Assessment of the sustainability of the iodine-deficiency disorders control program in Lesotho

BACKGROUND: Evaluation of the sustainability of iodine-deficiency disorders control programs guarantees successful and sustained virtual elimination of iodine deficiency. The Lesotho universal salt iodization legislation was enacted in 2000 as an iodine-deficiency disorders control program and has never been evaluated. OBJECTIVES: To assess the sustainability of the salt iodization program in Lesotho, 2 years after promulgation of the universal salt iodization legislation. METHODS: The proportion to population size method of sampling was used in 2002 to select 31 clusters in all ecological zones and districts of Lesotho. In each cluster, 30 women were selected to give urine and salt samples and 30 schoolchildren to give urine samples. The salt samples were analyzed by the iodometric titration method, and the ammonium persulfate method was used to analyze the urine samples. The chairperson of the iodine-deficiency disorders control program was interviewed on programmatic indicators of sustainability. SAS software was used for statistical analysis of the data. RESULTS: The urinary iodine concentrations of very few children (10.1% and 21.5%) and women (9.8% and 17.9%) were lower than 50 microg/L and 100 microg/L, respectively. At the household level, 86.9% of the households used adequately iodized salt. Only four indicators of sustainability have been attained by the salt iodization program in Lesotho. CONCLUSIONS; Iodine-deficiency disorders have been eliminated as a public health problem in Lesotho, but this elimination is not sustainable. Effective regular monitoring of salt iodine content at all levels, with special attention to iodization of coarse salt, is recommended, together with periodic evaluation of the iodization program.     

Urinary iodine concentration of pregnant women and female adolescents as an indicator of excessive iodine intake in Sri Lanka

BACKGROUND: Mild deficiencies and excesses of iodine have deleterious effects in both females and males. The iodine status of the population after implementation of the universal salt iodization program in Sri Lanka is not known. OBJECTIVE: This cross-sectional study was carried out to assess the iodine status of pregnant women and female adolescents, with urinary iodine concentration used as the measure of outcome. METHODS: The participants were 100 women in the first trimester of pregnancy and 99 female adolescents in Kuliyapitiya, Kurunegala District, North-Western Province, Sri Lanka. The urinary iodine concentration was measured in a casual urine sample from each subject. The iodate contents of salt samples collected from households of the adolescents participating in the study were also measured. RESULTS: The median urinary iodine concentration of 185.0 microg/L and the prevalence of values under 50 microg/L of only 1% among the pregnant women indicate adequate iodine intake and optimal iodine nutrition. The median urinary iodine concentration (213.1 microg/L) among female adolescents indicates a more than adequate iodine intake and a risk of iodine-induced hyperthyroidism. Approximately 8% and 4% of the adolescents and pregnant women, respectively, had urinary iodine concentrations in the range of mild iodine deficiency (51 to 100 microg/L). More than half of the adolescents (56%) and 39% of the pregnant women had urinary iodine concentrations higher than optimal. The median iodine content in salt samples was 12.7 ppm. Only 20.2% of the samples were adequately iodized, and 10.1% of the samples had very high iodine levels. CONCLUSIONS: Female adolescents and pregnant women had no iodine deficiency, but a considerable proportion of them, especially female adolescents, were at risk for iodine-induced hyperthyroidism. There is thus a need for proper monitoring of the salt iodization program to achieve acceptable iodine status.     

加碘盐与人体健康

20世纪90年代以来,全世界实行普遍食盐碘化(universalsaltiodization,USI)政策,在我国食盐加碘是持续消除碘缺乏病的重要策略,关系到国计民生。本文对碘缺乏危害(IDD)进行了详尽的介绍,包括其概念、临床症状以及缺碘与人口素质的关系,对依照《全国碘盐监测方案》开展的碘盐监测结果进行分析比较,并对今后IDD控制工作提出了建议。     

