Vitamin C and vitamin D3 alleviate metabolic-associated fatty liver disease by regulating the gut microbiota and bile acid metabolism via the gut-liver axis

Special correlation between diet and MASLD: positive or negative?

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a chronic and systemic metabolic liver disease characterized by the presence of hepatic steatosis and at least one cardiometabolic risk factor (CMRF). The pathogenesis of MASLD involves multiple mechanisms, including lipid metabolism disorders, insulin resistance, inflammatory responses, and the hepato-intestinal axis of metabolic dysfunction. Among these factors, diet serves as both an inducement and a potential remedy in the disease's development. Notably, a high-lipid diet exacerbates fat accumulation, oxidative stress, and inflammatory responses, thereby promoting the progression of MASLD. Consequently, dietary induction models have become vital tools for studying the pathological mechanisms of MASLD, providing a foundation for identifying potential therapeutic targets. Additionally, we summarize the therapeutic effects of dietary optimization on MASLD and elucidate the role of specific dietary components in regulating the hepato-intestinal axis, lipid metabolism, and inhibiting inflammatory responses. In conclusion, studies utilizing animal models of MASLD offer significant insights into dietary therapy, particularly concerning the regulation of lipid metabolism-related and hepatoenteric axis-related signaling pathways as well as the beneficial mechanism of probiotics in hepatoenteric regulation. By understanding the specific mechanisms by which different dietary patterns affect MASLD, we can assess the clinical applicability of current dietary strategies and provide new directions for research and treatment aimed at disease modification.

Effects of Multivitamin Supplementation on Metabolic Parameters in High- and Low-Fat Diet-Fed C57BL/6J Mice: Potential Links to Adipose Tissue Browning and Gut Microbiome

BACKGROUND/OBJECTIVES

The relationship between diet, micronutrient supplementation, and metabolic regulation emphasizes the potential of nutritional strategies to address obesity and related disorders. Certain vitamins have the potential to enhance thermogenesis and metabolic health. However, the impact of multivitamin supplementation on white adipose tissue (WAT) browning, the gut microbiome (GM), and metabolic function is not well understood. This study investigated the effects of multivitamin supplementation on obesity-related metabolic dysfunction in mice fed a high-fat diet (HFD) or a low-fat diet (LFD).

METHODS

Male C57BL/6J mice were assigned to group 1: control chow diet (CHD); 2: control HFD; 3: multivitamin-supplemented HFD (Mv-HFD); 4: control LFD; or 5: multivitamin-supplemented LFD (Mv-LFD). Diets, either supplemented with multivitamins A, D, B1, B5, and C or non-supplemented, were administered for 12 weeks. Metabolic parameters, adipose tissue browning, and the GM composition were analyzed.

RESULTS

The Mv-HFD significantly reduced weight gain, adipose tissue mass, blood glucose levels, and insulin resistance induced by an HFD. Additionally, it increased energy expenditure and thermogenic gene expression in WAT. Both the Mv-HFD and Mv-LFD improved the GM composition by increasing beneficial bacteria.

CONCLUSIONS

Multivitamin supplementation improved metabolic health by potentially promoting WAT browning, enhancing energy expenditure, and modulating the GM composition. These findings suggest that multivitamins could offer a promising strategy for combating obesity and associated metabolic dysfunction.

Effects of supplementation with vitamin D3 on growth performance, lipid metabolism and cecal microbiota in broiler chickens

Lower intramuscular fat (IMF) and excessive abdominal fat reduce carcass quality in broilers. The study aimed to investigate the effects of dietary VD3 on growth performance, lipid metabolism and cecal microbiota in broilers over an 84-d feeding experiment. One-day-old male Luhua broilers (210) were randomly assigned to control (basal diet) and VD group (basal diet supplemented with 3,750 IU/kg VD3). Samples were collected after a 12-h fasted feeding on days 28, 56, and 84. Supplementary VD3 significantly enhanced average daily gain (ADG) in broilers aged 57-84 d and 1-84 d, and increased leg muscle rate and fat content in breast and leg muscles and reduced abdominal fat rate of broilers at 84 d. VD3 increased TG and glycogen content in the liver of 28- and 84-d-old broilers, serum TG and VLDL-C content at 56 and 84 d, and TC, HDL-C and LDL-C at 84 d. VD3 increased mRNA expressions of genes related to de novo lipogenesis (DNL) (mTOR, SREBP-1c, FAS and ACC), lipid oxidation (AMPK, PPARα, CPT-1α and ACO) and lipid transport (ApoB and MTTP), and FAS, ACC and CPT1 enzyme activities in the liver. However, mRNA levels of genes involved in DNL and cellular lipid uptake (LPL and FATP1) and LPL activity were decreased in abdominal adipose tissue, and that of genes involved in lipid oxidation and lipolysis (HSL and ATGL) was increased by VD3. LPL and FATP1 expression in breast and leg muscles was increased by VD3. Moreover, VD3 increased the abundance of cecum Bacteroides at 28 and 84 d, Rikenellaceae_RC9_gut_group and Faecalibacterium at 56 and 84 d, and Lachnoclostridium at 84 d. These bacteria were correlated with increased DNL, lipid oxidation and lipid transport in liver, and cellular lipid uptake in muscle, as well as decreased DNL and cellular lipid uptake, and increased lipid oxidation and lipolysis in abdominal adipose tissue. Altogether, supplementary VD3 in basal diet improved growth performance, increased IMF, and reduced abdominal fat rate, which is significant for enhancing feed utilization and improving the carcass quality of broilers. The regulation of VD3 on lipid metabolism could was associated with variation in cecal microbiota composition.

