South East Asian Nutrition Surveys (SEANUTS) II - a multi-country evaluation of nutrition and lifestyle indicators in children aged 12 years and below: Rationale and Design.

OBJECTIVE: To assess the nutritional status, growth parameters and lifestyle behaviours of children between 0.5-12 years in nationally representative samples in Malaysia, Indonesia, Thailand, and Vietnam. DESIGN: A cross-sectional study was conducted in the four countries, between May 2019 and April 2021. Data collected can be categorized into four categories: (1) Growth - anthropometry, body composition, development disorder, (2) Nutrient intake and dietary habits - 24-hour dietary recall, child food habits, breast feeding and complementary feeding, (3) Socio-economic status - food insecurity and child health status/environmental, and (4) Lifestyle behaviours - physical activity patterns, fitness, sunlight exposure, sleep patterns, body image and behavioural problems. Blood samples were also collected for biochemical and metabolomic analyses. With the pandemic emerging during the study, a COVID-19 questionnaire was developed and implemented. SETTING: Both rural and urban areas in Malaysia, Indonesia, Thailand, and Vietnam. PARTICIPANTS: Children who were well, with no physical disability or serious infections/injuries and between the age of 0.5-12 years old were recruited. RESULTS: The South East Asian Nutrition Surveys II recruited 13,933 children. Depending on the country, data collection from children were conducted in schools and commune health centres, or temples, or sub-district administrative organizations. CONCLUSIONS: The results will provide up-to-date insights into nutritional status and lifestyle behaviours of children in the four countries. Subsequently, these data will facilitate exploration of potential gaps in dietary intake among Southeast Asian children and enable local authorities to plan future nutrition and lifestyle intervention strategies.

Prediction of subclinical atherosclerosis in low Framingham risk score individuals by using the metabolic syndrome criteria and insulin sensitivity index.

Background: Subclinical atherosclerosis can be present in individuals with an optimal cardiovascular risk factor profile. Traditional risk scores such as the Framingham risk score do not adequately capture risk stratification in low-risk individuals. The aim of this study was to determine if markers of metabolic syndrome and insulin resistance can better stratify low-risk individuals. Methods: A cross-sectional study of 101 healthy participants with a low Framingham risk score and no prior morbidities was performed to assess prevalence of subclinical atherosclerosis using computed tomography (CT) and ultrasound. Participants were compared between groups based on Metabolic Syndrome (MetS) and Insulin-Sensitivity Index (ISI-cal) scores. Results: Twenty three individuals (23%) had subclinical atherosclerosis with elevated CT Agatston score ≥1. Presence of both insulin resistance (ISI-cal <9.23) and fulfillment of at least one metabolic syndrome criterion denoted high risk, resulting in significantly improved AUC (0.706 95%CI 0.588-0.822) over the Framingham risk score in predicting elevated CT Agatston score ≥1, with net reclassification index of 50.9 ± 23.7%. High-risk patients by the new classification also exhibited significantly increased carotid intima thickness. Conclusions: The overlap of insulin resistance and presence of ≥1 criterion for metabolic syndrome may play an instrumental role in identifying traditionally low-risk individuals predisposed to future risk of atherosclerosis and its sequelae.

Gender differences in fasting and postprandial metabolic traits predictive of subclinical atherosclerosis in an asymptomatic Chinese population.

The prediction utility of Framingham Risk Score in populations with low conventional cardiovascular risk burden is limited, particularly among women. Gender-specific markers to predict cardiovascular risk in overtly healthy people are lacking. In this study we hypothesize that postprandial responses triggered by a high-calorie meal test differ by gender in their ability to triage asymptomatic subjects into those with and without subclinical atherosclerosis. A total of 101 healthy Chinese subjects (46 females, 55 males) at low risk of coronary heart disease completed the study. Subjects underwent cardiovascular imaging and postprandial blood phenotyping after consuming a standardized macronutrient meal. Prediction models were developed using logistic regression and subsequently subjected to cross-validation to obtain a de-optimized receiver operating characteristic (ROC) curve. Distinctive gender differences in postprandial trajectories of glucose, lipids and inflammatory markers were observed. We used gender-specific association with different combinations of postprandial predictors to develop 2 models for predicting risk of subclinical atherosclerosis in males (ROC AUC = 0.7867, 95% CI 0.6567, 0.9166) and females (ROC AUC = 0.9161, 95% CI 0.8340, 0.9982) respectively. We report novel postprandial models for predicting subclinical atherosclerosis in apparently healthy Asian subjects using a gender-specific approach, complementing the conventional Framingham Risk Score.Clinical Trial Registration: The trial was registered at clinicaltrials.gov as NCT03531879.

