Insufficient Iodine Intake Research Articles

Quality of fresh and stored carrots depending on iodine and nitrogen fertilization

IntroductionIodine is an important mineral nutrient essential for a proper functioning of human and animal organism. Despite current programmes of iodine prophylaxis (mainly based on salt iodization) approximately 30–38% of human population has insufficient iodine intake. Crop plants can become an efficient vector of this element in the food chain. Iodine is not a nutrient for plants. For that reason, in addition to determining the possibility of increasing iodine content in crop plant it is necessary to describe its impact on yield quality. The aim of the study was to analyze the influence of soil fertilization with iodine and nitrogen on the quality of carrot roots and its storage ability. MethodsIn 2008–2010 the field study with carrot cv. ‘Kazan F1’ was conducted. A differential soil fertilization with iodine (in the form of I− or IO3−) and nitrogen (as NO3− or NH4+) was applied in the experiment: (1) control without N and I, (2) KI application without N, (3) KIO3 application without N, (4) KI+Ca(NO3)2, (5) KIO3+Ca(NO3)2, (6) KI+(NH4)2SO4 and (7) KIO3+(NH4)2SO4. The experiment was arranged in a split-plot design. Iodine (in both forms) was applied pre-sowing in a dose of 2kgIha−1. Nitrogen in the form of Ca(NO3)2 and (NH4)2SO4 was introduced pre-sowing and as a top dressing, each dose of 100kgNha−1. Results and discussionA diverse, statistically significant influence of tested factors on the activity of free radical-scavenging (DPPH) and the content of: dry matter, glucose, fructose, sucrose, total soluble sugars, soluble solids – Brix %, phenolic compounds, phenylpropanoids, flavonols, anthocyanins and carotenoids was noted in carrot roots directly after the harvest as well as at the end of four-month storage. Iodine applied with relatively high doses of nitrogen decreased the quality of fresh carrot. After storage, opposite relations were noted for tested combinations (with I and N application) with respect to carrot quality when compared to results obtained after the harvest. The lowest storage ability was found for carrot treated with KI without N. Obtained results directly suggest the need for developing individual agronomic rules for iodine biofortification of carrot for: (a) consumption and/or processing directly after the harvest and (b) long-term storage.

Dietary Factors and the Risk of Thyroid Cancer: A Review

In the past few decades, the incidence of thyroid cancer has rapidly increased worldwide. Thyroid cancer incidence is relatively high in regions where the population's daily iodine intake is insufficient. While low dietary iodine has been considered as a risk factor for thyroid cancer development, previous studies found controversial results across different food types. Among different ethnic groups, dietary factors are influenced by various dietary patterns, eating habits, life-styles, nutrition, and other environmental factors. This review reports the association between dietary factors and thyroid cancer risk among ethnic groups living in different geologic regions. Iodine-rich food such as fish and shellfish may provide a protective role in populations with insufficient daily iodine intake. The consumption of goitrogenic food, such as cruciferous vegetables, showed a positive association with risk. While considered to be a risk factor for other cancers, alcohol intake showed a protective role against thyroid cancer. High consumption of meat such as chicken, pork, and poultry showed a positive association with the risk, but dairy products showed no significant association. Regular use of multivitamins and dietary nitrate and nitrite also showed a positive association with thyroid cancer risk. However, the study results are inconsistent and investigations into the mechanism for how dietary factors change thyroid hormone levels and influence thyroid function are required.

