Urine metabolomics unravel the effects of short-term dietary interventions on oxidative stress and inflammation: a randomized controlled crossover trial.

Dietary biomarkers in urine remain elusive when evaluating diet-induced oxidative stress and inflammation. In our previous study, we conducted a randomized controlled crossover trial to compare the short-term (4-weeks) effects of the balanced Korean diet (BKD) with Western diets, including the 2010 dietary guidelines for Americans (2010 DGA) and typical American diet (TAD), on various metabolic indices in obese Korean adults. Building on this work, the current research focuses on the impact of these dietary interventions on oxidative stress (d-ROMs and BAP) and inflammation (CRP, TNF-α, IL-6, IL-1ß, MCP-1) biomarkers in serum, and the concurrent urine metabolomes. Each dietary regimen was in silico and experimentally examined for their antioxidant levels using ABTS, DPPH, and FRAP assays, as well as total flavonoid (TFC) and total phenolic (TPC) contents. We assessed post-intervention variations in oxidative stress and inflammation biomarkers in serum, as well as the urine metabolite profiles for the participants (n = 48, average age: 41 years). Antioxidant contents and associated total antioxidant capacity (TAC) were significantly higher for the recommended diets (BKD and 2010 DGA) compared to TAD (p < 0.05). Butanol extracts from recommended diets (BKD and 2010 DGA) showed significantly higher antioxidant activity compared to TAD in ABTS (p < 0.01), DPPH, and FRAP (p < 0.05) assays. Consistent results were observed in total phenolic and flavonoid contents, mirroring their respective antioxidant activities. Following the intervention period, oxidative stress & inflammation markers in serum varied marginally, however, the urine metabolite profiles were clearly demarcated for the BKD and Western dietary groups (PC1 = 5.41%). For BKD group, the pre- and post-intervention urine metabolite profiles were clearly segregated (PLS2 = 2.93%). Compared to TAD, urine extracts from the recommended dietary group showed higher abundance of benzoic acid & phenolic derivatives (VIP > 0.7, p < 0.05). Metabolites associated with oxidative stress were observed higher in the urine samples from Western dietary groups compared to BKD. Urine metabolomics data delineated the post-intervention effects of three dietary interventions which corroborates the respective findings for their effects on metabolic indices.

Traditional Korean diet high in one-carbon nutrients increases global DNA methylation: implication for epigenetic diet.

PURPOSE: DNA methylation is a major epigenetic phenomenon through which diet affects health and disease. This study aimed to determine the epigenetic influence of the traditional Korean diet (K-diet) on global DNA methylation via one-carbon metabolism. METHODS: A crossover study was conducted on 52 women. Two diets, a K-diet, high in plant foods and low in calories and animal fat, and a control diet, similar to the diet currently consumed in Korea, were provided to all subjects alternately for 4 weeks with a 4-week washout period. Clinical parameters were measured before and after each dietary intervention. Nutrient intake was calculated by using a computer-aided nutritional analysis program. One-carbon metabolites in the serum and global DNA methylation in peripheral mononuclear cells were determined using ultra-performance liquid chromatography-tandem mass spectrometry. RESULTS: The K-diet group consumed more folate (669.9 ± 6.7 µg vs. 502.7 ± 3.0, p < 0.001), B6, B12, serine, and choline, and less methionine (992.6 ± 63 vs. 1048.3 mg ± 34.1, p < 0.0001) than the control group did. In the K-diet group, the increment of plasma 5-methyltetrahydrofolate (0.08 µg/mL ± 0.11 vs 0.02 ± 0.10, p < 0.009) and decrement of L-homocysteine (- 70.7 ± 85.0 vs - 39.3 ± 69.4, p < 0.0168) were greater than those of the control group. Global DNA methylation was significantly increased in the K-diet group (6.70 ± 3.02% to 9.45 ± 3.69, p < 0.0001) but not in the control group. CONCLUSIONS: A K-diet high in one-carbon nutrients can enhance the global DNA methylation status, suggesting an epigenetic mechanism by which the K-diet conveys health effects. Trial registration Korean Clinical Trial Registry (trial number: KCT0005340, 24/08/2020, retrospectively registered).