Prevalence of goiter in children 6 to 12 years of age in Ethiopia

BACKGROUND: Iodine-deficiency disorders are a major public health problem in Ethiopia. In conjunction with implementing control programs, baseline information needs to be established. OBJECTIVE: To investigate the distribution and degree of severity of iodine-deficiency disorders in terms of goiter prevalence, urinary iodine excretion (UIE) levels, and proportion of households with iodated salt in Ethiopia. METHODS: A nationwide, community-based, cross-sectional study was conducted from February to May 2005 among 10,965 children aged 6 to 12 years. A multistage, proportional-to-population-size sampling method was used. Goiters were classified by the method recommended by the World Health Organization/UNICEF/International Council for the Control of Iodine Deficiency Disorders (WHO/UNICEF/ICCIDD), in which the thyroid gland is graded as 0 (normal), 1 (palpable goiter), or 2 (visible goiter); urinary iodine was determined by the wet digestion method; and salt samples were analyzed by a rapid test kit. RESULTS: The national total goiter weighted prevalence rate among children aged 6 to 12 years was 39.9% (95% confidence interval, 38.6% to 41.2%), representing more than 4 million children. The median UIE was 2.45 microg/ dL; 45.8% of children had UIE values of 2 microg/dL or less, and 22.8% had UIE values of 2.01 to 5.0 pg/dL. Only 4.2% of the households had iodated salt. CONCLUSIONS: According to the WHO/UNICEF/ ICCIDD classification, both goiter prevalence and UIE levels indicate that the whole country appears to be severely affected by iodine deficiency. Furthermore, the virtual absence of iodated salt in the households shows that currently there is no salt iodization program in the country. Dietary sources of iodine in Ethiopia are not dependable, and hence a sustainable universal salt iodization program needs to be implemented without delay.     

Iodine content in bread,milk and the retention of inherent iodine in commonly used Indian recipes

Iodine deficiency disorders (IDD) is still a major public health problem and iodized salt remains the most effective means to control IDD in India. Few reports indicate that vegans have inadequate iodine intake while at the same time concerns are being raised on the implementation of universal salt iodization in the country. Therefore, we investigated the iodine content in bread, milk and commonly used Indian recipes prepared without iodized salt and the retention of inherent iodine therein. Results showed considerable iodine content in bread (25 μg/100 g) and milk (303 μg/L) as a positive fallout of universal salt iodization. Iodine content in 38 vegetarian recipes prepared without iodized salt was very low (2.9 ± 2.4 μg/100 g). Retention of inherent iodine (65.6 ± 15.4%) and iodine from iodized salt (76.7 ± 10.3%) in the same recipes was comparable. Thus, universal salt iodization programme remains the single most important source of dietary iodine for the Indian population.     

2013-2020年郑州市二七区碘缺乏病监测结果统计分析

目的 统计分析2013-2020年郑州市二七区碘缺乏病(IDD)监测结果.方法 2013-2020年按照《全国碘缺乏病监测方案》在郑州市二七区开展盐碘监测,同时收集同期新婚育龄妇女、孕妇、哺乳期女性、0～2岁婴幼儿、8～10岁儿童5类人群的尿样,测定尿碘含量.结果 2013-2020年,郑州市二七区居民盐碘含量中位数与...     

Thirty years of a ban on the sale of noniodized salt: impact on iodine nutrition in children in Himachal Pradesh, India

BACKGROUND: A survey conducted by the central iodine-deficiency disorders team in Himachal Pradesh, a state in the goiter-endemic belt of India, revealed that 10 of its 12 districts have an endemic prevalence of goiter. The survey was conducted to provide health program managers data to determine whether it would be necessary to initiate intervention measures. OBJECTIVE: To assess the status of urinary iodine excretion and household salt iodization levels after three decades of a complete ban on the sale of noniodized salt in this goiter-endemic state in India as measured by assessment of urinary iodine excretion levels and iodine content of salt at the household level. METHODS: The guidelines recommended by WHO/ UNICEF/ICCIDD for a rapid assessment of salt iodization were adopted. In each of the 12 studied districts, all senior secondary schools were enlisted and one school was selected by using a random sampling procedure. Two hundred fifty children 11 to 18 years of age were included in the study. Urine samples were collected from a minimum of 170 children and analyzed using the wet digestion method. Salt samples were also collected from a minimum of 170 children and analyzed using the spot testing kit. RESULTS: All districts had a median urinary iodine excretion level > 200 microg/L and 82% of the families were consuming salt with an iodine content of 15 ppm or higher. CONCLUSIONS: The results of the present study high-light the successful implementation of the salt iodization program in the state of Himachal Pradesh. This positive impact may be due to the comprehensive strategy adopted by the state government to improve the quality of salt, development of an effective monitoring information system and effective information, education, and communication activities.     

