1.Main revisions to carbohydrate intake reference values in the 2025 Dietary Reference Intakes for Koreans
Miae DOO ; YoonJu SONG ; Jeong Hyun LIM ; Ja Young JEON ; Wookyoung KIM
Journal of Nutrition and Health 2026;59(2):148-158
The recommendations for carbohydrate intake were revised in the 2025 Korean Dietary Reference Intakes to reflect updated evidence on chronic disease risk and to clarify the interpretation of the Estimated Average Requirement (EAR) and Recommended Nutrient Intake (RNI). These revisions aim to strengthen both the scientific basis and the practical interpretation of carbohydrate intake guidance across the life course of an individual. For individuals aged 1 year and older, the Acceptable Macronutrient Distribution Range for carbohydrates was lowered from 55–65% of total energy to 50–65%. This adjustment reflects accumulating evidence from prospective cohort studies and meta-analyses indicating that very high carbohydrate intake is associated with an increased risk of adverse health outcomes. In contrast, an intake of approximately 50–55% of total energy is associated with the lowest mortality risk. Importantly, this change does not imply a preference for low-carbohydrate diets, as overall dietary quality, including carbohydrate quality, remains a critical consideration. The EAR (100 g/day) and RNI (130 g/day) are derived from estimates of brain glucose utilization and metabolic adaptation and should be interpreted as physiological minimum intake levels rather than population-based intake targets. In addition, life-stage-specific recommendations were updated based on new evidence, including recalculating the Adequate Intake (AI) for infants (55 g/day for 0–5 months and 85 g/day for 6–11 months) and revising the additional requirements during pregnancy (+35 g/day) and lactation (+55 g/day).Because no Tolerable Upper Intake Level (UL) has been established for total carbohydrate intake, excess intake should be managed through dietary adjustments, including limiting added sugars and refined carbohydrates, ensuring adequate fiber intake, and maintaining overall macronutrient balance. Collectively, these revisions provide an updated evidencebased framework for carbohydrate intake guidance for the Korean population.
2.Diallyl disulfide suppresses weight gain, adipogenesis, and matrix metalloproteinases (MMPs) expression in high-fat-diet-induced obese animal model
SooMin JUNG ; Ae Wha HA ; WooKyoung KIM
Nutrition Research and Practice 2026;20(1):46-61
BACKGROUND/OBJECTIVES:
Excessive adipogenesis and angiogenesis, mediated by matrix metalloproteinases (MMPs), contribute to the development of obesity-related complications.Diallyl disulfide (DADS), an organosulfur compound derived from garlic, has been reported to exhibit anti-obesity properties, but studies on the expression of MMPs as an anti-obesity effect of DADS are limited. This study investigated the potential role of DADS in regulating weight gain, adipogenesis, and MMP expression in mice fed a high-fat diet.MATERIALS/METHODS: Six-week-old male C57BL/6N mice were divided into 4 groups:a normal-fat diet (NF), a high-fat diet (HF), a high-fat diet supplemented with 12.5 mg/kg DADS (HFDADS12.5), and a high-fat diet supplemented with 25 mg/kg DADS (HFDADS25) for 14 weeks. This study measured plasma lipid concentrations, glycerol-3-phosphate dehydrogenase (GPDH) activity, mRNA expression of transcription factors related to adipocyte differentiation in the liver, and the mRNA expression and concentrations of MMP-2 and MMP-9 in epididymal adipose tissue. The plasma concentrations of adiponectin and leptin were also measured.
RESULTS:
DADS intake significantly reduced the body weight gain and epididymal adipose tissue weight (P < 0.05). The GPDH activity, mRNA expressions of the transcription factors related to adipocyte differentiation, the mRNA expression and concentrations of MMP-2 and MMP-9, and plasma leptin concentration were significantly higher in the HF group than in the NF group, but they were significantly lower in the DADS intake groups (P < 0.05).The plasma adiponectin concentrations were lower in the HF group than the NF group, but they were significantly higher in the HFDADS25 group (P < 0.05).
