Jung Hyun Kwak

Dietary treatment with rice containing resistant starch improves markers of endothelial function with reduction of postprandial blood glucose and oxidative stress in patients with prediabetes or newly diagnosed type 2 diabetes

OBJECTIVE We aimed to evaluate whether 4-week of dietary treatment with rice containing resistant starch reduces blood glucose and oxidative stress as well as improves endothelial function. METHODS Patients with impaired fasting glucose (IFG), impaired glucose tolerance (IGT) or newly diagnosed type 2 diabetes (n = 90) were randomly assigned to either a group ingesting rice containing 6.51 g resistant starch daily or a control rice group for 4-weeks. We assessed fasting and postprandial levels of glucose and insulin, oxidative stress markers and endothelial function using reactive hyperemia peripheral arterial tonometry (RH-PAT). RESULTS The diet containing rice with resistant starch reduced fasting insulin and insulin resistance, postprandial glucose (P = 0.010) and insulin levels at 30 min, and glucose and insulin areas under the response curve after the standard meal. Rice with resistant starch also decreased urinary 8-epi-PGF(2α) and plasma malondialdehyde (MDA) and increased the RH-PAT index (P < 0.001) and total nitric oxide (NO). Postprandial changes in glucose at 60 and 120 min and areas under the glucose response curve, MDA, RH-PAT, and total NO of the test group differed significantly from those in the control even after adjusting for baseline values. Overall, changes in the RH-PAT index correlated positively with changes in total NO (r = 0.336, P = 0.003) and superoxide dismutase activity (r = 0.381, P = 0.001) and negatively with changes in MDA (r = -0.358, P = 0.002) and 8-epi-PGF(2α). CONCLUSIONS In patients with IFG, IGT or newly diagnosed type 2 diabetes, 4-weeks of dietary treatment with rice containing resistant starch was associated with improved endothelial function with reduction of postprandial glucose and oxidative stress compared with control.

FADS gene polymorphisms in Koreans: Association with ω6 polyunsaturated fatty acids in serum phospholipids, lipid peroxides, and coronary artery disease

OBJECTIVE We investigated the association of polymorphisms in FADS genes with polyunsaturated fatty acids (PUFAs) in serum phospholipids, lipid peroxides, and coronary artery disease (CAD) in Koreans. METHODS In this case-control study, CAD patients (n=756, 40-79 years) and healthy controls (n=890) were genotyped for rs174537 near FADS1 (FEN1 rs174537G>T), FADS2 (rs174575, rs2727270), and FADS3 (rs1000778). We calculated the odds ratios (ORs) for CAD risk and measured serum PUFA composition and lipid peroxide. RESULTS Among four SNPs, only rs174537G>T differed in allele frequencies between controls and CAD patients after adjustment for age, BMI, cigarette smoking, alcohol consumption, hypertension, diabetes mellitus, and hyperlipidemia (P=0.017). The minor T allele was associated with a lower risk of CAD [OR 0.75 (95%CI 0.61-0.92), P=0.006] after adjustment. rs174537T carriers had a significantly higher proportion of linoleic acid (LA, 18:2ω6), lower arachidonic acid (AA, 20:4ω6), and lower ratios of AA/dihomo-γ-linolenic acid (DGLA, 20:3ω6) and AA/LA than G/G subjects in both control and CAD groups. In the control group, 174537T carriers had significantly lower levels of total- and LDL-cholesterol, malondialdehyde, and ox-LDL. In CAD patients, rs174537T carriers showed a larger LDL particle size than G/G subjects. The proportion of AA in serum phospholipids positively correlated with LDL-cholesterol, ox-LDL, and malondialdehyde in controls and with 8-epi-prostaglandin F(2α) in both control and CAD groups. CONCLUSION The rs174537T is associated with a lower proportion of AA in serum phospholipids and reduced CAD risk, in association with reduced total- and LDL-cholesterol and lipid peroxides.

Beneficial immunostimulatory effect of short-term Chlorella supplementation: enhancement of Natural Killer cell activity and early inflammatory response (Randomized, double-blinded, placebo-controlled trial)

