High Iodine Intake Research Articles

The role of iodine in thyroid function and iodine impact on the course of Hashimoto’s thyroiditis - review

Introduction: Iodine is one of the most important micronutrients necessary for the proper functioning of the thyroid gland. It is an essential component of thyroxine and triiodothyronine, hormones produced and secreted by the thyroid gland. Severe iodine deficiency impairs thyroid hormone synthesis and can lead to gland enlargement. This deficiency results in various disorders collectively termed iodine deficiency disorders. Not only iodine deficiency but also excess iodine intake can be harmful and affect thyroid function. Doses of iodine above physiological levels can result in both hypothyroidism and hyperthyroidism. Numerous studies have linked chronic high iodine intake to an increased frequency of autoimmune thyroiditis. This review examines the mechanisms of iodine regulation and the role of excess iodine can play in the development of Hashimoto’s thyroiditis. Aim of the study: The aim of the study is to present and summarize the role of iodine in thyroid function and its impact on the course of Hashimoto’s thyroiditis. This review explains the potential increased risk of thyroid autoimmune disorder connected with iodine over-supplementation. Materials and Methods: For this current literature review, the important studies published from 1986-2024 in PubMed database was searched. The literature available in the PubMed database was reviewed with the following keywords: iodine, Hashimoto’s thyroiditis, autoimmune thyroiditis. Conclusion: Iodine is crucial for thyroid health and fetal development, but its excessive intake can be harmful. Maintaining optimal levels of this microelement is essential to prevent both iodine deficiency and autoimmune disorders. Iodine supplementation is recommended only for pregnant and lactating women.

Too Much Too Little: Clarifying the Relationship Between Maternal Iodine Intake and Neurodevelopmental Outcomes

BackgroundIn 2009, the Australian government mandated the fortification of bread salt with iodine. In 2010, pregnant and lactating women were also advised to take an iodine-containing supplement. Our assessment of this policy in an iodine-sufficient population showed that children whose mothers were in the highest and lowest quartiles of iodine intake performed more poorly on early childhood tests of cognition and language than those in the second quartile. However, we did not quantify the iodine intake associated with optimal neurodevelopment. ObjectivesThe aim was to establish the iodine intake range in pregnancy associated with optimal child neurodevelopment. MethodsA prospective cohort study of pregnant women and their young children (n = 699). Iodine intake was assessed by a validated food frequency questionnaire at 16 and 28 wk of gestation. Child neurodevelopment at 18 mo of age was measured using the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III). The relationship between average iodine intake during pregnancy and child neurodevelopment was assessed using linear regression with fractional polynomials and adjustment for confounders. ResultsMean (SD) iodine intake was similar at study entry and 28 wk, 308 (120) μg/d, with 82% of women taking iodine supplements at study entry. The relationship between iodine intake during pregnancy and Bayley-III cognitive and language scores was curvilinear (P = 0.001 and P = 0.004, respectively), with the lowest Bayley-III scores observed at lower and higher iodine intakes. The inflection point that drove the association between lower iodine intake in pregnancy and poorer child neurodevelopment scores was around 185 μg/d; for the higher pregnancy iodine intakes, language and cognitive scores were negatively affected from ∼350 μg/d to 370 μg/d, respectively. Higher iodine intakes were being driven by supplement use. ConclusionsTargeted, not blanket, iodine supplementation may be needed for pregnant women with low-iodine intake from food.

Association between iodine nutrition and cervical lymph node metastasis of papillary thyroid microcarcinoma.

We aimed to investigate the association between iodine intake and nodal metastasis stratified by central lymph node metastasis (CLNM) and lateral lymph node metastasis (LLNM) of papillary thyroid microcarcinoma (PTMC). Urinary iodine concentration (UIC) and clinicopathological characteristics were used to identify factors associated with CLNM and LLNM using logistic regression analysis. A sum of 3,858 PTMC patients were enrolled. The median UIC (MUI) of patients with CLNM or LLNM was not statistically different from those without nodal metastasis. Male patients had a higher MUI than females (183.4 μg/L vs. 173.6 μg/L). Female patients with extracapsular extension had a higher MUI than those without it (210.0 μg/L vs. 172.1 μg/L). Male patients with LLNM had a significantly lower MUI than those without LLNM (134.7 μg/L vs. 187.9 μg/L). Female patients with more than adequate iodine intake were more likely to present with CLNM and extrathyroidal extension than those with adequate iodine intake with an odds ratio (95% confidence interval) of 1.23 (1.01-1.51) and 1.59 (1.09-2.32) after adjustment. Iodine nutrition was not found to be associated with LLNM. In addition, patients with a younger age, larger tumors, extrathyroidal extension, and intrathyroidal spread were more likely to be CLNM, whereas nodular goiter presented with a protective factor; CLNM was the only factor associated with LLNM of PTMC in both genders. In conclusion, iodine nutrition has a much closer association with female than male patients, and high iodine intake may be associated with CLNM and extrathyroidal extension in female PTMC patients.

