Flavonoid intake and its association with atrial fibrillation

Exploring flavonoid intake and all-cause mortality in diverse health conditions: Insights from NHANES 2007-2010 and 2017-2018

OBJECTIVES

Flavonoids exhibit antioxidative, anti-inflammatory, and anticancer properties, yet the relationship between flavonoid intake and all-cause mortality in the obese population remains unclear.

METHODS

This study included NHANES participants from 2007 to 2010 and 2017 to 2018. Cox regression analysis evaluated the impact of total flavonoid intake on all-cause mortality among participants with varying comorbidity profiles. Subgroup analysis was conducted by separately analyzing the six sub-classes of total flavonoids (anthocyanidins, flavan-3-ols, flavanones, flavones, flavonols, and isoflavones). Sensitivity analysis was used to investigate the impact of total flavonoid intake on all-cause mortality among patients with different comorbidities.

RESULTS

During a median follow-up period of 9.92 years (interquartile range (IQR), 5.54-14.29 years), a total of 639 participants died. COX regression analysis revealed a positive impact of flavonoid intake on all-cause mortality among participants with chronic kidney disease, with greater benefits observed in obese participants [hazard ratio (HR): 0.22, 95% CI: 0.11-0.44). In metabolically healthy obese participants (HR: 0.15, 95% CI: 0.07-0.35), obese individuals with diabetes (HR: 0.51, 95% CI: 0.29-0.88), and obese individuals with comorbid cardiovascular disease (HR: 0.37, 95% CI: 0.17-0.83), flavonoid intake was associated with a reduced risk of all-cause mortality. Restricted cubic spline (RCS) analysis indicated a non-linear relationship in obese participants, with optimal intake levels ranging from 319.4978 to 448.6907 mg/day, varying based on different comorbidity profiles. Subgroup analysis revealed varying effects of total flavonoid components in different health conditions, with hazard ratios ranging from 0.06 for higher levels of flavonol to 0.59 for higher levels of anthocyanidins in the Cox model. Sensitivity analyses further indicated that individuals with obesity and comorbid diabetes or CKD see the greatest benefit from flavonoid intake.

CONCLUSIONS

The consumption of flavonoids may be associated with a decreased risk of all-cause mortality. Consumption of flavonoids is particularly beneficial for individuals with obesity and comorbidities.

Evaluation of Polyphenol Intake in Pregnant Women from South-Eastern Spain and the Effect on Anthropometric Measures at Birth and Gestational Age

During pregnancy, controlling nutrition is crucial for the health of both mother and foetus. While polyphenols have positive health effects, some studies show harmful outcomes during pregnancy. This study evaluated polyphenol intake in a cohort of mother-child pairs and examined its effects on foetal anthropometric parameters. Polyphenol intake was assessed using food frequency questionnaires (FFQs) and 24-h dietary recalls, and analysed with the Phenol-Explorer database. Gestational age and birth measurements were retrieved from medical records. Statistical analyses validated dietary records and assessed polyphenol impact using multivariate generalised linear models. The study found that mean gestational age was 39.6 weeks, with a mean birth weight of 3.33 kg. Mean total polyphenol intake by FFQ was 2231 mg/day, slightly higher than 24-h recall data. Flavonoids and phenolic acids constituted 52% and 37% of intake, respectively, with fruits and legumes as primary sources. This study highlights the use of FFQs to estimate polyphenol intake. Furthermore, the study found associations between polyphenol consumption and anthropometric parameters at birth, with the effects varying depending on the type of polyphenol. However, a more precise evaluation of individual polyphenol intake is necessary to determine whether the effects they produce during pregnancy may be harmful or beneficial for foetal growth.

Myricetin and morin hydrate inhibit amyloid fibril formation of bovine α-lactalbumin (BLA)

Amyloid fibrils are self-assembled aggregates of proteins and peptides that can lead to a broad range of diseases called amyloidosis. So far, no definitive and approved treatment to target directly amyloid fibrils has been introduced. Nevertheless, the search for small molecules with ability to inhibit and suppress fibril formation is an active and promising area of the research. Herein, the binding interactions and inhibitory effects of myricetin and morin hydrate on the in vitro fibrillation of bovine α-lactalbumin (BLA) have been investigated. The intrinsic fluorescence of BLA was quenched by myricetin and morin hydrate through combination of the static and dynamic quenching along with non-radiative Förster energy transfer mechanisms. The binding of these two flavonoids to BLA were not accompanied by major alteration in the conformation of BLA as evidenced by CD studies. The results of the fluorescence quenching analyses indicated almost the same binding affinities of myricetin and morin hydrate toward BLA (Kb ~ 106 M-1). However, the results of thioflavin T (ThT) assays showed that myricetin is a stronger inhibitor against BLA fibrillation compared to morin hydrate.