Effects of Korean Versus Western Diets on Reproductive Function in Young Korean Men: A 12-Week Randomized Parallel Clinical Trial.

Background: Studies report that diet may have contributed to a 50-60% decrease in human sperm quality over the past few decades. Unhealthy lifestyles affect the structure of spermatozoa, affecting the male reproductive potential. This study aimed to compare the effects of Korean and Western diets on reproductive function in young male Koreans. Methods: Study participants were provided either the Korean Diet (KD group) or the Western Diet (WD group) for 12 weeks. Semen quality parameters such as volume, motility, cell count, and sex hormone levels were evaluated. Sexual function was assessed using the International Index of Erectile Function and the Male Sexual Health Questionnaire. Efficacy and safety evaluations were conducted at baseline, 8 weeks, and 12 weeks. Results: The KD group demonstrated a significantly increased sperm motility after 8 weeks relative to baseline but decreased after 12 weeks. In contrast, sperm motility in the WD group significantly decreased after 8 weeks compared with baseline and remained constant after 12 weeks. Statistically, a near-significant difference was observed between groups (p = 0.057). Similarly, free testosterone levels in the KD group increased after 12 weeks compared with baseline, whereas that in the WD group decreased. The free testosterone levels in the KD group were significantly higher than those in the WD group (p = 0.020). There were no statistically significant differences in other sex hormone and sexual function questionnaires between the groups. None of the participants reported any severe side effects, and no significant alterations in clinical diagnostic test values were detected. Conclusion: The results of the study strongly reveal that KD positively affects sperm motility and male hormone levels in young men, indicating potential benefits for reproductive function.

Inverse association of a traditional Korean diet composed of a multigrain rice-containing meal with fruits and nuts with metabolic syndrome risk: The KoGES.

Background: Hansik, a traditional Korean diet, may have a beneficial impact on metabolic syndrome (MetS) risk as dietary westernization increases its prevalence. We examined the hypothesis that adherence to the hansik diet may be inversely associated with the risk of MetS and its components and sought to understand the gender differences in 58,701 men and women aged over 40. Materials and methods: Hansik was defined using 14 components from which the Korean dietary pattern index (Kdiet-index) was generated by summing their scores. Low-hansik intake was defined as the Kdiet-index with <8. MetS was categorized based on the 2005 revised NCEP-ATP III criteria modified for Asians. Results: The Kdiet-index score was negatively associated with the dietary inflammation index and showed that the high intake of a meal with multigrain rice, fruits, and their products, and nuts, and low intake of fried foods were inversely associated with MetS by 0.707, 0.864, 0.769, and 0.918 times, respectively, after adjusting for covariates. More women and participants with more educated and lower income belonged to the high-hansik group, and participants with high self-rated health scores consumed more hansik. All participants on a high-hansik diet were associated with a 0.87 time lower risk of MetS. Specifically, the association between hansik intake and MetS risk was not significant among men following stratification by gender. Body composition, including the body mass index, waist circumference, and fat mass, was inversely associated with hansik intake, while the skeletal muscle mass index was positively associated with the hansik intake in each gender and all participants. In all the participants in the high-hansik group, no significant changes were seen in the serum glucose and HDL concentration. However, a high-hansik intake showed lower blood pressure and serum LDL and triglyceride concentrations only in men and a higher glomerular filtration rate in both genders. Conclusions: Hansik intake might improve MetS risk, with its primary beneficial effects on body composition, dyslipidemia, and blood pressure gender-dependently.

Alleviation of Dyslipidemia via a Traditional Balanced Korean Diet Represented by a Low Glycemic and Low Cholesterol Diet in Obese Women in a Randomized Controlled Trial.