CONCLUSION
DADS suppressed body weight gain and adipogenesis, potentially by inhibiting MMP-2 and MMP-9 in mice fed a high-fat diet.
3.Analysis of pork consumption attribute factors by consumer lifestyle in Korea: a cross-sectional study
Jounghee LEE ; Juhyun LEE ; Wookyoung KIM
Korean Journal of Community Nutrition 2025;30(1):75-88
Objectives:
This study aims to identify and analyze how different South Korean lifestyles impact attitudes towards pork consumption.
Methods:
We implemented a cross-sectional survey targeting 705 adult consumers in South Korea using hierarchical and K-means cluster analyses. Respondents were classified into three relevant lifestyles: (1) domestic preference, (2) price-sensitive, and (3) quality-experience-oriented. The importance-performance analysis was employed to evaluate discrepancies between how they rated pork consumption using factors of “importance” and “satisfaction”. We employed Borich’s needs assessment and the Locus for Focus model to prioritize management areas.
Results:
The research findings highlight that unpleasant odor/smell (Q7) and hygiene (Q1) were common key areas for management across all consumer groups, emphasizing their importance in enhancing pork consumption satisfaction. Among the groups, the domestic preference group showed high importance-performance discrepancies in attributes like expiry date (D2), suggesting a need for strengthened trust in domestic pork distribution and information transparency. The price-sensitive group prioritized economic factors, with fat thickness (Q8) identified as an essential management area. The quality-experience-oriented group emphasized sensory qualities such as juiciness (Q6) and meat color (Q5), with off-flavors (Q7) displaying the largest discrepancy. These results show the significant role of sensory attributes in consumer satisfaction.
Conclusion
This study demonstrated the multidimensional nature of pork consumption behavior, emphasizing the need for tailored strategies across consumer groups. Managing hygiene (Q1) and reducing off-flavors (Q7) are critical for all segments, while group-specific strategies include managing sensory quality for the quality-experience-oriented group, providing product information (D2) to increase trust for the domestic preference group, and emphasizing value for money for the price-sensitive group.
4.The effect of curcumin on blood pressure and cognitive impairment in spontaneously hypertensive rats
Ji Young LIM ; Wookyoung KIM ; Ae Wha HA
Nutrition Research and Practice 2023;17(2):192-205
BACKGROUND/OBJECTIVES:
It is known that the renin-angiotensin system (RAS) in the brain could regulate cognitive functions as well as blood pressure. Inhibition of RAS for the improvement of cognitive function may be a new strategy, but studies so far have mostly reported on the effects of RAS inhibition by drugs, and there is no research on cognitive improvement through RAS inhibition of food ingredients. Therefore, this study investigated the effect of curcumin on blood pressure and cognitive function and its related mechanism in spontaneously hypertensive rat/Izm (SHR/Izm).MATERIALS/METHODS: Six-week-old SHR/Izm rats were divided into 5 groups: control group (CON), scopolamine group (SCO, drug for inducing cognitive deficits), positive control (SCO and tacrine [TAC]), curcumin 100 group (CUR100, SCO + Cur 100 mg/kg), and curcumin 200 group (CUR200, SCO + Cur 200 mg/kg). Changes in blood pressure, RAS, cholinergic system, and cognitive function were compared before and after cognitive impairment.
RESULTS:
The SCO group showed increased blood pressure and significantly reduced cognitive function based on the y-maze and passive avoidance test. Curcumin treatments significantly improved blood pressure and cognitive function compared with the SCO group.In both the CUR100 and CUR200 groups, the mRNA expressions of angiotensin-converting enzyme (ACE) and angiotensin II receptor type1 (AT1), as well as the concentrations of angiotensin II (Ang II) in brain tissue were significantly decreased. The mRNA expression of the muscarinic acetylcholine receptors (mAChRs) and acetylcholine (ACh) content was significantly increased, compared with the SCO group.
