Associations between an inflammatory diet index and severe non-alcoholic fatty liver disease: a prospective study of 171,544 UK Biobank participants

Associations of a proinflammatory diet, habitual salt intake, and the onset of type 2 diabetes: A prospective cohort study from the UK Biobank

AIM

To explore the relationship between proinflammatory diet, habitual salt intake and the onset of type 2 diabetes.

METHODS

This prospective study was conducted among 171 094 UK Biobank participants who completed at least one 24-h dietary questionnaire and were free of diabetes at baseline. Participants were followed up until 1 March 2023 for type 2 diabetes incidence, with diagnosis information obtained from linked medical records. An Energy-adjusted Diet Inflammatory Index (E-DII) was calculated based on 28 food parameters. Habitual salt intake was determined through the self-reported frequency of adding salt to foods. The associations between E-DII, habitual salt intake and type 2 diabetes incidence were tested by the Cox proportional hazard regression model.

RESULTS

Over a median follow-up period of 13.5 years, 6216 cases of type 2 diabetes were documented. Compared with participants with a low E-DII (indicative of an anti-inflammatory diet), participants with a high E-DII (indicative of a proinflammatory diet) had an 18% heightened risk of developing type 2 diabetes. The association between E-DII and type 2 diabetes tends to be linear after adjustment for major confounders. Participants with a proinflammatory diet and always adding salt to foods had the highest risk of type 2 diabetes incidence (hazard ratio 1.60, 95% confidence interval 1.32-1.94).

CONCLUSIONS

Our findings indicate that a proinflammatory diet and higher habitual salt intake were associated with an increased risk of type 2 diabetes. These results support the public health promotion of an anti-inflammatory diet and reducing salt intake to prevent the onset of type 2 diabetes.

Combined transcriptomics and proteomics unveil the impact of vitamin C in modulating specific protein abundance in the mouse liver

BACKGROUND

Vitamin C (ascorbate) is a water-soluble antioxidant and an important cofactor for various biosynthetic and regulatory enzymes. Mice can synthesize vitamin C thanks to the key enzyme gulonolactone oxidase (Gulo) unlike humans. In the current investigation, we used Gulo-/- mice, which cannot synthesize their own ascorbate to determine the impact of this vitamin on both the transcriptomics and proteomics profiles in the whole liver. The study included Gulo-/- mouse groups treated with either sub-optimal or optimal ascorbate concentrations in drinking water. Liver tissues of females and males were collected at the age of four months and divided for transcriptomics and proteomics analysis. Immunoblotting, quantitative RT-PCR, and polysome profiling experiments were also conducted to complement our combined omics studies.

RESULTS

Principal component analyses revealed distinctive differences in the mRNA and protein profiles as a function of sex between all the mouse cohorts. Despite such sexual dimorphism, Spearman analyses of transcriptomics data from females and males revealed correlations of hepatic ascorbate levels with transcripts encoding a wide array of biological processes involved in glucose and lipid metabolisms as well as in the acute-phase immune response. Moreover, integration of the proteomics data showed that ascorbate modulates the abundance of various enzymes involved in lipid, xenobiotic, organic acid, acetyl-CoA, and steroid metabolism mainly at the transcriptional level, especially in females. However, several proteins of the mitochondrial complex III significantly correlated with ascorbate concentrations in both males and females unlike their corresponding transcripts. Finally, poly(ribo)some profiling did not reveal significant enrichment difference for these mitochondrial complex III mRNAs between Gulo-/- mice treated with sub-optimal and optimal ascorbate levels.

CONCLUSIONS

Thus, the abundance of several subunits of the mitochondrial complex III are regulated by ascorbate at the post-transcriptional levels. Our extensive omics analyses provide a novel resource of altered gene expression patterns at the transcriptional and post-transcriptional levels under ascorbate deficiency.

Association between dietary inflammatory index and risk of fatty liver disease: A systematic review and meta-analysis

AIMS

This meta-analysis aimed to investigate the correlation between dietary inflammatory index (DII) and risks of fatty liver disease.

METHODS

A comprehensive systematic literature search was conducted to select studies published from database inception to 6 September 2023 from five databases. Observational studies examining the association between elevated DII levels and the prevalence of fatty liver disease/liver fibrosis were included. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were calculated using either random-effects or fixed-effect models.