A traditional balanced Korean diet (K-diet) may improve energy, glucose, and lipid metabolism. To evaluate this, we conducted a randomized crossover clinical trial, involving participants aged 30-40 years, who were randomly assigned to two groups-a K-diet or westernized Korean control diet daily, with an estimated energy requirement (EER) of 1900 kcal. After a 4-week washout period, they switched the diet and followed it for 4 weeks. The carbohydrate, protein, and fat ratios based on energy intake were close to the target values for the K-diet (65:15:20) and control diet (60:15:25). The glycemic index of the control diet and the K-diet was 50.3 ± 3.6 and 68.1 ± 2.9, respectively, and daily cholesterol contents in the control diet and K-diet were 280 and 150 mg, respectively. Anthropometric and biochemical parameters involved in energy, glucose, and lipid metabolism were measured while plasma metabolites were determined using UPLC-QTOF-MS before and after the 4-week intervention. After the four-week intervention, both diets improved anthropometric and biochemical variables, but the K-diet significantly reduced them compared to the control diet. Serum total cholesterol, non-high-density lipoprotein cholesterol, and triglyceride concentrations were significantly lower in the K-diet group than in the control diet group. The waist circumference (p = 0.108) and insulin resistance index (QUICKI, p = 0.089) tended to be lower in the K-diet group than in the control diet group. Plasma metabolites indicated that participants in the K-diet group tended to reduce insulin resistance compared to those in the control diet group. Amino acids, especially branched-chain amino acids, tyrosine, tryptophan, and glutamate, and L-homocysteine concentrations were considerably lower in the K-diet group than in the control diet group (p < 0.05). Plasma glutathione concentrations, an index of antioxidant status, and 3-hydroxybutyric acid concentrations, were higher in the K-diet group than in the control diet group. In conclusion, a K-diet with adequate calories to meet EER alleviated dyslipidemia by decreasing insulin resistance-related amino acids and increasing ketones in the circulation of obese women.

A Traditional Korean Diet with a Low Dietary Inflammatory Index Increases Anti-Inflammatory IL-10 and Decreases Pro-Inflammatory NF-κB in a Small Dietary Intervention Study.

Chronic low-grade inflammation may increase the risk of chronic disease, while diets rich in anti-inflammatory components may reduce it. To determine the anti-inflammatory properties of the traditional Korean diet (K-diet) that comprises high amounts of vegetables, fiber and phytochemicals, moderate amounts of legumes, and low amounts of animal fat, ten obese women aged 50-60 years were randomly assigned to the K-diet or control diet group. The control diet was a Westernized Korean diet commonly consumed in Korea, which is high in animal fat and protein. Subjects were housed in metabolic unit-like conditions during the 2-week intervention. Plasma was collected before and after the intervention to measure inflammatory cytokines using ELISA. The dietary inflammatory index (DII) was calculated based on nutrients and food intake. The DII score for the K-diet was lower than that of the control diet (-0.94 ± 1.39 vs. 1.04 ± 1.61, p < 0.001). In the K-diet group, anti-inflammatory interleukin (IL)-10 levels increased (4.45 ± 0.34 pg/mL vs. 5.94 ± 0.33 pg/mL, p = 0.0102), whereas pro-inflammatory nuclear factor kappa B (NF-κB) levels decreased (7.70 ± 0.62 pg/mL vs. 2.71 ± 0.49 pg/mL, p = 0.0015), but not in the control group. In the K-diet group, NF-κB levels negatively correlated with IL-10 levels (r = -0.794, p = 0.006). The K-diet has anti-inflammatory properties, and IL-10 and NF-κB are putative inflammatory markers for K-diet studies.

A Traditional Korean Diet Alters the Expression of Circulating MicroRNAs Linked to Diabetes Mellitus in a Pilot Trial.