Clinical- and omics-based models of subclinical atherosclerosis in healthy Chinese adults: a cross-sectional exploratory study.

BACKGROUND: Classical risk factors, such as fasting cholesterol, blood pressure (BP), and diabetes status are used today to predict the risk of developing cardiovascular disease (CVD). However, accurate prediction remains limited, particularly in low-risk groups such as women and younger individuals. Growing evidence suggests that biomarker concentrations following consumption of a meal challenge are better and earlier predictors of disease development than biomarker concentrations. OBJECTIVE: To test the hypothesis that postprandial responses of circulating biomarkers differ between healthy subjects with and without subclinical atherosclerosis (SA) in an Asian population at low risk of coronary artery disease (CAD). METHODS: One hundred healthy Chinese subjects (46 women, 54 men) completed the study. Subjects consumed a mixed-meal test and 164 blood biomarkers were analyzed over 6 h by using a combination of chemical and NMR techniques. Models were trained using different methodologies (including logistic regression, elastic net, random forest, sparse partial least square) on a random 75% subset of the data, and their performance was evaluated on the remaining 25%. RESULTS: We found that models based on baseline clinical parameters or fasting biomarkers could not reliably predict SA. By contrast, an omics model based on magnitude and timing of postprandial biomarkers achieved high performance [receiving operating characteristic (ROC) AUC: 91%; 95% CI: 77, 100). Investigation of key features of this model enabled derivation of a considerably simpler model, solely based on postprandial BP and age, with excellent performance (AUC: 91%; 95% CI: 78, 100). CONCLUSION: We report a novel model to detect SA based on postprandial BP and age in a population of Asian subjects at low risk of CAD. The use of this model in large-scale CVD prevention programs should be explored. This trial was registered at ClinicalTrials.gov as NCT03531879.

Plasma Branched-Chain Amino Acids Are Associated With Greater Fasting and Postprandial Insulin Secretion in Non-diabetic Chinese Adults.

Background: Plasma branched-chain amino acids (BCAA) are consistently elevated in subjects with obesity and type 2 diabetes (T2DM) and correlate with insulin resistance. The association of BCAA with insulin secretion and clearance rates has not been adequately described. Objective: To evaluate the relationships between fasting and postprandial plasma BCAA, insulin secretion and insulin clearance. Design: Ninety-five non-diabetic Chinese subjects (43 females) underwent a mixed-meal tolerance test; blood biomarkers including BCAAs (leucine, isoleucine, valine) were measured for 6 h. Fasting and postprandial insulin secretion rates (ISR) and insulin clearance were determined by oral minimal modeling of glucose and C-peptide. Results: Fasting and postprandial plasma BCAA correlated strongly with each other (ρ = 0.796, P < 0.001), and both were positively associated with basal ISR (ρ = 0.45/0.36, P < 0.001), total postprandial ISR AUC (ρ = 0.37/0.45, P < 0.001), and negatively with insulin clearance (ρ = -0.29/-0.29, P < 0.01), after adjusting for sex and body mass index. These relationships largely persisted after adjusting further for insulin resistance and postprandial glucose. Compared with subjects in the middle and lowest tertiles for fasting or postprandial plasma BCAA, subjects in the highest tertile had significantly greater postprandial glucose (by 7-10%) and insulin (by 74-98%) concentrations, basal ISRs (by 34-53%), postprandial ISR AUCs (by 41-49%), and lower insulin clearance rates (by 17-22%) (all P < 0.05). Conclusions: Fasting and postprandial plasma BCAA levels are associated with greater fasting and postprandial insulin secretion and reduced insulin clearance in healthy Chinese subjects. These observations potentially highlight an additional layer of involvement of BCAA in the regulation of glucose homeostasis.

