Jihye Kim

A rice-based traditional dietary pattern is associated with obesity in Korean adults

BACKGROUNDnDietary patterns are critical in the prevention of chronic disease. The relationship between specific dietary patterns and obesity has not been evaluated in a Korean adult population.nnnOBJECTIVEnThis study examined whether specific dietary patterns are associated with obesity using survey data of the largest, nationally representative, general Korean population.nnnDESIGNnThe cross-sectional study was comprised of 10,089 Korean adults (19 years or older) who participated in the second and third Korean National Health and Nutrition Examination Surveys conducted in 2001 and 2005, respectively. Dietary data were assessed by 24-hour recall method. Obesity was defined as body mass index (calculated as kg/m(2)) ≥25, which is the cutoff point for adults in the Asian and Pacific regions.nnnRESULTSnFour dietary patterns were derived using factor analysis (white rice and kimchi pattern; high-fat, sweets, and coffee pattern; meat and alcohol pattern; and grains, vegetables, and fish pattern). Each dietary pattern explained 8.6%, 6.7%, 5.7%, and 5.7% of the variation in food intake, respectively. The white rice and kimchi pattern (P for trend=0.0039) and the high-fat, sweets, and coffee pattern (P for trend=0.0054) were positively associated with obesity after adjustments for age, sex, energy intake, alcohol intake, smoking status, physical activity, and chronic diseases. No significant association was found among the meat and alcohol pattern; the grains, vegetables, and fish pattern; and obesity.nnnCONCLUSIONSnSpecific dietary patterns, which include the white rice and kimchi and high-fat, sweets, and coffee patterns, may be independently associated with obesity in Korean adults.

Effect of Dietary Phytate on Zinc Homeostasis in Young and Elderly Korean Women

Background: Previous studies suggest that consumption of predominantly plant-based diets with high phytate content contribute to zinc deficiency by inhibiting zinc absorption. Age of the individual may also affect the ability to maintain zinc homeostasis. Objective: This study was designed to determine the effect of dietary phytate on zinc homeostasis and to evaluate the effect of age on the capacity to maintain the zinc homeostasis with changes in dietary phytate in young and elderly Korean women. Design and Methods: Seven healthy young women (22–24 yr) and 10 healthy elderly women (66–75 yr) were studied consecutively for 3 months in 2 metabolic periods (MP) in two different metabolic units. During MP1 the women consumed a high phytate (HP) diet (P:Zn molar ratio = 23) for 9 days. After a 10 d wash-out period at home eating their usual diets, a lower phytate diet (LP) (P:Zn molar ratio = 10) was fed in MP2 for 9 d. Phytase was added to selected foods in the high phytate diet to reduce the phytate content of the meals in the LP period. The zinc content of both diets was about 6.5 mg/d. Stable isotopes of Zn (70Zn) were administered intravenously on d 5 of MP 1 and 2 for measuring endogenous fecal zinc excretion. Plasma samples were also collected on d 5 for measuring plasma zinc concentrations by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). 24 hr urine samples were collected for 5 d and complete fecal samples were collected for 9 d after isotope administration. Fractional zinc absorption (FZA) was calculated from mass balance corrected for endogenous fecal zinc (EFZ) excretion and EFZ was determined by using an isotopic dilution technique. Isotopic ratios for FZA and EFZ were measured by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Statistical analyses were done using ANOVA. Results: Both the young and elderly women were in negative zinc balance during the HP period. This was due to a significant decrease in FZA and total absorbed zinc (TAZ) with a HP diet (43 vs 22% in young women, 34 vs 20% in elderly women, p < 0.001). EFZ excretion did not differ in the young and elderly women during the LP and HP periods. Dietary phytate did not alter plasma zinc concentrations or and urinary zinc excretion in either group. Conclusions: Adjustments in zinc homeostasis with an increase in dietary phytate did not differ between young and elderly women in this study.

High serum isoflavone concentrations are associated with the risk of precocious puberty in Korean girls

Objectiveu2002 The gradual decrease in the age of onset of puberty raises concerns about the contribution of phytoestrogen intake on sexual maturation. However, no data are available on the association between serum isoflavone (genistein, daidzein) concentration and central precocious puberty (CPP). The aim of the study was to test the association between serum isoflavone concentrations and the risk of CPP in Korean girls.

High carbohydrate intake was inversely associated with high-density lipoprotein cholesterol among Korean adults.