The traditional Korean diet (K-diet) is considered to be healthy and circulating microRNAs (miRs) have been proposed as useful markers or targets in diet therapy. We, therefore, investigated the metabolic influence of the K-diet by evaluating the expression of plasma and salivary miRs. Ten women aged 50 to 60 years were divided into either a K-diet or control diet (a Westernized Korean diet) group. Subjects were housed in a metabolic unit-like condition during the two-week dietary intervention. Blood and saliva samples were collected before and after the intervention, and changes in circulating miRs were screened by an miR array and validated by individual RT-qPCRs. In the K-diet group, eight plasma miRs were down-regulated by array (p < 0.05), out of which two miRs linked to diabetes mellitus, hsa-miR26a-5p and hsa-miR126-3p, were validated (p < 0.05). Among five down-regulated salivary miRs, hsa-miR-92-3p and hsa-miR-122a-5p were validated, which are associated with diabetes mellitus, acute coronary syndrome and non-alcoholic fatty liver disease. In the control diet group, validated were down-regulated plasma hsa-miR-25-3p and salivary hsa-miR-31-5p, which are associated with diabetes mellitus, adipogenesis and obesity. The K-diet may influence the metabolic conditions associated with diabetes mellitus, as evidenced by changes in circulating miRs, putative biomarkers for K-diet.

Effect of a balanced Korean diet on metabolic risk factors among overweight/obese Korean adults: a randomized controlled trial.

PURPOSE: This study was to see the effects of a balanced Korean diet (BKD) on metabolic risk factors in overweight or obese Korean adults, comparing with those of a typical American diet (TAD) and a diet recommended by the 2010 Dietary Guidelines for Americans (2010DGA). METHODS: The study was designed as a randomized crossover controlled trial, in which 61 overweight or obese volunteers were divided into six groups and each consumed the BKD, 2010DGA, and TAD in a random order for 4 weeks separated by 2-week washout intervals. Anthropometric indices, blood pressure, blood lipid content, fasting blood glucose, and blood insulin level were measured at the beginning and end of each diet period. RESULTS: A total of 54 participants completed the trial. The BKD caused more significant reductions of body mass index (BMI) (p < 0.001), body fat percent (p < 0.001), blood total cholesterol (p < 0.001), and low-density lipoprotein (LDL) cholesterol (p = 0.007) compared with the 2010DGA or TAD (all p values for differences between diets < 0.05). All three diets significantly lowered blood triglyceride levels (p < 0.05). The BKD decreased high-density lipoprotein (HDL) cholesterol (p = 0.001) and increased fasting blood glucose (p = 0.018), whereas TAD and 2010DGA increased HDL cholesterol and did not affect blood glucose levels. Furthermore, the BKD significantly decreased the proportion of individuals with elevated total cholesterol (p < 0.001) and LDL cholesterol (p < 0.01), whereas the 2010DGA significantly reduced the number of obese individuals (p < 0.05), and the TAD decreased the number of participants with elevated triglyceride levels (p < 0.05), but increased that of those with elevated LDL cholesterol (p < 0.05). CONCLUSIONS: The Korean diet based on dietary guidelines improved metabolic risk factors such as BMI, body fat percent, and blood lipid profiles in overweight or obese Korean adults. These results provide evidence to recommend the Korean diet for preventing various metabolic diseases. CLINICAL TRIAL REGISTRATION: The trial was registered at the Clinical Research Information Service (CRIS) in Korea, the primary registry of the World Health Organization (WHO) international clinical trial registry platform, under number KCT0002437.

Differential Effects of Typical Korean Versus American-Style Diets on Gut Microbial Composition and Metabolic Profile in Healthy Overweight Koreans: A Randomized Crossover Trial.

The Westernized diet has been associated with the pathogenesis of metabolic diseases, whereas a Korean diet has been reported to exert beneficial effects on health in several studies. However, the effects of Western and Korean diets on the gut microbiome and host metabolome are unclear. To examine the diet-specific effects on microbiome and metabolome, we conducted a randomized crossover clinical trial of typical Korean diet (TKD), typical American diet (TAD), and recommended American diet (RAD). The trial involved a 4-week consumption of an experimental diet followed by a 2-week interval before diet crossover. 16S rRNA sequencing analysis identified 16, 10, and 14 differential bacteria genera specific to TKD, RAD, and TAD, respectively. The Firmucutes-Bacteroidetes ratio was increased by TKD. Nuclear magnetic resonance metabolome profiling revealed that TKD enriched branched chain amino acid metabolism, whereas ketone body metabolism was evident in RAD and TAD. Microbiome and metabolome responses to the experimental diets varied with individual enterotypes. These findings provide evidence that the gut microbiome and host metabolome rapidly respond to different cultural diets. The findings will inform clarification of the diet-related communication networks of the gut microbiome and host metabolome in humans.

