Association between dietary flavonoid intake and obesity among adults in Korea

Urinary Equol and Equol-Predicting Microbial Genera Are Favorably Associated with Body Fat Measures among Chinese Adults

BACKGROUND

Many studies have investigated the intake of dietary isoflavones in relation to obesity risk, whereas the association using objective biomarkers of isoflavones, particularly equol (a gut-derived metabolite of daidzein with greater bioavailability than other isoflavones) has been less studied. In addition, the associations between equol and gut microbiota profile at the population level remain to be fully characterized.

OBJECTIVES

We aimed to identify equol-predicting microbial species and to investigate the associations of equol-predicting microbial species and urinary excretion of isoflavones including glycitein, genistein, daidzein, and equol with diverse obesity markers in free living-individuals.

METHODS

In this 1-y longitudinal study of 754 community-dwelling adults, urinary isoflavones, fecal microbiota, height, weight, and circumferences of waist and hip were measured at baseline and again after 1 y. Liver fat [indicated by the controlled attenuation parameter (CAP)] and other body composition were also measured after 1 y. Linear models and linear mixed-effects models were used to analyze the associations for single measure and repeated measures, respectively.

RESULTS

Among 305 participants (median age: 50 y, IQR, 37-59 y) including 138 males and 167 females, higher urinary excretion of equol was associated with lower CAP (β = -0.013, P < 0.001) and body fat mass (β= -0.014, P = 0.046). No association was found between any other urinary isoflavones and obesity markers (all P > 0.05). We identified 21 bacterial genera whose relative abundance were positively associated with urinary equol concentrations (all Pfalsediscovery rate < 0.05), and constructed an equol-predicting microbial score to reflect the overall equol-producing potential of host gut microbiota. This score was inversely associated with CAP (β = -0.040, P = 0.011).

CONCLUSIONS

High urinary equol concentrations and equol-predicting microbial species could be favorably associated with liver fat and other obesity markers.

Association between intake of flavanones and the overweight/obesity and central obesity in children and adolescents: a cross-sectional study from the NHANES database

Aim

The prevalence of obesity (Ob), overweight (Ow) and central obesity (CO) in children and adolescents has increased dramatically over the past decades globally. Flavanones have been recently studied as adjuvants for the treatment of obesity. This study was aimed at evaluating the association between intake of flavanones and its subclasses and the Ow/Ob and CO in children and adolescents.

Methods

This cross-sectional study extracted the data of children and adolescents with Ow/Ob and CO from the National Health and Nutrition Examination Survey (NHANES) database for 2007-2010 and 2017-2018. Ow and Ob were defined as a body mass index (BMI) ≥ 85th percentile. CO was defined as a waist circumference (WC) ≥ 90th percentile. The association between intake of flavanones and its subclasses and the Ow/Ob and CO in children and adolescents was determined by weighted univariate and multivariate Logistic regression models adjusted for potential covariates, and odds ratios (ORs) with 95% confidence intervals (CIs) was calculated. To further explore association between intake of flavanones and its subclasses and the Ow/Ob and CO in children and adolescents, subgroup analyses stratified by age, and gender.

Results

Of the total 5,970 children and adolescents, 2,463 (41.2%) developed Ow/Ob and 1,294 (21.7%) patients developed CO. High intake of flavanones, eriodictyol, hesperetin, and naringenin were associated with lower odds of Ow/Ob in children and adolescents. (OR: 0.75, 95%CI: 0.62-0.92, OR: 0.69, 95%CI: 0.55-0.87, OR: 0.69, 95%CI: 0.55-0.87, and OR: 0.76, 95%CI: 0.63-0.92, respectively). In addition, high intake of flavanones, eriodictyol, and naringenin were associated with lower odds of CO in children and adolescents (OR: 0.71, 95%CI: 0.57-0.88, OR: 0.67, 95%CI: 0.51-0.86, and OR: 0.69, 95%CI: 0.55-0.86, respectively). Subgroup analyses showed that among all the different subgroups, high intake of flavanones was associated with lower odds of Ow/Ob and CO in children and adolescents.

Conclusion

A diet loaded with high flavanones were associated with lower odds of Ow/Ob and CO in children and adolescents, and children and adolescents should be encouraged to increase their intake of flavanones.

