Korean Food Research Institutes

Gyeonggi, South Korea

Korean Food Research Institutes

Gyeonggi, South Korea
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Park S.,Hoseo University | Kim D.S.,Hoseo University | Kang S.,Hoseo University | Kwon D.Y.,Korean Food Research Institutes
Life Sciences | Year: 2011

Aims: Diabetes increases the chances of stroke and the stroke itself is thought to induce hyperglycemia and diabetes. However, this latter contention remains uncorroborated. We investigated whether ischemic hippocampal neuronal cell death induces glucose dysregualtion by modulating insulin resistance, glucose-stimulated insulin secretion, and β-cell mass in Mongolian gerbils fed either a high fat or low fat diet. Main methods: Gerbils were subjected to either an occlusion of the bilateral common carotid arteries for 8 mins to render them ischemic, or a sham operation. Ischemic gerbils were fed either an 11% fat diet (LFD) or a 40% fat diet (HFD) for 7, 14 or 28 days. Key findings: Artery occlusion resulted in a 70% or greater initial reduction in hippocampal CA1 neurons and only HFD decreased the percentage of CA1 neurons as the ischemic periods became longer. Oral glucose tolerance test (OGTT) results revealed that ischemia induced glucose intolerance, and longer ischemic periods and HFD exacerbated this glucose intolerance in ischemic gerbils. Insulin secretion during the OGTT was lower in ischemic gerbils than sham gerbils and the decrease was greatest in the 28 day-HFD among all the groups. Insulin resistance was elevated the most in 28 day-HFD ischemic gerbils. There was a progressive loss of pancreatic β-cell mass as the post-ischemic time period increased as consequence of HFD; the decrease being caused by increased apoptosis. This increase in apoptosis was partly associated with increased serum levels of IL-1β, TNF-α and non-esterified fatty acids. Significance: Hippoccampal neuronal cell death deteriorates glucose homeostasis initially through the modulation of insulin secretion and also causes a decrease in β-cell mass while HFD negatively impacts glucose regulation. © 2011 Elsevier Inc.

Park S.,Hoseo University | Kim D.S.,Hoseo University | Kwon D.Y.,Korean Food Research Institutes | Yang H.J.,Korean Food Research Institutes
Journal of Neuroendocrinology | Year: 2011

Adiponectin is known to be an anti-diabetic adipocytokine. However, the action mechanism by which it produces this effect remains controversial. In the present study, we investigated the long-term central effect of adiponectin on energy homeostasis, peripheral insulin resistance, β-cell function and mass in rats and aimed to determine the mechanism by which its effect was achieved. Intracerebroventricular infusion of adiponectin (50ng/h) and artificial cerebrospinal fluid (CSF) was conducted by means of an osmotic pump for 4weeks on nondiabetic rats and 90% pancreatectomised diabetic rats that were both fed 45% energy fat diets. After 4-weeks of treatment, i.c.v. adiponectin improved hypothalamic insulin/leptin signalling in nondiabetic and diabetic rats compared to i.c.v. CSF but it did not change the phosphorylation of AMP kinase (AMPK) in the hypothalamus. Adiponectin infusion decreased epididymal fats, representing visceral fat, by increasing energy expenditure and fat oxidation. During the euglycaemic hyperinsulinaemic clamp, i.c.v. adiponectin improved whole body insulin sensitivity and decreased hepatic glucose output in the hyperinsulinaemic state by attenuating hepatic insulin resistance. Central infusion of adiponectin did not modulate glucose-stimulated insulin secretion during the hyperglycaemic clamp compared to i.c.v. CSF infusion but it enhanced insulin sensitivity at a hyperglycaemic state. Although there were no changes in insulin secretion capacity, central adiponectin increased pancreatic β-cell mass in nondiabetic and diabetic rats as a result of decreasing β-cell death. In conclusion, long-term central infusion of adiponectin enhanced energy homeostasis by increasing energy expenditure via activating hypothalamic leptin and insulin signalling pathways but without potentiating AMPK signalling; it also improved glucose homeostasis by attenuating insulin resistance. © 2011 The Authors. Journal of Neuroendocrinology © 2011 Blackwell Publishing Ltd.