Roles of gut microbiota in atrial fibrillation: insights from Mendelian randomization analysis and genetic data from over 430,000 cohort study participants

BACKGROUND

Gut microbiota imbalances have been suggested as a contributing factor to atrial fibrillation (AF), but the causal relationship is not fully understood.

OBJECTIVES

To explore the causal relationships between the gut microbiota and AF using Mendelian randomization (MR) analysis.

METHODS

Summary statistics were from genome-wide association studies (GWAS) of 207 gut microbial taxa (5 phyla, 10 classes, 13 orders, 26 families, 48 genera, and 105 species) (the Dutch Microbiome Project) and two large meta-GWASs of AF. The significant results were validated in FinnGen cohort and over 430,000 UK Biobank participants. Mediation MR analyses were conducted for AF risk factors, including type 2 diabetes, coronary artery disease (CAD), body mass index (BMI), blood lipids, blood pressure, and obstructive sleep apnea, to explore the potential mediation effect of these risk factors in between the gut microbiota and AF.

RESULTS

Two microbial taxa causally associated with AF: species Eubacterium ramulus (odds ratio [OR] 1.08, 95% confidence interval [CI] 1.04-1.12, P = 0.0001, false discovery rate (FDR) adjusted p-value = 0.023) and genus Holdemania (OR 1.15, 95% CI 1.07-1.25, P = 0.0004, FDR adjusted p-value = 0.042). Genus Holdemania was associated with incident AF risk in the UK Biobank. The proportion of mediation effect of species Eubacterium ramulus via CAD was 8.05% (95% CI 1.73% - 14.95%, P = 0.008), while the proportion of genus Holdemania on AF via BMI was 12.01% (95% CI 5.17% - 19.39%, P = 0.0005).

CONCLUSIONS

This study provided genetic evidence to support a potential causal mechanism between gut microbiota and AF and suggested the mediation role of AF risk factors.

Higher Habitual Dietary Intakes of Flavanols and Anthocyanins Differentially Associate with Lower Incidence of Ischemic Stroke Subtypes-A Follow-Up Analysis

BACKGROUND

We previously reported that habitual consumption of dietary flavanol oligomers + polymers and anthocyanins is associated with a lower risk of ischemic stroke. However, no studies have investigated their relationship with ischemic stroke subtypes.

OBJECTIVES

In this follow-up analysis, we aimed to examine the association of flavanol oligomers + polymers and anthocyanin intake with ischemic stroke subtypes, including the following: 1) large-artery atherosclerosis, 2) cardioembolism, 3) small-vessel occlusion, 4) other determined etiology, and 5) undetermined etiology.

METHODS

Participants (n = 55,094) from the Danish Diet, Cancer, and Health Study were followed up for <16 y for first-time ischemic stroke events, which were classified according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) criteria. Intakes of flavanol oligomers + polymers and anthocyanins were calculated from food frequency questionnaires using the Phenol-Explorer database, and their relationships with ischemic stroke subtypes were investigated using restricted cubic splines within Cox proportional hazards models. After multivariable adjustment, higher habitual intakes (quintile 5 compared with quintile 1) of flavanol oligomers + polymers and anthocyanins were associated with a lower risk of specific ischemic stroke subtypes, including large-artery atherosclerosis [flavanol oligomers + polymers, hazard ratio {HR} (95% confidence interval {CI}): 0.64 (0.47, 0.87)], cardioembolism [anthocyanins, HR (95% CI): 0.45 (0.25, 0.82)], and small-vessel occlusion [flavanol oligomers + polymers, HR (95% CI): 0.65 (0.54, 0.80); anthocyanins, HR (95% CI): 0.79 (0.64, 0.97)], but not stroke of other determined or undetermined etiology.

CONCLUSIONS

Higher habitual intakes of flavanols and anthocyanins are differentially associated with a lower risk of ischemic stroke from atherosclerosis and/or cardioembolism but not with other subtypes.

The association between dietary intake of flavonoids and its subclasses and the risk of metabolic syndrome

Background

The healthiest way to prevent metabolic syndrome (MetS) is through behavioral and nutritional adjustments. We examined the relationship between total flavonoids intake, flavonoid subclasses, and clinically manifest MetS.

Methods

A cross-sectional analysis was conducted among 28,719 individuals from the National Health and Nutrition Examination Survey (NHANES) and Food and Nutrient Database for Dietary Studies (FNDDS) 2007-2011 and 2017-2018. Two 24-h reviews were conducted to determine flavonoids intake and subclasses. The link between flavonoids intake and MetS was investigated using a multivariate logistic regression model.