RESULTS

In total, 10 studies comprising 242,006 participants were included in the meta-analysis. Individuals with higher DII had a significantly increased risk of fatty liver disease (OR 1.63; 95% CI 1.08-2.45) and liver fibrosis (OR 1.15; 95% CI 1.09-1.21) compared to those with lower DII.

CONCLUSIONS

This meta-analysis demonstrated an association between higher DII and increased odds of fatty liver disease. However, additional prospective studies are required to further address this question.

Maternal smoking, nutritional factors at different life stage, and the risk of incident type 2 diabetes: a prospective study of the UK Biobank

BACKGROUND

This study aims to investigate potential interactions between maternal smoking around birth (MSAB) and type 2 diabetes (T2D) pathway-specific genetic risks in relation to the development of T2D in offspring. Additionally, it seeks to determine whether and how nutritional factors during different life stages may modify the association between MSAB and risk of T2D.

METHODS

This study included 460,234 participants aged 40 to 69 years, who were initially free of T2D from the UK Biobank. MSAB and breastfeeding were collected by questionnaire. The Alternative health eating index(AHEI) and dietary inflammation index(DII) were calculated. The polygenic risk scores(PRS) of T2D and pathway-specific were established, including β-cell function, proinsulin, obesity, lipodystrophy, liver function and glycated haemoglobin(HbA1c). Cox proportion hazards models were performed to evaluate the gene/diet-MSAB interaction on T2D. The relative excess risk due to additive interaction (RERI) were calculated.

RESULTS

During a median follow-up period of 12.7 years, we identified 27,342 cases of incident T2D. After adjustment for potential confounders, participants exposed to MSAB had an increased risk of T2D (HR=1.11, 95%CI:1.08-1.14), and this association remained significant among the participants with breastfeeding (HR= HR=1.10, 95%CI: 1.06-1.14). Moreover, among the participants in the highest quartile of AHEI or in the lowest quartile of DII, the association between MSAB and the increased risk of T2D become non-significant (HR=0.94, 95%CI: 0.79-1.13 for AHEI; HR=1.09, 95%CI:0.99-1.20 for DII). Additionally, the association between MSAB and risk of T2D became non-significant among the participants with lower genetic risk of lipodystrophy (HR=1.06, 95%CI:0.99-1.14), and exposed to MSAB with a higher genetic risk for β-cell dysfunction or lipodystrophy additively elevated the risk of T2D(RERI=0.18, 95%CI:0.06-0.30 for β-cell function; RERI=0.16, 95%CI:0.04-0.28 for lipodystrophy).

CONCLUSIONS

This study indicates that maintaining a high dietary quality or lower dietary inflammation in diet may reduce the risk of T2D associated with MSAB, and the combination of higher genetic risk of β-cell dysfunction or lipodystrophy and MSAB significantly elevate the risk of T2D in offspring.

The sulfur microbial diet and risk of nonalcoholic fatty liver disease: a prospective gene-diet study from the UK Biobank

BACKGROUND

The gut microbiota is closely related to liver diseases. The dietary pattern associated with sulfur-metabolizing bacteria in stool has been found to influence intestinal health.

OBJECTIVE

We aimed to investigate whether consuming the sulfur microbial diet is associated with nonalcoholic fatty liver disease (NAFLD).

METHODS

We included 143,918 participants of European descent from the UK Biobank. Information on serving sizes used per diet component was recorded by an online 24-h dietary assessment tool (Oxford WebQ). The total sulfur microbial diet score was constructed by summing the product of β-coefficients and corresponding serving sizes. NAFLD was ascertained using hospital inpatient and death records. Cox proportional hazard models were used to estimate the adjusted hazard ratio (HR) and 95% confidence interval (CI). Mediation analyses were used to investigate underlying mediators including body mass index, waist circumference, glucose, triglyceride, urate, and C-reactive protein. A polygenic risk score for NAFLD was constructed and stratified to assess whether the association is modified by genetic predisposition.

RESULTS

After a median follow-up of 11.7 y (interquartile range: 11.3-12.5 y), we documented 1540 incident cases of NAFLD. After adjustment for covariates, we observed an overall J-shaped relationship between the sulfur microbial diet and risk of NAFLD. Those in the highest quartile of sulfur microbial diet score had a 46% increased risk of NAFLD [HRQ4vsQ1 (95% CI): 1.46 (1.26, 1.69)]. We also found that this association is partly mediated by metabolic disorders and systemic inflammation. In addition, the positive association was stronger among individuals at higher genetic risk for NAFLD (Pinteraction = 0.044).

