scholarly journals Iodine, Seaweed, and the Thyroid

2021 ◽  
pp. 1-8
Author(s):  
Peter P.A. Smyth

<b><i>Backgound:</i></b> Even a minor iodine deficiency can result in adverse thyroidal health consequences while excess iodine intake can also result in thyroid function disorders. One source of iodine is seaweed which as a foodstuff is enjoying an increasing profile in Western countries. Apart from its potential involvement in thyroidal health, gaseous iodine released from seaweeds plays a significant role in influencing coastal climate through cloud formation. <b><i>Summary:</i></b> Sources of dietary iodine, its assessment, recommended dietary intake, and consequences of iodine excess are outlined. The benefits and possible dangers of dietary intake of iodine-rich seaweed are described. Studies linking seaweed intake to breast cancer prevalence are discussed as is the role of gaseous iodine released from seaweeds influencing weather patterns and contributing to iodine intake in coastal populations. <b><i>Key Messages:</i></b> Universal salt iodization remains the optimum method of achieving optimum iodine status. Promoting increased dietary iodine intake is recommended in young women, in early pregnancy, and in vegan and vegetarian diets. Even where iodine intake is enhanced, regular assessment of iodine status is necessary. Caution against consumption of brown seaweeds (kelps) is required as even small amounts can have antithyroid actions while product labelling may be insufficient. Gaseous iodine produced from seaweeds can have a significant effect on cloud formation and associated global warming/cooling. Increased overall iodine deposition through rainfall and apparent uptake in populations dwelling in seaweed-rich coastal regions may provide a partial natural remedy to global iodine deficits.

F1000Research ◽  
2021 ◽  
Vol 10 ◽  
pp. 858
Author(s):  
Tedson Lukindo ◽  
Ray Masumo ◽  
Adam Hancy ◽  
Sauli E. John ◽  
Heavenlight A. Paulo ◽  
...  

Background: Deficient and excess iodine intake during pregnancy can lead to serious health problems. In Tanzania, information available on iodine status during pregnancy is minimal. The aim of this study was to assess the iodine status and its association with sociodemographic factors in pregnant women in the Mbeya region, Tanzania. Method: A cross sectional survey involving 420 pregnant women (n=420) aged between 15-49 years registered in antenatal care clinics was conducted. Data were collected via interviews and laboratory analysis of urinary iodine concentration (UIC). Results: Median UIC was 279.4μg/L (+/-26.1) to 1915μg/L. Insufficient iodine intake (UIC below 150μg/L) was observed in 17.14% of participants, sufficient intake in 24.29% and 58.57% had intakes above the recommended level (>250μg/L). Rungwe district council (DC) had the highest proportion of patients (27.9%) with low iodine levels, while Chunya and Mbarali DCs had the greatest proportion of those with UIC’s, over the WHO recommended level. Fish consumption and education status were associated with increased risk of insufficient iodine while individuals in Mbalali DC aged between 35-49 years were associated with increased risk of UIC above recommended level. Conclusion: Both deficient and excess iodine intake remains a public health problem, especially in pregnant women in Tanzania. Therefore, educational programs on iodine intake are needed to ensure this population has an appropriate iodine intake to prevent any health risks to the mother and the unborn child.


2018 ◽  
Vol 48 (6) ◽  
pp. 873-885
Author(s):  
Naima Saeid ◽  
Anass Rami ◽  
Samir Mounach ◽  
Abdeslam Hamrani ◽  
Asmaa El Hamdouchi ◽  
...  

Purpose Iodine deficiency has several adverse effects on human growth and development and it is categorized collectively as iodine deficiency disorders (IDDs). Recent estimations showed that 29.8 per cent of school-age children have insufficient iodine intake. Salt iodization is widely accepted as the best method for increasing iodine intake. In 1995, Morocco adopted the universal salt iodization strategy to reduce iodine deficiency and consequently prevent and control IDDs. This study aims to determine the benefit of this strategy on schoolchildren and adolescent by assessing iodine intake and evaluating iodine deficiency. Design/methodology/approach This transversal study was conducted on 131 children and adolescents. Iodine intake was assessed using a food frequency questionnaire. Iodine status was evaluated on 24-h urine samples and the creatinine excretion was used to validate completeness of urine collection. Findings The medians of urinary iodine excretion and concentration were 77 µg/day and 96 µg/L, respectively. Overall, 72.5 per cent are deficient, so mild and moderate iodine deficiencies were reported in 58 per cent and 14.5 per cent, respectively, and no child exhibited severe deficiency. A significant difference was reported between iodine deficiency and, sex and age; iodine deficiency was more pronounced in boys and children under eight years. In this study, iodine status in deficient children does not change with the consumption pattern of dairy products and eggs, and results showed no significant association (p > 0.05). However, fish consumption was significantly associated to urinary iodine concentration = 100 µg/L (p = 0.044). Average UIC in school-aged children is still inadequate and consumption of foods high in iodine remains very insufficient. Therefore, additional efforts must focus on nutritional education of Moroccan school-aged children. Originality/value In the author’s knowledge, this is the first study evaluating schoolchildren iodine status by 24-h iodine collection; the study reported association of iodine deficiency with dietary habit concerning sources of food rich on iodine.


