Korean Journal of Community Nutrition

Research Article

[Korean]
Dietary Iron Intake of Koreans Estimated using 2 Different Sources of Iron Contents are Comparable: Food & Nutrient Database and Iron Contents of Cooked Foods in the Korean Total Diet Study: Jeeyeon Lee, Sung Ok Kwon, Yoonjae Yeoh, Min Jeong Seo, Gae Ho Lee, Cho-il Kim; Korean J Community Nutr 2022;27(3):245-253. Published online June 30, 2022; DOI: https://doi.org/10.5720/kjcn.2022.27.3.245

Objectives
This study was conducted to find out if the dietary iron intake of Koreans estimated by 2 different methods (iron content sources) using the food intake data from the Korea National Health and Nutrition Examination Survey (KNHANES) are comparable. One method was based on the KNHANES's Food & Nutrient Database (FND) derived mainly from the Korean Food Composition Table and the other used the iron content (IC) of food samples processed in the Korean Total Diet Study (KTDS).
Methods
Dietary intake data from the 2013-2016 KNHANES was used to select representative foods (RFs) in KTDS for iron analysis. Selection of the RFs and cooking methods for each RF (RF × cooking method pair) was performed according to the ‘Guidebook for Korean Total Diet Studies’ and resulted in a total of 132 RFs and 224 ‘RF × cooking method’ pairs. RFs were collected in 9 metropolitan cities nationwide once or twice (for those with seasonality) in 2018 and made into 6 composites each, based on the origin and season prior to cooking. Then, the RF composites prepared to a ‘table ready’ state for KTDS were analyzed by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Dietary iron intake of the Korean population was estimated using only RFs’ intake data based on the 2 sources of iron content, namely FND-KNHANES and IC-KTDS.
Results
RFs in KTDS covered 92.0% of total food intake of Koreans in the 2016-2018 KNHANES. Mean iron intake of Koreans was 7.77 mg/person/day by IC-KTDS vs 9.73 mg/person/day by FND-KNHANES. The major food groups contributing to iron intake were meats (21.7%), vegetables (20.5%), and grains & cereals (13.4%) as per IC-KTDS. On the other hand, the latter source (FND-KNHANES) resulted in a very different profile: grains & cereals (31.1%), vegetables (16.8%), and meats (15.3%). While the top iron source was beef, accounting for 8.6% in the former, it was polished rice (19.2%) in the latter. There was a 10-fold difference in the iron content of polished rice between 2 sources that iron intakes excluding the contribution by polished rice resulted in very similar values: 7.58 mg/person/day by IC-KTDS and 7.86 mg/person/day by FNDKNHANES.
Conclusions
This study revealed that the dietary iron intake estimated by 2 different methods were quite comparable, excluding one RF, namely polished rice. KTDS was thus proven to be a useful tool in estimating a ‘closer-to-real’ dietary intake of nutrients for Koreans and further research on various nutrients is warranted.

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Dietary sodium and potassium intake of Koreans estimated using 2 different sources of their contents in foods, Food & Nutrient Database and the Korean Total Diet Study: a comparative study
Jee Yeon Lee, Sung Ok Kwon, Soo Hyun Lee, Min Jeong Seo, Gae Ho Lee, Cho-il Kim
Korean Journal of Community Nutrition.2023; 28(3): 235. CrossRef

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Original Articles

[English]
The Association between Changes in Food and Nutrient Intakes and Changes in Bone Metabolic Indicators in Postmenopausal Women with Osteopenia after a 12-week Intervention of Nutrition Education and Aerobic Exercise: Seo Jin Kim, Suh Jung Kang, Yoon Jung Park, Ji Yun Hwang; Korean J Community Nutr 2013;18(3):213-222. Published online June 30, 2013; DOI: https://doi.org/10.5720/kjcn.2013.18.3.213