Lack of dietary sources of iodine and the prevalence of iodine deficiency in rural women from Sidama zone, southern Ethiopia

Iodine deficiency has been reported to affect a large number of people in Ethiopia. Although significant progress against iodine deficiency disorders (IDD) has been reported worldwide, millions of people remain with insufficient iodine intake. Multiple factors may contribute to iodine deficiency. Hence, the objective of this study was to investigate iodine deficiency and dietary intake of iodine. A cross-sectional survey design was used to assess urinary iodine concentration (UIC), goiter and dietary intake of iodine in a sample of 202 non-pregnant women living in three rural communities of Sidama Zone, southern Ethiopia. Urinary iodine concentration was analyzed using the Sandell-Kolthoff reaction, goiter was assessed using palpation and dietary source of iodine was assessed using a food frequency questionnaire. Data were analyzed using selected descriptive and analytical statistical measures with SAS software. Mean (SD) age, mid upper arm circumference (MUAC) and body mass index [BMI -Wt(kg)/(Ht(m))2] were 30.8(7.9) y, 24.8(2.5) cm and 20 (2.2) respectively. Median UIC was 37.2 µg/L. Participants with UIC <20 µg/L, classified as severely iodine deficient were 22.8%; 46.5% had UIC between 20 to <50 µg/L, classified as moderately iodine deficient, and 27.2 % had UIC in the mild deficiency range of 50 to <100 µg/L. Only 3.5% of the women had UIC ≥ 100 μg/L. The total goiter rate was 15.9%, which was 1.5% visible and 14.4% palpable goiter. A majority of the participants consumed Enset (E. ventricosum), corn and kale frequently and meat was consumed rarely. None of the participants reported ever consuming iodized salt or ever having heard about use of iodized salt. Adjacent communities (Alamura, Tullo and Finchawa) showed significant differences in UIC, goiter rate and frequency of fish and dairy consumption. The findings of the present study revealed that iodine status of the population is a significant public health problem. Hence, there is a need to supply iodized salt in order to achieve the goal of elimination of iodine deficiency disorders in the community.

Urinary iodine concentrations of pregnant women in rural Bangladesh: A longitudinal study

Iodine is an essential dietary element required for normal fetal growth and development. We aimed to explore intraindividual and interindividual variations in iodine intake in pregnant women and whether non-dietary factors might influence the intake. Iodine intake was assessed in 271 women, residing in Matlab, rural Bangladesh, by measuring their urinary iodine concentration (UIC) at gestational week (GW) 8, 14, 19, and 30 with inductively coupled plasma mass spectrometry. The women's UIC increased significantly during pregnancy (median 241 (GW8) and 300 μg/l (GW30)). About 6% of the women had insufficient iodine intake (UIC<150 μg/l) and 10% had excessive iodine intake (UIC≥500 μg/l) at all of their four sampling occasions. The women's UIC were dependent on their education, socio-economic status, and BMI, as well as the season of sampling and iodine concentrations in drinking water. Supplementation with a multi-micronutrient capsule, including 150 μg potassium iodine, increased the UIC in women with the lowest UIC (10th percentile) at GW30 but decreased the UIC in women with the highest UIC (90th percentile) at GW30. In conclusion, median UIC throughout pregnancy indicated adequate intake of iodine among pregnant women in Matlab, but, notably, consistently insufficient and excessive intake was also prevalent.

Iodine status in Korean preschool children as determined by urinary iodine excretion

Iodine is a trace element of thyroid hormones. Excessive or insufficient iodine intake is associated with various thyroid diseases. Urinary iodine (UI) is a sensitive indicator and a recommended barometer of population iodine intake. In Korea, there has been no available data regarding iodine intake in preschool children. We investigated the iodine intake status of Korean preschool children through examination of their UI. This cross-sectional study was performed in 611 healthy preschool children (302 from Seoul and 309 from Masan), aged from 2 to 7 in 2010. UI concentration was measured by inductively coupled plasma-mass spectrometry. The median UI concentration was 438.8 μg/L. Insufficient iodine intakes (<100 μg/L) were seen in 24 children (3.9%), and excessive iodine ingestion (>300 μg/L) was found in 406 children (66.4%). There were no significant differences in UI between different sexes and ages. Additionally, the median UI concentration was higher in children from Seoul (512.2 μg/L) than that in children from Masan (362.4 μg/L, P < 0.001). About two-thirds of Korean preschool children were in the state of excessive iodine intake, and 3.9% of children showed insufficient iodine intake. Preventive measures and follow-up for iodine intake in preschool children are needed.

