevant to the topic; (4) Full text unavailable; and (5) Data incomplete for conversion.

2.3. Data extraction

Literature was screened, information was collected, and data were extracted independently by 2 researchers, cross-checked, and discussed and analyzed to resolve differences. The literature was screened by removing duplicates using Endnote software, skimming the title and abstract to exclude literature unrelated to the topic, and then reading the full text for secondary screening according to the inclusion and exclusion criteria.

The primary data collected included the last name of the first author, year of publication, animal species, sex, subgroups, sample size per group, dose, duration of intervention, and outcome metrics. Data related to outcome indicators were extracted. For chapters that reported data only in the form of images, Origin 2021 software (OriginLab, Inc., Northampton, MA) was used to extract the means and standard deviations from the images. For studies that provided only standard errors, these were converted into a standard deviation.

2.4. Quality assessment

Two investigators independently evaluated the risk of bias of the included studies using the SYRCLE tool to assess the included literature in terms of the following 10 criteria: sequence generation, baseline characteristics, hidden grouping, animal placement randomization, blinding of the animal keeper and investigator, assessment of randomness outcome, blinding of the outcome evaluator, incomplete reporting of conjunctive data, selective reporting bias, and other sources of bias. Outcomes were assessed as a low, uncertain, and high risk of bias.

2.5. Outcome indicators

The primary outcome indicators were: serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, NAFLD activity score (NAS), and triglyceride (TG) and total cholesterol (TC) levels. The secondary outcome indicators were: serum interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels, and occludin and zonula occludens-1 (ZO-1) expression levels.

2.6. Statistical analysis

Meta-analysis was performed using Stata 17.0 software (StataCorp, College Station, TX) and Revman 5.3 software (International Cochrane Collaboration). Continuous variables were expressed as standardized mean differences (SMD) and 95% confidence interval (CI). A small heterogeneity value (I2 < 50%) indicated homogeneity among the studies, and a fixed-effects model was selected for analysis, whereas a large heterogeneity value (I2 ≥ 50%) indicated heterogeneity among the studies and a random-effects model was selected for analysis. When the heterogeneity was too large, subgroup and sensitivity analyses were performed to further explore the source of heterogeneity. Subgroup analyses grouped animals according to species, sex, dose, and intervention duration. Sensitivity analyses were performed using the case-by-case exclusion method. Publication bias was evaluated using Egger’s test; if P > .05, there was no publication bias.

3. Results

3.1. Study identification and selection

A total of 1008 relevant studies were retrieved from the 8 Chinese and English databases. After eliminating duplicates, 733 articles remained. 24 relevant papers were obtained by reading the article titles and abstracts; 12 papers were excluded after reading the full text, and 12 papers met the inclusion and exclusion criteria. See Figure 1 for the process and results of literature screening.

Figure 1.

Figure 1.

Open in a new tab

Flow diagram of studies identified.

3.2. Study characteristics

Twelve studies[14,16–26] were included, involving 192 animals (96 in the NaB group and 96 in the model group), of which 136 were male and 56 were female. 8 studies used C57BL/6J mice, 2 used Sprague-Dawley rats, 1 used Wistar rats, and 1 used C57BLKS/J db/db mice. The NaB dose ranged from 20 to 600 mg/kg body weight in the 12 studies. The duration of the intervention was 5 weeks in 1 study, 6 weeks in 6 studies, 7 weeks in 2, and 8 weeks in 3. The basic characteristics of the included studies are presented in Table 1.

Table 1.

Basic characteristics of included studies.

Study Animal Sex Sample size
(I/C)		 Dose Treatment duration Outcome
A. Adeyanju et al, 2020[16] Wistar rat rat Female 6/6 200 mg/kg 6 weeks ALT,AST,TG,TC
Baumann et al, 2020[14] C57BL/6J mice Female 8/8 600 mg/kg 5 weeks ALT,AST,NAS,IL-6,TNFα,occludin, ZO-1
Cheng et al, 2015[17] C57BL/6J mice Female 6/6 600 mg/kg 6 weeks ALT,NAS,IL-1β,TNFα,occludin, ZO-1
Cheng et al, 2016[18] C57BL/6J mice Male 6/6 600 mg/kg 6 weeks ALT,TNFα,occludin, ZO-1expression
Raso et al, 2013[19] Sprague-Dawley rat Male 6/6 20 mg/kg 6 weeks ALT,AST,TG,TC,IL-1β,IL-6,TNF-α
Sun et al, 2018[20] Sprague-Dawley rat Female 8/8 300 mg/kg 7 weeks TG,TC,IL-1β,IL-6,TNF-α
Yang et al, 2020[21] C57BLKS/Jdb/db mice Male 6/6 500 mg/kg 6 weeks ALT,AST,IL-1β,IL-6,TNFα,occludin,ZO-1
Ye et al, 2018[22] C57BL/6J mice Male 16/16 600 mg/kg 6 weeks ALT,AST,TG,IL-1β,IL-6,TNFα,ZO-1
Zhang et al, 2020[23] C57BL/6J mice Male 6/6 200 mg/kg 8 weeks ALT,AST,NAS,IL-1β,IL-6,TNFα
Zhao et al, 2021[24] C57BL/6J mice Male 7/7 200 mg/kg 8 weeks ALT,AST,TG,TC
Zhou et al, 2017[25] C57BL/6J mice Male 15/15 200 mg/kg 8 weeks ALT,AST,TG,TC,NAS,IL-6,TNFα,ZO-1
Zhang et al, 2019[26] C57BL/6J mice Male 10/10 200 mg/kg 7 weeks ALT,AST,TG,TC
Open in a new tab