Abstract PDF PubReader

Few studies investigated the effects of nutrition education and exercises in women with osteopenia. This study examined the relationship between changes in dietary intakes and changes in indicators related to bone health in postmenopausal women with osteopenia (-2.5 < or = T-score < or = 1) after a 12-week intervention. Thirty-one postmenopausal women aged > 50 years residing in Seoul were recruited and participated in nutritional education regarding bone health and general nutrition practices and aerobic exercises (three times a week; 60 min per session). Twenty-five subjects completed the study and were eligible for the analysis. Bone mineral density (BMD) at femoral neck was measured by dual energy x-ray absorptiometry. Serum calcium, osteocalcin, and intact parathyroid hormone (PTH) were also measured. Dietary intake was estimated by using a one-day 24 recall by a clinical dietitian. After 12 weeks, meat consumption increased (P = 0.028) but vegetable intake decreased (P = 0.005). Intakes of animal protein (P = 0.024), vitamin B1 (P = 0.012) and vitamin B2 (P = 0.047) increased, and sodium intake decreased (P = 0.033). Intact PTH (P = 0.002) decreased and osteocalcin (P = 0.000) increased, however, BMD decreased (P = 0.000). Changes in mushroom consumption were positively correlated with femoral neck BMD (r = 0.673, P = 0.003). Changes in animal iron intake were negatively correlated with intact PTH (r = -0.488, P = 0.013) but were positively correlated with osteocalcin (r = 0.541, P = 0.005). These results suggested that the association between animal iron intake and biochemical markers of bone turnover may play an important role in bone metabolism. Further studies are needed to shed light on complicated mechanisms of diet, hormonal levels of bone metabolism, and bone density.

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A Comparison of Salty Taste Assessment, Dietary Attitude and Dietary Behavior among Adult and Senior Women by Region and by Age in Korea
Lin Jiang, Yun-Young Jung, Hyung-Sook Kim, Gi-Seon Nam, Jin-Sook Yun, Jong-Wook Kim, Yeon-Kyung Lee
Korean Journal of Community Nutrition.2015; 20(2): 109. CrossRef

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[English]
A Study on the Changes of Maternal Dietary Iron Intakes, Its Bioavailability, and Iron Status during Pregnancy: Jeong A Lee, Jong Im Lee, Hyeon Sook Lim; Korean J Community Nutr 2004;9(2):142-150. Published online April 30, 2004

Abstract PDF: To increase both iron and enhancers for iron absorption through diets should be a basic strategy to sufficiently provide increased iron for pregnancy. Previous studies reported that iron intakes of Korean pregnant women were short and their iron status deteriorated as pregnancy progressed. However, there is little data about the bioavailability of dietary iron during pregnancy. Therefore, this study was conducted to determine the changes of dietary iron intakes, its bioa-vailability and iron status during pregnancy longitudinally in Korean women. A total of 151 pregnant women in their first trimester of pregnancy voluntarily participated. Among them, 72 women finished the research protocol during the second trimester and 55 did it during the third trimester. Dietary intakes of total iron, both non-heme and heme iron, as well as enhancers, both MPF (meat, poulty, and fish) and vitamin C, increased significantly as pregnancy progressed. As the results, bioavailability of dietary iron and iron absorbed increased significantly as pregnancy progressed. However, the amount of iron absorbed at each trimester did not meet considerably the iron needed during pregnancy. All five indices examined in the study, Hb level, Hct, serum concentrations of ferritin and sTfR (soluble transferrin receptor), and sTfR:ferritin ratio, showed that iron status of the subjects deteriorated as pregnancy progressed. The rate of anemia of the subjects increased as pregnancy progressed although more than 80% of the subjects took iron supplements after the 20th week of pregnancy. These results imply that it is needed to provide more iron especially, heme iron and dietary enhancers to prevent the deterioration of iron status during pregnancy. Future research on bioavaila-blility of supplemental iron should be performed to determine the iron balance precisely.

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[English]
Nutritional Status of Iron of Elderly in Jeon-Ju Area: Eun Jung Joo, In Sook Kim, Eun A Seo; Korean J Community Nutr 2000;5(3):493-501. Published online September 30, 2000