Kwon D.Y.,Korean Food Research Institutes | Daily III J.W.,Daily Manufacturing Inc. | Kim H.J.,Korean Food Research Institutes | Park S.,Hoseo University
Nutrition Research | Year: 2010

Historically, the incidence of type 2 diabetes has been lower in Asian populations compared with those in Western countries. One possible reason for the lower incidence among Asians is that they consume fermented soybean products, which are unique to the traditional Asian diet. Some have hypothesized that dietary phytoestrogens and soy peptides in fermented soybean foods consumed in traditional Asian diets may help prevent and slow the progression of type 2 diabetes. This review evaluates the existing evidence from animal studies and clinical and epidemiologic investigations on fermented soybeans in the prevention and treatment of type 2 diabetes. Nutritional studies performed in animals and intervention studies with humans suggest that the ingestion of soy protein with isoflavones improves glucose control and reduces insulin resistance. Korean fermented soybean products such as doenjang, kochujang, and chungkookjang contain alterations in the structures and content of isoflavonoids and small bioactive peptides, which are produced during fermentation. Several studies revealed improvements in insulin resistance and insulin secretion with the consumption of these fermented products. Therefore, fermented soybean products may help prevent or attenuate the progression of type 2 diabetes. Although the lack of human intervention trials does not permit definitive conclusions, the evidence does suggest that fermented soy products may be better for preventing or delaying the progression of type 2 diabetes compared with nonfermented soybeans. © 2010 Elsevier Inc. All rights reserved.

Yang H.J.,Korean Food Research Institutes | Kwon D.Y.,Korean Food Research Institutes | Kim M.J.,Korean Food Research Institutes | Kang S.,Hoseo University | Park S.,Hoseo University
Nutrition and Metabolism | Year: 2012

Background: Although soybeans have the ability to attenuate insulin resistance, it is insufficient to alleviate type 2 diabetic symptoms and different types of fermented soybeans may have even better anti-diabetic effects. Meju, unsalted fermented soybeans exhibited better insulin sensitizing and insulinotropic actions than unfermented cooked soybeans (CSB). We investigated whether meju fermented in the traditional (TMS) manner for 60 days and meju fermented in the standardized (MMS) method inoculating Bacillus subtilis and Aspergillus oryzae for 6 days modulated insulin resistance, insulin secretion, and pancreatic -cell growth and survival in 90% pancreatectomized (Px) diabetic rats, a moderate and non-obese type 2 diabetic animal model. Methods. Diabetic rats were divided into 3 groups: 1) TMS (n = 20), 2) MMS (n = 20) or 3) casein (control; n = 20). Rats were provided with a high fat diet (40 energy % fat) containing assigned 10% meju for 8 weeks. At the end of experiment insulin resistance and insulin secretion capacity were measured by euglycemic hyperinsulinemic clamp and by hyperglycemic clamp, respectively. Additionally, -cell mass and islet morphohometry were determined by immunohistochemistry and insulin signaling in the liver was measured by western blot. Results: TMS and MMS increased isoflavonoid aglycones much more than CSB. CSB and TMS/MMS improved glucose tolerance in diabetic rats but the mechanism was different between treatments (P < 0.05). CSB enhanced peripheral insulin sensitivity including hepatic insulin sensitivity better than the control but TMS and MMS enhanced only hepatic insulin sensitivity through activating insulin signaling in diabetic rats (P < 0.05). However, TMS and MMS, but not CSB, potentiated glucose-stimulated insulin secretion and -cell mass (P < 0.05). MMS had better insulinotropic actions than the control (P < 0.05). Conclusions: The anti-diabetic action of MMS, especially when fermented with Bacillus subtilis and Aspergillus oryzae, was superior to CSB by increasing isoflavonoid aglycones and small peptides with regard to type 2 diabetic rats. © 2012 Yang et al.; licensee BioMed Central Ltd.

Yang H.J.,Korean Food Research Institutes | Hwang J.T.,Korean Food Research Institutes | Kwon D.Y.,Korean Food Research Institutes | Kim M.J.,Korean Food Research Institutes | And 3 more authors.
Journal of Nutrition | Year: 2013