Lessons from successful micronutrient programs. Part III: program impact

Micronutrient-deficiency control programs have been greatly extended at the national level in the last 10 to 15 years. However, rigorous evaluations of these are scarce, so that conclusions on impact are tentative and based mainly on indirect evidence. The coverage of vitamin A capsule distribution programs has exceeded 70% in most study countries. In countries implementing national iodized salt programs, the coverage reaches 60% to 90% of households with adequately iodized salt. Of the three micronutrients, coverage of iron tablet supplementation is the least well documented due to inadequate program monitoring systems and population survey data. Supplementation of preschool children 6 to 59 months of age with vitamin A capsules has plausibly contributed to the reduction in clinical vitamin A deficiency and its near-elimination in many countries. The impact of vitamin A capsule supplementation on children's biochemical vitamin A status (serum retinol) in national programs may be less. National data on salt iodization show a consistent relation to reduced prevalence of iodine-deficiency disorder symptoms (goiter); the rates of cretinism and other results of iodine deficiency are almost certainly falling too. The evaluation of the impact of salt iodization programs on biochemical iodine status is limited by a lack of data. Although trials have demonstrated the efficacy of iron supplementation in reducing the prevalence of anemia, the interpretation of national-level data is not so clear. Given the substantial financial and technical commitment required to implement national micronutrient-deficiency control programs, it is vital that investment enable the evaluation of the impact of these programs. It is becoming increasingly important to collect data on subclinical deficiency (e.g., biochemical data) to assess program impact.     

Iodine deficiency persists in the Zanzibar Islands of Tanzania

BACKGROUND: Iodine is an essential micronutrient for normal human growth and development. It is estimated that more than 1.6 billion people live in iodine-deficient environments, yet there are still some countries and areas where the prevalence of iodine-deficiency disorders is unknown. OBJECTIVE: To establish the prevalence of iodine-deficiency disorders in the Zanzibar Islands, a community assumed to have ready access to iodine-rich seafoods. METHODS: In a cross-sectional study, 11,967 schoolchildren were palpated for goiter prevalence, a subsample was evaluated for urinary iodine concentration, and the availability of iodated salt was assessed at the household and retail levels. RESULTS: The mean total goiter prevalence was 21.3% for Unguja and 32.0% for Pemba. The overall median urinary iodine concentration was 127.5 microg/L. For Unguja the median was 185.7 microg/L, a higher value than the median of 53.4 microg/L for Pemba (p < .01). The household availability of iodated salt was 63.5% in Unguja and 1.0% in Pemba. The community was not aware of the iodine-deficiency problem and had never heard of iodated salt. CONCLUSIONS: The inadequate intake of iodine documented in the Zanzibar Islands belies the common assumption that an island population with access to seafood is not at risk for iodine-deficiency disorders. We urge health planners to implement mandatory salt iodation and education efforts to alleviate the situation.     

Effect of iodine status and other nutritional factors on psychomotor and cognitive performance of Filipino schoolchildren

BACKGROUND: Until 1998, iodine deficiency was a public health problem in the Philippines. A law entitled "An Act Promoting Salt Iodization Nationwide" (ASIN) has been passed and implemented by the government to eliminate iodine deficiency. The contribution of salt iodization, as well as dietary, health, and environmental factors, to improving the intellectual performance of Filipino schoolchildren remains to be determined. OBJECTIVE: The objectives of the study were to determine the relationship between iodine status and levels of psychomotor and cognitive performance in first-grade children aged 6 to 10 years, and to examine the extent to which dietary, biochemical, health, and environmental factors contribute to children's mental performance. METHODS: Two hundred ninety children in six classroom sections from a public school in Manila were examined by measurement of urinary iodine excretion (UIE) and thyroid palpation. The median UIE level for each section was determined. Sixty-five children classified as iodine deficient (UIE < 90 microg/L with grade 1 goiter, n = 34) and non-iodine deficient (UIE > 100 microg/L without goiter, n = 31) were given psychomotor and cognitive function tests (Bender-Gestalt and Raven's Colored Progressive Matrices). Scores from the two tests were used to determine each child's general ability percentile rank. Other variables examined were dietary intake (% RDA of nutrients ingested based on two nonconsecutive 24-hour recalls); deficiencies in iron, vitamin A, and selenium; parasitic infection; coliform contamination of drinking water; household use of iodized salt; illness in the past 2 weeks; and wasting and stunting. RESULTS: Children whose general ability scores were at or above the 50th percentile had higher UIE levels, but the relationship was not significant. Children from sections with higher median UIE levels had higher percentile ranks for general ability (p = .002). Backward logistic regression showed that the variance in deficient and adequate mental performance was explained by dietary intakes that met > or = 80% of the RDA for energy, protein, thiamin, and riboflavin; the use of iodized salt; child's iodine status; and stunting (R2 = .520, p = .0016). Higher class median UIE was associated with better psychomotor and cognitive performance in children who were tested. Factors that contributed to better performance include higher intakes of energy, protein, thiamin, and riboflavin; household use of iodized salt; normal iodine status; and absence of stunting or chronic malnutrition. CONCLUSIONS: Salt iodization, accompanied by adequate intakes of energy, protein, and foods rich in thiamin and riboflavin, can contribute to improved mental performance in Filipino schoolchildren. Longer-term factors that can contribute to improved performance are achievement of normal iodine status and elimination of protein-energy malnutrition.     