The Prevalence of Using Iodine-Containing Supplements Is Low among Reproductive-Age Women, NHANES 1999–2006

During pregnancy, the iodine requirement rises to meet demands for neurological development and fetal growth. If these requirements are not met, irreversible pathological cognitive and behavioral changes to the fetus may ensue. This study estimated the prevalence of iodine-containing dietary supplement (DS) use and intakes of iodine from DSs among pregnant women and nonpregnant women of reproductive age (15–39 y) who were interviewed and examined in NHANES 1999–2006 (n = 6404). Although 77.5% of pregnant women reported taking one or more DSs in the past 30 d, only 22.3% consumed an iodine-containing supplement. Most pregnant women reported using one DS and reported taking this product daily. The vast majority of iodine-containing DSs reported by pregnant women claimed an iodine content of 150 μg iodine/serving on the label. Pregnant women using at least one DS containing iodine had a mean daily iodine intake of 122 μg/d from supplements; the median value was 144 μg/d. Median urinary iodine concentrations (UICs) were similar for pregnant and nonpregnant women in the population aged 15–39 y. The median UIC was 148 μg/L for pregnant women and 133 μg/L for nonpregnant women. The WHO has established a cutoff for insufficient iodine intake at <150 μg/L for pregnant women and <100 mg/L for those who are not pregnant. This suggests that as a population, we may not be meeting adequate intakes of iodine for pregnant women. More research is needed on the iodine intakes of pregnant women and women of reproductive age on their total iodine intake from all sources, not just DSs.

Risk of Suboptimal Iodine Intake in Pregnant Norwegian Women

Pregnant women and infants are exceptionally vulnerable to iodine deficiency. The aims of the present study were to estimate iodine intake, to investigate sources of iodine, to identify predictors of low or suboptimal iodine intake (defined as intakes below 100 μg/day and 150 μg/day) in a large population of pregnant Norwegian women and to evaluate iodine status in a sub-population. Iodine intake was calculated based on a validated Food Frequency Questionnaire in the Norwegian Mother and Child Cohort. The median iodine intake was 141 μg/day from food and 166 μg/day from food and supplements. Use of iodine-containing supplements was reported by 31.6%. The main source of iodine from food was dairy products, contributing 67% and 43% in non-supplement and iodine-supplement users, respectively. Of 61,904 women, 16.1% had iodine intake below 100 μg/day, 42.0% had iodine intake below 150 μg/day and only 21.7% reached the WHO/UNICEF/ICCIDD recommendation of 250 μg/day. Dietary behaviors associated with increased risk of low and suboptimal iodine intake were: no use of iodine-containing supplements and low intake of milk/yogurt, seafood and eggs. The median urinary iodine concentration measured in 119 participants (69 μg/L) confirmed insufficient iodine intake. Public health strategies are needed to improve and secure the iodine status of pregnant women in Norway.

Infant neurocognitive development is independent of the use of iodised salt or iodine supplements given during pregnancy

The benefits of iodine supplements during pregnancy remain controversial in areas with a mild-to-moderate iodine deficiency. The aim of the present study was to determine the effect of improving iodine intakes, with iodised salt (IS) or iodine supplements, in pregnant Spanish women. A total of 131 pregnant women in their first trimester were randomly assigned to three groups: (1) IS in cooking and at the table, (2) 200 μg potassium iodide (KI)/d or (3) 300 μg KI/d. No differences were found in thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) or thyroid volume (TV) between the three groups. Regardless of the group in which women were included, those who had been taking IS for at least 1 year before becoming pregnant had a significantly lower TV in the third trimester (P= 0.01) and a significantly higher urinary iodine in the first (173.7 (sd 81.8) v. 113.8 (sd 79.6) μg/l, P= 0.001) and third trimesters (206.3 (sd 91.2) v. 160.4 (sd 87.7) μg/l, P= 0.03). Also, no differences were seen in TSH, FT4 or FT3. Children's neurological development was not significantly associated with the consumption of IS for at least 1 year before becoming pregnant and no differences were found according to the treatment group. In conclusion, in pregnant women with insufficient iodine intake, the intake of IS before becoming pregnant was associated with a better maternal thyroid function. The form of iodide intake was not associated with maternal thyroid function or children's neurological development.