CONCLUSIONS

The sulfur microbial diet had adverse associations with incident NAFLD, particularly in those at a higher genetic risk. Our study may provide evidence on the role of sulfur-metabolizing bacteria in the diet-NAFLD association.

Exploring a novel therapeutic strategy: the interplay between gut microbiota and high-fat diet in the pathogenesis of metabolic disorders

In the past two decades, the rapid increase in the incidence of metabolic diseases, including obesity, diabetes, dyslipidemia, non-alcoholic fatty liver disease, hypertension, and hyperuricemia, has been attributed to high-fat diets (HFD) and decreased physical activity levels. Although the phenotypes and pathologies of these metabolic diseases vary, patients with these diseases exhibit disease-specific alterations in the composition and function of their gut microbiota. Studies in germ-free mice have shown that both HFD and gut microbiota can promote the development of metabolic diseases, and HFD can disrupt the balance of gut microbiota. Therefore, investigating the interaction between gut microbiota and HFD in the pathogenesis of metabolic diseases is crucial for identifying novel therapeutic strategies for these diseases. This review takes HFD as the starting point, providing a detailed analysis of the pivotal role of HFD in the development of metabolic disorders. It comprehensively elucidates the impact of HFD on the balance of intestinal microbiota, analyzes the mechanisms underlying gut microbiota dysbiosis leading to metabolic disruptions, and explores the associated genetic factors. Finally, the potential of targeting the gut microbiota as a means to address metabolic disturbances induced by HFD is discussed. In summary, this review offers theoretical support and proposes new research avenues for investigating the role of nutrition-related factors in the pathogenesis of metabolic disorders in the organism.

A low-inflammatory diet is associated with a lower incidence of diabetes: role of diabetes-related genetic risk

BACKGROUND

Whether a low-inflammatory diet relates to type 2 diabetes risk remains unclear. We examined the association between a low-inflammatory diet and risk of type 2 diabetes among normoglycemic and prediabetic participants. We also explored whether a low-inflammatory diet modifies genetic risk for type 2 diabetes.

METHODS

Among 142,271 diabetes-free UK Biobank participants (aged 39-72 years), 126,203 were normoglycemic and 16,068 were prediabetic at baseline. Participants were followed for up to 15 years to detect incident type 2 diabetes. At baseline, dietary intake was assessed with a 24-h dietary record. An inflammatory diet index (IDI) was generated based on high-sensitivity C-reactive protein levels and was a weighted sum of 34 food groups (16 anti-inflammatory and 18 pro-inflammatory). Participants were grouped into tertiles corresponding to inflammatory level (low, moderate, and high) based on IDI scores. Prediabetes at baseline was defined as HbA1c 5.7-6.4% in diabetes-free participants. Incident type 2 diabetes and age of onset were ascertained according to the earliest recorded date of type 2 diabetes in the Primary Care and Hospital inpatient data. A diabetes-related genetic risk score (GRS) was calculated using 424 single-nucleotide polymorphisms. Data were analyzed using Cox regression and Laplace regression.

RESULTS

During follow-up (median 8.40 years, interquartile range 6.89 to 11.02 years), 3348 (2.4%) participants in the normoglycemia group and 2496 (15.5%) in the prediabetes group developed type 2 diabetes. Type 2 diabetes risk was lower in normoglycemic (hazard ratio [HR] = 0.71, 95% confidence interval [CI] 0.65, 0.78) and prediabetic (HR = 0.81, 95% CI 0.73, 0.89) participants with low IDI scores compared to those with high IDI scores. A low-inflammatory diet may prolong type 2 diabetes onset by 2.20 (95% CI 1.67, 2.72) years among participants with normoglycemia and 1.11 (95% CI 0.59, 1.63) years among participants with prediabetes. In joint effect analyses, normoglycemic or prediabetes participants with low genetic predisposition to type 2 diabetes and low IDI scores had a significant 74% (HR = 0.26, 95% CI 0.21, 0.32) or 51% (HR = 0.49, 95% CI 0.40, 0.59) reduction in type 2 diabetes risk compared to those with high genetic risk plus high IDI scores. There were significant additive and multiplicative interactions between IDI and GRS in relation to type 2 diabetes risk in the normoglycemia group.