Flavonoids intake and weight-adjusted waist index: insights from a cross-sectional study of NHANES

This study conducted data on 15,446 adults to explore the impact of flavonoids on weight-adjusted waist index (WWI). This was a nationwide cross-sectional study among US adults aged 20 years or older. Dietary intake of flavonoids was assessed through 24-h recall questionnaire. WWI was calculated by dividing waist circumference (WC) by the square root of weight. We utilized weighted generalized linear regression to evaluate the association between flavonoids intake and WWI, and restricted cubic splines (RCS) to explore potential non-linear relationships. Our findings indicated that individuals with lower WWI experienced a notable increase in their consumption of total flavonoids, flavanones, flavones, flavan-3-ols, and anthocyanidins intake (β (95% CI); -0.05(-0.09, -0.01); -0.07(-0.13, 0.00); -0.07(-0.11, -0.02); -0.06(-0.11, 0.00); -0.13(-0.18, -0.08), respectively), with the exception of flavonols and isoflavones. Additionally, consumption of total flavonoids, flavonols, flavanones, isoflavones, and flavan-3-ols had a non-linear relationship with WWI (all P for non-linearity < 0.05). Furthermore, the effect of total flavonoids on WWI varied in race (P for interaction = 0.011), gender (P for interaction = 0.038), and poverty status (P for interaction = 0.002). These findings suggested that increase the intake of flavonoids might prevent abdominal obesity, but further prospective studies are requested before dietary recommendation.

Sexual dimorphism in the context of nutrition and health

Diets and dietary constituents that we consume have a considerable impact on disease risk. Intriguingly these effects may be modulated to some extent by sex. Lack of female representation in nutritional studies as well as a lack of stratification by sex has and continues to limit our understanding of these sex × diet interactions. Here we provide an overview of the current and available literature describing how exposure to certain dietary patterns (Western-style diet, Mediterranean diet, vegetarian/vegan, ketogenic diet) and dietary constituents (dietary fibre, PUFA and plant bioactive) influences disease risk in a sex-specific manner. Interestingly, these sex differences appear to be highly disease-specific. The identification of such sex differences in response to diet stresses the importance of sex stratification in nutritional research.

Role of flavonoids in controlling obesity: molecular targets and mechanisms

Obesity presents a major health challenge that increases the risk of several non-communicable illnesses, such as but not limited to diabetes, hypertension, cardiovascular diseases, musculoskeletal and neurological disorders, sleep disorders, and cancers. Accounting for nearly 8% of global deaths (4.7 million) in 2017, obesity leads to diminishing quality of life and a higher premature mortality rate among affected individuals. Although essentially dubbed as a modifiable and preventable health concern, prevention, and treatment strategies against obesity, such as calorie intake restriction and increasing calorie burning, have gained little long-term success. In this manuscript, we detail the pathophysiology of obesity as a multifactorial, oxidative stress-dependent inflammatory disease. Current anti-obesity treatment strategies, and the effect of flavonoid-based therapeutic interventions on digestion and absorption, macronutrient metabolism, inflammation and oxidative stress and gut microbiota has been evaluated. The use of several naturally occurring flavonoids to prevent and treat obesity with a long-term efficacy, is also described.

The Impact of Dietary Flavonols on Central Obesity Parameters in Polish Adults

Background: Central obesity is defined as the excessive fat tissue located in abdominal region accompanied by systemic inflammation, which drives to cardiovascular disease. Flavonols are antioxidative agents present in food. The aim of this study was investigating the relationship between dietary flavonols intake and central obesity. Methods and results: 80 participants (40 central obese and 40 healthy controls) were administered a food frequency questionnaire dedicated to flavonols intake assessment. Body composition was measured with bioelectrical impedance analysis. The analysis showed significant differences between central obese participants and healthy controls in total flavonol (p = 0.005), quercetin (p = 0.003), kaempferol (p = 0.04) and isorhamnetin (p < 0.001) habitual intake. Among central obese participants, there was a moderate inverse correlation between fat mass (FM) and total flavonol (R = −0.378; 95% CI: −0.620 to −0.071; p = 0.02), quercetin (R = −0.352; 95% CI: −0.601 to −0.041; p = 0.03), kaempferol (R = −0.425; 95% CI: −0.653 to −0.127; p = 0.01) and myricetin intake (R = −0.352; 95% CI: −0.601 to −0.041; p = 0.03). BMI was inversely correlated with total flavonol (R = −0.330; 95% CI: −0.584 to −0.016; p = 0.04) and quercetin intake (R = −0.336; 95% CI: −0.589 to −0.023; p = 0.04). Waist circumference was inversely correlated with total flavonol (R = −0.328; 95% CI: −0.586 to −0.009; p = 0.04), quercetin (R = −0.322; 95% CI: −0.582 to −0.002; p = 0.048) and myricetin intake (R = −0.367; 95% CI: −0.615 to −0.054; p = 0.02). Among flavonols’ dietary sources, there was an inverse correlation between black tea consumption and FM (R: −0.511; 95% CI: −0.712 to −0.233; p < 0.001) and between coffee and waist circumference (R: −0.352; 95% CI: −0.604 to −0.036; p = 0.03) in central obese participants. Conclusions: The higher flavonol intake could play a protective role in abdominal obesity development. What is more, total and selected flavonol dietary intakes are inversely correlated with the parameters used for obesity assessment in central obese participants. The habitual consumption of products rich in flavonols, mainly tea and coffee, could possibly have a preventive role in abdominal obesity development.