Temporal variation of iodine in Danish groundwater

Iodine is an essential element for human health, and both high and low iodine intake could have negative health outcomes. The spatial variation of iodine in Danish groundwater has been studied before, but to the author’s knowledge, this is the first time that the temporal variation is characterised. Nationwide data from the Danish groundwater monitoring programme (GRUMO) were analysed between 2011 and 2021, including 2924 samples from 1242 well screens at 893 wells. The sampling frequency varied and so the robust coefficient of variation (rCV) was calculated for 930 (75%) of well screens, and time-series analysis was performed for 23 (2%). Key findings are (1) iodine in Danish groundwater varies over time (0–124%, median = 10%), (2) in one quarter of the well screens rCV exceeds 20% and (3) this variation cannot be attributed solely to analytical uncertainty at 14% of the well screens. The impact of temporal variation of iodine in Danish drinking water of groundwater origin should be evaluated in future exposure or epidemiological studies with respect to the study goal, location and time period. Since the temporal variation could not be quantified over the entire concentration range, monitoring of iodine in Danish groundwater should continue.

Seaweed as food: survey of the UK market and appraisal of opportunities and risks in the context of iodine nutrition

Purpose Seaweeds are gaining broader interest in Western societies through their use in product development and the health-food industry. High nutritional value, low carbon footprint and sustainability are key drivers for seaweed uptake in Europe; yet high iodine intake from seaweed remains a concern. This study seeks to identify seaweed food products available on the UK retail market between 2018 and 2021 and assess their safety in the context of iodine exposure.Design/methodology/approach Here, a market survey (n = 37–40 retailers) was conducted in three annual waves to evaluate seaweed food product availability in the UK. The iodine dose of products was estimated based on a comprehensive literature review of seaweed iodine content.Findings This study shows a young, dynamic market with 2.3-fold increase in seaweed food product availability since the last available published data (2015). Specific iodine content labelling remains uncommon, and median iodine doses in a single serving of food exceeded 400 µg in all years. Some products, especially seaweed supplements, provide iodine doses above the tolerable upper limit and upper level of tolerance.Originality/value This study presents the most contemporary and comprehensive overview of the market for seaweed food products in the UK. With increasing popularisation of seaweed as a food, this study highlights the need for improved dialogue amongst producers, retailers, legislators and public health specialists to address the risk of iodine excess, and the concurrent scope for processing methods to reduce the iodine content in seaweeds.

Prenatal iodine supplementation and early childhood neurodevelopment: the PoppiE trial – study protocol for a multicentre randomised controlled trial

IntroductionObservational studies suggest both low and high iodine intakes in pregnancy are associated with poorer neurodevelopmental outcomes in children. This raises concern that current universal iodine supplement recommendations for pregnant...

High dietary iodine intake may contribute to the low death rate from COVID-19 infection in Japan with activation by the lactoperoxidase system.

We draw the attention of readers and governments to the death rate from coronavirus disease 2019 in Japan, continuing as a fraction of that experienced by many other developed nations. We think this is due to the activity of the powerful, protective lactoperoxidase system (LPO) which prevents serious airborne infections. The LPO system requires iodine, which is liberally provided by the typical Japanese diet but lacking in many others. One might consider the Japanese experience an incredibly large, open-label study exhibiting the preventative power of a high-iodine diet. We predict this favourable trend will continue for Japan because deadly variants of the severe, acute respiratory syndrome coronavirus 2 will be with us, forever.

IL-9-Producing Th9 Cells Participate in the Occurrence and Development of Iodine-Induced Autoimmune Thyroiditis.

