• Journal of Nutrition and Health
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• v.54 no.6
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• pp.644-663
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• 2021

Purpose: This study was conducted to evaluate the safety of iodine intake based on ingestion levels and urinary iodine excretion of women of childbearing age (15-45 years old) using data from the 2013-2015 Korea National Health and Nutrition Examination Survey. Methods: Iodine intake was calculated using the 24 hours dietary recall method and urinary iodine excretion. The iodine nutrition database for the analysis of dietary iodine intake was constructed using the food composition database of the Rural Development Administration (RDA), the Korean Nutrition Society (KNS), the Ministries of Food and Drug Safety, China and, Japan. The World Health Organization (WHO) evaluation criteria and hazard quotient (HQ) calculated using biomonitoring equivalents (BE) were applied to evaluate the safety of the iodine intake. Results: Of the study subjects, 15.22% had a urinary iodine concentration level of less than 100 ㎍/L, which was diagnosed as deficient, and 48.16% had an excessive iodine concentration of over 300 ㎍/L. Urinary iodine concentration was 878.71 ㎍/L, iodine/creatinine was 589.00 ㎍/g, and iodine/creatinine was significantly higher at the age of 30-45 years. The dietary iodine intake was 273.47 ㎍/day, and the iodine intake calculated from the urinary iodine excretion was 1,198.10 ㎍/day. Foods with a high contribution to iodine intake were vegetables, seafood, seaweed and processed foods. The HQ was 1.665 when the urinary iodine content was > 1,000 ㎍/L. Conclusion: The results of this study implicate that the urinary iodine concentration, rather than the dietary iodine intake, is more appropriate to evaluate the iodine status under the current situation that a comprehensive iodine database for Koreans has not been established.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.432-432
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• 2005

사용후핵연료시료 중에 함유된 요오드(I-127 및 129)를 정량하기 위하여 화학적 방법으로 분리 회수하고 중성자방사화분석법을 이용하였다. 사전실험으로 모의사용후핵연료를 이용하여 회수율을 측정하였다. 모의 및 실제사용후핵연료시료를 $90^{\circ}C$에서 8 M $HNO_3$ 용액으로 용해하고 용해 후 용해용액 중의 잔류 요오드, 응축 및 휘발된 요오드 각각을 정량하였다. 응축 요오드는 핵연료 용해 후 재증류하여 회수하였다. 잔류 및 응축 요오드는 시료의 산화상태를 조절한 후 용매추출로 요오드를 회수한 다음 이온교환 또는 침전법으로 방사화학적으로 분리한 후 중성자방사화분석(RNAA)으로 정량하였다. 제작한 이온교환분리관 및 여과키트에 요오드를 흡착 또는 침전시켜 분리한 다음 중성자조사를 위한 삽입체(Insert)로 이용하였다. 휘발 요오드는 제조한 흡착체(Ag-silica gel)를 담은 흡착관에 포집하고 홉착체를 구간별 균질시료로 만든 다음 비파괴중성자 방사화분석(INAA)으로 정량하였다. 침전 및 흡착 요오드의 화학적 특성을 EPMA(electron probe microanalysis) 분석으로 조사하였다. 요오드 정량결과를 다른 방법으로 비교분석하기 위하여 음이온교환수지상에서 요오드를 정제 및 회수하기 위한 용리거동을 조사하였다.

• Journal of Nutrition and Health
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• v.50 no.6
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• pp.624-644
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• 2017

Purpose: This study analyzed iodine intake by establishing an iodine database of general Korean foods eaten by Korean adults based on the data from the 1998 ~ 2014 KNHANES (Korea National Health and Nutrition Examination Survey). Methods: Data on 56,818 subjects aged 19 years and older were obtained from health behavior interviews and a 24-hour dietary recall survey. Iodine intake of subjects was analyzed according to general characteristics, dietary lifestyle, food groups, and cooking method. Results: An iodine database was established for 312 food items. The mean iodine intake of Korean adults decreased from $641.6{\mu}g$ in 1998 to $236.2{\mu}g$ in 2014 per day. Iodine intake of women was higher than that of men. For age distribution, those aged 30 ~ 49 years constituted more than 39 ~ 46% of subjects by survey year. Regarding iodine intake according to dietary lifestyle, the highest iodine intake was 29.4 ~ 34.4% for lunch while that of breakfast decreased. The highest iodine contribution by food group was seaweed such as kelp, sea mustard, and laver. Conclusion: The results of this study indicate that iodine intake of Korean adults has been decreasing, and iodine intake is associated with the prevalence of thyroid disease. This study provides basic data for the estimation of iodine intake in Korean adults.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.375-382
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• 2008