In this table shows basic characteristics of included studies.

ALT = alanine aminotransferase, AST = aspartate aminotransferase, C = control group, I = intervention group, IL = interleukin, NAS = NAFLD activity score, TC = total cholesterol, TG = triglyceride, TNFα = tumor necrosis factor α, ZO-1 = zonula occludens-1.

3.3. Quality assessment

None of the 12 included studies described the allocation sequence. 9 studies were randomized into subgroups. None of the studies used concealed grouping. 7 of the studies used the same animal husbandry conditions. None of the studies mentioned the method of blinding the animal keepers and related personnel, and did not state whether the animals were randomly selected when evaluating the outcome. Data reporting was complete in all studies, with no selective reporting chapter bias and no mention of other sources of bias. The results are shown in Figure 2.

Figure 2.

Figure 2.

Open in a new tab

Result of the assessment of bias risk in the included studies.

3.4. Meta-analysis results

3.4.1. ALT levels

Eleven studies reported the effect of NaB on serum ALT levels in mice with NAFLD, with a total of 176 animals. Because the results showed high heterogeneity among the studies (I2 = 78%), a random-effects model was chosen for further analysis. The results showed a significant reduction in ALT levels after NaB treatment [SMD = −1.29, 95% CI (−2.08, −0.49), P = .002]. Considering the high inter-study heterogeneity, predefined subgroup analyses were performed, and the results showed that NaB achieved a better therapeutic effect in males [SMD = −1.88, 95% CI (−2.56, −1.20)] than in females [SMD = 0.35, 95% CI (−0.28,0.98)], whereas the animal category, dosage, and intervention duration intervention did not show significant differences (Fig. 3).

Figure 3.

Figure 3.

Open in a new tab

(A) Forest plots of ALT. (B) Subgroup analysis of ALT. ALT = alanine aminotransferase.

3.4.2. AST levels

Nine studies reported the effect of NaB on serum AST levels in mice with NAFLD, with a total of 152 animals. Heterogeneity among the studies was high (I2 = 64%), and a random-effects model was selected for further study. The results showed a significant reduction in ALT levels after NaB treatment [SMD = −1.13, 95% CI (−1.75, −0.50), P = .0004]. The predefined subgroup analysis suggested that NaB achieved better therapeutic effects in male animals [SMD = −1.47, 95% CI (−2.04, −0.89)] than in female animals [SMD = 0.05, 95% CI (−0.69,0.79)], whereas no significant differences were seen in the animal categories, dosages and duration of the intervention (Fig. 4).

Figure 4.

Figure 4.

Open in a new tab

(A) Forest plots of AST. (B) Subgroup analysis of AST. AST = aspartate aminotransferase.

3.4.3. NAS levels

Five studies reported the effect of NaB on hepatic NAS levels in mice with NAFLD, with a total of 96 animals. Heterogeneity among the studies was high (I2 = 82%), and a random-effects model was selected for further analysis. The results showed a significant reduction in NAS levels after NaB treatment [SMD = −3.19, 95% CI (−4.80, −1.58), P = .0001], see Figure 5. The heterogeneity of the studies included in this metric was high (I2 = 82%); however, when fewer studies were included (n = 5), the stability of the results was better, and subgroup analyses were no longer performed.

Figure 5.

Figure 5.

Open in a new tab

Forest plots of NAS. NAS = NAFLD activity score.

3.4.4. TG levels

Eight studies reported the effect of NaB on TG levels in mice with NAFLD, totaling 140 animals. There was no significant heterogeneity among the studies (I2 = 0%) and a fixed-effects model was selected for further analysis. The results showed a significant reduction in TG levels after NaB treatment in the NAFLD animal model [SMD = −1.28, 95% CI (−1.66, −0.90), P < .00001] (Fig. 6). No significant differences in the treatment effects were observed within the groups in the predefined subgroup analysis (Fig. 7).

