Hee Young Paik

Sex- and gender-specific disparities in colorectal cancer risk

Colorectal cancer is one of the most common causes of cancer morbidity both in men and in women. However, females over 65 years old show higher mortality and lower 5-year survival rate of colorectal cancer compared to their age-matched male counterparts. The objective of this review is to suggest gender-based innovations to improve colorectal cancer outcomes in females. Women have a higher risk of developing right-sided (proximal) colon cancer than men, which is associated with more aggressive form of neoplasia compared to left-sided (distal) colon cancer. Despite differences in tumor location between women and men, most of scientific researchers do not consider sex specificity for study design and interpretation. Also, colorectal cancer screening guidelines do not distinguish females from male, which may explain the higher frequency of more advanced neoplasia when tumors are first detected and false negative results in colonoscopy in females. Moreover, socio-cultural barriers within females are present to delay screening and diagnosis. Few studies, among studies that included both men and women, have reported sex-specific estimates of dietary risk factors which are crucial to establish cancer prevention guidelines despite sex- and gender-associated differences in nutrient metabolism and dietary practices. Furthermore, anti-cancer drug use for colorectal cancer treatment can cause toxicity to the reproductive system, and gender-specific recurrence and survival rates are reported. Therefore, by understanding sex- and gender-related biological and socio-cultural differences in colorectal cancer risk, gender-specific strategies for screening, treatment and prevention protocols can be established to reduce the mortality and improve the quality of life.

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.

Traditional v. modified dietary patterns and their influence on adolescents' nutritional profile.

Korea has experienced exceptionally rapid economic developments. Even though the country has managed to maintain aspects of its traditional diet, dietary habits are changing, especially among adolescents. This study was carried out to identify prevailing dietary patterns among Korean adolescents and to compare the nutrient intakes and dietary behaviours between the patterns. A 3 d diet record, collected from 671 Korean adolescents aged 12-14 years in Seoul, Korea, was assessed. By cluster analysis, subjects were classified into a modified (69.9 %) and a traditional (30.1 %) dietary pattern group. The modified group consumed more bread, noodles, cookies and pizza/hamburgers compared with the traditional group, which consumed mainly rice and kimchi (fermented cabbage). The modified group had significantly higher intakes of all nutrients. It had a higher total daily energy intake (7719 kJ), a higher daily energy intake from fat (29.8 %) and a higher cholesterol intake (326 mg/d), compared with the traditional group (6686 kJ, 24.8 % and 244 mg/d, respectively). The modified group was more likely to consume fast foods, fried foods and carbonated beverages even though they consumed more fresh fruits and milk, while the traditional group was more likely to have a rice-based diet and not to skip breakfast. These results suggest that monitoring dietary behaviours of adolescents, especially in a society experiencing a nutrition transition, is necessary in order to identify both negative and positive changes in respect of risk factors for nutrition-related chronic diseases as well as for undernutrition.

Carbohydrate Intake and Refined-Grain Consumption Are Associated with Metabolic Syndrome in the Korean Adult Population

BACKGROUND Metabolic syndrome is prevalent in the Asian population, but little is known about its associations with sources or types of dietary carbohydrates. OBJECTIVE We examined relationships between metabolic syndrome prevalence and dietary carbohydrate intake, including total carbohydrate, energy from carbohydrates, dietary glycemic index, dietary glycemic load, total grains, refined grains, and white rice in Korean men and women. DESIGN This cross-sectional study was based on data from the Fourth Korea National Health and Nutrition Examination Survey (KNHANES 2007-2009) and a nationally representative sample. PARTICIPANTS/SETTING A total of 6,845 adults (2,631 men, 4,214 women) aged 30 to 65 years with no diagnosed diabetes, hypertension, or dyslipidemia were selected. Dietary intake data were obtained using the 24-hour recall method and all dietary carbohydrate intakes were divided into quintiles by sex. MAIN OUTCOME MEASURES Metabolic syndrome and its components were defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. STATISTICAL ANALYSES PERFORMED All statistical analyses accounted for the complex sampling design effect and used appropriate sample weights. Multivariate adjusted logistic regression was used to estimate odds ratios and 95% CIs for metabolic syndrome across quintiles of dietary carbohydrate intake. RESULTS After controlling for potential confounding variables, the determinants of metabolic syndrome were the percentage of energy from carbohydrates in men and intakes of refined grains, including white rice, in women. Triglyceride, high-density lipoprotein cholesterol, and fasting blood glucose levels were associated with the percentage of energy from carbohydrates in men and white rice intake in women. CONCLUSIONS Our findings suggest that the sources and types of carbohydrates were differentially associated with metabolic syndrome according to sex in the Korean adult population. The percentage of energy from carbohydrates in men and intake of refined grains, including white rice, in women were associated with metabolic syndrome.