Iodine excess may cause and aggravate autoimmune thyroiditis (AIT), which is regarded as a typical kind of autoimmune disease mainly mediated by CD4+ T cells. Thus far, it is unclear whether T helper (Th) 9 cells, a novel subpopulation of CD4+ T cells, play a potential role in AIT. Therefore, in the present study, changes in Th9 cells were detected in murine models of AIT induced by excess iodine intake to explore the possible immune mechanism. Female C57BL/6 mice were divided into 7 groups (n = 8) and were supplied with water containing 0.005% sodium iodide for 0, 2, 4, 6, 8, 10, and 12weeks. With the extension of the high-iodine intake duration, the incidence of thyroiditis and the spleen index were significantly increased, and serum thyroglobulin antibody (TgAb) titers and interleukin 9 (IL-9, major cytokine from Th9 cells) concentrations were also increased. Additionally, it was revealed that the percentages of Th9 cells in spleen mononuclear cells (SMCs) and thyroid tissues were both markedly elevated and accompanied by increased mRNA and protein expression of IL-9 and key transcription factors of Th9 cells (PU.1 and IRF-4). Significantly, dynamic changes in Th9 cells were found, with a peak at 8weeks after high iodine intake, the time point when thyroiditis was the most serious. Importantly, Th9 cells were detected in the areas of infiltrating lymphocytes in thyroid sections. In conclusion, the continuously increasing proportions of Th9 cells may play an important role in the occurrence and development of AIT induced by high iodine intake.

Iodine Status in Pregnant Women Having Urinary Fluoride in Contaminated Areas: A Case Study of Phayao Province.

Fluoride naturally occurs in the Earth's crust and is widely dispersed in groundwater. The high consumption of fluoride can inhibit iodine metabolism in the human body, especially in the thyroid gland. This study assessed iodine knowledge, iodine consumption behavior, urinary iodine (UI), thyroid stimulating hormone (serum TSH), and free triiodothyronine3 (serum FT3) and examined the connection between fluoride exposure and UI and thyroid function as serum concentrations of TSH and FT3 in pregnant women dwelling in an area of endemic fluorosis. This was a cross-sectional study. The population included 152 pregnant women within the 1st trimester of pregnancy, during which they were provided antenatal care (ANC) in seven public community hospitals in Phayao province, Thailand. The study consisted of two components. First, the study consisted of a questionnaire in which we evaluated the iodine knowledge and iodine consumptive behaviors in subjects. Second, biochemical data were investigated to evaluate thyroid function in the subjects. The gestational age of most subjects was 8-12 weeks. The study population has lived in fluoride-contaminated areas since birth (76.97%). The iodine and iodine consumption levels were moderate (50.00%). Their food iodine consumption was 3-4 days/week, and the top five consumption ranks were iodized salt, cooked pork, eggs, sticky rice, and iodine fish sauce. In terms of biochemical parameters, 63.16% of respondents had UI levels below 150.00 g/L, which is below the normal reference range of 150.00-249.00 g/L. 89.47% of the risk of hypothyroidism was associated with serum TSH levels below 2.50 g/L. In 38.16% of the samples, normal levels of serum FT3 (2.00-4.40 pg/L) were identified in the subjects. In addition, 61.84% of the samples had FT3 concentrations greater than 4.40 pg/L (high intake of iodine). The approved association between positive serum FT3 data and serum TSH was positive (r = 260 and p < 0.05). These studies imply that these elevated levels of TSH and FT3 place pregnant women in their first trimester at risk for hypothyroidism.

Association between Elevated Iodine Intake and IQ among School Children in Portugal.