Effects of adherence to Korean diets on serum GGT and cardiovascular disease risk factors in patients with hypertension and diabetes / 한국영양학회지

PURPOSE: This study examined whether the supply of healthy Korean diets for 12 weeks is effective in improving the risk factors related to serum GGT and cardiovascular diseases in patients with hypertension and diabetes. METHODS: This study selected 41 patients, who were treated with hypertension and diabetes. The Korean diet was composed of cooked-rice, soup, kimchi, and various banchan with one serving called bapsang, which emphasize proportionally high consumption of vegetables and fermented foods, moderate to high consumption of legumes and fish, and low consumption of animal foods. The control group was instead instructed to “eat and exercise as usual” while following the Korean Diabetes Association's dietary guidelines with an intake that can assist in glycemic control, maintain adequate weight, and meet the nutritional requirements. The Korean diet group (21 patients) were served three healthy Korean meals a day for 12 weeks, and the control group (20 patients, who trained in the diet guideline of diabetes) maintained their usual diabetic diet. The serum GGT, blood pressure, heart rate, glycemic control data, cardiovascular risk indicators, and changes in diet measured at the four visits (week 0, 4, 8, and 12) during the course of 12 weeks were compared and evaluated. RESULTS: The serum GGT (p < 0.001), HbA1c (p = 0.004), heart rate (p = 0.007), weight (p = 0.002), Body Mass Index (p = 0.002), body fat mass (p < 0.001), body fat (%) (p < 0.001), and free fatty acid (p = 0.007) in the Korean diet group decreased significantly after the dietary intervention compared to the control group. The amount of intake of rice, whole grains, green vegetables, Kimchi, and soybean fermented food were increased significantly compared to the control group (p < 0.001). The Korean diet group showed significant decreases (p < 0.001) in the intake of animal protein, lipid, and cholesterol derived from animal foods compared to the control group but significant increases (p < 0.001) in the intake of total calories, folic acid, dietary fiber, sodium, potassium, and vitamins A, E, and C. CONCLUSION: In patients with hypertension and diabetes, it was confirmed that regular eating of a healthy Korean diet helps improve the risk factors for GGT and cardiovascular diseases.

Dietary Patterns and Cardiovascular Disease Risk in People with Type 2 Diabetes.

PURPOSE OF REVIEW: The primary objective of this review is to identify dietary patterns with beneficial effects on cardiovascular health of adults with type 2 diabetes. RECENT FINDINGS: The prevalence of diabetes is increasing globally. People with diabetes have a greater risk for cardiovascular disease. Mediterranean diet, dietary approaches to stop hypertension diet, vegetarian diet, traditional Korean diet, Japanese diet, and low-glycemic-index diet can reduce cardiovascular disease risk in people with diabetes. Dietary intake is a key modifiable factor in the management of diabetes and plays a significant role in limiting the incidence of cardiovascular diseases.

Effects of lymphocyte DNA damage levels in Korean plant food groups and Korean diet regarding to glutathione S-transferase M1 and T1 polymorphisms / 한국영양학회지