In vivo assessment about the effects of a diet containing iodine-enriched foodstuffs. A pilot study in 30 volunteers.

Iodine deficiency (ID) still now represents one of the major worldwide health problems. ID is the result of insufficient dietary iodine intake. Iodine is an essential micronutrient but scarcely present in nature. The main strategy for the correction of ID is the fortification of table salt with iodide/iodine but Italy is far from reaching an iodized salt use higher 90% of population. Also because of the evidence for the risk on blood pressure, it is recommended to decrease the daily salt intake to less than 5 g/d. An opportunity to increase the iodine intake is the possibility to introduce iodine fortification in the industrial processing of foods. The aim was to evaluate the effectiveness of a diet containing iodized foods enriched during industry processing with protected iodized salt (Presal®). The evaluation of increasing of iodine intake was assessed by measuring the urinary iodine excretion (UIE) in 30 healthy volunteers who added to their alimentary habits a basket of iodine-enriched foodstuffs. Median UIE at baseline was 105 μg/l, 156 μg/l during the enriched diet and 90.5 μg/l a week after withdrawal of enriched diet. Stable iodized salt (Presal®) represents a good way to introduce iodine with the normal diet without increasing the normal consumption of salt for the healthy problems related to the blood pressure. The availability of stable iodized salt (Presal®) allows the preservation of iodine after cooking.

Global Efforts to Address Severe Acute Malnutrition

476 5. C hildhood malnutrition encompasses a plethora of nutritional disorders that include stunting, underweight, wasting, severe acute malnutrition (SAM), and micronutrient deficiency disorders. Overweight and obesity, at the other end of the nutritional spectrum, are also manifestations of childhood malnutrition. Nearly 24 million children (younger than 5 years) worldwide experience SAM. The vast majority is located in Africa and Asia (8 million are in India alone). A child with SAM is 10 times more likely to die than a wellnourished child. SAM is one of the top 3 nutrition-related causes of death in children younger than 5 years. Estimates of deaths directly attributable to SAM varied from 0.5 to 2 million annually. Moderate and severe child malnutrition account for 40% to 50% of all deaths in children younger than 5 years. If the United Nations Millennium Development Goals (http://www.un.org/millennium goals) of reducing children malnutrition and mortality by 50% by 2015 are to be met, SAM needs to be prevented and controlled effectively.

Update on iodine status worldwide

Salt iodization has been introduced in many countries to control iodine deficiency. The two most commonly used approaches to assessing iodine nutrition on the population level are estimation of the household penetration of adequately iodized salt (HHIS) and measurement of urinary iodine concentrations (UICs). The aim of this review is to assess global and regional iodine status in 2012 by using each of these indicators. The most recent national data on HHIS were obtained from UNICEF. The most recent data on UICs, primarily national data in school-age children, were obtained from a systematic literature search, the International Council for the Control of Iodine Deficiency Disorders and the WHO Micronutrients Database. The median UIC was used to classify national iodine status and the UIC distribution to estimate the number of individuals with low iodine intakes. Thirty-two countries are iodine deficient based on the national median UIC. Globally, 29.8% of school-age children (246 million) are estimated to have insufficient iodine intake. Out of 128 countries with HHIS data, 37 countries have salt iodization coverage that meets the international goal of at least 90% of households consuming adequately iodized salt and 39 countries have coverage rates of less than 50%. Overall, ≈70% of households worldwide have access to iodized salt. Iodized salt programs need to be strengthened and extended to reach nearly one-third of the global population that still has inadequate iodine intakes.