Power from below: enabling communities to ensure the provision of iodated salt in Kyrgyzstan

BACKGROUND: In Kyrgyzstan, as in many countries around the world, progress in universal salt iodization has been slow because of difficulties in enforcing existing national regulations. OBJECTIVE: To study the effects of community testing of the iodine content of salt in households, at local retailers, and at wholesale markets on the percentage of households using iodized salt in Naryn Oblast, a region of Kyrgyzstan. METHODS: In response to a stated community priority to address iodine deficiency in Naryn Oblast, volunteers from village health committees and personnel of Primary Health Care units living in the communities were trained in testing salt using test kits. A phased introduction of two testing components was conducted in 2002-2003 in two areas with a combined population of 160,000. The two components included testing of salt for iodine content by community members in as many households as possible (Component 1) and testing of retail salt for iodate content by community members and by retailers at wholesale markets (Component 2). Results from these two components provided the data for this study. RESULTS: For Component 1, salt testing reached 65% of households; coverage of iodized salt increased from 87.6% to 96.8% within 5 to 7 months (averages of the two areas; p < .001), mostly owing to a great decrease in the variation among settlements. For Component 2, in area 1, the percentage of households using iodated salt increased from 71.0% to 90.3% within 5 to 7 months, whereas the percentage of households using iodinated salt decreased from 18.6% to 5.6%. In area 2, the percentage of households using iodated salt increased from 65.2% to 76.2% within 5 to 7 months, with no change in the percentage of households using iodinated salt (21.7% and 20.8%). The differences between areas I and 2 are highly significant (p < .001). At 18 to 21 months, the percentage of households using iodated salt was 97.5% in area 1 and 90.2% in area 2. The intervention cost around U.S. dollars 1500. CONCLUSIONS: Testing salt in a large percentage of households is an effective, low-cost approach to increasing the percentage of households using iodized salt to satisfactory levels in a very short time. Empowering community members to check salt at retailers and retailers to check salt at wholesale markets with test kits for iodated salt can rapidly ensure almost exclusive consumption of iodated salt in households.     

A multicenter community study on the efficacy of double-fortified salt

BACKGROUND: Iron and iodine deficiencies affect more than 30% of the world's population. Typical Indian diets contain adequate amounts of iron, but the bioavailability is poor. This serious limiting factor is caused by low intake of meat products rich in heme iron and intake of phytates in staple foods in the Indian diet, which inhibits iron absorption. OBJECTIVE: To test the stability of double-fortified salt (DFS) during storage and to assess its efficacy in improving the iron and iodine status of the communities. METHODS: The stability of both iodized salt and DFS during storage for a 2-year period was determined. The bioefficacy of DFS was assessed in communities covering three states of the country for a period of 1 year. This was a multicenter, single-blind trial covering seven clusters. The experimental group used DFS and the control group used iodized salt. The salts were used in all meals prepared for family members, but determination of hemoglobin by the cyanmethemoglobin method was performed in only two or three members per family, and not in children under 10 years of age (n = 393 and 436 in the experimental and control groups, respectively). The family size was usually four or five, with a male: female ratio of 1:1, consisting of two parents with two or three children. Hemoglobin was measured at baseline, 6 months (midpoint), and 12 months (endpoint). Urinary iodine was measured in only one cluster at baseline and endpoint. All the participants were dewormed at baseline, 6 months, and 12 months. RESULTS: The iron and iodine in the DFS were stable during storage for 2 years. Over a period of 1 year, there was an increase of 1.98 g/dL of hemoglobin in the experimental group and 0.77 g/dL of hemoglobin in the control group; the latter increase may have been due to deworming. The median urinary iodine changed from 200 microg/dL at baseline to 205 microg/dL at the end of the study in the experimental group and from 225 microg/dL to 220 microg/dL in the control group. There was a statistically significant (p < .05) improvement in the median urinary iodine status of subjects who were iodine deficient (urinary iodine < 100 microg/L) in both the experimental and the control groups, a result showing that DFS was as efficient as iodized salt in increasing urinary iodine from a deficient to sufficient status. There was a statistically significant increase (p < .05) in hemoglobin in all seven clusters in the experimental group compared with the control. CONCLUSIONS: The iron and iodine in the DFS are stable in storage for 2 years. The DFS has proved beneficial in the delivery of bioavailable iron and iodine.     