PURPOSE: GST (glutathione S-transferase) M1 and T1 gene polymorphisms are known to affect antioxidant levels. This study was carried out to evaluate genetic susceptibility by measuring the effect of DNA damage reduction in the Korean diet by vegetable food according to GST gene polymorphisms using the ex vivo method with human lymphocytes. METHODS: Vegetable foods in the Korean diet based the results of the KNHANES V-2 (2011) were classified into 10 food groups. A total of 84 foods, which constituted more than 1% of the total intake in each food group, were finally designated as a vegetable food in the Korean diet. The Korean diet applied in this study is the standard one-week meals for Koreans (2,000 Kcal/day) suggested by the 2010 Dietary Reference Intakes for Koreans. Ex vivo DNA damage in human lymphocytes was assessed using comet assay. RESULTS: In the Korean food group, the DNA damage protective effect of GSTM1 and GSTT1 was found to be greater in mutant type and wild-type, respectively. and the DNA damage protective effect according to the combined genotype of GSTM1 and GSTT1 was different depending on the food group. On the other hand, in Korean Diet, the DNA damage protective effect appeared to be larger in GSTM1 wild-type than in mutant type and was found to not be affected by GSTT1 genotype. CONCLUSION: These results can be used as basic data to demonstrate the superiority of the antioxidant function of Korean dietary patterns and food groups. Furthermore, it may be a starting point to begin research on customized antioxidant nutrition according to individual genes.

Meat and milk intake in the rice-based Korean diet: impact on cancer and metabolic syndrome.

Over a few decades, Korean diet has changed from traditional diet, mainly composed of rice and vegetables, to Westernised diet rich, in meat and milk, along with the economic development and globalisation. Increasing prevalence of diet-related chronic diseases such as cancer and metabolic syndrome (MetS) is becoming a heavy burden to society and requires further attention. In this review, the association of meat and milk consumption with cancer and MetS among Koreans was discussed. Previous meta-analyses showed that meat intake was positively associated with increased risk of cancers, especially colon, as well as obesity and type 2 diabetes mellitus, and that the intake of milk and dairy products was negatively associated with colorectal cancer, obesity, and type 2 diabetes mellitus, based on studies conducted mostly in Western countries. In Korea and other Asian countries, the association of meat and milk intake with cancers were inconclusive and varied by types of cancers. Conversely, milk intake was negatively associated with MetS risk as reported in Western countries. The difference in results between Korea and Western countries might come from the differences in dietary patterns and study designs. Most Koreans still maintain traditional dietary pattern, although rapid change towards Westernised diet is underway among the younger age group. Randomised clinical trials or prospective cohort studies with consideration of combined effects of various dietary factors in Korea and other Asian countries are needed to elucidate the impact of meat and milk or related dietary patterns in their diet.

Protective effect of Korean diet food groups on lymphocyte DNA damage and contribution of each food group to total dietary antioxidant capacity (TDAC) / 한국영양학회지

PURPOSE: This study was performed to compare total phenolic contents, in vitro antioxidant capacity, and reduction effect of Korean food groups on ex vivo DNA damage in human cells and analyze correlations between each indicator. METHODS: Vegetable foods in the Korean diet based the results of the KNHANES V-2 (2011) were classified into 10 food groups: cereals, fruits, vegetables, nuts, kimchi, seaweeds, potatoes, mushrooms, legumes, and oils. Eighty-four foods constituted more than 1% of the total intake in each food group and finally designated as vegetable foods in the Korean diet. Total phenolic content of each food group was measured. Further, in vitro antioxidant capacity was measured based on DPPH radical scavenging assay, TEAC assay, and ORAC(ROO)• assay. Ex vivo DNA damage in human lymphocytes was assessed using comet assay. RESULTS: Total phenolic contents of food groups of the Korean diet increased in the order of mushrooms, fruits, vegetables, seaweeds, and kimchi. Meanwhile, antioxidant rankings of food groups as mean values from the three in vitro test methods increased in the order of mushrooms, seaweeds, vegetables, kimchi, and fruits. Protection against ex vivo DNA damage in human lymphocytes was highest in mushrooms, followed by vegetables, fruits, seaweeds, and kimchi. The rankings of the food groups for total phenolic content, in vitro DAC, and ex vivo DNA protection activity were similar, and correlations between each indicator were significantly high. CONCLUSION: Mushrooms, fruits, vegetables, and seaweeds among the tested food groups in the Korean diet showed high total phenolic contents, in vitro antioxidant capacities, and protection against DNA damage. Correlations between each indicator in terms of total phenolic content, in vitro antioxidant capacity, and ex vivo DNA protection between each food group were found to be particularly high.