The goal of this work was to examine whether elevated iodine intake was associated with adverse effects on IQ among school-age children in Portugal. In a representative sample of children from the north of the country, IQ percentiles by age (assessed with Raven's Colored Progressive Matrices) were dichotomized to &lt;50 ("below-average" IQs) and ≥50. Morning urine iodine concentrations, corrected for creatinine, were dichotomized to &lt;250 µg/g and ≥250 µg/g, according to the European Commission/Scientific Committee on Food's tolerable upper level of daily iodine intake for young children. Data were examined with Chi-square tests, logistic regression, and GLM univariate analysis. The sample (N = 1965) was classified as generally iodine-adequate (median urinary iodine concentration = 129 µg/L; median iodine-to-creatinine ratio = 126 µg/g) according to the WHO's criteria. A greater proportion of children in the ≥250 µg/g group had below-average IQs, compared to children with less than 250 µg/g (p = 0.037), despite a sizable (though non-significant) proportion of children in the less-than-250 µg/g group also presenting below-average IQs, at the bottom of the iodine distribution (&lt;50 µg/g). The proportion of below-average IQs increased with increasingly elevated iodine concentrations (p = 0.047). The association remained significant after the adjustment for confounders, with the elevated iodine group showing increased odds of having below-average IQs when compared with the non-elevated iodine group (OR 1.55; 95% CI 1.11-2.17; p = 0.011). Consistently, the former group presented a lower mean IQ than the latter (p = 0.006). High iodine intake was associated with lower IQs even in a population classified as iodine-adequate. These results bear on child cognition and on initiatives involving iodine supplementation.

Prevalence of Excessive Iodine Intake in Pregnancy and Its Health Consequences: Systematic Review and Meta-analysis.

The objective was to estimate the prevalence of excessive iodine intake in pregnant women and to investigate the consequences for maternal-fetal health. The systematic review was based on PRISMA. The search was conducted in September 2021 in LILACS, PubMed/MEDLINE, Science Direct, and SCOPUS databases. Observational studies that assessed excessive nutritional iodine status in pregnancy diagnosed by urinary iodine concentration and associated it with biomarkers of thyroid health function were included. Study selection, data extraction, and risk of biased evaluation were performed independently. Meta-analysis was calculated using a fixed and random effect model, and heterogeneity was assessed by the chi-square test. Meta-regressions were performed to identify the causes of heterogeneity using the Knapp and Hartung test. Nine studies were included in the systematic review, and eight in the meta-analysis. The prevalence of excessive iodine intake in 10,736 pregnant women in different regions of the world was 52%. The main implications for pregnant women were hypothyroxinemia, hypothyroidism, and hyperthyroidism. For the newborn, macrosomia and thyroid dysfunction. In addition, drinking water with high iodine intake contributed to excessive iodine intake. Therefore, the prevalence of iodine excess was 52%, with high heterogeneity among studies, explained by trimester of gestation and FT4 level; therefore, the farther the trimester of gestation and the lower the FT4, the higher the prevalence of iodine excess. PROSPERO Registration: CRD420206467 ( https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=206467 ).

Databases of Iodine Content of Foods and Dietary Supplements–Availability of New and Updated Resources

The iodine status of the U.S. population is adequate overall, but some people might have insufficient or overly high iodine intakes and would benefit from certain dietary changes. Identifying these individuals can be challenging, however, due to a lack of data on the iodine content of foods and dietary supplements. To fill this gap, a new online database--the USDA, FDA, and ODS-NIH Database for the Iodine Content of Common Foods--was released in 2020. It contains about 430 foods and beverages, such as dairy products and eggs, baby foods, vegetables, meats, mixed dishes, juices, seafood, various types of salt, restaurant foods, and baked goods, including breads made with and without iodate-containing dough conditioners. Data are presented as mean iodine content for both standard serving sizes and per 100 g of food, along with standard deviations, value ranges, and sample sizes. The new database, combined with the existing Dietary Supplement Ingredient Database, which contains chemically analyzed values for the iodine content of dietary supplements, and the newly updated Dietary Supplement Label Database, which contains label information from thousands of dietary supplements on the market, provides comprehensive data to help assess the iodine intakes of individuals and populations.