Use of Iodized Salt in Processed Foods in Select Countries Around the World and the Role of Food Processors

Executive Summary: The Micronutrient Initiative (MI) issued the Institute of Food Technologists (IFT) a project to assess the extent to which iodized salt is used in processed foods, as well as food processors’ level of knowledge on iodine nutrition. Iodine is an essential micronutrient required by the body that is found in a limited number of foods, thus many individuals require additional sources of iodine to meet their daily requirement. Without these additional sources, a range of disorders referred to as iodine deficiency disorders (IDD), including mental impairment, may become present, with over 2 billion people worldwide at risk due to insufficient iodine nutrition. IDD is especially damaging during the early stages of pregnancy and in early childhood. In their most severe form, IDD includes cretinism, stillbirth, and miscarriage, and increased infant mortality. Since 1994 the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF) have recommended universal salt iodization (USI) as a safe, cost‐effective, and sustainable strategy to ensure sufficient intake of iodine by all individuals. However, USI has in practice tended to focus only on table salt and not all salt destined for human consumption. Recent trends, particularly in industrialized countries, show that individuals are consuming the majority of their salt through processed foods, in which iodized salt is generally not used, rather than through iodized table salt. Additionally, recent initiatives to encourage reduced sodium consumption have prompted many consumers to reduce their intake of iodized table salt. While these trends in sodium consumption are more frequently observed in industrialized countries, they are expanding into many developing countries where iodine deficiency is also a concern. Thus countries which focus on iodization of table salt alone may not achieve optimal iodine nutrition of their population. This report provides an overview of the 2 Phases of this project. Phase I was to conduct an environmental scan/desk review of processed food consumption patterns in 39 countries selected by MI (see Table 1 ). Phase II was to conduct an electronic survey of food processors and detailed telephone interviews with a small sample of select company representatives from 16 countries (see Table 2 ). Per the scope of work, IFT conducted a desk review to determine the types and level of processed food consumption in the 39 countries of interest, as well as to identify suppliers of the major processed foods consumed and the use of salt as an ingredient in those products. Whenever possible, IFT also gathered information on the sodium content of widely consumed processed foods and the sources of salt currently used in these products; the types of processed foods and extent to which they are consumed by different socioeconomic groups; if iodized salt was used in processed foods; and whether or not there are policies in place to influence dietary salt reduction and how these efforts are implemented. For Phase II, IFT reached out to food company representatives to determine their use of iodized salt in processed food products; their sources of salt; their awareness of iodine nutrition and salt as a fortification vehicle; and their interest in learning more about salt iodization. For the purposes of this project, processed foods are considered to be all food products that have undergone a change of character or been altered from their original form.

Table 1–. Preselected countries (from MI) for Phase I of the iodized salt in processed foods project.

Difference in goiter rates between regular and occasional users of iodized salt in Mongolia

In Mongolia many households use iodized salt only occasionally. We investigated whether the occasional use of iodized salt had an impact on the reduction of goiter size. We examined 685 children (8-11 years old) in five groups of households that (1) used iodized salt regularly, (2) used more than 10 kg of iodized salt annually, (3) used 6 to 10 kg annually, (4) used less than 6 kg annually, (5) and regularly used noniodized salt. The prevalence of goiter as determined by ultrasound in these five groups was 31.1%, 30.3%, 40.6%, 52.1%, 56.6%, respectively. There was no difference between goiter rates among the first three groups, but these groups had significantly lower rates than the last two groups. We concluded that annual use of more than 6 kg of iodized salt, preferably more than 10 kg, by a household had a beneficial effect on the rate of goiter. In addition, the possibility was suggested that households that consumed only iodized salt consumed less salt than other households.     