Results

Q2 and Q3 of total flavonoids intake were associated with 20 and 19% lower risk of incident MetS after adjusting age and sex. Anthocyanidins and flavanones intake in Q2 and Q3 substantially reduced the MetS risk compared to Q1. MetS risk decreased steadily as the total intake of flavonoids increased to 237.67 mg/d. Flavanones and anthocyanidins also displayed V-shaped relationship curves (34.37 and 23.13 mg/d).

Conclusion

MetS was adversely linked with total flavonoids intake, flavanones, and anthocyanidins. Moreover, the most effective doses of total flavonoids, flavanones, and anthocyanidins were 237.67, 34.37, and 23.13 mg/d, respectively, potentially preventing MetS.

Novel preventive effect of isorhamnetin on electrical and structural remodeling in atrial fibrillation

Isorhamnetin, a natural flavonoid, has strong antioxidant and antifibrotic effects, and a regulatory effect against Ca2+-handling. Atrial remodeling due to fibrosis and abnormal intracellular Ca2+ activities contributes to initiation and persistence of atrial fibrillation (AF). The present study investigated the effect of isorhamnetin on angiotensin II (AngII)-induced AF in mice. Wild-type male mice (C57BL/6J, 8 weeks old) were assigned to three groups: (1) control group, (2) AngII-treated group, and (3) AngII- and isorhamnetin-treated group. AngII (1000 ng/kg/min) and isorhamnetin (5 mg/kg) were administered continuously via an implantable osmotic pump for two weeks and intraperitoneally one week before initiating AngII administration, respectively. AF induction and electrophysiological studies, Ca2+ imaging with isolated atrial myocytes and HL-1 cells, and action potential duration (APD) measurements using atrial tissue and HL-1 cells were performed. AF-related molecule expression was assessed and histopathological examination was performed. Isorhamnetin decreased AF inducibility compared with the AngII group and restored AngII-induced atrial effective refractory period prolongation. Isorhamnetin eliminated abnormal diastolic intracellular Ca2+ activities induced by AngII. Isorhamnetin also abrogated AngII-induced APD prolongation and abnormal Ca2+ loading in HL-1 cells. Furthermore, isorhamnetin strongly attenuated AngII-induced left atrial enlargement and atrial fibrosis. AngII-induced elevated expression of AF-associated molecules, such as ox-CaMKII, p-RyR2, p-JNK, p-ERK, and TRPC3/6, was improved by isorhamnetin treatment. The findings of the present study suggest that isorhamnetin prevents AngII-induced AF vulnerability and arrhythmogenic atrial remodeling, highlighting its therapeutic potential as an anti-arrhythmogenic pharmaceutical or dietary supplement.

Total dietary flavonoid intake and risk of cardiometabolic diseases: A dose-response meta-analysis of prospective cohort studies

Several epidemiological studies have suggested that flavonoid intake is associated with a decreased risk of cardiometabolic disease. However, the results remained inconsistent and there is no dose-response meta-analysis for specific outcomes. We conducted a meta-analysis to synthesize the knowledge about their associations and to explore their dose-response relationships. We comprehensively searched the PubMed, Embase, and Web of Science databases for prospective cohort studies published up to December 1, 2021. Summary relative risks (RR) and 95% confidence intervals (CI) were pooled for the association between flavonoid intake and cardiometabolic disease. Evaluations of linear or nonlinear dose-response were presented by restricted cubic splines. We identified 47 articles, including 1,346 676 participants and 127,507 cases in this meta-analysis. The summary of RR per 500 mg/d increase in flavonoid intake was 0.93 (95% CI 0.88-0.98) for cardiovascular disease, 0.89 (95% CI 0.84-0.94) for diabetes, and 0.97 (95% CI 0.94-0.99) for hypertension, respectively. We also found a linearity dose-response association between total flavonoid intake and cardiovascular disease (p nonlinearity = 0.541), and diabetes (p nonlinearity = 0.077). Our finding based on quantitative data suggested that a higher level of flavonoid intake is beneficial for the prevention of cardiometabolic diseases.

Novel luciferase-based GLP-1 reporter assay reveals naturally-occurring secretagogues

BACKGROUND AND PURPOSE

Glucagon-like peptide 1 (GLP-1) is a hormone derived from preproglucagon. It is secreted by enteroendocrine cells in response to feeding, and, in turn, acts as a critical regulator of insulin release. Modulating GLP-1 secretion thus holds promise as a strategy for controlling blood glucose levels.

EXPERIMENTAL APPROACH

To dissect GLP-1 regulation and to discover specific secretagogues, we engineered a reporter cell line introducing a luciferase within proglucagon sequence in GLUTag cells. The assay was validated using western blotting and ELISA. A focused natural compounds library was screened. We measured luminescence, glucose uptake and ATP to investigate the mechanism by which newly found secretagogues potentiate GLP-1 secretion.