Reproducibility and validity of an FFQ developed for the Korea National Health and Nutrition Examination Survey (KNHANES)

OBJECTIVE We aimed to evaluate the reproducibility and validity of the newly developed FFQ for the Korean National Health and Nutrition Examination Survey (KNHANES) and to estimate the measures calibration factors. DESIGN The 109-item FFQ was administered twice, approximately 9 months apart. We also collected four seasonal 3 d dietary records (DR) as a reference method. Correlation coefficients and joint classification were computed to compare intakes of energy, thirteen nutrients and eleven food groups between the two FFQ to evaluate reproducibility. For validity, de-attenuated and energy-adjusted correlation, joint classification and Bland-Altman statistics were calculated for energy and nutrients between the first FFQ and the DR. To calibrate the FFQ, we performed a linear regression analysis in which the DR were the dependent variables and FFQ, age and sex were the independent variables. SETTING Seoul metropolitan area, Republic of Korea. SUBJECTS A total of 126 adults aged 20-65 years. RESULTS The average correlation coefficients measuring reproducibility were 0·54 for nutrients and 0·57 for food groups. The mean correlation coefficient measuring validity was 0·40 for all nutrients between the first FFQ and the DR. On average, 75 % of the participants were classified into the same or adjacent quartiles, while 5 % of the participants were grossly misclassified. The mean energy and nutrient intakes estimated by the calibrated FFQ were similar to the means estimated by the DR. CONCLUSIONS The newly developed FFQ for assessing dietary intake in the KNHANES has acceptable reproducibility and modest validity compared with a 12 d DR collected over a 9-month period.

Reanalysis of 2007 Korean National Health and Nutrition Examination Survey (2007 KNHANES) Results by CAN-Pro 3.0 Nutrient Database

This study aimed to reanalyze energy and nutrient intakes of 2007 Korean Nutrition and Health Examination Survey (KNHANES) using CAN-Pro 3.0, a commonly used nutrient analysis software in Korea. Food items and their codes were selected from 2007 KNHANES dietary intake file and converted to food codes of CAN-Pro 3.0 nutrient database (NDB). Of the 1,324 total food items, 1,155 items were converted by direct matching, 123 items were matched using other items in CAN-Pro 3.0 NDB and 42 items were matched using external sources. Consumption frequencies of items converted by direct matching contributed 94.5% of total consumption. Nutrient intakes of 4,091 participants of 2007 KNHANES, over 1 year old, were recalculated using CAN-Pro 3.0 NDB and compared with intakes in 2007 KNHANES dietary intake file. Intakes for energy and all nutrients except protein and Vitamin C calculated by two NDBs were significantly different by paired t-test (p (below 5%) but high for phosphorus, retinol, vitamin A, and -carotene (over 10%). Age group, sex, and their interactions significantly influenced six nutrients (p , vitamin E, and folate by age and sex groups revealed that some groups had mean levels below RI (Recommended Intake) or AI (Adequate Intake) levels. Intake level of cholesterol was higher than the recommended level (below 300 mg/day) in some groups, especially males. Results of the present study indicate the need for comparable and more comprehensive NDB to be used for dietary assessment of KNHANES and other researches. More rigorous evaluation of nutrients which have not been reported in KNHANES is needed.