Acute dose-response effect of coffee-derived chlorogenic acids on the human vasculature in healthy volunteers: a randomized controlled trial.

BACKGROUND: Epidemiological studies have reported lower risk of cardiovascular disease with moderate coffee consumption. In addition, emerging evidence indicates that consumption of coffee beverages enriched in chlorogenic acids (CGAs) may influence blood pressure and endothelial function, suggesting that the beneficial cardiovascular effect of coffee may relate to its CGA content. OBJECTIVES: We conducted a double-blind randomized crossover trial to test the effect of acute consumption of a decaffeinated green coffee extract (DGCE), rich in CGAs, on endothelial function in healthy subjects. METHODS: We compared 3 different doses of DGCE (302, 604, and 906 mg, respectively) with a placebo. Endothelial function was defined as the percentage change in the internal diameter of the brachial artery in response to flow-mediated dilation (%FMD). In addition, we followed the plasma concentration-time profiles of 25 systemic CGA metabolites over 24 h after DGCE consumption and we explored the relation between systemic concentrations of CGAs and the effect on %FMD. RESULTS: The DGCE formulations containing different amounts of CGAs resulted in dose-proportional increases in overall total polyphenol concentrations. The systemic appearance of total CGAs was biphasic, in agreement with previous results suggesting 2 sites of absorption in the gastrointestinal tract. Compared with the placebo group, a significant FMD increase (>1%) was observed 8.5, 10, and 24 h after consumption of 302 mg DGCE (∼156.4 mg CGAs). The differences with placebo observed in the other 2 groups were not statistically significant. Evaluation of the relation between phenolic exposure and %FMD showed a positive tendency toward a larger effect at higher concentrations and different behavior of CGA metabolites depending on the conjugated chemical position. CONCLUSIONS: We demonstrated an acute improvement in %FMD over time after ingestion of a DGCE, explained at least partly by the presence in the blood circulation of CGAs and their metabolites. This trial was registered at clinicaltrials.gov as NCT03520452.

The Influence of Different Foods and Food Ingredients on Acute Postprandial Triglyceride Response: A Systematic Literature Review and Meta-Analysis of Randomized Controlled Trials.

The use of postprandial triglyceride (ppTG) as a cardiovascular disease risk indicator has gained recent popularity. However, the influence of different foods or food ingredients on the ppTG response has not been comprehensively characterized. A systematic literature review and meta-analysis was conducted to assess the effects of foods or food ingredients on the ppTG response. PubMed, MEDLINE, Cochrane, and CINAHL databases were searched for relevant acute (<24-h) randomized controlled trials published up to September 2018. Based on our selection criteria, 179 relevant trials (366 comparisons) were identified and systematically compiled into distinct food or food ingredient categories. A ppTG-lowering effect was noted for soluble fiber (Hedges' giAUC = -0.72; 95% CI: -1.33, -0.11), sodium bicarbonate mineral water (Hedges' gAUC = -0.42; 95% CI: -0.79, -0.04), diacylglycerol oil (Hedges' giAUC = -0.38; 95% CI: -0.75, -0.00), and whey protein when it was contrasted with other proteins. The fats group showed significant but opposite effects depending on the outcome measure used (Hedges' giAUC = -0.32; 95% CI: -0.61, -0.03; and Hedges' gAUC = 0.16; 95% CI: 0.06, 0.26). Data for other important food groups (nuts, vegetables, and polyphenols) were also assessed but of limited availability. Assessing for oral fat tolerance test (OFTT) recommendation compliance, most trials were ≥4 h long but lacked a sufficiently high fat challenge. iAUC and AUC were more common measures of ppTG. Overall, our analyses indicate that the effects on ppTG by different food groups are diverse, largely influenced by the type of food or food ingredient within the same group. The type of ppTG measurement can also influence the response.