Urinary iodine concentrations of pregnant women in Ukraine

Iodine requirements increase during pregnancy and previous studies have reported the inadequate iodine status of pregnant women in areas that have achieved iodine sufficiency in the general population. We examined the urinary iodine (UI) concentrations of pregnant women in Ukraine, where the iodine status is showing improvement among the general population. We enrolled 148 pregnant women<16 weeks pregnant and 80 healthy women as a control group living in Zhitomir, Ukraine. UI concentration, thyroid-stimulating hormone (TSH), antithyroglobulin antibodies (TGAb), and antithyroid peroxidase antibodies (TPOAb) were measured. The median UI concentrations were significantly lower in pregnant women than in control women [13.0 (ND–51.0) μg/L vs. 62.0 (35.3–108.5) μg/L, p<0.001]. TSH concentrations were significantly lower in pregnant women than in control women [1.7 (1.2–2.7) IU/L vs. 2.2 (1.4–3.1) IU/L, p=0.011], but this difference disappeared when adjusted for age (2.1±0.1 IU/L vs. 2.4±0.2 IU/L, p=0.097). The frequency of TSH over 6.2 IU/L and the frequency of positive TGAb and/or TPOAb were not statistically different between groups (p=0.70 and p=0.48, respectively). The UI concentrations of 142 pregnant women (95.9%) were <150 μg/L indicating insufficient iodine intake. The UI concentration of pregnant women in Ukraine revealed severe iodine deficiency. Regular monitoring and appropriate nutrition education are essential because iodine deficiency can be easily prevented by adequate iodine intake. The risk of iodine deprivation during pregnancy needs to be assessed locally over time because it may occur in areas that are not globally recognized as being iodine-deficient.

Iodine deficiency in pregnant women in the apparently iodine‐sufficient capital city of Turkey

Previous studies of the current iodine status in Turkey have yielded contradictory results. Although urinary iodine concentration (UIC) in school age children (SAC) suggests sufficient iodine status, studies on neonatal thyroid-stimulating hormone (TSH) indicate that iodine deficiency is a continuing problem. We aimed to assess the iodine nutritional status of pregnant women living in Ankara, an area that has appeared to be iodine sufficient in earlier studies. Hospital-based, noninterventional, prospective, cross-sectional study. A total of 162 pregnant women in their second trimester were examined regarding iodized salt use, UIC, presence or absence of goitre and thyroid function. Goitre status was determined by palpation. UIC was measured using colorimetric method based on Sandell-Kolthoff reaction. Thyroid hormones and TSH were measured by chemiluminescence immunoassays. While the proportion of iodized salt use was 80·2%, UIC was below 150 μg/l in 72·8% of the women. The median UIC was 80·5 (8·9-340·3) μg/l, indicating insufficient iodine intake. Total goitre rate was 15·4%. Preferential T3 secretion reflected by elevated molar ratios of FT3/FT4 was present in 89·5% of the women. 12·4% had subclinical hypothyroidism or isolated hypothyroxinaemia based on serum TSH and FT4 levels. Our study shows that iodine deficiency is a serious problem among pregnant women in Ankara. These data confirm that iodine nutritional status among SAC does not reflect the iodine supply for pregnant women. We propose that nationwide surveillance studies should urgently be performed to directly assess and monitor the iodine status of pregnant women. We also consider that pregnant women in Turkey should be supplemented by iodine-containing preparations in addition to iodized salt.

