Erythrocyte membrane n-3 polyunsaturated fatty acids are inversely associated with the presence and progression of nonalcoholic fatty liver disease in Chinese adults: a prospective study

Omega-3 world map: 2024 update

In 2016, the first worldwide n3 PUFA status map was published using the Omega-3 Index (O3I) as standard biomarker. The O3I is defined as the percentage of EPA + DHA in red blood cell (RBC) membrane FAs. The purpose of the present study was to update the 2016 map with new data. In order to be included, studies had to report O3I and/or blood EPA + DHA levels in metrics convertible into an estimated O3I, in samples drawn after 1999. To convert the non-RBC-based EPA + DHA metrics into RBC we used newly developed equations. Baseline data from clinical trials and observational studies were acceptable. A literature search identified 328 studies meeting inclusion criteria encompassing 342,864 subjects from 48 countries/regions. Weighted mean country O3I levels were categorized into very low ≤4%, low >4-6%, moderate >6-8%, and desirable >8%. We found that the O3I in most countries was low to very low. Notable differences between the current and 2016 map were 1) USA, Canada, Italy, Turkey, UK, Ireland and Greece (moving from the very low to low category); 2) France, Spain and New Zealand (low to moderate); and 3) Finland and Iceland (moderate to desirable). Countries such as Iran, Egypt, and India exhibited particularly poor O3I levels.

Cohort Profile: Guangzhou Nutrition and Health Study (GNHS): A Population-based Multi-omics Study

BACKGROUND

The Guangzhou Nutrition and Health Study (GNHS) aims to assess the determinants of metabolic disease in nutritional aspects, as well as other environmental and genetic factors, and explore possible biomarkers and mechanisms with multi-omics integration.

METHODS

The population-based sample of adults in Guangzhou, China (baseline: 40-83 years old; n = 5,118) was followed up about every 3 years. All are tracked via on-site follow-up and health information systems. We assessed detailed information on lifestyle factors, physical activities, dietary assessments, psychological health, cognitive function, body measurements, and muscle function. Instrument tests included dual-energy X-ray absorptiometry scanning, carotid artery and liver ultrasonography evaluations, vascular endothelial function evaluation, upper-abdomen and brain magnetic resonance imaging, and 14-day real-time continuous glucose monitoring tests. We also measured multi-omics, including host genome-wide genotyping, serum metabolome and proteome, gut microbiome (16S rRNA sequencing, metagenome, and internal transcribed spacer 2 sequencing), and fecal metabolome and proteome.

RESULTS

The baseline surveys were conducted from 2008 to 2015. Now, we have completed 3 waves. The 3rd and 4th follow-ups have started but have yet to end. A total of 5,118 participants aged 40-83 took part in the study. The median age at baseline was approximately 59.0 years and the proportion of female participants was about 69.4%. Among all the participants, 3,628 (71%) completed at least one on-site follow-up, with a median duration of 9.48 years.

CONCLUSION

The cohort will provide data that will be influential in establishing the role of nutrition in metabolic diseases with multi-omics.

Associations between dietary fatty acid patterns and non-alcoholic fatty liver disease in typical dietary population: A UK biobank study

Background and Aims

Dietary fatty acid composition is associated with non-alcoholic fatty liver disease (NAFLD). Few evidence had identified a clear role of dietary fatty acid composition of typical diet in NAFLD. We aimed to investigate the relationship between dietary patterns and NAFLD in populations with typical diets and to explore the effect of fatty acid composition in dietary patterns on NAFLD.

Methods

Principal component analysis was used to identify 4 dietary patterns in UK Biobank participants. Logistic regression was used to estimate the association between dietary patterns and NAFLD. Mediation analysis was performed to evaluate the extent to which the relationship between dietary patterns and NAFLD was explained by dietary fatty acid combinations, as surrogated by serum fatty acids measured by nuclear magnetic resonance.

Results

A dietary fatty acid pattern (DFP1) characterized by "PUFA enriched vegetarian" was negatively associated with NAFLD risk. Serum fatty acids were significantly associated with DFP1 and NAFLD. Mediation analysis showed SFA (27.8%, p < 0.001), PUFA (25.1%, p < 0.001), ω-6 PUFA (14.3%, p < 0.001), LA (15.6%, p < 0.001) and DHA (10%, p < 0.001) had a significant indirect effect on the association between DFP1 and NAFLD. A dietary pattern characterized by "PUFA enriched carnivore" (DFP2) was not associated with NAFLD risk.

Conclusion

A "PUFA enriched vegetarian" dietary pattern with increased LA and DHA, may be beneficial for the treatment or prevention of NAFLD, while a "PUFA enriched carnivore" dietary pattern may not be harmful to NAFLD.

Associations of serum n-3 and n-6 polyunsaturated fatty acids with prevalence and incidence of nonalcoholic fatty liver disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is a major cause of liver diseases worldwide, and lifestyle and diet are significant factors in its development. Recent studies have suggested that dietary fat quality is associated with the development of NAFLD.