Estimation of curcumin intake in Korea based on the Korea National Health and Nutrition Examination Survey (2008-2012).

BACKGROUND/OBJECTIVES: Turmeric and its active component curcumin have received considerable attention due to their many recognized biological activities. Turmeric has been commonly used in food preparation and herbal remedies in South Asia, leading to a high consumption rate of curcumin in this region. However, the amount of curcumin in the Korean diet has not yet been estimated, where turmeric is not a common ingredient. SUBJECTS/METHODS: This study utilized the combined data sets obtained from the Korea National Health and Nutrition Examination Survey conducted from 2008 to 2012 in order to estimate the curcumin intake in the Korean diet. The mean intake of curcumin was estimated from the amount of curcumin-containing foods (curry powder and ready-made curry) consumed using reported curcumin content in commercial turmeric and curry powders. RESULTS: Only 0.06% of Koreans responded that they consumed foods containing curcumin in a given day, and 40% of them were younger than 20 years of age. Curcumin-containing foods were largely prepared at home (72.9%) and a significant proportion (20.4%, nearly twice that of all other foods) was consumed as school and workplace meals. The estimated mean turmeric intake was about 0.47 g/day corresponding to 2.7-14.8 mg curcumin, while the average curry powder consumption was about 16.4 g, which gave rise to curcumin intake in the range of 8.2-95.0 mg among individuals who consumed curcumin. The difference in estimated curcumin intake by using the curcumin content in curry powder and turmeric may reflect that curry powder manufactured in Korea might contain higher amounts of other ingredients such as flour, and an estimation based on the curcumin content in the turmeric might be more acceptable. CONCLUSIONS: Thus, the amount of curcumin that can be obtained from the Korean diet in a day is 2.7-14.8 mg, corresponding to nearly one fourth of the daily curcumin intake in South Asia, although curcumin is rarely consumed in Korea.

Total antioxidant capacity of the Korean diet.

BACKGROUND/OBJECTIVES: The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet. MATERIALS/METHODS: Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC). RESULTS: Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 µmol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each. CONCLUSIONS: The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables.

Total antioxidant capacity of the Korean diet

BACKGROUND/OBJECTIVES: The objective of this study was to measure and/or estimate the total antioxidant capacity of the Korean diet. MATERIALS/METHODS: Eighty-one plant foods that were expected to exhibit rather high antioxidant activities were selected from the Korean diet using the Fifth Korean National Health and Nutrition Survey (KNHANES V). These foods were categorized into 11 food groups: cereals, potatoes, legumes, nuts, vegetables, kimchies, mushrooms, fruits, fruit juices, sea weeds, and oils. The foods were mixed in the proportions specified in traditional Korean recipes and analyzed. The measured indicators for antioxidant capacities were total phenolics, 2,2-diphenyl-1-picrylhydrazyl (DPPH), oxygen radical absorbance capacity (ORAC), and Trolox equivalent antioxidant capacity (TEAC). RESULTS: Total phenolics were high in the fruit juices, nuts, vegetables, and fruits; and the average DPPH, ORAC, and TEAC values were high in the vegetables, fruits, fruit juices, and nuts. The correlation coefficient between the content of total phenolics of each food and the in vitro antioxidant capacity was relatively high at 0.851. The intake of total phenolics per capita per day in the Republic of Korea was estimated to be 127 mg. The total dietary antioxidant capacity (TDAC) values, which were obtained from the total antioxidant capacity of each food, taking into account the intake of each food, were 20,763, 54,335, and 876.4 micromol of Trolox equivalents using the DPPH, ORAC, and TEAC methods, respectively. The food group that contributed the most to the Korean TDAC was cereals at 39.7%, followed by fruits and vegetables at 27.8% and 13.9%, respectively. The contribution of legumes, nuts, fruit juices, and mushrooms was quite minimal at less than 2% each. CONCLUSIONS: The content of total phenolics and the antioxidant capacity of the Korean diet are significantly correlated and the high contributing food groups are cereals, fruits, and vegetables.