2020 ◽  
Author(s):  
Radhouene DOGGUI ◽  
Myriam El Ati-Hellal ◽  
Jalila El Ati ◽  
Pierre Traissac

Abstract Background In the Middle East and North Africa (MENA) region, universal salt iodization (USI) programs defaults were sometimes shown to increase the risk of iodine excess. Also, the nutrition transition which underlies the obesity epidemic in the MENA region is characterized by salt-rich diets, so that there could be a cumulative effect with respect to iodine status. We assess the within-subject co-existence of overweight and inadequate iodine intake, and associated factors.Methods A national cross-sectional study used a stratified, clustered random sample and conducted among Tunisian school-age children aged from 6 to 12 y. (n = 1560). Overweight (Ow) was body mass index (BMI)-for-age ≥ + 1z. Iodine deficiency was UIC (Urinary Iodine Content) < 100 µg/L and iodine intake above requirements (IAR) UIC ≥ 200 µg/L. Association of covariables with the within-subject double burden Ow–IAR was assessed by multinomial regression.Results The prevalences of Ow-ID or Obe-ID were marginal, but not so for excess adiposity and IAR as for example prevalence of Ow-IAR was 9.8% (95% CI:[7.7–12.3]). OW and IAR were found to co-occur independently (P = 0.29). Socio-economic patterning of Ow-IAR was mild. Nevertheless, prevalence were the lowest among children of mother with no formal schooling and in the South-East region. Beyond school-age children, we estimated that this double burden of overweight and excess iodine could concern a third of Tunisian adults (all the more for women).Conclusions Among Tunisian children, iodine deficiency coupled with excess adiposity was quite marginal. Coexistence of overweight and excess iodine may affect a tenth of these children. More data would be needed to document a possibly even higher rate among adults. Cumulative effects of unhealthy lifestyle due to the nutrition transition interacting with metabolic pathways may be involved in this potential overweight-high iodine intake double burden. In the MENA region, obesity and salt reduction policies should continue to be monitored.


2018 ◽  
Vol 14 (2) ◽  
pp. 100-112

Over the last two decades, there has been remarkable progress towards eliminating iodine deficiency (ID). While there has been remarkable success, there have been several notable changes in the way that salt iodization programs have been designed and monitored, as well as the general landscape in which salt iodization is being implemented. This article is based on the “Guidance on the monitoring of salt iodization programmes and determination of population iodine status”. It summarizes important lessons learned on how to better track the performance of and refine salt iodization programs. The adequacy of iodine intakes should be examined among different subsets of the population (not only school-aged children), especially among groups vulnerable to deficiency (such as pregnant women). The acceptable range of ‘adequate’ iodine intake among school-age children can be widened from 100–199 µg/L to 100–299 µg/L eliminating the range of 200–299 µg/L that previously indicates ‘more than adequate’ iodine intake. The interpretation of mUIC of ≥ 300 µg/L as ‘excessive iodine intake’ remains unchanged. With currently available methods, the mUIC can only be used to define population iodine status and not to quantify the proportion of the population with iodine deficiency or iodine excess. National salt iodization programmes should monitor the use of iodized salt in processed foods. If the salt contained in such foods is well iodized, it can be an important source of iodine and may help explain iodine sufficiency in settings where household iodized salt coverage is low.


2020 ◽  
Vol 79 (OCE2) ◽  
Author(s):  
Katie Nicol ◽  
Cara Swailes ◽  
Layla Alahmari ◽  
Emilie Combet