Figure 6.

Figure 6.

Open in a new tab

(A) Forest plots of TG. (B) Subgroup analysis of TC. TC = total cholesterol, TG = triglyceride.

Figure 7.

Figure 7.

Open in a new tab

(A) Subgroup analysis of TG. (B) Subgroup analysis of TC. TC = total cholesterol, TG = triglyceride.

3.4.5. TC levels

Seven studies reported the effect of NaB on TC levels in mice with NAFLD, totaling 108 animals. Heterogeneity among the studies was high (I2 = 59%), and a random-effects model was chosen. The results showed a significant reduction in TC levels after NaB treatment [SMD = −1.39, 95% CI (−2.11, −0.67), P = .0002] (Fig. 6). By prior subgroup analysis, the ≤ 200 mg/kg group [SMD = −1.79, 95% CI (−2.45, −1.14)] was more susceptible than the > 200 mg/kg [SMD = −0.35, 95% CI (−1.10,0.41)] and achieved better treatment outcomes, while no significant differences were seen related to sex, animal type, and duration of intervention (Fig. 7).

3.4.6. IL-1β levels

Six studies reported the effect of NaB on hepatic IL-1β expression levels in mice with NAFLD, totaling 96 animals. Heterogeneity among the studies was low (I2 = 45%), and a fixed-effects model was chosen. The results showed a significant reduction in the expression level of IL-1β after NaB treatment [SMD = −1.40, 95% CI (−1.87, −0.92), P < .00001] (Fig. 8). Owing to the small number of studies included in this metric (n = 6), low heterogeneity among studies (I2 = 45%), and good stability of the results, the subgroups were not further analyzed.

Figure 8.

Figure 8.

Open in a new tab

(A) Forest plots of IL-1β levels. (B) Forest plots of IL-6 levels. (C) Forest plots of TNF-α levels. TNF-α = tumor necrosis factor-α.

3.4.7. IL-6 levels

Six studies reported the effect of NaB on hepatic IL-6 expression levels in mice with NAFLD, totaling 92 animals. Heterogeneity among the studies was low (I2 = 49%), and a fixed-effects model was chosen. The results showed a significant reduction in IL-6 expression levels after NaB treatment [SMD = −1.38, 95% CI (−1.87, −0.90), P < .00001] (Fig. 8). Owing to the small number of studies included in this metric (n = 6), the heterogeneity among the studies was low (I2 = 49%), the stability of the results was better, and the subgroups were not further analyzed.

3.4.8. TNF-α levels

Eight studies reported the effect of NaB on hepatic TNF-α expression levels in mice with NAFLD e, with a combined sample size of 148 animals, 74 in the NaB group and 74 in the model group. Heterogeneity among the studies was low (I2 = 46%), and a fixed-effects model was chosen. The results showed a significant reduction in the levels of TNF-α expression after NaB treatment [SMD = −1.69, 95% CI (−2.10, −1.29), P < .00001] (Fig. 8). A preemptive subgroup analysis suggested no significant difference in the treatment effect between the groups (Fig. 9).

Figure 9.

Figure 9.

Open in a new tab

Subgroup analysis of TNF-α levels. TNF-α = tumor necrosis factor-α.

3.4.9. Occludin expression levels

Four studies reported the effect of NaB on intestinal occludin expression levels in mice with NAFLD, with a combined total of 50 animals. Heterogeneity among the studies was high (I2 = 80%), and a random-effects model was selected for further analysis. The results showed no significant difference in the occludin expression level after NaB treatment [SMD = 0.14, 95% CI (−1.28,1.57), P = .85] (Fig. 10).

Figure 10.

Figure 10.

Open in a new tab

(A) Forest plots of expression levels of occluding. (B) Forest plots of expression levels of ZO-1. ZO-1 = zonula occludens-1.

3.4.10. ZO-1 expression levels

Six papers reported the effect of NaB on intestinal ZO-1 protein expression in mice with NAFLD, totaling 106 animals. Heterogeneity among the studies was high (I2 = 52%), and a random-effects model was chosen. The results showed a significant increase in ZO-1 protein expression levels NaB treatment [SMD = 1.06, 95% CI (0.43,1.69), P = .0009] (Fig. 10). By predefined subgroup analysis, the ≤ 200 mg/kg group [SMD = 2.76, 95% CI (1.59,3.93)] was more susceptible than the > 200 mg/kg group [SMD = 0.74, 95% CI (0.28,1.19)] and achieved a better treatment outcome, while no significant differences were seen related to sex, animal category, and duration of intervention (Fig. 11).