Poor knowledge and dietary practices related to iodine in breastfeeding mothers a year after introduction of mandatory fortification

AbstractAim: Public health has refocused attention on low iodine status of vulnerable groups. The purpose of this research was to identify knowledge and dietary practices related to iodine nutrition in breastfeeding women in the Illawarra region following introduction of the mandatory iodine fortification programme.Methods: A cross‐sectional study was undertaken at four early childhood centres. Sixty mothers in their first six months of breastfeeding completed a short knowledge questionnaire, an iodine‐specific food frequency questionnaire, and reported use of nutritional supplements.Results: The women were generally limited in their ability to identify good dietary sources of iodine such as milk and bread but 45 women (75%) correctly identified seafood as a good source. There was some confusion in identifying health problems associated with insufficient iodine intake. Mean reported iodine intake was 146 mg/day (standard deviation: 58 mg; range: 43–342 mg); 48 women (80%) had intakes below the estimated average requirement of 190 mg/day. After allowance was made for fortification of bread, mean iodine intake significantly increased to 182 mg/day (P &lt; 0.001) and the number of women having intakes below the estimated average requirement decreased to 36 (60%). Milk was the highest contributor to iodine intake, on average representing 62% of total iodine consumed. Only 27 (45%) mothers reported consuming supplements that contained iodine.Conclusion: The combination of inadequate knowledge regarding iodine and the limited use of iodine supplements highlights a potential public health issue of concern. However, mandatory fortification may be overcoming this knowledge and behaviour deficit.

Study on the iodine status of pregnant women and thyroid function of neonate in high iodine area

To reveal the iodine status of pregnant women and its impact on thyroid function of neonates in high iodine area. A total of 210 pregnant women were chosen from a hospital in Haixing county, Hebei province. Pregnant women's random urinary and neonates' cord blood were collected. The urinary iodine concentration (UIC) was examined by arsenic-cerium catalytic spectrophotometry. The levels of free triiodothyronine (FT3), free thyroxine (FT4) and sensitive thyroid-stimulating hormone (sTSH) in serum were measured by chemiluminescence. The age of 210 pregnant women was (27.69 +/- 4.73) years old, whose urinary iodine median (inter-quartile range ) was 1240.70 (1292.68) microg/L. 84.3% (177/210) of the pregnant women had excessive iodine intake (UIC > or = 500 microg/L), 13.8% (29/210) had more than adequate iodine intake( UIC within 250 - 499 microg/L), 0.5% (1/210) had adequate iodine intake (UIC within 150 - 249 microg/L) and 1.4% (3/210) had insufficient iodine intake (UIC < 150 microg/L). The average serum level of FT3, FT4 in neonates were (2.93 +/- 0.59), (15.03 +/- 1.92) pmol/L, respectively. The median (inter-quartile range) of serum sTSH in neonates were 7.33 (5.59) mU/L 78.1% (164/210) of the neonates' serum TSH were beyond 5 mU/L. There were no correlation between pregnant women's urinary iodine level and neonates' serum FT3 and sTSH level (P > 0.05), but there was a positive correlation between pregnant women's urinary iodine level and neonates' serum FT4 level (P < 0.01). Serum FT4 level of the neonates with whose mothers had insufficient iodine intake ((12.99 +/- 1.10) pmol/L) were statistically lower than those with their mothers had excessive iodine intake (15.16 +/- 1.83) pmol/L) (P < 0.05). Most of the pregnant women in high iodine area were excessive for iodine nutrition, but still a few pregnant women had insufficient iodine nutrition. The level of neonates' serum sTSH were relatively high and monitoring of risk of hypothyroidism and subclinical hypothyroidism should be strengthened.

Iodine Deficiency: Current Aspects and Future Prospects

Iodine deficiency disorders (IDD) result from inadequate thyroid hormone production due to inadequate iodine intake. It is estimated that 2 billion individuals worldwide have insufficient iodine intake. Iodine deficiency is the most common cause of preventable mental impairment worldwide. The usually recommended strategy to control iodine deficiency is through universal salt iodization and more recently through iodine fortification of flour. Introduction of iodized salt to regions of chronic iodine-deficiency disorders might transiently increase the proportion of thyroid disorders due to iodine excess, but overall the small risks of iodine excess are far outweighed by the substantial risks of iodine deficiency. Food authorities in different countries should be empowered to implement suitable protocols and ensure that effective follow-up procedures are in place, such as those used by the Food Standards in Australia and New Zealand. Future aspects and recommendations are also highlighted in this review.