CONCLUSIONS

A low-inflammatory diet is associated with a decreased risk of type 2 diabetes and may delay type 2 diabetes onset among participants with normal blood glucose or prediabetes. A low-inflammatory diet might significantly mitigate the risk of genetic factors on type 2 diabetes development.

The association between telomere length and non-alcoholic fatty liver disease: a prospective study

BACKGROUND

Research on the association between telomere length (TL) and incident non-alcoholic fatty liver disease (NAFLD) is limited. This study examined this association and further assessed how TL contributes to the association of NAFLD with its known risk factors.

METHODS

Quantitative PCR (polymerase chain reaction) was employed to assess leucocyte telomere length. Polygenic risk score (PRS) for NAFLD, air pollution score, and lifestyle index were constructed. Cox proportional hazard models were conducted to estimate the hazard ratios (HRs) and 95% confidence intervals.

RESULTS

Among 467,848 participants in UK Biobank, we identified 4809 NAFLD cases over a median follow-up of 12.83 years. We found that long TL was associated with decreased risk of incident NAFLD, as each interquartile range increase in TL resulted in an HR of 0.93 (95% CI 0.89, 0.96). TL partly mediated the association between age and NAFLD (proportion mediated: 15.52%). When assessing the joint effects of TL and other risk factors, the highest risk of NAFLD was found in participants with low TL and old age, low TL and high air pollution score, low TL and unfavorable lifestyle, and low TL and high PRS, compared to each reference group. A positive addictive interaction was observed between high PRS and low TL, accounting for 14.57% (2.51%, 27.14%) of the risk of NAFLD in participants with low telomere length and high genetic susceptibility.

CONCLUSIONS

Long telomere length was associated with decreased risk of NAFLD incidence. Telomere length played an important role in NAFLD.

The Coumarin-Derivative Esculetin Protects against Lipotoxicity in Primary Rat Hepatocytes via Attenuating JNK-Mediated Oxidative Stress and Attenuates Free Fatty Acid-Induced Lipid Accumulation

Coumarin derivates have been proposed as a potential treatment for metabolic-dysfunction-associated fatty liver disease (MAFLD). However, the mechanisms underlying their beneficial effects remain unclear. In the present study, we explored the potential of the coumarin derivate esculetin in MAFLD, focusing on hepatocyte lipotoxicity and lipid accumulation. Primary cultures of rat hepatocytes were exposed to palmitic acid (PA) and palmitic acid plus oleic acid (OA/PA) as models of lipotoxicity and lipid accumulation, respectively. Esculetin significantly reduced oxidative stress in PA-treated hepatocytes, as shown by decreased total reactive oxygen species (ROS) and mitochondrial superoxide production and elevated expression of antioxidant genes, including Nrf2 and Gpx1. In addition, esculetin protects against PA-induced necrosis. Esculetin also improved lipid metabolism in primary hepatocytes exposed to nonlipotoxic OA/PA by decreasing the expression of the lipogenesis-related gene Srebp1c and increasing the expression of the fatty acid β-oxidation-related gene Ppar-α. Moreover, esculetin attenuated lipid accumulation in OA/PA-treated hepatocytes. The protective effects of esculetin against lipotoxicity and lipid accumulation were shown to be dependent on the inhibition of JNK and the activation of AMPK, respectively. We conclude that esculetin is a promising compound to target lipotoxicity and lipid accumulation in the treatment of MAFLD.

Association of dietary inflammatory potential and non-alcoholic fatty liver disease in US adults

OBJECTIVES

Long-term inflammatory effects of diet may elevate the risk of non-alcoholic fatty liver disease (NAFLD). The present study aims to investigate dietary patterns associated with inflammation and whether such diets were associated with the risk of NAFLD.

METHODS

Data were collected from the 2017-2018 National Health and Nutrition Examination Survey. Dietary intake was obtained through two 24-hour dietary recall interviews, and levels of inflammatory biomarkers were assessed in blood samples. NAFLD was defined as a controlled attenuation parameter (CAP) ≥ 274 dB/m. Reduced-rank regression (RRR) analysis was used to derive sex-specific inflammatory dietary patterns (IDPs). Logistic regression analysis was used to examine the association between IDPs and NAFLD.