Figure 11.

Figure 11.

Open in a new tab

Subgroup analysis of ZO-1 expression levels. ZO-1 = zonula occludens-1.

3.5. Sensitivity analysis

The 5 outcome indicators of serum ALT, AST, NAS, TG, and ZO-1 expression levels, had less variable I2 and P-values, with better outcome stability and an imprecise source of heterogeneity. Regarding the TC level, the P value changed less and the heterogeneity was significantly reduced after excluding the study by Sun et al (I2 = 34%). The stability of the TC level indicator improved, and the heterogeneity might have originated from the study by Sun et al Regarding the IL-1β level, the P-value changes were small, and the heterogeneity was significantly reduced after excluding the study by Cheng et al (I2 = 0%). The stability of the IL-1β level was good, and the heterogeneity may have originated from the study by Cheng et al Regarding the IL-6 level, the P-value change was small, and the heterogeneity was significantly reduced after excluding the study by Yang et al (I2 = 23%); the index stability of the IL-6 level was better, and the heterogeneity might have originated from the study by Yang et al Regarding the TNF-α level, the P-value changes were small, and after excluding the study by Cheng et al, the heterogeneity was significantly reduced (I2 = 0%), the stability of the TNF-α level index was better, and the heterogeneity might have originated from the study by Cheng et al.

3.6. Publication bias

Egger regression test (P = .147) was performed on the included ALT-related studies (n = 11), and no publication bias was found (P > .05; Fig. 12).

Figure 12.

Figure 12.

Open in a new tab

Egger test of ALT. ALT = alanine aminotransferase.

4. Discussion

4.1. NaB treatment improves liver function

A total of 12 studies were included in this meta-analysis of the effectiveness of NaB in improving NAFLD using ALT, AST, NAS, TG, TC, IL-1β, IL-6, TNF-α, occludin, and ZO-1 levels as outcome indicators. The meta-analysis showed that NaB treatment significantly improves serum ALT and AST levels and liver function in animals with NAFLD. However, the studies showed high heterogeneity, and the sources of heterogeneity were further determined by subgroup and sensitivity analyses. Predefined subgroup analyses were performed, and the results of subgroup analyses based on sex showed significant differences in the effect of the treatment between the 2 groups when compared with the model group control. This indicated that the treatment effect was greater in male mice than in female mice, suggesting that sex may be the main source of heterogeneity among studies. Subgroup analyses based on animal species, dose, and duration of intervention, showed no significant differences, suggesting that animal species, dose, and duration of intervention were not the main sources of heterogeneity in ALT and AST levels between studies. NaB has been shown[20] to attenuate HFD-induced NAFLD by stimulating fatty acid β-oxidation and inhibiting inflammation through upregulation of peroxisome proliferator-activated receptor-α expression. A recent study has shown[27] that adipose tissue insulin resistance, high hepatic TG content, and low plasma lipocalin are major factors in the elevation of plasma aminotransferase levels in patients with NAFLD; however, hepatic insulin resistance seems to be less important in this regard.

4.2. NaB treatment improves NAS levels

NaB treatment significantly improved NAS levels and reduced liver tissue inflammation and steatosis in animals with NAFLD. However, the meta-analysis suggested high heterogeneity among studies, considering that the number of included studies for this outcome index was small and subgroup analysis was not carried out. Sensitivity analysis suggested that the I2 and P-value variations were small, the stability of the outcome was good, and the source of heterogeneity was imprecise. Therefore, large sample sizes and high-quality studies are still needed to be included in the analysis to improve the reliability of the findings. NAFLD comprises a range of histopathological abnormalities, including benign steatosis, lobular inflammation, and balloon-like degeneration that may lead to liver fibrosis.[28] NaB increases hepatic expression of the glucagon-like peptide-1 receptor through inhibition of histone deacetylase-2, which increases fatty acid oxidation and inhibits lipid synthesis in hepatocytes, thereby reducing hepatic steatosis.[29] Rapid oxidation of fatty acids in hepatic mitochondria leads to the production of large amounts of reactive oxygen species, oxidative stress, and NAFLD progression.[30,31]