Reaching the goal of Universal Salt Iodization (USI): experience of Uttar Pradesh, India

BACKGROUND: In 2002, the percentage of households consuming iodized salt in the state of Uttar Pradesh (UP) in India dropped to as low as 6%. This implied that 3.5 million newborns in this non-salt producing state, with 180 million population, were at risk of brain damage unless universal accessibility and consumption of iodized salt was ensured and sustained. OBJECTIVES: Urgent measures were introduced in 3 phases in the statefor accelerating procurement, distribution and consumption of iodized salt. METHODS: In the first phase, a study on mapping of salt wholesalers and understanding the salt trading system--including understanding the knowledge, attitudes, and practices of salt traders was undertaken to accelerate efforts to influence availability, marketing, and accessibility of iodized salt. The study revealed that a total of only 344 primary wholesalers supplied salt to the entire state. Of these, 126 wholesalers marketed 80% of salt and were located in only 15 of the total 70 districts of the state. This finding became a very strong basis for the program in phase II, which focused on the critical group of wholesalers and set up a system to frequently interact with them. The salt wholesalers were equipped with Salt Testing Kits (STKs) to ensure adequate iodine content in the salt procured by them and adherence to the legal ban on the sale of non-iodized salt for human consumption. Simultaneously, a "child-to-community" approach was launched through involvement of middle and high school children to create demand and monitor consumption of iodized salt at the household level. Over 217,000 salt samples (about 26,000 samples per quarter) were brought in by school children and tested for iodine content. RESULTS: The school activities resulted not only in influencing consumption of iodized salt, but also galvanized the entire chain linking consumers, retailers, and wholesalers. In less than 2 years, salt procured with nil iodine decreased from 38% to 15.3%, and salt marketed with adequate iodine level increased from 28.6% to 64.9%. School data revealed an increase in consumption of iodized salt from 6% to 46.7%. In phase 3, additional standardized activities at the school level were included and the program was taken to scale in the state. CONCLUSION: The findings revealed that identification and inclusion of salt wholesalers-not only the salt manufacturers-was important for achieving a rapid positive shift in iodized salt marketing and consumption practices.     

Stability of iodine in iodized fresh and aged salt exposed to simulated market conditions

BACKGROUND: The salt iodization law of the Philippines required that iodized salt sold at retail not be exposed to direct sunlight, high temperature and relative humidity, and contamination with moisture and dust from the environment. However, because the majority of local consumers buy salt displayed in open heaps, it was suggested that iodized salt should be sold in the same manner for greater accessibility and availability. Objective. We aimed to provide evidence on the stability of iodine in local aged and fresh salt iodized at 100 ppm iodine and exposed to various market and storage conditions. METHODS: Samples of salt in open heaps and repacked salt were exposed for 4 weeks, and salt packed in woven polypropylene bags was stored for 6 months. The iodine content of the salt was determined by the iodometric titration method, and the moisture content was determined by the oven-drying method. RESULTS: For all types of exposed salt, iodine levels were above 60 ppm after the end of the study (4 weeks). Within each salt type, losses were greater for open-heap salt than for repacked salt. The greatest drop in moisture content occurred in the first week for most types of salt and exposure combinations. Moisture content was linearly correlated with iodine content. Iodine levels in stored salt remained above 60 ppm even after 6 months. CONCLUSIONS: Iodized salt is able to retain iodine above the recommended levels despite exposure to an open environment and use of ordinary packaging materials while being sold at retail and kept in storage.     

Fast and reliable salt iodine measurement: evaluation of the WYD Iodine Checker in comparison with iodometric titration

Iodine deficiency persists as the leading cause of preventable brain damage and reduced intellectual capacity in the world. The most effective method for the elimination of iodine deficiency is the consumption of adequately iodized salt. Ensuring that a population receives adequately iodized salt demands careful monitoring of the salt iodine content. We evaluated the WYD Iodine Checker, a hand-held instrument that quantitatively measures the salt iodine content on the basis of a colorimetric method, and compared its performance with iodometric titration. Performance testing results indicated that the WYD Iodine Checker is a highly precise, accurate, and sensitive tool for measuring salt iodine content. It is a user-friendly instrument that is based on a simple methodology and a straightforward salt sample preparation and testing procedure. We recommend further testing to examine the field performance of the WYD Iodine Checker when measuring iodate salt samples.     