Our preliminary study revealed that dementia induced by β-amyloid accumulation impairs peripheral glucose homeostasis (unpublished). We therefore evaluated whether long-term oral consumption of yuzu (Citrus junos Tanaka) extract improves cognitive dysfunction and glucose homeostasis in β-amyloid-induced rats.Male rats received hippocampal CA1 infusions of β-amyloid (25-35) [plaque forming β-amyloid; Alzheimer disease (AD)] or β-amyloid (35-25) [non-plaque forming β-amyloid; C (non-Alzheimer disease control)] at a rate of 3.6 nmol/d for 14 d. AD rats were divided into 2 dietary groups that received either 3% lyophilized 70% ethanol extracts of yuzu (AD-Y) or 3% dextrin (AD-C) in high-fat diets (43% energy as fat). The AD-C group exhibited greater hippocampal β-amyloid deposition, which was not detected in the C group, and attenuated hippocampal insulin signaling. Yuzu treatment prevented β-amyloid accumulation, increased tau phosphorylation, and attenuated hippocampal insulin signaling observed in AD-C rats. Consistent with β-amyloid accumulation, the AD-C rats experienced cognitive dysfunction, which was prevented by yuzu. AD-C rats gained less weight than did C rats due to decreased feed consumption, and yuzu treatment prevented the decrease in feed consumption. Serum glucose concentrations were higher in AD-C than in C rats at 40-120 min after glucose loading during an oral-glucose-tolerance test, but not at 0-40 min. Serum insulin concentrations were highly elevated in AD-C rats but not enough to lower serum glucose to normal concentrations, indicating that rats in the AD-C group had insulin resistance and a borderline diabetic state. Although AD-C rats were profoundly insulin resistant, AD-Y rats exhibited normal first and second phases of glucose tolerance and insulin sensitivity and secretion. In conclusion, yuzu treatment prevented the cognitive dysfunction and impaired energy and glucose homeostasis induced by β-amyloid infusion. © 2013 American Society for Nutrition.

Kwon D.Y.,Korean Food Research Institutes | Hong S.M.,Hoseo University | Ahn I.S.,Hoseo University | Kim M.J.,Korean Food Research Institutes | And 2 more authors.
Nutrition | Year: 2011

Objective: Although soybeans have been shown to alleviate metabolic syndromes, fermented soybeans may have even greater effects. We investigated the antidiabetic effects of meju, a soy food that is fermented up to 2 mo, and the mechanism by which it exerts its effects. Methods: Meju was prepared by a traditional fermentation process: soybeans were fermented outdoors for 20 or 60 d. Methanol (M-60) and water (W-60) extracts from meju that had fermented for 60 d contained mostly isoflavonoid aglycones and small peptides, respectively, as opposed to mostly glycosylated isoflavonoids and proteins in the original soybeans. Results: Daidzein, M-60, and W-60 had better insulin-sensitizing actions by activating peroxisome proliferator-activated receptor-γ in 3T3-L1 adipocytes than did unfermented soybeans. In addition, Min6 insulinoma cells treated with genistein, M-60, and W-60 had greater glucose-stimulated insulin secretion capacity and greater β-cell viability than those treated with unfermented soybeans. This improvement was associated with insulin/insulin-like growth factor-1 signaling that was activated by the tyrosine phosphorylation of insulin receptor substrate-2 and serine phosphorylation of Akt, and this in turn increased pancreatic and duodenal homeobox-1 expression. Furthermore, genistein, daidzein, and M-60 stimulated glucagon-like peptide-1 secretion in enteroendocrine NCI-H716 cells, which generated insulinotropic actions. Conclusion: The compositional changes in isoflavonoids and peptides that occurred during a longer fermentation period, without the use of salt, enhanced the antidiabetic effect of soybeans. © 2011 Elsevier Inc.

Kim J.Y.,Yonsei University | Park J.Y.,Yonsei University | Kim O.Y.,Yonsei University | Ham B.M.,Yonsei University | And 5 more authors.
Journal of Proteome Research | Year: 2010

Obesity is currently epidemic in many countries worldwide and is strongly related to diabetes and cardiovascular disease. This study investigated the differences in metabolomic profiling between overweight/obese and normal-weight men. Overweight/obese (n = 30) and age-matched, normal-weight men (n = 30) were included. Anthropometric parameters, conventional metabolites, and biomarkers were measured. Metabolomic profiling was analyzed with UPLC-Q-TOF MS. Overweight/obese men showed higher levels of HOMA-IR, triglycerides, total cholesterol, and LDL-cholesterol, and lower levels of HDL-cholesterol and adiponectin than lean men. Overweight/obese men showed higher proportion of stearic acid and lower proportion of oleic acid in serum phospholipids. Additionally, overweight/obese individuals showed higher fat intake and lower ratio of polyunsaturated fatty acids to saturated fatty acids. We identified three lyso-phosphatidylcholine (lysoPC) as potential plasma markers and confirmed eight known metabolites for overweight/obesity men. Especially, overweight/obese subjects showed higher levels of lysoPC C14:0 and lysoPC C18:0 and lower levels of lysoPC C18:1 than lean subjects. Results confirmed abnormal metabolism of two branched-chain amino acids, two aromatic amino acids, and fatty acid synthesis and oxidation in overweight/obese men. Additionally, the amount of dietary saturated fat may influence the proportion of saturated fatty acids in serum phospholipids and the degree of saturation of the constituent acyl group of plasma lysoPC. © 2010 American Chemical Society.