4.3. NaB treatment improves TG and TC levels

NaB treatment significantly improved TG and TC levels and fat accumulation in animals with NAFLD. There was no significant heterogeneity among the included studies regarding TG outcomes, and greater heterogeneity regarding TC outcomes; the source of heterogeneity was further determined by subgroup and sensitivity analyses. Predefined subgroup analyses were performed, and revealed a significant difference between the ≤ 200 and > 200 mg/kg groups compared with the control group, suggesting that the treatment achieved a better therapeutic effect at a dose of ≤ 200 mg/kg and that the dose might be the main source of heterogeneity among the studies. When subgroup analyses were performed based on sex, animal species, and duration of intervention, these differences were not significant, suggesting that these 3 variables were not the main sources of heterogeneity in ALT and AST levels. Sensitivity analyses suggested that the results for TG levels were more stable, and that the heterogeneity of TC-level metrics may have originated from the study by Sun et al A recent cytologic study showed[32] that butyrate enhances adipogenesis and lipid accumulation in adipocytes, reduces lipolysis, and induces lipocalin expression, leading to the activation of downstream target genes such as adenosine 5’-monophosphate-activated protein kinase. In addition, butyrate acts on gut-brain neural circuits to improve energy metabolism, thereby reducing energy intake and inducing fat oxidation by enhancing brown adipose tissue activity.[33]

4.4. NaB treatment inhibits inflammatory response

NaB treatment significantly improved serum IL-1β, IL-6, and TNF-α levels and alleviated inflammatory responses in animals with NAFLD. This is consistent with the results of previous studies; the meta-analysis suggested less heterogeneity among studies, while the sensitivity analysis suggested more stable results. The accumulation of lipid metabolites in tissues increases signaling by mitogen-activated protein kinase (mitogen-activated protein kinase) and nuclear factor-κB, leading to the expression of inflammatory and oxidative molecules.[34] Kupffer cells are also involved in the development of NASH and release various inflammatory cytokines upon activation, such as TNF-α, IL-6, and IL-1β.[35,36] In addition, compared with the HF group, lipopolysaccharide or the endotoxin receptor toll-like receptor-4 and its downstream protein, articulation-myeloid differentiation factor 8, were significantly reduced, and endotoxins derived from gut microbiota was significantly reduced in both serum and liver.[25] TLR activation leads to translocation of nuclear factor κB into the nucleus, inducing transcription of proinflammatory genes such as TNF-α, IL-1β, and IL-6[37] which are classical pathways involved in NAFLD progression.[38] These inflammatory factors seem to be associated with intestinal microbiota dysfunction, intestinal barrier damage, intestinal motility disorders and brain-gut axis dysfunction, and thus may improve NAFLD and irritable bowel syndrome.[39,40]

4.5. NaB treatment protects intestinal barrier function

NaB treatment significantly improves intestinal ZO-1 expression and intestinal barrier function in animals with NAFLD. However, NaB treatment did not result in significant improvement in intestinal atresia protein, which was possibly related to the small number of studies and the lack of high-quality studies with large sample sizes. Further subgroup analyses of ZO-1 expression levels were performed, and dose-based subgroup analyses revealed a significant difference between the ≤ 200 and > 200 mg/kg groups compared with the control group, suggesting that the treatment achieved a better therapeutic effect at doses of ≤ 200 mg/kg and that the dose might be the main source of heterogeneity among the studies. When subgroup analyses were performed based on sex, animal species, and duration of intervention, these differences were not significant, suggesting that these 3 variables were not the main sources of heterogeneity in ALT and AST levels. Sensitivity analyses indicated a relatively stable ZO-1 outcome index. Indeed, in vitro and in vivo findings suggest that butyrate may, at least in part, increase intestinal integrity and regulate tight junction protein (TJ)[41–43] to exert its beneficial effects on intestinal homeostasis. In addition, deletion of tight junction proteins in the upper small intestine, elevated plasma endotoxin levels, and increased mRNA expression of lipopolysaccharide binding protein have all been repeatedly associated with the development of NAFLD.[41] In contrast, the permeability of the epithelial barrier is maintained by TJs, which play a crucial role in preventing harmful substances (e.g., bacteria and endotoxins) from entering the bloodstream.[41] By inducing the tight junction assembly of ZO-1 and occludin, the short-chain fatty acid butyric acid has a similar beneficial effect.[44,45] Previous studies have suggested that butyrate may promote the restoration of the tight junction barrier by upregulating ZO-1 protein levels, which may be attributed to its histone deacetylase inhibitory effect.[37,46]

4.6. Limitations of the study

This study had several limitations. Due to the relatively new direction of research on NaB for the treatment of NAFLD, the amount of relevant literature is small, and there is still a need for high-quality studies with large sample sizes for inclusion in the analysis. Owing to the lack of data, only relevant outcome indicators could be described, and no meta-subgroup analysis was performed to explore the sources of heterogeneity. Second, most of the included animal studies had small sample sizes (6–16 animals per group), which may have reduced the overall quality of evidence. Although meta-subgroup analyses were performed based on predefined subgroups, a considerable number of results still suggest imprecise sources of heterogeneity given the small sample sizes, and the conclusions generated by subgroup analyses still need validation.