Estimation of curcumin intake in Korea based on the Korea National Health and Nutrition Examination Survey (2008-2012)

BACKGROUND/OBJECTIVES: Turmeric and its active component curcumin have received considerable attention due to their many recognized biological activities. Turmeric has been commonly used in food preparation and herbal remedies in South Asia, leading to a high consumption rate of curcumin in this region. However, the amount of curcumin in the Korean diet has not yet been estimated, where turmeric is not a common ingredient. SUBJECTS/METHODS: This study utilized the combined data sets obtained from the Korea National Health and Nutrition Examination Survey conducted from 2008 to 2012 in order to estimate the curcumin intake in the Korean diet. The mean intake of curcumin was estimated from the amount of curcumin-containing foods (curry powder and ready-made curry) consumed using reported curcumin content in commercial turmeric and curry powders. RESULTS: Only 0.06% of Koreans responded that they consumed foods containing curcumin in a given day, and 40% of them were younger than 20 years of age. Curcumin-containing foods were largely prepared at home (72.9%) and a significant proportion (20.4%, nearly twice that of all other foods) was consumed as school and workplace meals. The estimated mean turmeric intake was about 0.47 g/day corresponding to 2.7-14.8 mg curcumin, while the average curry powder consumption was about 16.4 g, which gave rise to curcumin intake in the range of 8.2-95.0 mg among individuals who consumed curcumin. The difference in estimated curcumin intake by using the curcumin content in curry powder and turmeric may reflect that curry powder manufactured in Korea might contain higher amounts of other ingredients such as flour, and an estimation based on the curcumin content in the turmeric might be more acceptable. CONCLUSIONS: Thus, the amount of curcumin that can be obtained from the Korean diet in a day is 2.7-14.8 mg, corresponding to nearly one fourth of the daily curcumin intake in South Asia, although curcumin is rarely consumed in Korea.

Post-prandial lipid levels for assessing target goal achievement in type 2 diabetic patients taking statin.

It is inconvenient to perform serum lipid analysis in fasting state in diabetic patients with drug treatment. In patients with statin treatment and Asian diet, it has not been clearly known whether non-fasting values could be used for the clinical decision making in diabetic patients. In this study, fasting and post-prandial plasma lipid profiles of hospitalized type 2 diabetic patients taking statin, were measured in whom standard diabetic breakfast in traditional Korean style were provided. In repeated-measures ANOVA, there were no significant differences among fasting, post-prandial 2 and 4 hr low-density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol values. When compared to fasting levels, both post-prandial 2 hr and 4 hr LDL cholesterol levels were misclassified as not achieved target goal only in 4% of patients. Post-prandial HDL cholesterol matched with fasting values in women, without exception. In conclusion, the fasting and post-prandial LDL and HDL cholesterol levels are not significantly different each other and can be used in the assessment of achieving target goal in type 2 diabetes taking statin after Korean diet.

Post-Prandial Lipid Levels for Assessing Target Goal Achievement in Type 2 Diabetic Patients Taking Statin

It is inconvenient to perform serum lipid analysis in fasting state in diabetic patients with drug treatment. In patients with statin treatment and Asian diet, it has not been clearly known whether non-fasting values could be used for the clinical decision making in diabetic patients. In this study, fasting and post-prandial plasma lipid profiles of hospitalized type 2 diabetic patients taking statin, were measured in whom standard diabetic breakfast in traditional Korean style were provided. In repeated-measures ANOVA, there were no significant differences among fasting, post-prandial 2 and 4 hr low-density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol values. When compared to fasting levels, both post-prandial 2 hr and 4 hr LDL cholesterol levels were misclassified as not achieved target goal only in 4% of patients. Post-prandial HDL cholesterol matched with fasting values in women, without exception. In conclusion, the fasting and post-prandial LDL and HDL cholesterol levels are not significantly different each other and can be used in the assessment of achieving target goal in type 2 diabetes taking statin after Korean diet.