A low iodine diet (LID) is the recommended preparation for radioactive iodine treatment. However, the recommended duration and stringency of LID are different among each recommendation. More stringent LID is expected in Korea because Korea is a iodine-rich region. We investigated the decrement of urine iodine excretion by two-week stringent LID for remnant thyroid ablation with radioactive iodine in Korean patients with thyroid cancer, prospectively. Material and Method: From November 2006, patients who referred to our hospital for remnant ablation after total thyroidectomy were included in this study. To decrease total body iodine, our protocol included three strategies. First, we checked medication which could inhibit the radioactive iodine uptake. Second, the date of 1-131 treatment was scheduled at least 3 months later if contrast agent had been used. The last strategy was two-week stringent LID education by specialized nutritionist. Before and after two-week stringent LID, 24hr-urine iodine was analyzed respectively. 24hr-urine creatinine was also analyzed for determining more valid 24hr urine sampling subgroup. Results: Total 51 patients were finally enrolled. Average of 24hr-urine iodine excretion was significantly lowered ($787{\pm}2242\;{\rightarrow}\;85{\pm}85\;{\mu}g/d$, p=0.03) after LID and 74.4% of patients reached below the recommended urine iodine excretion level ($<100\;{\mu}g/d$). In subgroup (n=14), similar results was showed ($505{\pm}666\;{\rightarrow}\;99{\pm}116\;{\mu}g/d$, p=0.05) and 78.6% of patients met the criteria. Conclusion: Most patients could reach below the recommended urine iodine level after two-week stringent LID. Therefore, in our opinion, at least two-week stringent LID should be recommended in Korea.

• Journal of Nutrition and Health
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• v.53 no.3
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• pp.271-287
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• 2020

Purpose: Variations in the iodine contents of foods is critical for estimating the iodine intake. This study aimed to update the iodine database of common Korean foods and evaluated the iodine intake in Korean adults. Methods: A list of 855 Korean foods was selected for the updated iodine database. The updated database was established with Version 1 and 2 by applying an average or minimum value for the imputed values. The iodine intake was estimated in 5,927 Korean adults using the data from the 2013-2015 Korea National Health and Nutrition Examination Survey. Results: The analytical values in the updated database were 166 (19.4%), followed in order by 318 (37.2%), 247 (28.9%), and 124 (14.5%) for the adapted, imputed, and missing values, respectively. The median of dietary iodine intake was 352.1 ㎍/day (± 2,166.1) and 343.4 ㎍/day (± 2,161.9) in Version 1 and 2 among the total population. The contribution rates of each food group to the iodine intake were 55.7% for seaweeds, which showed a similar trend in Version 2. When subjects were divided by consumption of seaweeds, the median iodine intake was 495.7 ㎍ in the consumer group, which was almost double (241.2 ㎍) that of the non-consumer group. The proportion of subjects who consumed below the Estimated Average Requirement of iodine was 11.0% in the non-consumer group. In contrast, 11.6% in the consumer group of seaweed consumed above the Upper Level of iodine. When the dietary iodine and urinary iodine were examined, the regression coefficient was 0.11718 in Version 1 and 0.11512 in Version 2 after adjusting for age and sex. Conclusion: This study presented the variation of iodine intake in Korean adults by applying different versions of the iodine database. As the iodine intake can vary due to the highly variable concentrations in the major food sources, an iodine database is necessary to be monitored, and caution should be taken when the database is used in research.

• Nuclear Medicine and Molecular Imaging
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• v.40 no.6
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• pp.322-326
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• 2006

A low iodine diet (LID) for $1{\sim}2$ weeks is recommended for patients who undergoing radioiodine remnant ablation. However, the LID educations for patients are different among centers because there is no concrete recommendation for protocol of LID. In this investigation, we compared two representative types of LID protocols performed in several centers in Korea using urine iodine to creatinine ratio (urine I/Cr). Methods: From 2006, April to June, patients referred to our center for radioiodine remnant ablation of thyroid cancer from several local hospitals which had different LID protocols were included. We divided into two groups, stringent LID for 1week and less stringent LID for 2 weeks, then measured their urine I/Cr ratio with spot urine when patients were admitted to the hospital. Results: Total 27 patients were included in this investigation (M:F=1:26; 13 in one-week stringent LID; 14 in two-week less stringent LID. Average of urine I/Cr ratio was $127.87{\pm}78.52{\mu}g/g$ in stringent LID for 1 week, and $289.75{\pm}188.24{\mu}g/g$ in less stringent LID for 2 weeks. It was significantly lower in stringent LID for 1 week group (p=0.008). The number of patients whose urine I/Cr ratios were below $100{\mu}g/g$ was 6 of 13 in stringent LID for 1 week group, and 3 of 14 in less stringent LID for 2 weeks group. Conclusion: Stringent LID for 1 week resulted in better urinary I/Cr ratio in our investigation compared with the other protocol. However it still resulted in plenty of inadequate range of I/Cr ratio, so more stringent protocol such as stringent LID for 2 weeks is expected more desirable.