CONCLUSIONS
The administration of curcumin improved blood pressure and cognitive function in SCO-induced hypertensive mice, indicating that the cholinergic system was improved by suppressing RAS and AT1 receptor expression and increasing the mAChR expression.
5.Quercetin inhibits body weight gain and adipogenesis via matrix metalloproteinases in mice fed a highfat diet
SeungMin SONG ; Ae Wha HA ; WooKyoung KIM
Nutrition Research and Practice 2023;17(3):438-450
BACKGROUND/OBJECTIVES:
Limited studies reported that quercetin inhibited adipogenesis and neovascularization by inhibiting matrix metalloproteinases (MMPs) activity, but such mechanisms have not been elucidated in animal experiments. In this study, we investigated the inhibitory effects of quercetin on weight gain and adipose tissue growth through the regulation of mRNA expressions of adipogenic transcription factors and MMPs in mice fed a high-fat diet (HFD).MATERIALS/METHODS: Five-wk-old C57BL/6J mice were fed a normal diet (ND), HFD, HFD containing 0.05% of quercetin (HFQ0.05), or HFD containing 0.15% of quercetin (HFQ0.15) for 16 wks. Glycerol-3-phosphate dehydrogenase (GPDH) activity was measured using a commercial kit. The mRNA expressions of transcription factors related to adipocyte differentiation were determined by real-time polymerase chain reaction (PCR). The mRNA expressions of MMPs and concentrations of MMPs were measured by real-time PCR and enzyme-linked immunosorbent assay kit, respectively.
RESULTS:
Quercetin intake reduced body weight gain and epididymal adipose tissue weights (P < 0.05). GPDH activity was higher in the HFD group than in the ND group but lower in the quercetin groups (P < 0.05). The mRNA expressions of CCAAT/enhancer binding protein β (C/EBPβ), C/EBPα, peroxisome proliferator-activated receptor γ, and fatty acid-binding protein 4 were lower in the quercetin groups than in the HFD group (P < 0.05). Similarly, the mRNA expression and concentrations of MMP-2 and MMP-9 were significantly lower in the quercetin groups than in the HFD group (P < 0.05).
CONCLUSION
The study confirms that quercetin suppresses body weight gain and adipogenesis by inhibiting transcription factors related to adipocyte differentiation and MMPs (MMP-2 and MMP-9), in mice fed a HFD.
6.Issues pertaining to Mg, Zn and Cu in the 2020 Dietary Reference Intakes for Koreans
Hae-Yun CHUNG ; Mi-Kyung LEE ; Wookyoung KIM ; Mi-Kyeong CHOI ; Se-Hong KIM ; Eunmee KIM ; Mi-Hyun KIM ; Jung-Heun HA ; Hongmie LEE ; Yun-Jung BAE ; In-Sook KWUN
Nutrition Research and Practice 2022;16(S1):s113-s125
In the current years, it has now become necessary to establish standards for micronutrient intake based on scientific evidence. This review discusses issues related to the development of the 2020 Dietary Reference Intakes for Koreans (KDRI) for magnesium (Mg), zinc (Zn), and copper (Cu), and future research directions. Following issues were encountered when establishing the KDRI for these minerals. First, characteristics of Korean subjects need to be applied to estimate nutrient requirements. When calculating the estimated average requirement (EAR), the KDRI used the results of balance studies for Mg absorption and factorial analysis for Zn, which is defined as the minimum amount to offset endogenous losses for Zn and Mg. For Cu, a combination of indicators, such as depletion/repletion studies, were applied, wherein all reference values were based on data obtained from other countries. Second, there was a limitation in that it was difficult to determine whether reference values of Mg, Zn, and Cu intakes in the 2020 KDRI were achievable. This might be due to the lack of representative previous studies on intakes of these nutrients, and an insufficient database for Mg, Zn, and Cu contents in foods. This lack of database for mineral content in food poses a problem when evaluating the appropriateness of intake. Third, data was insufficient to assess the adequacy of Mg, Zn, and Cu intakes from supplements when calculating reference values, considering the rise in both demand and intake of mineral supplements. Mg is more likely to be consumed as a multi-nutrient supplement in combination with other minerals than as a single supplement. Moreover, Zn-Cu interactions in the body need to be considered when determining the reference intake values of Zn and Cu. It is recommended to discuss these issues present in the 2020 KDRI development for Mg, Zn, and Cu intakes in a systematic way, and to find relevant solutions.