5. Conclusion

A comprehensive analysis of available animal experimental studies conservatively concludes that NaB treatment improves liver function, protects liver tissues, lowers TG and TC levels, inhibits inflammatory responses, and protects intestinal barrier function in animals with NAFLD. Subgroup analysis suggested that sex might affect treatment efficacy. Better therapeutic effects were achieved at lower doses (≤200 mg/kg). Animal sex and dosage should be carefully considered when conducting animal experiments to design a reasonable therapeutic dose. Owing to the limited number and quality of the included studies, this conclusion and its clinical translation still need to be confirmed by high-quality randomized controlled studies with large sample sizes.

Author contributions

Conceptualization: Hongxin Xu.

Data curation: Hongxin Xu, Xia Wang.

Formal analysis: Hongxin Xu.

Funding acquisition: Hongxin Xu.

Investigation: Hongxin Xu.

Methodology: Hongxin Xu, Shoujun Song.

Project administration: Hongxin Xu, Lingyun Zhang.

Resources: Hongxin Xu.

Software: Hongxin Xu.

Supervision: Lingyun Zhang.

Validation: Hongxin Xu, Lingyun Zhang.

Visualization: Hongxin Xu.

Writing – original draft: Hongxin Xu.

Writing – review & editing: Hongxin Xu.

Abbreviations:

ALT
alanine aminotransferase
AST
aspartate aminotransferase
CI
confidence intervals
NaB
sodium butyrate
NAFLD
nonalcoholic fatty liver disease
NAS
NAFLD activity score
SMD
standardized mean difference
TC
total cholesterol
TG
triglyceride
TNF-α
tumor necrosis factor-α
ZO-1
zonula occludens-1

The authors have no funding and conflicts of interest to disclose.

The datasets generated during and/or analyzed during the current study are publicly available.

How to cite this article: Xu H, Wang X, Song S, Zhang L. Efficacy of sodium butyrate in improving nonalcoholic fatty liver disease: A meta-analysis of preclinical studies. Medicine 2025;104:15(e42101).

Contributor Information

Hongxin Xu, Email: xhx31415@163.com.

Xia Wang, Email: 2423308764@qq.com.

Shoujun Song, Email: 15169961206@126.com.