Soh J.,Chonbuk National University | Kwon D.Y.,Korean Food Research Institutes | Cha Y.-S.,Chonbuk National University
Journal of Nutrition and Metabolism | Year: 2011

We found that Chongkukjang, traditional unsalted fermented soybean, has an antiobesity effect in mice with diet-induced obesity and examined the changes in hepatic transcriptional profiles using cDNA microarray. High-fat diet-induced obese C57BL/6J mice were divided into three groups: normal-diet control group (NDcon, 10% of total energy from fat), high-fat diet control group (HDcon, 45% of total energy from fat), and HDcon plus 40% Chongkukjang (HDC) and were fed for 9 weeks. The HDC group mice were pair-fed (isocalorie) with mice in the HDcon group. Final body weight, epididymal fat accumulation, serum total cholesterol, and LDL-cholesterol were improved in HDC group. The cDNA microarray analyses revealed marked alterations in the expression of about 800 genes. Several genes involved in fatty acid catabolism (Acaa2, Mgll, Phyh, Slc27a2, and Slc27a5) were normalized by Chongkukjang consumption. This study showed beneficial effects of Chongkukjang consumption in preventing diet-induced obesity and related metabolic abnormalities. © 2011 JuRyoun Soh et al.

Kim J.Y.,Yonsei University | Kim J.Y.,Woosong University | Kim O.Y.,Dong - A University | Paik J.K.,Yonsei University | And 3 more authors.
Age | Year: 2013

The relationships between age-related changes in circulating endogenous metabolites, inflammatory and oxidative stress markers, and arterial stiffness in 57 middle-Aged (34-55 years), nonobese men were studied over the course of 3 years. Arterial stiffness was measured using brachial-Ankle pulse wave velocities (ba-PWV). Plasma metabolomic profiling was performed using ultra-performance liquid chromatography and quadrupole time-of-flight mass spectrometry. After 3 years, decreased HDL cholesterol and increased malondialdehyde (MDA) and ox-LDL levels were observed. Among 15 identified lipids, lysoPCs (C16:0, C18:0, C18:2, C20:4, and C20:5) and linoleyl carnitine were the major plasma metabolites that contributed to the age-related differences. LysoPC16:0 (variable importance in the projection value, 6.2029) was found as the most important plasma metabolite for evaluating these changes. Changes in lysoPC16:0 levels positively correlated with the changes in 8-epi-PGF2α (r00.608), MDA (r00.413), high-sensitivity C-reactive protein (r0 0.509), IL-6 (r00.497), and ba-PWV (r00.283) levels. ba-PWV levels positively correlated with the changes in waist-to-hip ratios (WHR), inflammatory and oxidative stress markers. In a subgroup analysis of subjects with decreased ba- PWVs vs. increased ba-PWVs, changes in WHR and levels of lysoPC16:0, ba-PWV, IL-6, 8-epi- PGF2α, MDA, and P-selectin were significantly different. Our results suggest that age-related increases in lysoPC16:0 may contribute to lipid peroxidation, thereby activating proinflammatory phenotypes and arterial stiffness. © The Author(s) 2012.

Bae C.-R.,Chonbuk National University | Kwon D.Y.,Korean Food Research Institutes | Cha Y.-S.,Chonbuk National University
Journal of the Korean Society of Food Science and Nutrition | Year: 2013

The aim of the present study is to elucidate the anti-obesity effects of Doenjang with and without salt in C57BL/6J mice. For the analysis, a total of forty mice were randomly divided into four groups: normal diet group (ND), high-fat diet group (HD), high-fat diet supplemented with 20% Doenjang group (DJ), high-fat diet supplemented with 20% unsalted Doenjang group (NS). During the study period, food intake and body weight were measured daily and weekly, respectively. The animals were sacrificed after 12 weeks. Body weight gain, epididymal fat pad weight and serum triglyceride levels of DJ group were found to be significantly lower than those of the HD and NS groups. Serum total-cholesterol levels of DJ and NS groups were significantly lower as compared to the HD group. There were significant decreases in plasma insulin and leptin levels in DJ group compared with the HD and NS groups. We did not observe any significant changes in the expression of hepatic lipogenic-related gene PPARγ among the HD, DJ and NS groups. However, ACC expression was found to be significantly decreased in DJ group. Lipolysis-related gene (PPARα and CPT-1) expression was significantly higher in the DJ group as compared to HD and NS groups. In conclusion, the results of this study showed that Doenjang supplementation lowers body weight gain and improves obesity-related parameters. © 2013 by The Korean Society of Food Science and Nutrition. All rights reserved.

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