Dose-response relationship between cocoa flavanols and human endothelial function: a systematic review and meta-analysis of randomized trials.

BACKGROUND: Several intervention studies have investigated the relationship between cocoa flavanols and endothelial function. However, the shape of the association and the type of compounds responsible for the effects are largely unknown. OBJECTIVE: To examine the dose-response association between the consumption of cocoa flavanols and endothelial function, measured by flow-mediated dilation (FMD). DESIGN: Two investigators searched Scopus® for the relevant human intervention studies, which were pooled and meta-analysed. Heterogeneity in the findings was explored with various subgroup analyses. RESULTS: Fifteen published articles with 18 intervention arms met the inclusion criteria. Participants in these intervention groups received 80 to 1248 mg (mean: 704 mg) more flavanols than control groups. A significant improvement of FMD by 1.17% (95% CI: 0.76% to 1.57%) was calculated, with strong evidence of a non-linear association (inverted U-shape) between cocoa flavanols and FMD. CONCLUSIONS: This meta-analysis provides evidence that cocoa flavanols could significantly improve endothelial function, with an optimal effect observed with 710 mg total flavanols, 95 mg (-)-epicatechin or 25 mg (+)-catechin. However, there was substantial variation in the results that could not be explained by the characteristics that we explored, and there were significant risk-of-bias concerns with a large majority of the studies.

The Impact of Epicatechin on Human Cognition: The Role of Cerebral Blood Flow.

Epicatechin is a monomeric flavanol found in food sources such as tea, apples, berries and cocoa. A number of large-scale epidemiological studies have demonstrated an association between the consumption of these foods and cognitive function, as well as improved blood flow. The aim of this review is to summarise the evidence from intervention studies to clarify the effect of epicatechin on cognition and to consider the role of increased cerebral blood flow as a mechanism for any effects. The effects of epicatechin as consumed in cocoa are, therefore, reviewed here as this represents the only dietary source where it is purported to be the major active component. Our main findings are that a) the positive modulation of tasks that involve memory, executive function and processing speed in older adults; b) the cognitive benefits are more often shown in studies containing more than 50 mg epicatechin/day; and c) all studies with a duration of 28 days or longer in populations >50 years old demonstrate a cognitive improvement. However, as highlighted by this review, it is not currently possible to attribute effects solely to epicatechin without consideration of synergies. In order to overcome this issue, further studies examining the cognitive effects of epicatechin in isolation are required. The role of cerebral blood flow also requires further investigation through simultaneous measurement alongside cognitive function.

Concentrations of Carotenoids and Tocopherols in Breast Milk from Urban Chinese Mothers and Their Associations with Maternal Characteristics: A Cross-Sectional Study.

Milk composition remains the best estimate of infant requirements. The aims of this study were to quantify carotenoids and tocopherols in human milk from healthy Chinese mothers, and to explore their associations with lactation stage, region, socio-economic and obstetric characteristics, and dietary intake. Human milk was obtained from 509 healthy mothers, and concentrations of carotenoids and tocopherols were analyzed by Ultra High Performance Liquid Chromatography. The mothers' socio-economic and obstetric characteristics and dietary intake through a single 24-h dietary recall were evaluated. The median concentrations (µg/100 mL) of each component of 0-4 days, 5-11 days, 12-30 days, 31-60 days, 61-120 days, and 121-240 days postpartum were respectively as follows: ß-carotene 8.0, 2.8, 2.1, 1.7, 1.9, 1.8; ß-cryptoxanthin 6.2, 3.4, 2.4, 1.7, 1.8, 2.1; lutein 5.7, 7.0, 2.2, 2.9, 2.8, 3.7; lycopene 6.3, 2.5, 1.8, 1.4, 1.4, 1.5; zeaxanthin 1.0, 1.4, 0.8, 0.8, 1.0, 1.1; α-tocopherol 645, 382, 239, 206, 212, 211; γ-tocopherol 68, 63, 70, 73, 68, 88. The levels of those components varied significantly among different lactation stages and presented regional differences. Associations of carotenoid contents with maternal education, delivery mode, and present body mass index were found in multivariate analyses. These results suggested that lactation stage, region, and socio-economic and obstetric factors were associated with human milk concentrations of carotenoids and tocopherols in healthy Chinese mothers.