A robust method for testing urinary iodine using a microtitre robotic system

Project Iodine deficiency disorders are due to inadequate thyroid hormone production and 2 billion individuals worldwide are estimated to have insufficient iodine intake. Laboratory assessment methods include urinary iodine (UI) concentration, blood FT3, FT4, TSH and Thyroglobulin. The aim of this study was to set up a robust method for testing urinary iodine using a microtitre robotic system. Procedure The UI method described is based on the Sandell–Kolthoff reaction, which utilizes the catalytic role of iodine in the reduction of ceric ammonium sulphate in the presence of arsenious acid. This method was automated for use on microtitre robotic system. Results The method was compared with the currently employed manual Sandell–Kolthoff reaction method in our laboratory as reference. The two methods correlated well using weighted Deming regression analysis (slope = 1.066, intercept = 6.5, r = 0.994; n = 211). Interassay and intraassay variations were similar to the reference method, but cost analysis indicated a large reduction in costs related to increased throughput, and reduced consumables and labour. Conclusions We have successfully adapted UI testing to an automated method, permitting cheaper, faster and robust screening of large numbers of patients and populations. The described protocol can be used on different microtitre robotic systems permitting up to 372 patient samples per run for 4 microtitre plate systems.

The Role of the Pediatrician in Preventing Congenital Malformations

The Role of the Pediatrician in Preventing Congenital Malformations

Review of analytical methods for the quantification of iodine in complex matrices

Iodine is an essential element of human nutrition. Nearly a third of the global population has insufficient iodine intake and is at risk of developing Iodine Deficiency Disorders (IDD). Most countries have iodine supplementation and monitoring programs. Urinary iodide (UI) is the biomarker used for epidemiological studies; only a few methods are currently used routinely for analysis. These methods either require expensive instrumentation with qualified personnel (inductively coupled plasma-mass spectrometry, instrumental nuclear activation analysis) or oxidative sample digestion to remove potential interferences prior to analysis by a kinetic colorimetric method originally introduced by Sandell and Kolthoff ∼75 years ago. The Sandell–Kolthoff (S–K) method is based on the catalytic effect of iodide on the reaction between Ce 4+ and As 3+. No available technique fully fits the needs of developing countries; research into inexpensive reliable methods and instrumentation are needed. There have been multiple reviews of methods used for epidemiological studies and specific techniques. However, a general review of iodine determination on a wide-ranging set of complex matrices is not available. While this review is not comprehensive, we cover the principal developments since the original development of the S–K method.

Results from the National Strategy for Improvement of Iodine Nutrition in Bulgaria. A study of children and pregnant women living in an iodine-deficient area

A significant part of Bulgaria is considered an iodine-deficient area. The National Strategy for Prevention and Control of Iodine Deficiency Disorders (IDD) was developed in 1994, and regular surveys undertaken in 2000–2003 indicated a normalization of the iodine supply in the Bulgarian population, including some at-risk population groups (children, schoolchildren, pregnant women). Despite the results achieved, mandating periodic cohort surveys for tracking the elimination of iodine deficiency is necessary. The aim of this study was to evaluate the results of the the national strategy for improvement of iodine nutrition in children and pregnant women living in an iodine-deficient area in Bulgaria 15 years after its update. Study subjects were 73 children aged 9.21 ± 2.07 years (29 boys and 44 girls) and 16 pregnant women living in the town of Asenovgrad. Urinary iodine concentration was measured and used as an index of iodine intake. The median urinary iodine of the inspected children was between 100–199 μg/l, which is an indicator of optimal iodine nutrition. Almost 1/3 of the children (31.5%) had iodine deficiency. The median urinary iodine concentration of the 16 pregnant women investigated was 127.0 μg/l, which is an indicator of insufficient iodine intake. Despite the normalization of the iodine supply in the past years in the at-risk population groups of children and pregnant women, a considerable portion of them still has iodine deficiency. Recommendations for improving health education and iodine nutrition in at-risk population groups were made.