Incidence of TPOAb over a 4-year follow-up period: results from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Although some previous data have suggested a high iodine intake in Brazil, the prevalence of antithyroperoxidase antibodies (TPOAb) in the country is compatible with rates from countries with adequate iodine intake. This observation emphasizes the importance of knowing the incidence of TPOAb in Brazil. This prospective analysis included euthyroid participants with negative TPOAb at baseline and a thyroid function assessment at a 4-year follow-up. TPOAb was measured by electrochemiluminescence and considered positive when titers were ≥34 IU/mL. TSH and free T4 (FT4) levels were determined by a third-generation immunoenzymatic assay. The incidence of TPOAb is expressed in percentage per year or as a cumulative incidence within the 4-year follow-up period. Of 8,922 euthyroid participants (mean age 51.1 years; 50.9% women) with a negative TPOAb test at baseline, 130 presented incident TPOAb at the 4-year follow-up, yielding an annual incidence of TPOAb of 0.38%/year (95% confidence interval [95% CI], 0.37-0.39%/year) and a cumulative incidence over 4 years of 1.46% (95% CI, 1.21-1.71%). In men, the annual incidence was 0.32% (95% CI, 0.31-0.33%), and the cumulative incidence over 4 years was 1.23% (95% CI, 0.90-1.56%). In women, the annual incidence was 0.43%/year (95% CI, 0.42-0.44%/year) and the cumulative incidence over 4 years was 1.67% (95% CI, 1.30-2.04%). The only factor associated with incident TPOAb was the occurrence of thyroid diseases at follow-up. No differences in TPOAb incidence were detected across ELSA-Brasil research centers. Based on the results of this study, the incidence of TPOAb per year and at a 4-year follow-up period are compatible with those of a country with adequate iodine intake.

Adaptation to a High Iodine Intake in Greenland Inuit Suggested by Thyroid Disease Pattern.

Objective: Arctic living is influenced by cold winters, short summers, and excessive iodine intake from the traditional Inuit diet providing for habitation of the Arctic for centuries. This is changing and we surveyed thyroid function in populations living in Greenland. Design: Population-based cross-sectional study. Methods: Data were collected in the capital city in West Greenland and in rural East Greenland. Information on lifestyle, dietary habits, and medical history was obtained using questionnaires. Thyrotropin, free thyroxine, free triiodothyronine, thyroglobulin, and thyroglobulin antibody were measured in serum, iodine, and creatinine in spot urine samples. Results: One percent of the Greenlandic population was invited and 535 participated with an overall participation rate of 95%. Iodine excretion was 225 μg/24 hours in East Greenland and 169 μg/24 hours among West Greenland Inuit. Hyperthyroidism occurred in 10.7% of West Greenlandic Inuit (men/women: 4.3%/16.3%) and 7.8% of East Greenlandic Inuit (3.8%/12.8%). Hypothyroidism was found in 2.7% in West Greenland (0.0%/5.0%) and 5.6% (5.6%/5.6%) in East Greenland. Conclusion: Hyperthyroidism was frequent among Inuit and the occurrence of hypothyroidism was low. The pattern of hyper- and hypothyroidism among Greenlandic Inuit with adequate iodine intake was comparable with those seen in populations with iodine deficiency. Inuit may thus have adapted to excessive iodine intake over centuries, causing a need for a higher iodine intake to prevent iodine deficiency disorders.

Age-specific thyrotropin references decrease over-diagnosis of hypothyroidism in elderly patients in iodine-excessive areas.

Acute or chronic exposure to excess iodine has detrimental effects on thyroid physiology; therefore, this study aimed to determine the prevalence of overt hypothyroidism (OH) and subclinical hypothyroidism (SCH) in an elderly population residing in geographical areas with chronic exposure to excess iodine intake and to analyse contributing risk factors. This cross-sectional study was conducted from 2016 to 2017 in areas of Jiangsu Province that have documented chronic exposure to high iodine intake. We enroled 2559 adult participants using a multistage, stratified sampling method. Urinary iodine concentration (UIC), serum thyroid-stimulating hormone (TSH) level and other relevant parameters were measured. Demographic information was recorded using a standardized questionnaire. The age-specific TSH references were determined by the National Academy of Clinical Biochemistry guidelines. Univariate and multivariate logistic regression analyses were performed to identify risk factors for hypothyroidism in the study population. The median UIC of participants was 307.3 µg/L (interquartile range: 200.7, 469.8 μg/L). The prevalence of OH in subjects ≥70 years using laboratory reference ranges was 2.37%; however, it decreased to 1.78% with the use of an age-specific reference range. Similarly, the prevalence of SCH also declined drastically from 29.59% to 2.96% with the application of an age-specific reference range. In both univariate and multivariate models, advanced age, female gender and high UIC were identified as risk factors for hypothyroidism. Usage of age-specific TSH reference ranges led to a significantly lower prevalence of OH and SCH in the study population, thus preventing unnecessary over-diagnosis and over-treatment.