Micronutrient (iron, selenium, vitamin D) supplementation and the gut microbiome

PURPOSE OF REVIEW

Deficiencies in micronutrients persist as widespread global challenges, where supplementation remains a crucial therapeutic approach. This review aims to elucidate the intricate relationships between micronutrient supplementation - specifically iron, selenium (Se), and vitamin D (Vit D) - and gut microbiota composition, investigating their collective impact on host health and disease susceptibility.

RECENT FINDINGS

Maintaining balanced iron levels is essential for gut microbiota equilibrium and host health, as both iron deficiency and excess disrupt gut bacterial balance, affecting colon health. Se supplementation can restore and improve the gut microbial balance, influencing health outcomes not only in the gut but also in areas such as neuroprotection in the brain, testicular health, and metabolic syndrome. Clinical and experimental models demonstrate that Vit D modulates the gut microbiome, enhancing anti-inflammatory effects, supporting metabolic health, and potentially reducing the risk of gut-related behavioral changes and diseases.

SUMMARY

Findings of this review emphasize that balanced iron levels are essential for maintaining a healthy gut microbiota composition and underscore the beneficial effects of Se and Vit D in modulating the gut microbiome. The interactions between micronutrients and the gut microbiome are complex but may have a broad spectrum of health outcomes.

Association between triglyceride-glucose related indices and mortality among individuals with non-alcoholic fatty liver disease or metabolic dysfunction-associated steatotic liver disease

BACKGROUND

The prognostic value of triglyceride-glucose (TyG) related indices in non-alcoholic fatty liver disease (NAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD) is still unclear. This study aimed to determine the associations between TyG-related indices and long-term mortality in this population.

METHODS

The data came from the National Health and Nutrition Examination Survey (NHANES III) and National Death Index (NDI). Baseline TyG, TyG combining with body mass index (TyG-BMI), and TyG combining with waist circumference (TyG-WC) indices were calculated, and mortality status was determined through 31 December 2019. Multivariate Cox and restricted cubic spline (RCS) regression models were performed to evaluate the relationship between TyG-related indices and long-term mortality among participants with NAFLD/MASLD. In addition, we examined the association between TyG-related indices and all-cause mortality within subgroups defined by age, sex, race/ethnicity, and fibrosis-4 index (FIB-4).

RESULTS

There were 10,390 participants with completed ultrasonography and laboratory data included in this study. NAFLD was diagnosed in 3672/10,390 (35.3%) participants, while MASLD in 3556/10,390 (34.2%) amongst the overall population. The multivariate Cox regression analyses showed high levels of TyG-related indices, particularly in TyG-BMI and TyG-WC indices were significantly associated with the all-cause mortality, cardiovascular mortality, and diabetes mortality in either NAFLD or MASLD. The RCS curves showed a nonlinear trend between three TyG-related indices with all-cause mortality in either NAFLD or MASLD. Subgroup analyses showed that TyG-BMI and TyG-WC indices were more suitable for predicting all-cause mortality in patients without advanced fibrosis.

CONCLUSION

Our study highlights the clinical value of TyG-related indices in predicting the survival of the NAFLD/MASLD population. TyG-BMI and TyG-WC indices would be the surrogate biomarkers for the follow-up of the population without advanced fibrosis.

