Kyeong-A Jang

Research findings on the relationship between dietary resistant starch (RS) intake and metabolic diseases using population-based data are very scarce. This study examined the association of dietary RS intake with obesity and metabolic syndrome in Korean adults. A total of 12,491 adults (5292 men and 7199 women) were selected from the 2016–2018 Korea National Health and Nutrition Examination Survey data. The individual RS intake (g) was calculated by linking the 1-day 24 h recall data with the RS content database for common Korean foods. Obesity was defined as a BMI ≥ 25.0 kg/m². Metabolic syndrome was defined as having three or more of the following: abdominal obesity, elevated triglycerides, low HDL cholesterol, elevated fasting blood glucose, and elevated blood pressure. Odds ratios (ORs) with 95% confidence intervals (CIs) for obesity and metabolic syndrome across quartiles (Qs) of RS intake were calculated using multiple logistic regression analysis. In men, the highest quartile of RS intake showed a significantly lower OR for metabolic syndrome compared to the lowest quartile after adjusting for covariates (OR = 0.71, 95% CI = 0.56–0.92, p-trend = 0.0057). Dietary RS intake in men was also inversely associated with obesity (Q4 vs. Q1: OR = 0.80, 95% CI = 0.67–0.97, p-trend = 0.0329) and elevated triglycerides (Q4 vs. Q1: OR = 0.80, 95% CI = 0.66–0.98, p-trend = 0.0314). In women, RS intake was not associated with metabolic syndrome. Our findings may serve as useful data for developing guidelines for RS intake and conducting further cohort and clinical studies to investigate the health effects of RS.

This study investigated the anti-oxidative and anti-inflammatory effects of Aster glehni (AG) extract in RAW 264.7 cells and Caenorhabditis elegans. The total polyphenol and flavonoid contents were higher in the ethanol extracts than in the hot water extracts. As a result of measuring the moisture contents (%) and extraction yields (%) of AG and drying A. glehni for processing (DAG), 70% ethanol, which has the highest percentage of extraction yield, was selected as the final solvent. DPPH radical scavenging activity showed higher antioxidant activity of ethanol extracts of DAG than AG. The cytotoxicity assay of the AG or DAG ethanol extracts was treated at different concentrations (25, 50, and 100 μg/mL), and cell viability rates were higher than 80% at all concentrations. The LPS-stimulated nitric oxide (NO) production in RAW 264.7 was significantly reduced at all concentrations of AG and DAG groups. As a result of measuring the gene expression of iNOS, which induces NO production, the AG or DAG group decreased by 33% and 32%, compared with the phosphate buffer saline (PBS) group. Under inflammatory stress conditions, the survival rate of C. elegans treated with AG or DAG ethanol extract with LPS showed concentration-dependent improvement in survival rate compared with the PBS group. Considering these results, AG could potentially be developed as an antioxidant and anti-inflammatory functional food material.

This study aimed to identify major dietary patterns associated with abdominal obesity in middle-aged and older Korean adults. Data from the Korean Genome and Epidemiology Study were used. A total of 48,037 Korean adults aged ≥40 years without abdominal obesity at baseline were followed-up. Dietary assessment was conducted using a validated 106-item food-frequency questionnaire, and dietary patterns were identified using factor analysis. Abdominal obesity was defined as a waist circumference of ≥90 cm for men and ≥85 cm for women, according to the Korean Society for the Study of Obesity. Multivariable Cox proportional-hazards models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the future risk of abdominal obesity for each dietary pattern after adjusting for potential covariates. After an average follow-up of 4.89 years, we reported 5878 cases (1932 men and 3946 women) of abdominal obesity. Based on factor analysis, three major dietary patterns were identified in both men and women: the “healthy”, “coffee and sweets”, and “multi-grain” patterns. In the fully adjusted model, the “healthy” pattern was inversely associated with the incidence of abdominal obesity (HR for fourth vs. first quartile: 0.86; 95% CI: 0.75–0.98; p for trend = 0.0358 for men; HR for fourth vs. first quartile: 0.90; 95% CI: 0.83–0.99; p for trend = 0.0188 for women), whereas the “coffee and sweets” pattern was positively associated with it (HR for fourth vs. first quartile: 1.23; 95% CI: 1.08–1.40; p for trend = 0.0495 for men; HR for fourth vs. first quartile: 1.14; 95% CI: 1.04–1.25; p for trend = 0.0096 for women). In contrast, the “multi-grain” pattern in men and women showed no significant association with the incidence of abdominal obesity. Diets rich in colorful vegetables, seaweeds, mushrooms, tubers, fruits, soy products, and fish and low in coffee, sweets, and oils/fats might be favorable for reducing the future risk of abdominal obesity, particularly in middle-aged and older Korean adults.