Mediation of coffee-induced improvements in human vascular function by chlorogenic acids and its metabolites: Two randomized, controlled, crossover intervention trials.

BACKGROUND & AIMS: Polyphenol intake has been linked to improvements in human vascular function, although data on hydroxycinnamates, such as chlorogenic acid (CGA) have not yet been studied. We aimed to investigate the impact of coffee intake rich in chlorogenic acid on human vascular function and whether CGAs are involved in potential effects. METHODS: Two acute randomized, controlled, cross-over human intervention trials were conducted. The impact of coffee intake, matched for caffeine but differing in CGA content (89, and 310 mg) on flow-mediated dilatation (FMD) was assessed in 15 healthy male subjects. In a second intervention trial conducted with 24 healthy male subjects, the impact of pure 5-caffeoylquinic acid (5-CQA), the main CGA in coffee (5-CQA; 450 mg and 900 mg) on FMD was also investigated. RESULTS: We observed a bi-phasic FMD response after low and high polyphenol, (89 mg and 310 mg CGA) intake, with increases at 1 (1.10 ± 0.43% and 1.34 ± 0.62%, respectively) and 5 (0.79% ± 0.32 and 1.52% ± 0.40, respectively) hours post coffee consumption. FMD responses to coffee intake was closely paralleled by the appearance of CGA metabolites in plasma, notably 3-, 4- and 5-feruloylquinic acid and ferulic-4'-O-sulfate at 1 h and isoferulic-3'-O-glucuronide and ferulic-4'-O-sulfate at 5 h. Intervention with purified 5-CQA (450 mg) also led to an improvement in FMD response relative to control (0.75 ± 1.31% at 1 h post intervention, p = 0.06) and concomitant appearance of plasma metabolites. CONCLUSIONS: Coffee intake acutely improves human vascular function, an effect, in part, mediated by 5-CQA and its physiological metabolites. STUDY REGISTRATION: The National Institutes of Health (NIH) on ClinicalTrials.govNCT01813981 and NCT01772784.

Effects of plant stanol or sterol-enriched diets on lipid profiles in patients treated with statins: systematic review and meta-analysis.

Efficacy and safety data from trials with suitable endpoints have shown that non-statin medication in combination with a statin is a potential strategy to further reduce cardiovascular events. We aimed to evaluate the overall effect of stanol- or sterol-enriched diets on serum lipid profiles in patients treated with statins by conducting a meta-analysis of randomized controlled trials (RCTs). We used the PubMed, Cochrane library and ClinicalTrials.gov databases to search for literature published up to December 2015. Trials were included in the analysis if they were RCTs evaluating the effect of plant stanols or sterols in patients under statin therapy that reported corresponding data on serum lipid profiles. We included 15 RCTs involving a total of 500 participants. Stanol- or sterol-enriched diets in combination with statins, compared with statins alone, produced significant reductions in total cholesterol of 0.30 mmol/L (95% CI -0.36 to -0.25) and low-density lipoprotein (LDL) cholesterol of 0.30 mmol/L (95% CI -0.35 to -0.25), but not in high-density lipoprotein cholesterol or triglycerides. These results persisted in the subgroup analysis. Our meta-analysis provides further evidence that stanol- or sterol-enriched diets additionally lower total cholesterol and LDL-cholesterol levels in patients treated with statins beyond that achieved by statins alone.

Acute effects of chlorogenic acids on endothelial function and blood pressure in healthy men and women.