Association between adherence to the Korean Food Guidance System and the risk of metabolic abnormalities in Koreans

Consumption of a diet consistent with dietary guidelines is believed to have a beneficial effect on the prevention of chronic diseases and the promotion of general health. This study was conducted to explore the relationship between adherence to the Korean Food Guidance System (KFGS), which was based on the 2010 revised KDRIs, and the risk of metabolic abnormalities. Five hundred and ninety-six Korean adults between 30 and 59 years of age were recruited by advertisement to the Bundang Jesaeng General Hospital (BJGH), and those not taking regular medications and without diagnoses of fulminant disease were included. Data were collected on anthropometric measurements, diagnostic parameters for metabolic syndrome (MetS), and 3-day dietary intakes from individuals in the study. The number of servings consumed from each food group was compared to the KFGS recommended servings for each of the 6 food groups. Poor adherence to the recommendations for servings of milk and dairy products (OR: 2.038, 1.128-3.682) was associated with a higher risk of MetS, and poor adherence to the guidelines for fruit consumption (OR: 1.849, 1.027-3.329) was associated with a higher risk for the existence an elevated waist circumference. Conversely, the consumption of meat, fish, eggs, and beans above the recommended number of servings was associated with a lower risk of having an elevated waist circumference (OR: 0.523, 0.288-0.950), and the consumption of vegetables above the recommended number of servings was associated with a reduced risk of having elevated fasting glucose (OR: 0.533, 0.298-0.954). These results suggest that adherence to the KFGS guidelines helps to prevent the development of MetS, but this association needs to be confirmed by prospective studies.

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.

Dietary patterns based on carbohydrate nutrition are associated with the risk for diabetes and dyslipidemia

Several studies have been conducted on dietary patterns based on carbohydrate nutrition in Asian populations. We examined the cross-sectional associations in dietary patterns based on carbohydrate nutrition, including the glycemic index (GI) with dyslipidemia and diabetes among the Korean adult population. We analyzed 9,725 subjects (3,795 men and 5,930 women, ≥ 20 years) from the Fourth Korea National Health and Nutrition Examination Survey. Dietary information was collected using single 24-hour recall. Reduced rank regression was used to derive dietary patterns from 22 food groups as predictor variables and four dietary factors related to the quantity and quality of carbohydrates as response variables. Two dietary patterns were identified: 1) the balanced pattern was characterized by high intake of various kinds of foods including white rice, and 2) the rice-oriented pattern was characterized by a high intake of white rice but low intake of vegetables, fruits, meat, and dairy products. Both patterns had considerable amounts of total carbohydrate, but GI values differed. The rice-oriented pattern was positively associated with hypertriglyceridemia in men and low high density lipoprotein-cholesterol in both men and women. The balanced pattern had no overall significant association with the prevalence of dyslipidemia or diabetes, however, men with energy intake above the median showed a reduced prevalence of diabetes across quintiles of balanced pattern scores. The results show that dietary patterns based on carbohydrate nutrition are associated with prevalence of dyslipidemia and diabetes in the Korean adult population.

Nutritional intake of Korean population before and after adjusting for within-individual variations: 2001 Korean National Health and Nutrition Survey Data

Accurate assessment of nutrient adequacy of a population should be based on usual intake distribution of that population. This study was conducted to adjust usual nutrient intake distributions of a single 24-hour recall in 2001 Korean National Health and Nutrition Surveys (KNHNS) in order to determine the magnitude of limitations inherent to a single 24-hour recall in assessing nutrient intakes of a population. Of 9,960 individuals who provided one 24-hour recall in 2001 KNHNS, 3,976 subjects provided an additional one-day 24-hour recall in 2002 Korean National Nutrition Survey by Season (KNNSS). To adjust for usual intake distribution, we estimated within-individual variations derived from 2001 KNHNS and 2002 KNNSS using the Iowa State University method. Nutritionally at risk population was assessed in reference to the Dietary Reference Intakes for Koreans (KDRIs). The Korean Estimated Average Requirement (Korean EAR) cut-point was applied to estimate the prevalence of inadequate nutrient intakes except for iron intakes, which were assessed using the probability approach. The estimated proportions below Korean EAR for calcium, riboflavin, and iron were 73%, 41%, and 24% from usual intake distribution and 70%, 51%, and 39% from one-day intake distribution, respectively. The estimated proportion of sodium intakes over the Intake Goal of 2,000 mg/day was 100% of the population after adjustment. The energy proportion from protein was within Korean Acceptable Macronutrient Distribution Ranges (Korean AMDR), whereas that of carbohydrate was higher than the upper limit and that of fat was below the lower limit in the subjects aged 30 years or older. According to these results, the prevalence of nutritional inadequacy and excess intake is over-estimated in Korea unless usual intake distributions are adjusted for one-day intakes of most nutrients.