Nightly fasting duration and meal timing are associated with metabolic disorders. This study aimed to investigate the relationships of nightly fasting duration and meal timing with type 2 diabetes mellitus (T2DM) using data from the 2016–2020 Korea National Health and Nutrition Survey. A total of 22,685 adults ≥ 19 years were included in this study. Nightly fasting duration was calculated by subtracting the interval between the day’s first and last meal eating times from 24 h. The meal timing were analyzed using various parameters, including the times of the first and last eating episodes and the percentage of energy intake during the morning (05:00 to 9:00 a.m.), evening (06:00 to 09:00 p.m.), and night (after 09:00 p.m.). Men who fasted nightly for ≥ 12 h had lower odds of T2DM (odds ratio (OR): 0.86; 95% confidence interval (CI): 0.75–0.99) than those who fasted for < 12 h. Individuals who had their last meal after 09:00 p.m. had higher odds of T2DM (OR: 1.19, 95% CI: 1.03–1.38, men; OR: 1.19, 95% CI: 1.01–1.40, women). Additionally, the percentage of energy intake during the evening was associated with increased odds of T2DM (OR: 1.41, 95% CI: 1.08–1.84, men; OR: 1.32, 95% CI: 1.02–1.70, women). These findings emphasize the importance of nightly fasting duration and meal timing in modulating the risk of T2DM among Korean adults.

The aim of this study was to analyze the physiological activity of 48 soybean resources harvested in 2020 to identify the soybean resources’ relationships with individual isoflavone compounds and their genetic properties. These data will subsequently be compared with the research results on soybeans harvested in 2019. Initially, with respect to the physiological activity (6 types) and substances (19 types), this study evaluated the differences between the cultivation year (two years), seed coat color (three colors), and the interaction of the year and seed coat color of soybeans through ANOVA. Among the physiological activities, there were differences in the estrogen, estrogen receptor alpha, and UCP-1 (uncoupling protein-1) activities depending on the cultivation year. Moreover, there were differences in NO (nitric oxide), revealing differences in the ABTS (2, 2′-azino-bis-3ethylbenzo-thiazoline-6-sulfonic acid) and DPPH (2, 2-diphenyl-2-picrylhydrazyl) radical scavenging activities due to the seed coat color and the interaction of the year and seed coat color. Soybeans harvested in 2020 exhibited increased ABTS, DPPH, and NO inhibitory activities and reduced estrogen, estrogen receptor alpha, and UCP-1 activities compared to those harvested in 2019. According to the ANOVA results, eight of the nineteen individual derivatives illustrated yearly differences, while three derivatives displayed differences due to the seed coat color. Secondly, according to the relationship between the efficacy, derivative substances, and genetic properties, it was determined that genistein 7-O-(2″-O-apiosyl)glucoside (F5) is the individual isoflavone derivative that affected the six types of physiological activity, on which the genome-wide association study (GWAS) showed no significant differences for genetic properties. These results were inconsistent with the 2019 data, where three types of individual compounds, including F5, were proposed as substances that correlated with efficacy and there was a high correlation with genetic properties. Therefore, this study selected B17, B23, B15, B24, and Y7 as excellent varieties that are stable and highly functional in the cultivation environment, producing only small annual differences. The results of this study will be utilized as basic data for predicting soybean varieties and their cultivation, which have high environmental stability under climate variation and properly retain the functional substances and efficacy.

The functionality of soybeans is an important factor in the selection and utilization of excellent soybean cultivars, and isoflavones are representative functional substances in soybeans, which exhibit effects on antioxidants, estrogen activity, and cancer, and prevent cardiovascular diseases. This study analyzed ABTS, DPPH, estrogen, ER (ER) alpha, UCP-1, and NO inhibition activities in 48 types of soybean cultivars, as well as the relationship with 19 isolated types of individual isoflavone derivatives. Statistical analysis was conducted to find individual isoflavone derivatives affecting physiological activities, revealing the high correlation of three types of derivatives: genistein 7-O-(6″-O-acetyl)glucoside (6″-O-acetylgenistin), genistein 7-O-(2″-O-apiosyl)glucoside, and glycitein. Based on these results, 15 types of soybean cultivars were selected (one control type, seven yellow types, six black types, and one green type), which have both high physiological activities and a high content of individual isoflavone derivatives. In addition, these high correlations were further verified through a genome-wide association study (GWAS) to determine the association between activities, substances, and genetic characteristics. This study comprehensively describes the relationship between the specific physiological activities of soybean resources, individual isoflavone derivative substances, and SNPs, which will be utilized for in-depth research, such as selection of excellent soybean resources with specific physiological activities.