KEY RESULTS

The newly created reporter cell line is ideal for the rapid, sensitive and quantitative assessment of GLP-1 secretion. The small molecule screen identified non-toxic GLP-1 modulators. Quercetin is the most potent newly found GLP-1 secretagogue, while other flavonoids also potentiate GLP-1 secretion. Quercetin requires glucose and extracellular calcium to act as GLP-1 secretagogue. Our results support a mechanism whereby flavonoids cause GLUTag cells to utilize glucose more efficiently, leading to elevated ATP levels, followed by K_ATP channel blockade and GLP-1 exocytosis.

CONCLUSION AND IMPLICATIONS

Our methodology enables finding of new GLP-1 secretagogues. Quercetin is a potent, naturally occuring GLP-1 secretagogue. Mechanistic studies of newly found secretagogues are possible in newly created reporter cell line. Further validation in more physiological systems, such as primary L-cells or whole organisms is needed. GLP-1 secretagogues might serve as leads for developing alternative glucose-lowering therapies.

Habitual flavonoid intake and ischemic stroke incidence in the Danish Diet, Cancer, and Health Cohort

BACKGROUND

Flavonoid-rich foods have antiinflammatory, antiatherogenic, and antithrombotic properties that may contribute to a lower risk of ischemic stroke.

OBJECTIVES

We aimed to investigate the relationship between habitual flavonoid consumption and incidence of ischemic stroke in participants from the Danish Diet, Cancer and Health Study.

DESIGN

In this prospective cohort study, 55,169 Danish residents without a prior ischemic stroke [median (IQR) age at enrolment of 56 y (52-60)], were followed for 21 y (20-22). We used Phenol-Explorer to estimate flavonoid intake from food frequency questionnaires obtained at study entry. Incident cases of ischemic stroke were identified from Danish nationwide registries and restricted cubic splines in Cox proportional hazards models were used to investigate relationships with flavonoid intake.

RESULTS

During follow-up, 4237 individuals experienced an ischemic stroke. Compared with participants in Q1 and after multivariable adjustment for demographics and lifestyle factors, those in Q5-for intake of total flavonoids, flavonols, and flavanol oligo + polymers-had a 12% [HR (95% CI): 0.88 (0.81, 0.96)], 10% [0.90 (0.82, 0.98)], and 18% [0.82 (0.75, 0.89)] lower risk of ischemic stroke incidence, respectively. Multivariable (demographic and lifestyle) adjusted associations for anthocyanins and flavones with risk of ischemic stroke were not linear, with moderate but not higher intakes associated with lower risk [anthocyanins Q3 vs. Q1 HR (95% CI): 0.85 (0.79, 0.93); flavones: 0.90 (0.84, 0.97)]. Following additional adjustment for dietary confounders, similar point estimates were observed; however, significance was only retained for anthocyanins and flavanol oligo + polymers [anthocyanins Q3 vs. Q1 HR (95% CI): 0.86 (0.79, 0.94); flavanol oligo + polymers Q5 vs. Q1 0.86 (0.78, 0.94)].

CONCLUSIONS

These findings suggest that moderate habitual consumption of healthy flavonoid-rich foods is associated with a lower risk of ischemic stroke and further investigation is therefore warranted.

An overview and update on the epidemiology of flavonoid intake and cardiovascular disease risk

There is an accumulating body of literature reporting on dietary flavonoid intake and the risk of cardiovascular disease (CVD) in prospective cohort studies. This makes apparent the need for an overview and update on the current state of the science. To date, at least 27 prospective cohorts (in 44 publications) have evaluated the association between estimated habitual flavonoid intake and CVD risk. At this time, the totality of evidence suggests long-term consumption of flavonoid-rich foods may be associated with a lower risk of fatal and non-fatal ischemic heart disease (IHD), cerebrovascular disease, and total CVD; disease outcomes which are principally, though not exclusively, composed of cases of atherosclerotic CVD (ASCVD). To date, few studies have investigated outcome specific ASCVD, such as peripheral artery disease (PAD) or ischemic stroke. Of the flavonoid subclasses investigated, evidence more often implicates diets rich in anthocyanins, flavan-3-ols, and flavonols in lowering the risk of CVD. Although inferences are restricted by confounding and other inherent limitations of observational studies, causality appears possible based on biological plausibility, temporality, and the relative consistency of the reported associations. However, whether the associations observed represent a benefit of the isolated bioactives per se, or are a signal of the bioactives acting in concert with the co-occurring nutrient matrix within flavonoid-bearing foods, are issues of consideration. Thus, the simple interpretation, and the one most relevant for dietary advice, is that consumption of flavonoid-rich foods or diets higher in flavonoids, appear nutritionally beneficial in the prevention of CVD.