BackgroundIn vitro and animal studies have demonstrated that Chlorella is a potent biological response modifier on immunity. However, there were no direct evidences for the effect of Chlorella supplementation on immune/inflammation response in healthy humans.MethodsThis study was designed for an 8-week randomized, double-blinded, placebo-controlled trial: 5g of Chlorella (n=23) or Placebo (n=28) as form of tablets. Mainly, cytotoxic activities of Natural killer (NK) cells and serum concentrations of interferon-γ, interleukin-1β and interleukin-12 were measured.ResultsAfter the 8-week, serum concentrations of interferon-γ (p<0.05) and interleukin-1β (p<0.001) significantly increased and that of interleukin-12 (p<0.1) tended to increase in the Chlorella group. The increments of these cytokines after the intervention were significantly bigger in the Chlorella group than those in the placebo group. In addition, NK cell activities (%) were significantly increased in Chlorella group, but not in Placebo group. The increments of NK cell activities (%) were also significantly bigger in the Chlorella group than the placebo group. Additionally, changed levels of NK cell activity were positively correlated with those of serum interleukin-1β (r=0.280, p=0.047) and interferon-γ (r=0.271, p<0.005). Signficantly positive correlations were also observed among the changed levels of serum cytokines; between interferon-γ and interleukin-1β (r=0.448, p<0.001), between interleukin-12 and interleukin-1β (r=0.416, p=0.003) and between interleukin-12 and interferon-γ (r=0.570, p<001).ConclusionThese results may suggest a beneficial immunostimulatory effect of short-term Chlorella supplementation which enhances the NK cell activity and produces interferon-γ and interleukin-12 as well as interleukin-1β, the Th-1 cell-induced cytokines in healthy people.

Korean Red Ginseng Improves Glucose Control in Subjects with Impaired Fasting Glucose, Impaired Glucose Tolerance, or Newly Diagnosed Type 2 Diabetes Mellitus

This study was designed to evaluate the effect of Korean red ginseng (KRG) supplementation on glucose control in subjects with impaired fasting glucose (IFG), impaired glucose tolerance (IGT), or newly diagnosed type 2 diabetes mellitus (T2DM). The study was a 12-week randomized, double-blinded, placebo-controlled (5 g of KRG [n=21] or placebo [n=20] in tablet form) trial. Glucose-related biomarkers, including serum and whole blood levels of glucose, insulin, and C-peptide, were measured by 2-h oral glucose tolerance tests (OGTTs) at baseline and after the 12-week intervention. After the intervention, the test group showed a significant decrease in serum levels of glucose at 30 min (-22.24±10.77 mg/dL) and whole blood levels of glucose at 30 min (-17.52±5.22 mg/dL). In addition, the test group tended to have lower whole blood levels of glucose at 0 min and glucose area under curve (AUC). However, the placebo group did not show any changes in blood glucose-related indices. The changes (difference from baseline) in serum glucose levels at 30 min, whole blood glucose levels at 60 min, and glucose AUC during OGTTs in the test group exhibited a tendency toward a decrease from those in the placebo group. There were significant decreases or trends toward a decrease in both serum insulin and C-peptide concentrations at most time intervals in the test group. In conclusion, KRG supplementation (5 g/day) may be beneficial for controlling serum and whole blood glucose levels compared with placebo among patients with IFG, IGT, or T2DM.

Increased arterial stiffness in subjects with impaired fasting glucose

AIMS The present study investigated the association between fasting glucose and arterial stiffness in subjects with normal fasting glucose (NFG) and impaired fasting glucose (IFG). METHODS The study group consisted of 1043 subjects, including 683 subjects with NFG and 360 subjects with IFG (100≤fasting glucose <126 mg/dL). All subjects were evaluated for glucose, insulin, lipid profiles, high sensitivity C-reactive protein (hs-CRP), malondialdehyde (MDA), 8-epi-prostaglandin F2α (8-epi-PGF2α) and brachial-ankle pulse wave velocity (ba-PWV). RESULTS MDA (P<0.001) and ba-PWV (P<0.001) in the IFG group were higher than those in the NFG group after adjustment for sex, age, BMI, smoking and drinking, waist, blood pressure, serum lipid profiles. Ba-PWV in the IFG group was still higher than that in the NFG group after further adjustment for hs-CRP, MDA, 8-epi-PGF2α (P=0.031). Through multiple linear regression analysis, ba-PWV was found to be independently and positively associated with fasting glucose, age, systolic blood pressure, triglyceride, hs-CRP and insulin and negatively associated with male:female ratio, BMI. CONCLUSION Arterial stiffness was higher in the IFG group than in subjects with NFG even after adjustment for all confounding variables including hs-CRP and oxidative stress markers. In addition, fasting glucose and insulin were positively and independently associated with the ba-PWV in non-diabetic healthy adults.

Association of polymorphisms in FADS gene with age-related changes in serum phospholipid polyunsaturated fatty acids and oxidative stress markers in middle-aged nonobese men.

