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 Article

[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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