Coffee is a rich source of polyphenols, primarily chlorogenic acids (CGA). Certain polyphenols and polyphenol-rich foods and beverages have been shown to improve endothelial function and lower blood pressure (BP). The aim of the present study was to investigate the acute effect of two doses of CGA (5-CGA) on endothelial function and BP. In a cross-over study, 16 healthy men and women received: (i) 0 mg purified 5-CGA (control group); (ii) 450 mg purified 5-CGA; (iii) 900 mg purified 5-CGA; and (iv) 200 mg purified (-)-epicatechin (positive control) in random order one week apart. Peak and continuous mean (60 to 240 s post ischaemia) flow-mediated dilation (FMD) was measured at baseline, 1 h and 4 h. BP was measured at baseline and every 30 min to 4 h. Plasma CGA and epicatechin levels were significantly increased at both 1 h and 4 h post their respective treatments. Peak FMD was not significantly altered by either dose of 5-CGA or the epicatechin, relative to control (p > 0.05). Relative to control, effects on continuous mean FMD response following 450 mg 5-CGA and 900 mg of 5-CGA (0.47 ± 0.16%, p = 0.016 and 0.65 ± 0.16%, p < 0.001, respectively) at 1 h and (0.18 ± 0.17%, p = 0.99 and 0.44 ± 0.16%, p < 0.05, respectively) at 4 h. There was no significant effect of any of the treatments on BP. In conclusion, the present study has found no significant effect of 5-CGA, at 450 and 900 mg, on peak FMD response. However, there were significant improvements in mean post-ischaemic FMD response, particularly at the 1 h time point in this group of healthy individuals.

The roasting process does not influence the extent of conjugation of coffee chlorogenic and phenolic acids.

Understanding the bioavailability and metabolism of coffee compounds will contribute to identify the unknown biological mechanism(s) linked to their beneficial effects. The influence of the roasting process on the metabolism of coffee chlorogenic acids in humans was evaluated. In a randomized, double-blind, crossover study, 12 healthy volunteers consumed four instant coffees namely, high roasted coffee (HRC), low roasted coffee (LRC), unroasted coffee (URC), and in vitro hydrolyzed unroasted coffee (HURC). The sum of areas under the curve (AUC) ranged from 8.65-17.6 to 30.9-126 µM/h (P < 0.05) for HRC, LRC, URC, and HURC, respectively. The AUC of HRC, LRC, and URC was correlated with the initial level of phenolic acids in the coffee drinks. Despite different absorption rates, the extent of conjugation was comparable between HRC, LRC, and URC coffees but different for HURC. The most abundant circulating metabolites during the first 5 H were dihydroferulic acid (DHFA), caffeic acid-3'-O-sulfate (CA3S) and isoferulic-3'-O-glucuronide (iFA3G). DHFA and 5-4-dihydro-m-coumaric acid (mDHCoA) were the main metabolites in the period of 5-24 H. The phenolic compounds after consumption of HURC were most rapidly absorbed (Tmax 1 H) compared with the other coffees (Tmax between 9 and 11 H). Using coffees with different degrees of roasting we highlighted that in spite of different absorption rates the extent of conjugation of phenolic acids was comparable. In addition, by using a hydrolyzed unroasted coffee we demonstrated an increased absorption of phenolic acids in the small intestine. © 2016 BioFactors, 42(3):259-267, 2016.

Effect of Glucuronidation on the Potential of Kaempferol to Inhibit Serine/Threonine Protein Kinases.

To study the effect of metabolic conjugation of flavonoids on the potential to inhibit protein kinase activity, the inhibitory effects of the dietary flavonol kaempferol and its major plasma conjugate kaempferol-3-O-glucuronide on protein kinases were studied. To this end, the inhibition of the phosphorylation activity of recombinant protein kinase A (PKA) and of cell lysate from the hepatocellular carcinoma cell line HepG2 on 141 putative serine/threonine phosphorylation sites derived from human proteins was assessed. Glucuronidation reduced the inhibitory potency of kaempferol on the phosphorylation activity of PKA and HepG2 lysate on average about 16 and 3.5 times, respectively, but did not appear to affect the target selectivity for kinases present in the lysate. The data demonstrate that, upon glucuronidation, kaempferol retains part of its intrinsic kinase inhibition potential, which implies that K3G does not necessarily need to be deconjugated to the aglycone for a potential inhibitory effect on protein kinases.

The effect of glucuronidation on isoflavone induced estrogen receptor (ER)α and ERß mediated coregulator interactions.