Background: To investigate the association of FADS gene polymorphisms with age-related changes in polyunsaturated fatty acids (PUFAs) in serum phospholipids and oxidative stress markers. Methods: We genotyped 122 nonobese men aged 35–59 years without any known diseases at baseline for rs174537 near FADS1 (FEN1 rs174537G > T), FADS2 (rs174575, rs2727270), and FADS3 (rs1000778), and followed them for 3 years. Results: Among the four single-nucleotide polymorphisms, the minor variants of rs174537 and rs2727270 were significantly associated with lower concentrations of long-chain PUFAs. However, rs174537G > T showed stronger association. At baseline, men with the rs174537T allele had lower arachidonic acid (AA) and AA/linoleic acid (LA), and higher interleukin (IL)-6 levels than rs174537GG counterparts. After 3 years, rs174537GG men had significantly increased AA (P = 0.022), AA/dihomo-γ-linolenic acid (DGLA) (P = 0.007), docosapentaenoic acid (DPA), low-density lipoprotein (LDL) cholesterol, and oxidized LDL (ox-LDL), but decreased eicosatrienoic acid. The rs174537T group showed significantly increased γ-linolenic acid and ox-LDL, and decreased eicosadienoic acid, eicosapentaenoic acid (EPA)/α-linolenic acid (ALA), and IL-6. After 3 years, the rs174537T group had lower AA (P < 0.001), AA/DGLA (P = 0.019), EPA, DPA, EPA/ALA, and urinary 8-epi-prostaglandin F2α (8-epi-PGF2α) (P = 0.011) than rs174537GG. Changes in AA (P = 0.001), AA/DGLA (P = 0.017), EPA, DPA, EPA/ALA, and urinary 8-epi-PGF2α (P < 0.001) were significantly different between the groups after adjusting for baseline values. Overall, changes in AA positively correlated with changes in urinary 8-epi-PGF2α (r = 0.249, P = 0.007), plasma ox-LDL (r = 0.199, P = 0.045), and serum IL-6 (r = 0.289, P = 0.004). Conclusion: Our data show that FADS polymorphisms can affect age-associated changes in serum phospholipid long-chain PUFAs, Δ5-desaturase activity, and oxidative stress in middle-aged nonobese men. In particular, the rs174537T allele did not show the age-associated increases in AA and Δ5-desaturase activity seen with the rs174537GG genotype.

Associations of plasma homocysteine level with brachial-ankle pulse wave velocity, LDL atherogenicity, and inflammation profile in healthy men.

AIMS To investigate the association of plasma total homocysteine (tHcy) with arterial stiffness, measured as brachial-ankle pulse wave velocity (baPWV), LDL atherogenicity, and inflammation profile in healthy men. METHODS AND RESULTS In this cross-sectional study, 612 healthy men aged 31-79 years were classified into quartiles according to plasma tHcy concentration. In the total study population, tHcy concentration showed positive correlation with age (r=0.083, P=0.040), interleukin (IL)-1β (r=0.249, P<0.001), TNF-α (r=0.150, P<0.001), IL-6 (r=0.154, P<0.001), oxidized LDL (oxLDL) (r=0.161, P=<0.001), and baPWV (r=0.087, P=0.032); and negative correlation with folate (r=-0.353, P<0.001) and vitamin B(12) (r=-0.269, P<0.001). In subgroup analysis based on plasma tHcy level, tHcy was associated with baPWV in men with high levels of tHcy (≥ 13.1μmol/L, n=153; r=0.258, P=0.001), but not in those with low-tHcy (<13.1 μmol/L, n=459; r=-0.033, P=0.478). The association between tHcy and baPWV in the high-tHcy group remained significant after adjustment for age, BMI, smoking, drinking, folate, and vitamin B₁₂. In the high-tHcy group, tHcy level was also positively correlated with IL-1β, TNF-α, oxLDL, and blood pressure; and negatively correlated with LDL particle size. In addition, baPWV showed negative correlation with LDL particle size and positive correlation with oxLDL in the high-tHcy group. CONCLUSION This study shows an association between high levels of plasma tHcy and more advanced arterial stiffness, smaller LDL particle size, and higher levels of oxLDL and cytokines in men with hyperhomocysteinemia. Enhanced arterial stiffness in hyperhomocysteinemia might be attributed, in part, to Hcy-related LDL atherogenicity.