Dietary antioxidant consumption and the risk of type 2 diabetes in South Korean adults: a prospective cohort study based on the Health Examinees study

OBJECTIVES

Antioxidants are common dietary compounds with multiple health benefits. This study aimed to identify the association between dietary antioxidant consumption and the incidence of type 2 diabetes (T2D) mellitus (defined using the Korean Diabetes Association criteria) in South Korean adults.

DESIGN

Baseline and follow-up data from the Health Examinees (HEXA) study, a large-scale community-based genomic cohort study conducted in South Korea SETTING: A South Korean community.

PARTICIPANTS

A total of 20 594 participants, aged 40-79 years, who participated in the baseline and follow-up surveys of the HEXA study were included. After an average of 5 years of follow-up, there were 332 men and 360 women with T2D.

RESULTS

Participants with the highest total flavonoid consumption (Q5) had a lower risk of T2D (men: HR 0.63; 95% CI 0.42 to 0.93; p value for trend=0.0169; and women: HR 0.54; 95% CI 0.438 to 0.78; p value for trend=0.0001) than those with the lowest consumption (Q1). Dietary total antioxidant capacity was significantly inversely associated with the development of T2D mellitus in women participants alone (HR 0.58; 95% CI 0.40 to 0.83; p value for trend=0.0004). Stratified analyses according to age and body mass index (BMI) showed that dietary total flavonoid consumption and total antioxidant capacity had a negative association with the development of T2D in women aged >52 years and women with BMI >25 kg/m².

CONCLUSIONS

Dietary flavonoid consumption and total antioxidant capacity were associated with a lower risk of T2D in South Korean adults, especially in women aged >52 years and overweight. The findings of this study may provide reference data for the modification of dietary guidelines for South Koreans.

Recent Development of Flavonoids with Various Activities

Flavonoids, a series of compounds with C6-C3-C6 structure, mostly originate from plant metabolism. Flavonoids have shown beneficial effects on many aspects of human physiology and health. Recently, many flavonoids with various activities have been discovered, which has led to more and more studies focusing on their physiological and pharmacodynamic activities. The anti-cancer and anti-viral activities especially have attracted the attention of many researchers. Therefore, the discovery and development of flavonoids as anti-disease drugs has great potential and may make significant contribution to fighting diseases. This review focus on the discovery and development of flavonoids in medicinal chemistry in recent years.

Soy Isoflavones Intake and Obesity in Chinese Adults: A Cross-Sectional Study in Shanghai, China

This study was designed to examine the association of soy isoflavones (SI) intake with different body measurements indicative of obesity in Chinese adults of Shanghai, a population consuming foods rich in SI. This study used baseline data from the Shanghai Gaofeng cohort study. SI intake was measured by using a self-reported food frequency questionnaire (FFQ). A restricted cubic spline (RCS) was performed to examine the possible nonlinear relationship of SI intake with obesity. A logistic regression model was applied to estimate the odds ratios (OR) and 95% confidence interval (CI). Compared with the lowest tertile group of SI intake, the highest tertile group had a lower prevalence of obesity and central obesity. The OR for overall obesity was 0.91 (95% CI: 0.85, 0.98) in the highest versus the lowest SI tertile group; the associations differed by sex and menopausal status. A negative association was also observed between SI intake and central obesity, and a significant modifying effect of sex was found on the association. No significant interactions were observed between SI intake and physical activity (PA) levels. Our results suggest that Chinese adults with higher dietary intake of SI may be less likely to be obese, particularly for postmenopausal women.