Non-prenylated isoflavone aglycones are known to have phyto-estrogenic properties and act as agonistic ligands on ERα and ERß due to their structural resemblance to 17ß-estradiol (E2). Genistein and daidzein are the two main dietary isoflavones; upon uptake they are extensively metabolized and exist nearly exclusively as their conjugated forms in biological fluids. Little is known about the effect of conjugation on the intrinsic estrogenic activities of these isoflavones. To characterize and compare the intrinsic estrogenic activities of genistein and daidzein, and their respective 7-O-glucuronide metabolites a cell-free assay system was employed that determines the ligand-induced changes in ERα- and ERß-ligand binding domain (LBD) interactions with 154 different binding motifs derived from 66 different nuclear receptor coregulators. The glucuronides were 8 to 4400 times less potent than their respective aglycones to modulate ERα-LBD and ERß-LBD-coregulator interactions. Glucuronidation changed the preferential activation of genistein from ERß-LBD to ERα-LBD and further increased the slightly preferential activation of daidzein for ERα-LBD. The tested isoflavone compounds were less potent than E2 (around 5 to 1580 times for the aglycones) but modulated the LBD-coregulator interactions in a manner similar to E2. Our results show that genistein and daidzein remain agonistic ligands of ERα-LBD and ERß-LBD in their conjugated form with a higher relative preference for ERα-LBD than the corresponding aglycones. This shift in receptor preference is of special interest as the preferential activation of ERß is considered one of the possible modes of action underlying the supposed beneficial instead of adverse health effects of isoflavones.

Gastrointestinal absorption and metabolism of hesperetin-7-O-rutinoside and hesperetin-7-O-glucoside in healthy humans.

SCOPE: Hesperetin-7-O-rutinoside (hesperidin) reduces blood pressure in healthy volunteers but its intestinal absorption and metabolism are not fully understood. Therefore, we aimed to determine sites of absorption and metabolism of dietary flavanone glycosides in humans. METHODS AND RESULTS: Using a single-blind, randomized crossover design, we perfused equimolar amounts of hesperetin-7-O-rutinoside and hesperetin-7-O-glucoside directly into the proximal jejunum of healthy volunteers. We assessed the appearance of metabolites in the perfusate, blood and urine, to determine the sites of metabolism and excretion, and compared this to oral administration. The glucoside was rapidly hydrolyzed by brush border enzymes without any contribution from pancreatic, stomach, or other secreted enzymes, or from bacterial enzymes. Only ∼3% of the dose was recovered intact in the perfusate, indicating high absorption. A proportion was effluxed directly back into the perfused segment mainly in the form of hesperetin-3'-O-sulfate. In contrast, very little hydrolysis or absorption of hesperetin-7-O-rutinoside was observed with ∼80% recovered in the perfusate, no hesperetin metabolites were detected in blood and only traces were excreted in urine. CONCLUSION: The data elucidate the pathways of metabolism of dietary hesperidin in vivo and will facilitate better design of mechanistic studies both in vivo and in vitro.

The effect of quercetin and kaempferol aglycones and glucuronides on peroxisome proliferator-activated receptor-gamma (PPAR-γ).

The consumption of dietary flavonoids has been associated with a variety of health benefits, including effects mediated by the activation of peroxisome proliferator-activated receptor-gamma (PPAR-γ). Flavonoids are extensively metabolized during and after uptake and there is little known on the biological effects of these conjugated metabolites of flavonoids that are found in plasma. To investigate the effect of glucuronidation on the ability of flavonoids to activate PPAR-γ we studied and compared the activity of quercetin, kaempferol and their relevant plasma conjugates quercetin-3-O-glucuronide (Q3G) and kaempferol-3-O-glucuronide (K3G) on different PPAR-γ related endpoints. The flavonoid aglycones increased PPAR-γ mediated gene expression in a stably transfected reporter gene cell line and glucuronidation diminished their effect. To study the intrinsic activity of the test compounds to activate PPAR-γ we used a novel microarray technique to study ligand induced ligand binding domain (LBD) - nuclear receptor coregulator interactions. In this cell-free system we demonstrate that, unlike the known PPAR-γ agonist rosiglitazone, neither the flavonoid aglycones nor the conjugates are agonistic ligands of the receptor. The increases in reporter gene expression in the reporter cells were accompanied by increased PPAR-γ receptor-mRNA expression and quercetin synergistically increased the effect of rosiglitazone in the reporter gene assay. It is concluded that flavonoids affect PPAR-γ mediated gene transcription by a mode of action different from agonist binding. Increases in PPAR-γ receptor mRNA expression and synergistic effects with endogenous PPAR-γ agonists may play a role in this alternative mode of action. Glucuronidation reduced the activity of the flavonoid aglycones.