References

  • [1].Nascimbeni F, Pais R, Bellentani S, et al. From NAFLD in clinical practice to answers from guidelines. J Hepatol. 2013;59:859–71. [DOI] [PubMed] [Google Scholar]
  • [2].Pouwels S, Sakran N, Graham Y, et al. Non-alcoholic fatty liver disease (NAFLD): a review of pathophysiology, clinical management and effects of weight loss. BMC Endocr Disord. 2022;22:63. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [3].Chalasani N, Younossi Z, Lavine JE, et al. The diagnosis and management of non-alcoholic fatty liver disease: practice guideline by the American Gastroenterological Association, American Association for the Study of Liver Diseases, and American College of Gastroenterology. Gastroenterology. 2012;142:1592–609. [DOI] [PubMed] [Google Scholar]
  • [4].Tilg H, Moschen AR. Evolution of inflammation in nonalcoholic fatty liver disease: the multiple parallel hits hypothesis. Hepatology. 2010;52:1836–46. [DOI] [PubMed] [Google Scholar]
  • [5].Yao HR, Liu J, Plumeri D, et al. Lipotoxicity in HepG2 cells triggered by free fatty acids. Am J Transl Res. 2011;3:284–91. [PMC free article] [PubMed] [Google Scholar]
  • [6].Williams CD, Stengel J, Asike MI, et al. Prevalence of nonalcoholic fatty liver disease and nonalcoholic steatohepatitis among a largely middle-aged population utilizing ultrasound and liver biopsy: a prospective study. Gastroenterology. 2011;140:124–31. [DOI] [PubMed] [Google Scholar]
  • [7].Rinella ME. Nonalcoholic fatty liver disease: a systematic review. JAMA. 2015;313:2263–73. [DOI] [PubMed] [Google Scholar]
  • [8].Zhao ZH, Lai JK, Qiao L, Fan JG. Role of gut microbial metabolites in nonalcoholic fatty liver disease. J Dig Dis. 2019;20:181–8. [DOI] [PubMed] [Google Scholar]
  • [9].Canani RB, Costanzo MD, Leone L, Pedata M, Meli R, Calignano A. Potential beneficial effects of butyrate in intestinal and extraintestinal diseases. World J Gastroenterol. 2011;17:1519–28. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [10].Ma X, Zhou Z, Zhang X, et al. Sodium butyrate modulates gut microbiota and immune response in colorectal cancer liver metastatic mice. Cell Biol Toxicol. 2020;36:509–15. [DOI] [PubMed] [Google Scholar]
  • [11].Yu C, Liu S, Chen L, et al. Effect of exercise and butyrate supplementation on microbiota composition and lipid metabolism. J Endocrinol. 2019;243:125–35. [DOI] [PubMed] [Google Scholar]
  • [12].Dong W, Jia Y, Liu X, et al. Sodium butyrate activates NRF2 to ameliorate diabetic nephropathy possibly via inhibition of HDAC. J Endocrinol. 2017;232:71–83. [DOI] [PubMed] [Google Scholar]
  • [13].Xu YH, Gao CL, Guo HL, et al. Sodium butyrate supplementation ameliorates diabetic inflammation in db/db mice. J Endocrinol. 2018;238:231–44. [DOI] [PubMed] [Google Scholar]
  • [14].Baumann A, Jin CJ, Brandt A, et al. Oral supplementation of sodium butyrate attenuates the progression of non-alcoholic steatohepatitis. Nutrients. 2020;12:951. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [15].Page MJ, McKenzie JE, Bossuyt PM, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. Bmj. 2021;372:n71. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [16].Adeyanju OA, Badejogbin OC, Areola DE, et al. Sodium butyrate arrests pancreato-hepatic synchronous uric acid and lipid dysmetabolism in high fat diet fed Wistar. Biomed Pharmacother. 2021;133. [DOI] [PubMed] [Google Scholar]
  • [17].Jin CJ, Sellmann C, Engstler AJ, Ziegenhardt D, Bergheim I. Supplementation of sodium butyrate protects mice from the development of non-alcoholic steatohepatitis (NASH). Br J Nutr. 2015;114:1745–55. [DOI] [PubMed] [Google Scholar]
  • [18].Jin CJ, Engstler AJ, Sellmann C, et al. Sodium butyrate protects mice from the development of the early signs of non-alcoholic fatty liver disease: role of melatonin and lipid peroxidation. Br J Nutr. 2016;116:1682–93. [DOI] [PubMed] [Google Scholar]
  • [19].Mattace Raso G, Simeoli R, Russo R, et al. Effects of sodium butyrate and its synthetic amide derivative on liver inflammation and glucose tolerance in an animal model of steatosis induced by high fat diet. PLoS One. 2013;8:e68626. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [20].Sun B, Jia Y, Hong J, et al. Sodium butyrate ameliorates high-fat-diet-induced non-alcoholic fatty liver disease through peroxisome proliferator-activated receptor alpha-mediated activation of beta oxidation and suppression of inflammation. J Agric Food Chem. 2018;66:7633–42. [DOI] [PubMed] [Google Scholar]
  • [21].Yang T, Yang H, Heng C, et al. Amelioration of non-alcoholic fatty liver disease by sodium butyrate is linked to the modulation of intestinal tight junctions in db/db mice. Food Funct. 2020;11:10675–89. [DOI] [PubMed] [Google Scholar]
  • [22].Ye J, Lv L, Wu W, et al. Butyrate protects mice against methionine-choline-deficient diet-induced non-alcoholic steatohepatitis by improving gut barrier function, attenuating inflammation and reducing endotoxin levels. Front Microbiol. 2018;9:1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [23].Zhang N, Qu Y, Qin B. Sodium butyrate ameliorates non-alcoholic fatty liver disease by upregulating miR-150 to suppress CXCR4 expression. Clin Exp Pharmacol Physiol. 2021;48:1125–36. [DOI] [PubMed] [Google Scholar]