Аутоиммунный тиреоидит и пищевые факторы

Аутоиммунный тиреоидит (АИТ) считается самым распространенным аутоиммунным заболеванием. В настоящее время признано, что генетическая восприимчивость, факторы окружающей среды и иммунные расстройства способствуют его развитию. Что касается пищевых факторов, данные свидетельствуют о высоком уровне потребления йода, дефиците селена и железа с потенциальной значимостью статуса витамина D. Для выяснения роли факторов питания в риске, патогенезе и лечении АИТ использованы источники PubMed относительно йода, железа, селена, витамина D, мио-инозитола и лечения АИТ. Хроническое воздействие чрезмерного потребления йода индуцирует аутоиммунный тиреоидит отчасти потому, что йодированный тиреоглобулин (Tg) более иммуногенный. Селенопротеины необходимы для поддержания функционального состояния щитовидной железы. Существуют данные рандомизированных конт­ролируемых исследований, что селен/селенопротеины могут уменьшить титры антител к тиреоидной пероксидазе (ТПО) у больных гипотиреозом и послеродовым тиреоидитом. У больных АИТ часто наблюдается дефицит железа, поскольку аутоиммунный гастрит, который ухудшает всасывание железа, является довольно частым сопутствующим заболеванием. В последние годы возникли доказательства, указывающие на положительную роль витамина D, включая пролиферацию и дифференциацию нормальных и раковых клеток, сердечно-сосудистую функцию и иммуномодуляцию. Дефицит витамина D особенно продемонстрирован у больных АИТ. У пациентов с АИТ обнаружен более низкий уровень витамина D, чем у лиц из контрольной группы, и сообщается об обратной зависимости содержания сывороточного витамина D от титра антител к ТПО/Tg. Адекватное потребление селена является жизненно важным в районах дефицита/избытка йода, а в регионах с низким потреблением селена может быть целесо­образным добавление 50–100 мкг/день селена. Мио-инозитол и селен способны восстановить эутиреоидное состояние, а также улучшить самочувствие у больных АИТ с субклиническим гипотиреозом. Принимая во внимание также безопасность использования двух молекул, отсутствие побочных эффектов, комбинацию мио-инозитола и селена можно считать очень эффективной и безопасной терапией для лечения АИТ.

Effects of iodine excess on serum thyrotropin-releasing hormone levels and type 2 deiodinase in the hypothalamus of Wistar rats.

Iodine is an important element in thyroid hormone biosynthesis. Thyroid function is regulated by the hypothalamic-pituitary-thyroid axis. Excessive iodine leads to elevated thyroid-stimulating hormone (TSH) levels, but the mechanism is not yet clear. Type 2 deiodinase (Dio2) is a Se-containing protease that plays a vital role in thyroid function. The purpose of this study was to explore the role of hypothalamus Dio2 in regulating TSH increase caused by excessive iodine and to determine the effects of iodine excess on thyrotropin-releasing hormone (TRH) levels. Male Wistar rats were randomised into five groups and administered different iodine dosages (folds of physiological dose): normal iodine, 3-fold iodine, 6-fold iodine, 10-fold iodine and 50-fold iodine. Rats were euthanised at 4, 8, 12 or 24 weeks after iodine administration. Serum TRH, TSH, total thyroxine (TT4) and total triiodothyronine (TT3) were determined. Hypothalamus tissues were frozen and sectioned to evaluate the expression of Dio2, Dio2 activity and monocarboxylate transporter 8 (MCT8). Prolonged high iodine intake significantly increased TSH expression (P < 0·05) but did not affect TT3 and TT4 levels. Prolonged high iodine intake decreased serum TRH levels in the hypothalamus (P < 0·05). Dio2 expression and activity in the hypothalamus exhibited an increasing trend compared at each time point with increasing iodine intake (P < 0·05). Hypothalamic MCT8 expression was increased in rats with prolonged high iodine intake (P < 0·05). These results indicate that iodine excess affects the levels of Dio2, TRH and MCT8 in the hypothalamus.

Effects of Daily Kelp (Laminaria japonica) Intake on Body Composition, Serum Lipid Levels, and Thyroid Hormone Levels in Healthy Japanese Adults: A Randomized, Double-Blind Study.