Anti-obesity properties and mechanism of action of flavonoids: A review

Obesity is a major public health problem, and there is increasing scientific interest in its mechanisms, as well as a search for new compounds with antioxidant and anti-inflammatory properties that can minimize the metabolic complications associated with its pathology. One potential source of these compounds is natural products; Among these, flavonoids are a promising group of natural substances. Flavonoids are active constituents with diverse biological activities and are widely found in plants kingdom. Numerous studies have shown that flavonoids can effectively inhibit obesity and related metabolic disorders. The review synthesizes recent evidence in respect of progress in the understanding of the anti-obesity effects of flavonoids. Such effects which occurs through the modulation of proteins, genes and transcriptional factors involved in decreasing lipogenesis, increasing lipolysis, expenditure energy, stimulating fatty acids B-oxidation, digestion and metabolism of carbohydrates. In addition to mitigating inflammatory responses and suppress oxidative stress. A better understanding of the modulating effects and mechanisms of flavonoids in relation to obesity will allow us to better use these compounds to treat or even prevent obesity and its associated comorbidities.

Dietary Assessment Methods to Estimate (Poly)phenol Intake in Epidemiological Studies: A Systematic Review

Nutritional epidemiological studies have frequently reported associations between higher (poly)phenol intake and a decrease in the risk or incidence of noncommunicable diseases. However, the assessment methods that have been used to quantify the intakes of these compounds in large-population samples are highly variable. This systematic review aims to characterize the methods used to assess dietary (poly)phenol intake in observational studies, report the validation status of the methods, and give recommendations on method selection and data reporting. Three databases were searched for publications that have used dietary assessment methods to measure (poly)phenol intake and 549 eligible full texts were identified. Food-frequency questionnaires were found to be the most commonly used tool to assess dietary (poly)phenol intake (73%). Published data from peer-reviewed journals were the major source of (poly)phenol content data (25%). An increasing number of studies used open-access databases such as Phenol-Explorer and USDA databases on flavonoid content since their inception, which accounted for 11% and 23% of the data sources, respectively. Only 16% of the studies reported a method that had been validated for measuring the target (poly)phenols. For future research we recommend: 1) selecting a validated dietary assessment tool according to the target compounds and target period of measurement; 2) applying and combining comprehensive (poly)phenol content databases such as USDA and Phenol-Explorer; 3) detailing the methods used to assess (poly)phenol intake, including dietary assessment method, (poly)phenol content data source; 4) follow the Strengthening the Reporting of Observational Studies in Epidemiology-Nutritional Epidemiology (STROBE-nut) framework; and 5) complementing dietary intake assessment based on questionnaires with measurement of (poly)phenols in biofluids using appropriate and validated analytical methods.

Effect of Quercetin on Lipids Metabolism Through Modulating the Gut Microbial and AMPK/PPAR Signaling Pathway in Broilers

The present study was conducted to investigate effects and mechanism of quercetin on lipids metabolism in broilers. 480 AA broilers were randomly allotted to four treatments (0, 0.2, 0.4, and 0.6 g/kg quercetin) for 42 days. Compared with the control, 0.6 g/kg quercetin significantly decreased percentage of abdominal fat (P < 0.05); 0.2, 0.4, and 0.6 g/kg quercetin significantly decreased relative abundance of Lachnospiraceae and Desulfovibrionaceae (P < 0.05, P < 0.05, P < 0.01; P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased mRNA expression of PI3K, AMPKα1, AMPKα2, AMPKβ2, LKB1 (P < 0.01, P < 0.01, P < 0.05, P < 0.01, P < 0.05), and significantly reduced mRNA expression of SREBP1 and PPARγ (P < 0.01, P < 0.05); 0.4 g/kg quercetin significantly increased mRNA expression of LKB1 and PKB (P < 0.05, P < 0.01) and significantly reduced mRNA expression of ACC, HMGR, PPARγ, and SREBP1 (P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.6 g/kg quercetin significantly increased mRNA expression of AMPKγ, LKB1, CPT1, PPARα, PKB (P < 0.01, P < 0.01, P < 0.01, P < 0.05, P < 0.05), and significantly reduced the mRNA expression of PI3K, ACC, HMGR, PPARγ, SREBP1 (P < 0.05, P < 0.05, P < 0.01, P < 0.01, P < 0.01); 0.2 g/kg quercetin significantly increased protein expression of AMPK (P < 0.01); 0.6 g/kg quercetin significantly increased protein expression of LKB1 (P < 0.01), 0.2 and 0.6 g/kg quercetin significantly increased protein expression of PI3K, PKB, CPT1 (P < 0.05, P < 0.01, P < 0.05, P < 0.01, P < 0.01, P < 0.01), and significantly reduced protein expression of ACC and SREBP1 (P < 0.01, P < 0.01, P < 0.01, P < 0.01). In conclusion, quercetin improved lipid metabolism by modulating gut microbial and AMPK/PPAR signaling pathway in broilers.