The traditional Asian diet, which is characterized as being high in carbohydrate with an abundance of vegetables, may be beneficial for preventing metabolic syndrome abnormalities within the Asian population. However, the prevalence of metabolic syndrome is increasing in Asian countries. This study explored the association between dietary carbohydrates and low high-density lipoprotein cholesterol (HDL-C) prevalence, one of the abnormalities of metabolic syndrome in Korean adults. We used the data from the Fourth Korea National Health and Nutrition Examination Survey and evaluated a total of 9947 Korean adults older 20 years. To measure carbohydrate quality and quantity, total carbohydrate intake (g/d), percentage of energy from carbohydrate, glycemic index, and glycemic load were divided into quintiles. Mean levels of HDL-C significantly decreased across the quintiles for all types of dietary carbohydrate intake except glycemic index after adjusting for potential variables in both men and women. Odds ratios for having low HDL-C in the highest quintile were 1.66 (95% confidence interval, 1.24-2.22) for total carbohydrate, 1.34 (1.02-1.75) for percentage of energy from carbohydrate, and 1.54 (1.17-2.03) for glycemic load in men as compared with the second quintile as a reference. Odds ratio for low HDL-C was 1.38 (1.12-1.71) for percentage of energy from carbohydrate in women. In conclusion, our study indicates that low HDL-C is associated with high carbohydrate intake without regard to energy or fat intake. Further studies would be necessary to optimize carbohydrate intake quantitatively on dyslipidemia for Asian population.

Expression of Heteropolymeric Ferritin Improves Iron Storage in Saccharomyces cerevisiae

ABSTRACT Saccharomyces cerevisiae was engineered to express different amount of heavy (H)- and light (L)-chain subunits of human ferritin by using a low-copy integrative vector (YIp) and a high-copy episomal vector (YEp). In addition to pep4::HIS3 allele, the expression host strain was bred to have the selection markers leu2− and ura3− for YIplac128 and YEp352, respectively. The heterologous expression of phytase was used to determine the expression capability of the host strain. Expression in the new host strain (2805-a7) was as high as that in the parental strain (2805), which expresses high levels of several foreign genes. Following transformation, Northern and Western blot analyses demonstrated the expression of H- and L-chain genes. The recombinant yeast was more iron tolerant, in that transformed cells formed colonies on plates containing more than 25 mM ferric citrate, whereas none of the recipient strain cells did. Prussian blue staining indicated that the expressed isoferritins were assembled in vivo into a complex that bound iron. The expressed subunits showed a clear preference for the formation of heteropolymers over homopolymers. The molar ratio of H to L chains was estimated to be 1:6.8. The gel-purified heteropolymer took up iron faster than the L homopolymer, and it took up more iron than the H homopolymer did. The iron concentrations in transformants expressing the heteropolymer, L homopolymer, and H homopolymer were 1,004, 760, and 500 μg per g (dry weight) of recombinant yeast cells, respectively. The results indicate that heterologously expressed H and L subunits coassemble into a heteropolymer in vivo and that the iron-carrying capacity of yeast is further enhanced by the expression of heteropolymeric isoferritin.

Serum levels of zinc, calcium, and iron are associated with the risk of preeclampsia in pregnant women

Evidence indicates that various elements, including antioxidant minerals, might play an important role in preeclampsia (PE). This study was carried out to investigate the relationship between serum mineral levelsof zinc, calcium, iron, and selenium and the risk of preeclampsia in Korean women. Twenty-nine normal controls and 30 women with preeclampsia were recruited for the study. Preeclampsia was defined as having high blood pressure (≥ 140/90 mm Hg after 20 weeks gestation) and proteinuria (≥300 mg/24 hours). Serum mineral content was determined by instrumental neutron activation analysis. Serum zinc (P < .0001) and calcium (P = .0188) levels were lower in women with preeclampsia than those of normal women, while serum iron was significantly higher in women with preeclampsia (P = .0045). The odds ratio for preeclampsia was lower in women with higher serum zinc levels than those with lower levels after adjustment for age, height, and weight before delivery (P < .0001). The adjusted odds ratio for preeclampsia also decreased across tertiles of serum calcium concentration (P = .0452). However, there was an increased adjusted odds ratio for preeclampsia across tertiles of serum iron level (P = .0104). These results suggest that levels of serum minerals such as zinc, calcium, and iron may be associated with the risk of preeclampsia in Korean pregnant women.

Zinc Supplementation Reduces Fractional Zinc Absorption in Young and Elderly Korean Women

Background: Adjustments in zinc losses and absorption are thought to maintain zinc homeostasis with changes in intake, but the capacity to make these adjustments appears to be affected by aging. Zinc status of the individual may also influence adjustments in fractional zinc absorption. Objective: The purpose of this study was to compare the effects of changes in zinc status due to zinc supplementation on fractional zinc absorption in young and elderly Korean women. Design: Zinc status and absorption were measured initially in 15 young (20–24 yr) and 15 elderly women (64–75 yr) confined to a metabolic unit and consuming a typical Korean diet. Upon discharge from the unit the women were supplemented with 22 mg zinc/d for 28 days. On d 20, the women returned to the unit for measurement of zinc status and absorption. Fractional zinc absorption (FZA) was estimated from the same typical Korean breakfast at both time points using the dual isotopic tracer method. Zinc stable isotopic ratios were measured in urine samples collected for 3 days following isotope administration. Results: Plasma and urinary zinc concentrations increased significantly with zinc supplementation in the young but not the elderly women. FZA decreased following zinc supplementation in the young women from 22 to 8% (p < 0.0001) and in the elderly women from 19 to 10% (p < 0.0001). The decline in young women was greater than that in elderly women (p < 0.05). Conclusions: Both young and elderly women reduced their efficiency of zinc absorption with zinc supplementation. But, plasma and urinary zinc concentrations did not increase in the elderly following zinc supplementation suggesting that age altered the use of the additional zinc.