Abstract PDF: The purpose of this study was to assess the nutritional status of iron of the elderly residing in the Jeonju area. The anthropometric parameters, nutrient intake and biochemical status of iron, were measured for 60 Korean elderly(23 elderly men and 37 elderly women aged 60 - 79 years old). The level of hemoglobin(Hb), hematocrint(Hct), serum iron(Fe), total iron binding capacity(TIBC) and serum ferritin(Ferritin) were measured and transferrin saturation(TFsaturation) was calculated. Mean values of Hb, Hct, Fe, TIBC, TFsaturation and Ferritin were 14.49+/-0.93g/dl, 42.47+/-2.59%, 125.48+/-52,.46 microgram/dl, 338.13+/-45.92 microgram/dl, 193.00+/-125.03 microgram/l in elderly men and 12.82+/-0.99 microgram/dl, 37.66+/-2.90%, 100.08+/-42.82 microgram/dl, 356.41+/-54.65 microgram/dl, and 99.35+/-117.22 microgram/l in elderly women, respectively. Prevalence of iron deficiency varied greatly with biochemical indices of iron. It was 13.0% when judged by Fe(60 microgram/dl) and TFsaturation(15%) whereas 34.78% by Hct(41%) in elderly men. However 13.5% of the elderly women showed iron depletion(Ferritin<20 microgram/l) and 43.2% showed suppressed erythropoiesis with iron deficiency(TIBC>360 microgram/dl). The anemic subjects assessed with TFsaturation(<15%) represented 13.5% of the elderly women, whereas 18.9% of the subjects possessed less than 12g/dl of Hb. The Hb concentration was positively correlated with Hct(r=0.980, p<0.001), Fe(r=0.384, p<0.01) and TFsaturation(r=0.349, p<0.01). On the other hand, Ferritin concentration showed a significantly negative correlation with TIBC(r=0.349, p<0.05) and a positive correlation with TFsaturation(r=0.362, p<0.01). Major food groups of iron intake in the elderly were vegetables, cereals, and fish. The mean daily intake of iron was not significantly different between elderly men and women(12.82mg vs 10.35mg). Intake of heme iron however, was significantly higher(p<0.01) in elderly men(1.03mg) than women(0.42mg). Total absorbable iron caculated by the method of Monsen was 0.55mg, 0.40mg in elderly men and women, respectively and bioavailability of dietary iron 4.29% and 3.87%.

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[English]
A Longitudinal Study of the Iron and Zinc Intakes of Korean Infants from 1 to 3 Months-Breast-Fed vs Formula-Fed Infants: Kyungsuk Choi, Sumi Mo, Haymie Choi, Jaeok Koo; Korean J Community Nutr 1999;4(1):30-36. Published online March 31, 1999

Abstract PDF: This study was carried out to longitudinally investigate the iron and zinc intakes and correlation with growth performance of 25 male breast-and formula-fed infants from 1 to 3 months postpartum, longitudinally. There were four groups breast fed(BF) and three formula fed groups((FFM, FFN and FFP). Milk intakes and the concentration of iron and zinc from human milk and the formulas were measured. The iron content of human milk was 2.07+/-1.05(0.63~5.65) microgram/ml. The zinc content was 2.43+/-1.14(0.70~5.30) microgram/ml. Both were not significantly different among postpartum months. The average iron intake of the breast-fed and formula-fed infants was 1.6+/-0.7mg/day and 8.4+/-2.3mg/day, respectively. The iron intake of breast-fed infants was higher than previous reports. And that of formula-fed infants was higher than the RDA. The average zinc intake of the breast-fed group was 1.9+/-0.9mg/day and formula-fed infants' was 2.7+/-0.7mg/day, which was higher than the RDA. There was no correlation between these mineral intakes and the growth performance during 1 to 3 postpartyum months. So, extensive studies of the iron content of human milk and wide cross-sectional studies for establishing iron and zinc recommended dietary allowances for infants are needed.

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[English]
Assessment of the Intake and Availability of Dietary Iron and Nutrition Knowledge in Pregnant Women: Eunkyung Kim, Kyuhee Lee; Korean J Community Nutr 1998;3(1):53-61. Published online February 28, 1998

Abstract PDF: This study was designed to estimate mean daily iron intake and its bioavailability and to assess nutrition knowledge for 144 pregnant women in the last trimester. Serum ferritin concentration was analyzed to estimate their iron stores. Dietary intakes of iron(heme iron and nonheme iron), the amounts of MPF(meat, poultry and fish) and ascorbic acid were assessed by modified 24-hr recall method. The food frequency questionnaire was used to assess subjects usual food consumption patterns. The mean value of serum ferritin was 21.3+/-15.3ng/ml and 26.4% of the pregnant women had a serum ferritin level<12ng/ml(i.e. depleted iron stores). The mean daily intake of total orin in the pregnant women was 56.5%(17.0 mg) of RDA and heme iron intake was 0.94 mg which was 5.5% of total iron intake. Total absorbable iron calculated by the method of Monsen was 2.41 mg and bioavailability of dietary iron was 2.41%. Food frequency test score of meats group was positively correlated(r=0.443) with the bioaavailability of dietary iron. The mean score on the nutrition knowledge test of subjects was 12.76(out of a possible 20 points). These results indicate that the nutritional iron status may be improved by increasing either the amount of iron in the diet or its availability.

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