Black Soy Peptide Supplementation Improves Glucose Control in Subjects with Prediabetes and Newly Diagnosed Type 2 Diabetes Mellitus

The present study aimed to determine the effect of black soy peptide supplementation on glucose control in subjects with prediabetes (impaired fasting glucose or impaired glucose tolerance) and newly diagnosed type 2 diabetes mellitus (DM). In this double-blind, placebo-controlled study, subjects with prediabetes and type 2 DM were randomly assigned to the placebo control group or the black soy peptide intervention group. We determined fasting serum concentrations of glucose, hemoglobin A1c, insulin, and free fatty acids, performed a 2-hour postload glucose (2-hour PG) test, and compared serum lipid profiles before and after the 12-week supplementation. In particular, subjects with fasting glucose ≥ 110 mg/dL who consumed black soy peptides tended to have lower fasting glucose levels (two-tailed test, P = .098; one-tailed test, P = .049) and had a significant reduction in 2-hour PG level (two-tailed P = .012, one-tailed P = .006), compared with baseline levels. The changes in 2-hour PG levels were also statistically significant in the intervention group (-41.25 ± 13.67 mg/dL) compared with the placebo group (12.42 ± 9.80 mg/dL; two-tailed P = .015, one-tailed P = .008). In contrast, hemoglobin A1c levels were not significantly improved by the dietary intervention. In conclusion, black soy peptide supplementation may be beneficial for controlling fasting blood glucose levels and 2-hour PG levels.

Effects of black soy peptide supplementation on blood pressure and oxidative stress: a randomized controlled trial.

Black soy peptides have been shown to possess properties that may decrease blood pressure (BP). To examine the effects of black soy peptide supplementation on BP and oxidative stress in subjects with prehypertension or stage I hypertension, 100 participants with an initial untreated systolic blood pressure (SBP) of 130–159 mm Hg, diastolic blood pressure (DBP) of 80–99 mm Hg or both were enrolled. Participants were randomly assigned to either a group ingesting supplement containing 4.5 g black soy peptides daily or a placebo group for 8 weeks. SBP and DBP decreased after 8-week black soy peptide supplementation versus controls (P<0.001). At 8 weeks, SBP decrease was significantly greater for the black soy peptide group (−9.69±12.37 mm Hg) than for the control group (−2.91±13.29 mm Hg) after adjusting for the baseline levels (P=0.015). Plasma malondialdehyde (MDA) and urinary 8-epi-prostaglandin F2α decreased (P=0.004 and P=0.046, respectively) and plasma superoxide dismutase (SOD) activity increased (P<0.001) following 8 weeks of black soy peptide supplementation versus baselines. The MDA decreases (P=0.022) and SOD activity and nitric oxide (NO) increases (P=0.022 and P<0.001, respectively) were greater for the black soy peptide group than for the control group. Changes in SBP negatively correlated with changes in NO (r=−0.343, P=0.001). Changes in angiotensin-converting enzyme activity negatively correlated with NO decreases (r=−0.490, P<0.001) and SOD activity increases (r=−0.338, P=0.001). Black soy peptide dietary supplementation significantly reduces SBP and oxidative stress in patients with prehypertension and stage I hypertension.

Supervised Exercise Program, BMI, and Risk of Type 2 Diabetes in Subjects With Normal or Impaired Fasting Glucose

OBJECTIVE To determine the association of regular exercise, BMI, and fasting glucose with the risk of type 2 diabetes and to predict the risk. RESEARCH DESIGN AND METHODS Korean subjects (n = 7,233; 40–79 years old) who were not diagnosed with diabetes at baseline were enrolled through the National Health Insurance Corporation. All participants underwent biennial examinations, and 1,947 of 7,233 subjects also underwent a 6-month program of moderate-intensity exercise (300 min/week) without dietary advice. RESULTS During follow-up (mean = 2 years), there were 303 incidents of type 2 diabetes in the nonexercise program group (n = 5,286) and 83 in the exercise program group (n = 1,947). After adjusting for confounders, the risk of type 2 diabetes was positively associated with BMI and inversely with regular exercise, especially among overweight/obese subjects. After further adjustment for BMI, the odds ratios for risk of diabetes associated without and with regular exercise were 1.00 and 0.77, respectively. Among subjects with normal fasting glucose, exercise reduced the diabetes risk; however, among those with impaired fasting glucose (IFG), the protective effect of exercise was found only among overweight/obese subjects. The overweight/obese subjects in the exercise program group exhibited improved fasting glucose compared with the nonexercise program group and showed 1.5 kg of weight loss and a 3-cm decrease in waist circumference. Among overweight/obese subjects with unchanged fasting glucose, weight loss was greater in the exercise program group. CONCLUSIONS Regular exercise reduces the risk of type 2 diabetes in overweight/obese individuals. Particularly, regular exercise and weight or waist circumference control are critical factors for preventing diabetes in overweight/obese individuals with IFG.