Association of multiple serum minerals and vitamins with metabolic dysfunction-associated fatty liver disease in US adults: National Health and Nutrition Examination Survey 2017-2018

Background

Despite the rapid increase in the global prevalence of Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD), there are no approved therapeutic drugs for MAFLD yet. Nutrient supplementation might mitigate the risk of MAFLD. It is more typical for individuals to consume multiple nutrients simultaneously. However, the studies exploring the combined effects of multiple nutrients on MAFLD are limited. This study aimed to investigate the relationship between both individual nutrients and their combined influence on the risk of MAFLD.

Methods

Data were obtained from National Health and Nutrition Examination Survey (NHANES), and 18 types of nutrients were considered in this study. Logistic regression analysis was performed to evaluate the correlation between single nutrients and the risk of MAFLD. The Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis was performed to pinpoint the most relevant nutrient associated with the risk of MAFLD. Subsequently, both Weighted Quantile Sum (WQS) regression and Quantile g-computation (Qgcomp) were used to assess the combined effects of multiple nutrients on the risk of MAFLD.

Results

A total of 3,069 participants were included in this study. LASSO regression analysis showed that Se, α-tocopherol, and γ-tocopherol exhibited a positive association with the risk of MAFLD. In contrast, the serum levels of Co, P, α-cryptoxanthin, LZ, and trans-β-carotene were inversely associated with the prevalence of MAFLD. When Se and two types of vitamin E were excluded, the WQS index showed a significant inverse relationship between the remaining 15 nutrients and the risk of MAFLD; α-cryptoxanthin showed the most substantial contribution. Similarly, Qgcomp suggested that the combined effects of these 15 nutrients were associated with a lower risk of MAFLD, with α-cryptoxanthin possessing the most significant negative weights.

Conclusion

This study suggested that the complex nutrients with either a low proportion of Se, α-tocopherol, and γ-tocopherol or without them should be recommended for patients with MAFLD to reduce its risk.

Intratumoral microorganisms in tumors of the digestive system

Tumors of the digestive system pose a significant threat to human health and longevity. These tumors are associated with high morbidity and mortality rates, leading to a heavy economic burden on healthcare systems. Several intratumoral microorganisms are present in digestive system tumors, and their sources and abundance display significant heterogeneity depending on the specific tumor subtype. These microbes have a complex and precise function in the neoplasm. They can facilitate tumor growth through various mechanisms, such as inducing DNA damage, influencing the antitumor immune response, and promoting the degradation of chemotherapy drugs. Therefore, these microorganisms can be targeted to inhibit tumor progression for improving overall patient prognosis. This review focuses on the current research progress on microorganisms present in the digestive system tumors and how they influence the initiation, progression, and prognosis of tumors. Furthermore, the primary sources and constituents of tumor microbiome are delineated. Finally, we summarize the application potential of intratumoral microbes in the diagnosis, treatment, and prognosis prediction of digestive system tumors. Video Abstract.

Lingguizhugan Decoction Improved Obesity by Modulating the Gut Microbiota and its Metabolites in Mice

BACKGROUND

The global obese population is rapidly increasing, urgently requiring the development of effective and safe weight-loss medications. The classic Chinese medicine formulation Lingguizhugan Decoction has exerted a significant anti-obesity effect. However, the underlying mechanism is still unclear.

OBJECTIVE

This study aimed to explore the mechanism of LGZGD in the treatment of obesity based on the gut microbiota and its metabolites.

METHODS

Three different dosages of LGZGD were gavaged to ob/ob mice for 8 weeks. Body mass and visceral fat mass were evaluated. Additionally, the changes in gut microbiota, fecal and plasma metabolites in mice after LGZGD treatment were analyzed by metagenomics and non-targeted metabolomics.

RESULTS

The results demonstrated a significant anti-obesity effect of LGZGD treatment in ob/ob mice. Furthermore, the metagenomic analysis revealed that LGZGD reduced the ratio of Firmicutes / Bacteroidetes (F to B) in the gut, restored gut microbiota diversity, and identified 3 enriched KEGG pathways, including energy metabolism, lipid metabolism, and energy production and conversion pathways. Based on non-targeted metabolomics analysis, 20 key metabolites in the feces and 30 key metabolites in the plasma responding to LGZGD treatment were identified, and the levels of Eicosapentaenoic acid (EPA) and Myristoleic acid (MA) might be the metabolites related to gut microbiota after LGZGD treatment. Their biological functions were mainly related to the metabolism pathway.

CONCLUSIONS

These findings suggested that LGZGD had therapeutic potential for obesity. The mechanism of LGZGD alleviating obesity was associated with improving dysbiosis of the gut microbiota. LDZGD affected gut microbiota-derived metabolites of EPA and MA and may act on energy metabolism pathways.