Modulation of (-)-epicatechin metabolism by coadministration with other polyphenols in Caco-2 cell model.

Widely consumed beverages such as red wine, tea, and cocoa-derived products are a great source of flavanols. Epidemiologic and interventional studies suggest that cocoa flavanols such as (-)-epicatechin may reduce the risk of cardiovascular diseases. The interaction of (-)-epicatechin with food components including other polyphenols could modify its absorption, metabolism, and finally its bioactivity. In the present study we investigate (-)-epicatechin absorption and metabolism when coexposed with other polyphenols in the intestinal absorptive Caco-2 cell model. Depending on the type of polyphenols coadministered, the total amount of 3'-O-methyl-epicatechin and 3'-O-sulfate-epicatechin conjugates found both in apical and basal compartments ranged from 19 to 801 nM and from 6 to 432 nM, respectively. The coincubation of (-)-epicatechin with flavanols, chlorogenic acid, and umbelliferone resulted in similar amounts of 3'-O-methyl-epicatechin effluxed into the apical compartment relative to control. Coincubation with isorhamnetin, kaempferol, diosmetin, nevadensin, chrysin, equol, genistein, and hesperitin promoted the transport of 3'-O-methyl-epicatechin toward the basolateral side and decreased the apical efflux. Quercetin and luteolin considerably inhibited the appearance of this (-)-epicatechin conjugate both in the apical and basolateral compartments. In conclusion, we could demonstrate that the efflux of (-)-epicatechin conjugates to the apical or basal compartments of Caco-2 cells is modulated by certain classes of polyphenols and their amount. Ingesting (-)-epicatechin with specific polyphenols could be a strategy to increase the bioavailability of (-)-epicatechin and to modulate its metabolic profile.

Identification of epicatechin as one of the key bioactive constituents of polyphenol-enriched extracts that demonstrate an anti-allergic effect in a murine model of food allergy.

Polyphenols are naturally derived bioactive compounds with numerous reported health benefits. We have previously reported on the beneficial effect of a polyphenol-enriched apple extract in a murine model of food allergy. The objectives of the present study were to elucidate the class of bioactive polyphenols that exhibit a beneficial anti-allergic effect and to assess whether the protective effect matches the in vivo bioavailable metabolite concentrations. Female BALB/c mice were sensitised to ovalbumin (OVA) following the protocol of a well-established murine model of food allergy. They were fed diets containing polyphenol-enriched extracts or purified epicatechin for 8 d after the last sensitisation. The sensitised mice were orally challenged with OVA after the intervention. The allergy symptoms, in addition to allergen-specific serum Ig concentrations and gene expression profiles in the intestine, of the control and treated mice were compared. Plasma samples were collected to compare the concentrations of bioavailable epicatechin metabolites in the treatment groups. Polyphenol-enriched fruit extracts containing epicatechin exhibited a significant anti-allergic effect in vivo. This effect was unambiguously attributed to epicatechin, as oral administration of this purified polyphenol to sensitised mice by inclusion in their diet modulated allergy symptoms in a dose-dependent manner. Immune parameters were also affected by the administration of epicatechin. Bioavailability measurements in plasma indicated that the attenuation of allergy symptoms could be due to the higher concentrations of bioavailable epicatechin metabolites. In conclusion, epicatechin is a key bioactive polyphenol that has the ability to modulate allergy outcomes in sensitised mice.