The Diverse Efficacy of Food-Derived Proanthocyanidins for Middle-Aged and Elderly Women

Middle-aged and elderly women are affected by various symptoms and diseases induced by estrogen deficiency. Proanthocyanidins, widely present in many kinds of fruits and berries, have many beneficial effects, such as antioxidative, anti-inflammatory, and antimicrobial activities. We researched the effects of proanthocyanidins for middle-aged and elderly women, finding that it has been revealed in many clinical trials and cohort studies that proanthocyanidins contribute to the prevention of cardiovascular disease, hypertension, obesity, cancer, osteoporosis, and urinary tract infection, as well as the improvement of menopausal symptoms, renal function, and skin damage. Thus, proanthocyanidins can be considered one of the potent representatives of complementary alternative therapy.

The Inhibitory Effects of Juglanin on Adipogenesis in 3T3-L1 Adipocytes

INTRODUCTION

Deregulation of adipogenesis plays an important role in obesity and other metabolism disorders. PPAR, C/EBP and SREBP1c are key transcriptional factors involved in adipogenesis and lipogenesis. Juglanin is a natural compound belonging to flavonoids, and it has been reported that juglanin has a potent inhibitory effect on inflammation and certain type of cancers. However, the effects of juglanin in adipogenesis have not been reported before.

MATERIALS AND METHODS

3T3-L1 preadipocytes were incubated with differentiation induction medium in the presence or absence of 0.5, 2.5, or 5 µM juglanin for an 8-day differentiation period. The lipid droplets accumulated in the cytoplasm were monitored by Oil Red O staining on days 0, 2, 5, and 8. The regulatory effects of juglanin on adipogenesis-related genes and proteins were investigated by real-time polymerase chain reaction and Western blot analysis.

RESULTS

Juglanin significantly decreased lipid accumulation in differentiated adipocytes. Our findings show that juglanin reduced the expression of C/EBPα, C/EBPβ, and SREBP-1c without affecting PPARα or PPARγ expression. Additionally, juglanin increased the activation of the SIRT1/AMPK signaling pathway through the phosphorylation of AMPKα. Finally, we performed an AMPK inhibitor experiment, which revealed that the inhibitory effects of juglanin on adipogenesis are mediated through AMPK.

DISCUSSION

Juglanin can prevent adipogenesis by suppressing lipid accumulation and the differentiation of preadipocytes. The mechanism of juglanin regulating adipogenesis requires further investigation. Future clinical study in vivo could shed more light on its implication in modulating obesity and metabolic disorders.

Association between the Phytochemical Index and Lower Prevalence of Obesity/Abdominal Obesity in Korean Adults

The relatively high levels of vegetable consumption have highlighted the need to examine the association between phytochemical intake and disease prevention. We examined the association between the phytochemical index (PI) and obesity/abdominal obesity among Korean adults. We analyzed the data of 57,940 adults aged ≥ 19 years obtained from the Korea National Health and Nutrition Examination Survey. We calculated PI using the 24 h recall data, and multivariable-adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression models. Dose–response patterns were analyzed using restricted cubic spline regression. After multivariable adjustment, a higher PI was found to be associated with a lower prevalence of obesity and abdominal obesity; this association was notable in women (obesity, OR: 0.86, CI: 0.78–0.94, p for trend = 0.01; abdominal obesity, OR: 0.81, CI: 0.73–0.90, p for trend < 0.001). Spline regression showed linearity of the associations between PI and obesity/abdominal obesity in women. Our findings suggested that maintaining a phytochemical-rich diet may help to prevent obesity and abdominal obesity, especially in women, as an increased PI corresponded to lower prevalence of obesity. This study, using evidence-based data, highlighted the importance of consuming plant-derived foods to prevent obesity.