7.Effects of quercetin on cell differentiation and adipogenesis in 3T3-L1 adipocytes
Seo Young HONG ; Ae Wha HA ; Wookyoung KIM
Nutrition Research and Practice 2021;15(4):444-455
BACKGROUND/OBJECTIVES:
Adipocytes undergo angiogenesis to receive nutrients and oxygen needed for adipocyte' growth and differentiation. No study relating quercetin with angiogenesis in adipocytes exists. Therefore, this study investigated the role of quercetin on adipogenesis in 3T3-L1 cells, acting through matrix metalloproteinases (MMPs).MATERIALS/METHODS: After proliferating preadipocytes into adipocytes, various quercetin concentrations were added to adipocytes, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to evaluate cell proliferation.Glycerol-3-phosphate dehydrogenase (GPDH) activity was investigated as an indicator of fat accumulation. The mRNA expressions of transcription factors related to adipocyte differentiation, CCAAT/enhancer-binding proteins (C/EBPs), peroxisomal proliferatoractivated receptors (PPAR)-γ, and adipocyte protein 2 (aP2), were investigated. The mRNA expressions of proteins related to angiogenesis, vascular endothelial growth factor (VEGF)-α, vascular endothelial growth factor receptor (VEGFR)-2, MMP-2, and MMP-9, were investigated. Enzyme activities and concentrations of MMP-2 and MMP-9 were also measured.
RESULTS:
Quercetin treatment suppressed fat accumulation and the expressions of adipocyte differentiation-related genes (C/EBPα, C/EBPβ, PPAR-γ, and aP2) in a concentration-dependent manner in 3T3-L1 cells. Quercetin treatments reduced the mRNA expressions of VEGF-α, VEGFR-2, MMP-2, and MMP-9 in 3T3-L1 cells. The activities and concentrations of MMP-2 and MMP-9 were also decreased significantly as the concentration of quercetin increased.
CONCLUSIONS
The results confirm that quercetin inhibits adipose tissue differentiation and fat accumulation in 3T3-L1 cells, which could occur through inhibition of the angiogenesis process related to MMPs.
8.Effects of quercetin on cell differentiation and adipogenesis in 3T3-L1 adipocytes
Seo Young HONG ; Ae Wha HA ; Wookyoung KIM
Nutrition Research and Practice 2021;15(4):444-455
BACKGROUND/OBJECTIVES:
Adipocytes undergo angiogenesis to receive nutrients and oxygen needed for adipocyte' growth and differentiation. No study relating quercetin with angiogenesis in adipocytes exists. Therefore, this study investigated the role of quercetin on adipogenesis in 3T3-L1 cells, acting through matrix metalloproteinases (MMPs).MATERIALS/METHODS: After proliferating preadipocytes into adipocytes, various quercetin concentrations were added to adipocytes, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays were performed to evaluate cell proliferation.Glycerol-3-phosphate dehydrogenase (GPDH) activity was investigated as an indicator of fat accumulation. The mRNA expressions of transcription factors related to adipocyte differentiation, CCAAT/enhancer-binding proteins (C/EBPs), peroxisomal proliferatoractivated receptors (PPAR)-γ, and adipocyte protein 2 (aP2), were investigated. The mRNA expressions of proteins related to angiogenesis, vascular endothelial growth factor (VEGF)-α, vascular endothelial growth factor receptor (VEGFR)-2, MMP-2, and MMP-9, were investigated. Enzyme activities and concentrations of MMP-2 and MMP-9 were also measured.