RESULTS

A total of 3570 participants were included in this study. We identified the IDP characterized by higher intake of added sugars, and lower intake of fruits, vegetables, whole grains, seafood high in n -3 fatty acids, soybean products, nuts, seeds, yogurt, and oils. After multivariate adjustment, the highest tertile of the IDP scores had a significantly higher risk of NAFLD than the lowest tertile [odds ratio (OR) = 1.884, 95% confidence interval (CI) = 1.003-3.539, P for trend = 0.044 for males; OR = 1.597, 95% CI = 1.129-2.257, P for trend = 0.010 for females].

CONCLUSION

Overall, the IDP was positively associated with the prevalence of NAFLD. The findings may provide dietary prevention strategies for controlling chronic inflammation and further preventing NAFLD.

Plasma Fatty Acid Composition, Oxidative and Inflammatory Status, and Adherence to the Mediterranean Diet of Patients with Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) is a complex and increasingly prevalent cardiometabolic disorder worldwide. As of today, NAFLD is a pathology without specific pharmacological treatment, with the Mediterranean diet (MedDiet) being the most widely used approach for its management. The objective of this study is to assess the effects of adherence to the Mediterranean diet on fatty acid plasma levels, as well as on the oxidative and inflammatory status of NAFLD patients. A total of 100 adult patients (40-60 years old) diagnosed with NAFLD and from the Balearic Islands, Spain, were classified into three groups according to their adherence to the MedDiet. Consumption was assessed using a validated 143-item semiquantitative Food Frequency Questionnaire. Food items (g/day) were categorised according to their processing using the NOVA system. Anthropometrics, blood pressure, aminotransferases, Dietary Inflammatory Index (DII), inflammatory biomarkers, and fatty acid levels were measured in the plasma of NAFLD patients. High adherence to the MedDiet is associated to a highly plant-based diet, low ultra-processed food (UPF) consumption, low intake of dietary lipids, low intake of animal fats, high intake of monounsaturated fatty acid (MUFA; mainly palmitoleic acid), low intake of saturated fatty acids (SFAs; practically all dietary SFAs), low intake of trans-fatty acids, high intake of omega-3 fatty acids (mainly eicosapentaenoic acid), a higher n-6:n-3 in ratio, low intake of omega-6 fatty acids, and a low level of interleukin-6 (IL-6). High adherence to the MedDiet is related to a better fatty acid profile in the plasma, fewer SFAs and more MUFA and polyunsaturated fatty acids (PUFAs), a plasma biochemical profile, better proinflammatory status, and decreased ultra-processed food consumption of NAFLD patients.

A healthy lifestyle, Life's Essential 8 scores and new-onset severe NAFLD: A prospective analysis in UK Biobank

BACKGROUND

The association of a healthy lifestyle and the American Heart Association (AHA) Life's Essential 8 (LE8) score with the risk of new-onset nonalcoholic fatty liver disease (NAFLD) remains uncertain. We aimed to explore the associations between a healthy lifestyle and higher LE8 scores with new-onset severe NAFLD in the general population.

METHODS

266,645 participants without prior liver diseases were included from the UK Biobank. A healthy lifestyle was determined based on body mass index, smoking, alcohol consumption, physical activity, sleep duration, and diet. LE8 score was generated from 8 metrics according to the AHA cardiovascular health (CVH) advisory, varying from 0 to 100 scores. The primary study outcome was new-onset severe NAFLD. The study outcomes were ascertained by hospital inpatient data, cancer registry, and death register records.

RESULTS

During a median follow-up of 11.9 years, 2284(0.9 %) participants developed severe NAFLD. Compared with those with a poor lifestyle, participants with intermediate (HR, 0.60; 95%CI: 0.55-0.67), or ideal (HR, 0.20; 95%CI: 0.15-0.27) lifestyles had a significantly lower risk of new-onset severe NAFLD. Compared to the low CVH group (LE8 scores: 0-49), the moderate (scores:50-79) (HR, 0.43; 95%CI: 0.39-0.48) and high CVH (scores:80-100) (HR, 0.10; 95%CI: 0.07-0.14) group had a significantly lower risk of new-onset severe NAFLD. Accordingly, adhering to a healthy lifestyle and attaining a high CVH in all individuals could prevent 66.8 % (95%CI: 58.5-75.1 %) and 77.3 % (95%CI:70.4-84.2 %) of severe NAFLD, respectively. Genetic risks of NAFLD did not modify these associations.

CONCLUSION

A favorable lifestyle and a higher LE8 score were significantly associated with a lower risk of new-onset severe NAFLD, independent of genetic risks of NAFLD.