Fecal Phytate Excretion Varies with Dietary Phytate and Age in Women

Objective: Information on the excretion of dietary phytate in humans under different conditions is limited. The purpose of this study was to investigate fecal excretion of dietary phytate and phosphorus in a group of young and elderly women consuming high and low phytate diets. Methods: Fifteen young and fourteen elderly women were fed two experimental diets, high phytate and low phytate, for 10 days each with a washout period of 10 days between the two diet periods. Duplicate diet samples from two different menus and complete fecal samples were collected for 5 days during each diet period and analyzed for phytate and phosphorus contents. Mean daily excretions and percentages of dietary intakes of phytate and phosphorus were calculated. Results: Dietary phytate level does impact phytate excretion, but the effect was observed only in young subjects. Fecal phytate excretion of young subjects during the high phytate diet (313mg/d) was significantly higher than during the low phytate diet (176mg/d), however, that of elderly subjects did not vary with dietary phytate levels. Phosphorus excretion, net absorption, and apparent absorption rate were affected by dietary phytate level but not by the age of the subjects. Conclusions: Results of this study indicate that phytate degradation in the gastrointestinal tract is substantial and more variable in young women than in elderly women. The high capacity of phytate degradation in elderly subjects may be related to long-term phytate intake but needs further clarification. Both beneficial and adverse health effects of phytate need to be studied considering the long-term phytate intake and age of subjects as well as dietary phytate levels.

Overnight urinary excretion of isoflavones as an indicator for dietary isoflavone intake in Korean girls of pubertal age

Little is known about the bioavailability of isoflavones in children. Previous studies have shown that children excrete more isoflavone in urine compared with adults. Thus we examined the relationship between usual dietary isoflavone intake and the urinary excretion of isoflavonoids in Korean girls of pubertal age. Twelve girls each were selected from the lowest and the highest quartiles of isoflavone intake among 252 Korean girls aged 8-11 years. Age, BMI and sexual maturation stage were matched between the two groups. Dietary intakes for 3 d by diet record and overnight urine samples were collected at baseline and at 6 and 12 months. Total and individual isoflavone (daidzein, genistein and glycitein) intakes were calculated from diet records. The parent isoflavone compounds (daidzein, genistein and glycitein) and their metabolites (equol, O-desmethylangolensin (O-DMA), dihydrodaidzein and dihydrogenistein) present in the urine samples were analysed using liquid chromatography-MS. Intake levels of total and individual isoflavone compounds were significantly higher in the high isoflavone (HI) group than the levels in the low isoflavone (LI) group (P < 0.05). Urinary excretion of all isoflavone parent compounds was significantly higher in the HI group than in the LI group (P < 0.0001). Among isoflavone metabolites, only O-DMA and total metabolites were significantly different (P < 0.05). Total isoflavone intake was highly correlated with the urinary excretion of total parent compounds (r 0.68; P < 0.01), parent compounds plus their metabolites (r 0.66-0.69; P < 0.01) and total isoflavonoids (r 0.72; P < 0.0001). In conclusion, overnight urinary excretion of total isoflavonoids is a reliable biomarker of usual isoflavone intake in Korean girls of pubertal age.

Plasma Zinc But Not the Exchangeable Zinc Pool Size Differs Between Young and Older Korean Women

This study was done to determine the effect of age on zinc metabolism and status among healthy Korean women. Measures of zinc metabolism and status were measured in eight young women (22–24xa0years) and seven elderly women (66–75xa0years) consuming a typical Korean diet. Oral and intravenous tracers highly enriched in 67Zn and 70Zn were administered simultaneously. Multiple plasma, 24-h urines, and fecal samples were collected after isotope administration. In the young women, additional plasma were collected to determine zinc kinetics using a seven-compartmental model. Exchangeable Zinc Pool (EZP) was estimated by Miller’s method. Plasma zinc concentrations were higher in older women than younger women (pu2009<u20090.05). EZP and urinary zinc tended to be higher in older women than younger women. Fractional and total zinc absorption and endogenous fecal zinc losses did not differ between young and older women. A comparison of the zinc kinetics of the Korean and American women showed no differences in plasma or EZP zinc parameters. However, absorbed zinc and zinc flux to slowly turning over tissues (Q7) were lower in Korean women than that of Americans (pu2009<u20090.01) suggesting the total body zinc content of Korean women is lower than that of American women.