RESULTS:
Quercetin treatment suppressed fat accumulation and the expressions of adipocyte differentiation-related genes (C/EBPα, C/EBPβ, PPAR-γ, and aP2) in a concentration-dependent manner in 3T3-L1 cells. Quercetin treatments reduced the mRNA expressions of VEGF-α, VEGFR-2, MMP-2, and MMP-9 in 3T3-L1 cells. The activities and concentrations of MMP-2 and MMP-9 were also decreased significantly as the concentration of quercetin increased.
CONCLUSIONS
The results confirm that quercetin inhibits adipose tissue differentiation and fat accumulation in 3T3-L1 cells, which could occur through inhibition of the angiogenesis process related to MMPs.
9.The development of the 2020 Dietary Reference Intakes for Koreans:carbohydrate
Journal of Nutrition and Health 2021;54(6):584-593
In the 2020 Dietary Reference Intakes for Koreans, an acceptable macronutrient distribution range (AMDR), similar to the one established in 2015, was determined for carbohydrates.AMDR is the ratio that signifies energy intake from carbohydrates to the total energy intake, and is a reference that indicates a decreasing risk of chronic diseases. The AMDR of carbohydrate was determined to be optimal at 55–65% for all ages above 1 year. For the first time, in the year 2020, the estimated average requirement (EAR) and recommended nutrient intake (RNI) for carbohydrates were established. The EAR was based on the amount of glucose used per day in the brain, and was set at 100 g/day for all ages above 1 year. The RNI was set at 130 g/day, by adding a double coefficient of variation using a 15% coefficient of variation, for all ages above 1 year. In pregnant women, the amount of glucose utilized by the fetus brain was considered additionally, and for lactating women the amount of lactose secreted into maternal milk was additionally taken into consideration. Since the EAR of carbohydrate indicates the minimum amount of glucose required by the brain and is not an appropriate intake amount as an energy source, it is incorrect to compare the carbohydrate intake with the EAR or RNI. To evaluate the nutritional status of carbohydrate, it is appropriate to use the AMDR. Carbohydrate intakes within the AMDR range has the possibility in reducing the risk of chronic diseases. Hence, it is important to consider the quality as well as quantity of carbohydrates consumed.
10.Frontal Alpha Asymmetry Correlates with Suicidal Behavior in Major Depressive Disorder
Yeonsoo PARK ; Wookyoung JUNG ; Sungkean KIM ; Hyunjin JEON ; Seung Hwan LEE
Clinical Psychopharmacology and Neuroscience 2019;17(3):377-387
OBJECTIVE: Based on the constant associations made between major depressive disorder (MDD) and alpha asymmetry, and MDD and suicide, this study aimed to examine the relationship between frontal alpha asymmetry and suicide in MDD patients. METHODS: Sixty-six MDD patients, of whom fifteen were male and fifty-one were female, were recruited. Independent groups were created based on the median score of frontal alpha asymmetry: the left dominant (LD) group and the right dominant (RD) group. The alpha band (8–12 Hz) and its sub-bands (i.e., low alpha band: 8–10 Hz; high alpha band: 10–12 Hz) were of interest. Source level alpha asymmetry was calculated as well. RESULTS: Suicidal behavior was positively correlated with the asymmetry indices of the low alpha band and the alpha band in the LD group and that of the high alpha band in the RD group. Source level analysis revealed positive correlations between suicidal behavior and the asymmetry index of the low alpha band in the LD group. CONCLUSION: Frontal alpha asymmetry, especially that of the low alpha band, might reflect the cognitive deficits associated with suicidal behaviors in MDD patients.
Cognition Disorders
;
Depression
;
Depressive Disorder, Major
;
Electroencephalography
;
Female
;
Humans
;
Male
;
Suicide

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