• KOREAN ASSOCIATION OF OCCUPATIONAL HEALTH NURSES
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• v.18 no.2
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• pp.17-24
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• 2011

갑상선 호르몬은 2가지 형태, 즉 L-thyroxine(tetraiodothyronine, T4)과 L-triiodothyronine(T3)으로서 갑상선(thyroid gland)에서 합성된다. 요오드는 갑상선 호르몬의 핵심요소이며 음식물에 포함된 요오드는 섭취 후 소장에서 흡수되어 혈류를 통해 갑상선으로 운반되고, 갑상선에서 농축, 산화되어 thyroglobulin이라는 단백질의 구성 아미노산 중 tyrosine에 삽입됨으로써 T4와 T3를 생성하게 된다. 갑상선 호르몬의 합성에는 요오드 이외에도 셀레니움이 필수적이다. 요오드와 셀레니움은 미량원소로서 부족하면, 갑상선 호르몬 결핍 또는 갑상선 비대를 초래할 수 있다.

• Korean Chemical Engineering Research
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• v.46 no.3
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• pp.633-638
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• 2008

The bunsen reaction, part of IS(Iodine-sulfur) cycle that one of the hydrogen production by the thermochemical water splitting, was investigated. It was observed that $H_2SO_4$ was uniformly generated and generation of $H_2SO_4$ was independent of iodine input. However, generation of HI was decreased with increasing iodine input. It was thought that HI and unreacted iodine were formed complex compound such as $HI_3$ $HI_5$ or $HI_7$. The complex compound accelerated liquid-liquid separation properties in the product. It was also revealed that reaction kinetics was increased with increasing iodine input. Liquid-liquid separation properties were improved with increasing iodine input and reaction temperature. Moreover, no side reaction was occurred at all reaction conditions.

• Journal of the Korean Chemical Society
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• v.18 no.5
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• pp.373-380
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• 1974

Direct electrochemical preparation of periodate from iodide $(I^-{\to}{IO_4}^-)$ was investigated using a none-diaphragm cell and lead dioxide anode. The direct electrolytic conditions were combinations of the respectively results on the processes of iodate from iodide$(I^-{\to}{IO_3}^-)$, and periodate from iodate$({IO_3}^-{\to}{IO_4}^-)$ which were reported by the author, previously. The optimum condition was achieved when 1.0 M potassium iodide solution containing 0.5 g/l potassium dichromate as an anti-reducing agent was electrolyzed at anodic current density of $15{\AA}/dm^2$ and electrolytic temperature of $60^{\circ}C$. Under such a condition, the current efficiency was found to be 84 % at 98 % conversion of iodide to periodate. The explanation of electrode reaction was also given a consideration based on the polarization curves at lead dioxide anode in various electrolyte solutions.

• Journal of the Korean Chemical Society
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• v.35 no.4
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• pp.301-307
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• 1991

The solubilities of the n-propyl iodide in nitrobenzene and m-xylene have been measured at 8$^{\circ}$, 15$^{\circ}$ and 25$^{\circ}C$ in the presence and the absence of gallium iodide. When gallium iodide does not exist in the system, the solubility of n-propyl iodide in m-xylene is greater than in nitrobenzene, indicating a stronger interaction of n-propyl iodide with m-xylene than that with nitrobenzene. It could be thought that n-propyl iodide forms unstable complex with gallium iodide in the presence of gaillium iodide in the system. This complex has been assumed in various ways and evaluated, that instability constant (K value) is relatively certain under the assumption of 1:1 complex, n-C$_3H_7I{\cdot}GaI_3$. Therefore, the complex would form the following equilibrium in the solution: n-C$_3H_7{\cdot}GaI _3{\rightleftharpoons}n-C_3H_7I+1/2Ga_2I_6$ the instability of the complex of n-propyl iodide with gallium iodide is compared with similar complexes of gallium iodide with methyl iodide. The changes of enthalpy, free energy and entropy for the dissociation of the complex are also calculated.