加碘精制食盐中碘酸钾的稳定性及其影响因素研究

目的：研究加碘精制食盐中碘酸钾在存储期间的稳定性及其影响因素。方法：在大理市内随机收集同一批次的碘盐样品40份,按设计要求分别存放,每隔3个月观察1次,连续3次,采用直接碘量法检测样品碘含量。结果：在阴暗的条件下,不论是以罐装或袋装的方式存放,碘样中碘的含量均值之间的差异有统计学意义,提示有碘损失。在明处的条件下,以开口方式及带盖罐装的方式存放的碘样中碘的含量均值之间的差异有统计学意义,提示有碘损失;而以小塑料袋密封的方式存放的碘样中碘的含量均值之间的差异无统计学意义,提示未发生明显碘损失。结论：经8个月的观察,发现除了以明处小塑料袋密封这种存放方式外,其他的存放方式碘都有损失,但损失量少;食盐质量、存放环境以及碘盐生产或采样时混匀程度均会影响碘含量变化而发生变异。     

Stability of iodine in salt fortified with iodine and iron

BACKGROUND: Determining the stability of iodine in fortified salt can be difficult under certain conditions. Current methods are sometimes unreliable in the presence of iron. OBJECTIVE: To test the new method to more accurately estimate iodine content in double-fortified salt (DFS) fortified with iodine and iron by using orthophosphoric acid instead of sulfuric acid in the titration procedure. METHODS: A double-blind, placebo-controlled study was carried out on DFS and iodized salt produced by the dry-mixing method. DFS and iodized salt were packed and sealed in color-coded, 0.5-kg, low-density polyethylene pouches, and 25 of these pouches were further packed and sealed in color-coded, double-lined, high-density polyethylene bags and transported by road in closed, light-protected containers to the International Council for the Control of Iodine Deficiency Disorders (ICCIDD), Delhi; the National Institute of Nutrition (NIN), Hyderabad; and the Orissa Unit of the National Nutrition Monitoring Bureau (NNMB), Bhubaneswar. The iodine content of DFS and iodized salt stored under normal room conditions in these places was measured by the modified method every month on the same prescribed dates during the first 6 months and also after 15 months. The iodine content of DFS and iodized salt stored under simulated household conditions was also measured in the first 3 months. RESULTS: After the color code was broken at the end of the study, it was found that the DFS and iodized salt stored at Bhubaneswar, Delhi, and Hyderabad retained more or less the same initial iodine content (30-40 ppm) during the first 6 months, and the stability was not affected after 15 months. The proportion of salt samples having more than 30 ppm iodine was 100% in DFS and iodized salt throughout the study period. Daily opening and closing of salt pouches under simulated household conditions did not result in any iodine loss. CONCLUSIONS: The DFS and iodized salt prepared by the dry-mixing method and stored at normal room conditions had excellent iodine stability for more than 1 year.     

Adding an oxidant increases the stability of iodine in iodized salt

It has been shown that moisture plays a critical role in the stability of iodine and that reducing agents in iodized salt reduce the stability of iodine. We question whether this is valid in all cases, and have found that the reducing agent may play a more important role than moisture in decreasing the stability of iodine. We reviewed current methods to enhance iodine retention in iodized salt, and propose methods to produce stable iodized salt and to analyze its stability. Our experiments showed that when reducing impurities are removed, iodine remains stable in iodized salt, even when the salt is "wet." We suggest that the stability of iodine in iodized salt can be improved by oxidizing iodized salt with sodium hypochloride, and that the iodine content of iodized salt, after heating at 120 degrees C for one hour, can be used to reflect the quality of iodized salt. We have demonstrated that reducing agents play a critical role in the stability of iodine in iodized salt. We have shown a method of purifying salt by removing reducing materials, which can be used to produce iodized salt with sufficient stability at lower cost. We also propose an analytical method to determine the stability of iodine in iodized salt. These methods could be further developed to achieve better accuracy, precision, and reliability and be applied to a greater variety of iodized salts.