OBJECTIVES

Our purpose was to investigate the cross-sectional and longitudinal associations of serum n-3 (ω-3) and n-6 (ω-6) PUFAs with NAFLD among middle-aged and older men and women from eastern Finland. We also investigated the associations of estimated Δ5-desaturase and Δ6-desaturase activities, enzymes involved in PUFA metabolism, with NAFLD.

METHODS

After exclusions, the cross-sectional analyses included 1533 men examined in 1984-1989 and 674 men and 870 women examined in 1998-2001 in the Kuopio Ischaemic Heart Disease Risk Factor Study. The longitudinal analyses included 520 men examined in 1991-1993 and 301 men and 466 women examined in 2005-2008. Fatty liver index (FLI) was used as a surrogate for NAFLD. Hepatic steatosis was defined as FLI >60. ANCOVA and logistic regression were used for analyses.

RESULTS

In the longitudinal analyses, participants with higher serum concentrations of total n-6 PUFA and linoleic acid, the major n-6 PUFA, had markedly lower FLI and lower odds for hepatic steatosis (e.g., odds ratios for incident hepatic steatosis in the highest compared with lowest quartiles were ≤0.41), whereas serum γ-linolenic acid concentration was associated with a higher FLI and higher odds for hepatic steatosis. The associations with the other PUFAs were generally weaker and nonsignificant. In the cross-sectional analyses, also the long-chain n-3 PUFAs had inverse associations. In most analyses, high estimated Δ5-desaturase activity was associated with lower risk and high estimated Δ6-desaturase activity with higher risk for NAFLD.

CONCLUSIONS

In middle-aged and older Finnish adults, higher serum concentrations of total n-6 PUFAs and linoleic acid were associated with lower odds for future NAFLD.

Identification of the Non-Alcoholic Fatty Liver Disease Molecular Subtypes Associated With Clinical and Immunological Features via Bioinformatics Methods

Background

Non-alcoholic fatty liver disease (NAFLD) is a manifestation of metabolic syndrome in the liver with varying severity. Heterogeneity in terms of molecules and immune cell infiltration drives NAFLD from one stage to the next. However, a precise molecular classification of NAFLD is still lacking, and the effects of complex clinical phenotypes on the efficacy of drugs are usually ignored.

Methods

We introduced multiple omics data to differentiate NAFLD subtypes via consensus clustering, and a weighted gene co-expression network analysis was used to identify eight co-expression modules. Further, eigengenes of eight modules were analyzed with regard to Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathways. Furthermore, the infiltration rates of 22 immune cell types were calculated with CIBERSORT and the ESTIMATE algorithm.

Results

In total, 111 NAFLD patients from three independent GEO datasets were divided into four molecular subtypes, and the corresponding clinical features and immune cell infiltration traits were determined. Based on high gene expression correlations, four molecular subtypes were further divided into eight co-expression modules. We also demonstrated a significant correlation between gene modules and clinical phenotypes. Moreover, we integrated phenotypic, immunologic, and genetic data to assess the potential for progression of different molecular subtypes. Furthermore, the efficacy of drugs against various NAFLD molecular subtypes was discussed to aid in individualized therapy.

Conclusion

Overall, this study could provide new insights into the underlying pathogenesis of and drug targets for NAFLD.

Inverse Association of Serum Adipsin with the Remission of Nonalcoholic Fatty-Liver Disease: A 3-Year Community-Based Cohort Study

PURPOSES

Adipokine alterations contribute to the development and remission of nonalcoholic fatty-liver disease (NAFLD). Adipsin is one of the most abundant adipokines and is almost exclusively produced by adipocytes. However, data on adipsin in human NAFLD are limited and controversial. We performed this study to investigate the association between adipsin and the remission of NAFLD in middle-aged and elderly Chinese adults.

METHODS

Whether adipsin is associated with the remission of NAFLD in a 3-year community-based prospective cohort study was investigated. Baseline levels of adipsin were measured in serum samples collected from 908 NAFLD participants. NAFLD was diagnosed using abdominal ultrasonography. Logistic regression analysis and a multiple stepwise logistic regression model including different variables were conducted to evaluate the association between serum adipsin levels and the remission of NAFLD.

RESULTS

During a mean follow-up of 3.14 ± 0.36 years, 247 (27.20%) participants with NAFLD at baseline were in remission. At baseline, serum adipsin concentration was positively correlated with body mass index (r: 0.39, p < 0.001), insulin (r: 0.31, p < 0.001), and homeostasis model assessment of insulin resistance (r: 0.31, p < 0.001) and was inversely associated with NAFLD remission with a fully adjusted odds ratio (OR) of 0.28 (0.16-0.48) (p trend < 0.001). In a multiple stepwise logistic regression model, circulating adipsin independently predicted NAFLD remission (OR: 0.284, 95% confidence interval [CI]: 0.172-0.471, p for trend <0.001). The area under the receiver operating characteristic curve was 0.751 (95% CI: 0.717-0.785) (p < 0.001) for the prediction model of NAFLD remission.

CONCLUSIONS

We provide evidence for an association between serum adipsin levels and the remission of NAFLD in a community-based prospective cohort study. Serum adipsin can be a potential biomarker for predicting NAFLD remission.