  • [24].Zhao Z-H, Wang Z-X, Zhou D, et al. Sodium butyrate supplementation inhibits hepatic steatosis by stimulating liver kinase B1 and insulin-induced gene. Cell Mol Gastroenterol Hepatol. 2021;12:857–71. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [25].Zhou D, Pan Q, Xin F-Z, et al. Sodium butyrate attenuates high-fat diet-induced steatohepatitis in mice by improving gut microbiota and gastrointestinal barrier. World J Gastroenterol. 2017;23:60–75. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [26].Zhang YL, Jiang JD, Kong WJ. Sodium butyrate in combination with berberine improves nonalcoholic fatty liver disease in C57BL/6J mice. Chin Pharmacological Bulletin. 2019;35:1664–70. [Google Scholar]
  • [27].Maximos M, Bril F, Portillo Sanchez P, et al. The role of liver fat and insulin resistance as determinants of plasma aminotransferase elevation in nonalcoholic fatty liver disease. Hepatology. 2015;61:153–60. [DOI] [PubMed] [Google Scholar]
  • [28].Marchisello S, Di Pino A, Scicali R, et al. Pathophysiological, molecular and therapeutic issues of nonalcoholic fatty liver disease: an overview. Int J Mol Sci . 2019;20:1948. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [29].Zhou D, Chen YW, Zhao ZH, et al. Sodium butyrate reduces high-fat diet-induced non-alcoholic steatohepatitis through upregulation of hepatic GLP-1R expression. Exp Mol Med. 2018;50:1–12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [30].Fernández-Sánchez A, Madrigal-Santillán E, Bautista M, et al. Inflammation, oxidative stress, and obesity. Int J Mol Sci. 2011;12:3117–32. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [31].Tariq Z, Green CJ, Hodson L. Are oxidative stress mechanisms the common denominator in the progression from hepatic steatosis towards non-alcoholic steatohepatitis (NASH)? Liver Int. 2014;34:e180–90. [DOI] [PubMed] [Google Scholar]
  • [32].Yan H, Ajuwon KM. Mechanism of butyrate stimulation of triglyceride storage and adipokine expression during adipogenic differentiation of porcine stromovascular cells. PLoS One. 2015;10:e0145940. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [33].Li Z, Yi CX, Katiraei S, et al. Butyrate reduces appetite and activates brown adipose tissue via the gut-brain neural circuit. Gut. 2018;67:1269–79. [DOI] [PubMed] [Google Scholar]
  • [34].DeFronzo RA. Insulin resistance, lipotoxicity, type 2 diabetes and atherosclerosis: the missing links. The claude bernard lecture 2009. Diabetologia. 2010;53:1270–87. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [35].Bilzer M, Roggel F, Gerbes AL. Role of Kupffer cells in host defense and liver disease. Liver Int. 2006;26:1175–86. [DOI] [PubMed] [Google Scholar]
  • [36].Cai C, Zhu X, Li P, et al. NLRP3 deletion inhibits the non-alcoholic steatohepatitis development and inflammation in Kupffer cells induced by palmitic acid. Inflammation. 2017;40:1875–83. [DOI] [PubMed] [Google Scholar]
  • [37].Zhang G, Ghosh S. Molecular mechanisms of NF-kappaB activation induced by bacterial lipopolysaccharide through Toll-like receptors. J Endotoxin Res. 2000;6:453–7. [DOI] [PubMed] [Google Scholar]
  • [38].Gkolfakis P, Dimitriadis G, Triantafyllou K. Gut microbiota and non-alcoholic fatty liver disease. Hepatobiliary Pancreat Dis Int. 2015;14:572–81. [DOI] [PubMed] [Google Scholar]
  • [39].Lewandowski K, Kaniewska M, Karłowicz K, Rosołowski M, Rydzewska G. The effectiveness of microencapsulated sodium butyrate at reducing symptoms in patients with irritable bowel syndrome. Prz Gastroenterol. 2022;17:28–34. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [40].Scalera A, Di Minno MN, Tarantino G. What does irritable bowel syndrome share with non-alcoholic fatty liver disease? World J Gastroenterol. 2013;19:5402–20. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [41].Endo H, Niioka M, Kobayashi N, Tanaka M, Watanabe T. Butyrate-producing probiotics reduce nonalcoholic fatty liver disease progression in rats: new insight into the probiotics for the gut-liver axis. PLoS One. 2013;8:e63388. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [42].Wang HB, Wang PY, Wang X, Wan YL, Liu YC. Butyrate enhances intestinal epithelial barrier function via up-regulation of tight junction protein Claudin-1 transcription. Dig Dis Sci. 2012;57:3126–35. [DOI] [PubMed] [Google Scholar]
  • [43].Ma X, Fan PX, Li LS, Qiao SY, Zhang GL, Li DF. Butyrate promotes the recovering of intestinal wound healing through its positive effect on the tight junctions. J Anim Sci. 2012;90(Suppl 4):266–8. [DOI] [PubMed] [Google Scholar]
  • [44].Peng L, He Z, Chen W, Holzman IR, Lin J. Effects of butyrate on intestinal barrier function in a Caco-2 cell monolayer model of intestinal barrier. Pediatr Res. 2007;61:37–41. [DOI] [PubMed] [Google Scholar]
  • [45].Yan H, Ajuwon KM. Butyrate modifies intestinal barrier function in IPEC-J2 cells through a selective upregulation of tight junction proteins and activation of the Akt signaling pathway. PLoS One. 2017;12:e0179586. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • [46].Plöger S, Stumpff F, Penner GB, et al. Microbial butyrate and its role for barrier function in the gastrointestinal tract. Ann N Y Acad Sci. 2012;1258:52–9. [DOI] [PubMed] [Google Scholar]

Articles from Medicine are provided here courtesy of Wolters Kluwer Health

RESOURCES