To investigate whether supplementation with iodine-reduced kelp (Laminaria japonica) powder decreases body fat composition in overweight Japanese subjects, a randomized, double-blind, placebo-controlled intervention study was conducted in 50 Japanese subjects with body mass index (BMI) ≥25 and <30 kg/m2. Subjects were randomly assigned to consume thirty tablets/d (10 tablets orally, 3 times/d) containing either iodine-reduced kelp powder (test, 6 g kelp powder corresponding to 3 g alginate/d) or kelp-free powder (placebo) for 8 weeks. Anthropometric measurements, blood lipids, and serum thyroid hormone levels were obtained before and after the trial. Body fat percentage was significantly decreased in male subjects from the test group compared with the placebo group. The same tendency was observed for body weight (p = 0.065) and BMI (p = 0.072) in male subjects. No significant changes in anthropometric measurements or visceral fat area were observed in female subjects. Serum thyroid hormone concentrations did not increase after 1.03 mg/d of iodine supplementation through kelp intake. The intake of iodine-reduced kelp powder led to significant and safe reductions in body fat percentage in overweight male subjects. The consumption of kelp high in alginate may contribute to preventing obesity without influencing thyroid function in Japanese subjects with a relatively high intake of iodine from seaweed.

Kirenol inhibited the cell survival and induced apoptosis in human thyroid cancer cells by altering PI3K/AKT and MAP kinase signaling pathways.

The thyroid cancer, especially papillary thyroid cancers are very common among population with high intake of iodine or iodine uptake. Even though several treatment options are available, there is still complication and side effects are still persistent. The role of signaling molecules in cancer signaling is very vast and their significance in progression of disease was increasing which leads to mortality of the patient. The major key players are PI3K, AKT and MAP kinase, involves in cell survival, proliferation, and inhibition of apoptosis and are the promising candidate for cancer treatment target, several researchers focuses these molecule to treat various acute and chronic diseases like cancer. On the other side, various literatures propose that natural compounds derived from plant source are shown potent anticancer property against several cancers. In our study we are looking in to one such active principle obtained from plant source, a diterpenoid compound kirenol, and its role thyroid cancer. Here, we report that kirenol role on various cellular mechanisms like induction of apoptosis, enhancing ROS indirectly by inhibiting antioxidants, altering the signaling mechanism of cell survival and apoptosis. Our study proposes that kirenol involved in the cancer cell cytotoxicity by inducing apoptosis and inhibition of cancer cell survival. Thus, targeting this signaling molecule with kirenol definitely favors and may lead to a therapeutic modality for thyroid cancer.

Consumption of multiple micronutrients or small-quantity lipid-based nutrient supplements containing iodine at the recommended dose during pregnancy, compared with iron and folic acid, does not affect women's urinary iodine concentration in rural Malawi: a secondary outcome analysis of the iLiNS DYAD trial.

Inadequate iodine intake during pregnancy increases the risk of neonatal morbidity and mortality. We aimed to evaluate whether prenatal supplements containing iodine affect urinary iodine concentrations (UIC) of pregnant women in Malawi. A randomised controlled trial. Pregnant women (n 1391) were assigned to consume 60 mg/d Fe and 400 µg/d folic acid (IFA) or 18 vitamins and minerals including 250 µg/d iodine (MMN) or 20 g/d small-quantity lipid-based nutrient supplements (SQ-LNS) with similar nutrient contents as MMN group, plus macronutrients (LNS) until childbirth. In a sub-study (n 317), we evaluated group geometric mean urinary iodine concentration (UIC) (µg/L) at 36 weeks of gestation controlling for baseline UIC and compared median (baseline) and geometric mean (36 weeks) UIC with WHO cut-offs: UIC < 150, 150-249, 250-499 and ≥500 reflecting insufficient, adequate, above requirements and excessive iodine intakes, respectively. Mangochi District, Malawi. Women ≤20 weeks pregnant. Groups had comparable background characteristics. At baseline, overall median (Q1, Q3) UIC (319 (167, 559)) suggested iodine intakes above requirements. At 36 weeks, the geometric mean (95 % CI) UIC of the IFA (197 (171, 226)), MMN (212 (185, 243)) and LNS (220 (192, 253)) groups did not differ (P = 0·53) and reflected adequate intakes. In this setting, provision of supplements containing iodine at the recommended dose to pregnant women with relatively high iodine intakes at baseline, presumably from iodised salt, has no impact on the women's UIC. Regular monitoring of the iodine status of pregnant women in such settings is advisable. Clinicaltrials.gov identifier: NCT01239693.