AbstractIntroduction: Most consumers remain unaware of iodine sources in the diet. With no prophylaxis, iodine insufficiency remains a largely unappreciated issue in the UK. Including seaweed to the food supply represents a solution and opportunity but this supply needs to be carefully curated and calibrated, as excess iodine may be harmful for thyroid health. This project aimed to test the efficacy of a proof-of-concept reformulated food using seaweed as an ingredient source of iodine, to supplement women who have a habitual low iodine intake.Materials and Methods: Self-reported healthy women, pre-menopausal who avoid iodine-rich foods were randomised to: P1) reformulated food (pizza)with seaweed ingredient, or P2) a control food, similar to P1 but without supplemental iodine, or S1) control, empty capsules, or S2) PureSea Natural ascophyllum nodosum seaweed capsules, the ingredient used in P1. Capsules or food were to be consumed three times per week (providing 400μg iodine per intake). At least 10 spot urine samples were collected per person over at least 3 days preceding each study point. Urinary iodine was measured with a modified Sandell-Koltoff assay.Results: Participants (n = 96, median age 29, IQR 23–42) had a habitual iodine intake of 64μg/d (IQR 39–119, no detectable difference between groups). Dropout rates at 3-month were 41% (P1 &P2 each), 21% for S1, 11% for S2.Baseline urinary iodine concentration (UIC) was low/marginal, at 66μg/L (IQR 34-71), 64μg/L (IQR 40-96), 54μg/L (IQR 31-86) and 39μg/L (IQR 21-64) for P1, P2, S1 and S2 respectively (no difference between groups, p > 0.05).Change in UIC differed between groups at week-2 (p < 0.001), increasing in P1 & S2: by 45μg/L (IQR 2-69), and 35μg/L (IQR 13-48), respectively, decreasing in S1: -14μg/L (IQR –24-(–1)), with no change in group P2. This remained true for groups S1 & S2 when urinary iodine excretion was corrected for creatinine.After 3 months, differences in changes from baselines remained between groups (p < 0.01), with an increase in groups P1 and S2: 28μg/L (IQR 1-112), 43μg/L (IQR 23-93) but not groups P2 or S1. This remained true when UIC was corrected for creatinine.Changes in weight between and within groups were not detected at either time points, with group median changes within 2 kg of baseline weight.Discussion: Iodine-rich seaweed is effective in increasing the iodine status of women with a low habitual iodine intake, as a supplement, or as an ingredient in a cooked reformulated product. In term of feasibility, large attrition in the food groups P1 and P2 demands further attention, for interpretation of data and future translation of the findings.


2019 ◽  
Vol 78 (4) ◽  
pp. 554-566 ◽  
Author(s):  
Sanjoy Saha ◽  
Brenda A. Z. Abu ◽  
Yasaman Jamshidi-Naeini ◽  
Upasana Mukherjee ◽  
Makenzie Miller ◽  
...  

Iodine is an essential trace mineral, vital for its functions in many physiological processes in the human body. Both iodine deficiency (ID) and excess are associated with adverse health effects; ID and excess iodine intake have both been identified in sub-Saharan Africa (SSA). The review aims to (1) review the iodine status among populations in SSA until October 2018, and (2) identify populations at risk of excess or inadequate iodine intakes. A systematic search of relevant articles was carried out by a seven-member research team using PubMed, Science Direct and Scopus. A total of twenty-two articles was included for data extraction. Of the articles reviewed, the majority sought to determine the prevalence of iodine status of the study populations; others measured the impact of uncontrolled and unmonitored salt iodisation on iodine excess and tested the effectiveness of water iodisation. Although iodine status varied largely in study populations, ID and excessive iodine intake often coexisted within populations. The implementation of nutrition interventions and other strategies across SSA has resulted in the reduction of goitre prevalence. Even so, goitre prevalence remains high in many populations. Improvements in access to iodised salt and awareness of its importance are needed. The emerging problem of excess iodine intakes, however, should be taken into consideration by policy makers and programme implementers. As excessive iodine intakes may have adverse health effects greater than those induced by iodine deficient diets, more population-based studies are needed to investigate iodine intakes of the different population groups.


2018 ◽  
Vol 14 (2) ◽  
pp. 100-112 ◽  

Over the last two decades, there has been remarkable progress towards eliminating iodine deficiency (ID). While there has been remarkable success, there have been several notable changes in the way that salt iodization programs have been designed and monitored, as well as the general landscape in which salt iodization is being implemented. This article is based on the “Guidance on the monitoring of salt iodization programmes and determination of population iodine status”. It summarizes important lessons learned on how to better track the performance of and refine salt iodization programs. The adequacy of iodine intakes should be examined among different subsets of the population (not only school-aged children), especially among groups vulnerable to deficiency (such as pregnant women). The acceptable range of ‘adequate’ iodine intake among school-age children can be widened from 100–199 µg/L to 100–299 µg/L eliminating the range of 200–299 µg/L that previously indicates ‘more than adequate’ iodine intake. The interpretation of mUIC of ≥ 300 µg/L as ‘excessive iodine intake’ remains unchanged. With currently available methods, the mUIC can only be used to define population iodine status and not to quantify the proportion of the population with iodine deficiency or iodine excess. National salt iodization programmes should monitor the use of iodized salt in processed foods. If the salt contained in such foods is well iodized, it can be an important source of iodine and may help explain iodine sufficiency in settings where household iodized salt coverage is low.


2020 ◽  
Author(s):  
Neda Milevska Kostova ◽  
Borislav Karanfilski ◽  
Daniela Miladinova ◽  
Sonja Kuzmanovska ◽  
Biljana Chuleva ◽  
...  

AbstractMany studies have shown that socio-economic status (SES) contributes to health inequalities, with nutrition as one of the major risk factors. Iodine intake entirely depends on external sources, and deficiencies are known to be more prevalent in lower social groups, especially in countries with limited access to iodized salt. This study aimed to determine the influence of SES on iodine status and iodine availability from household salt in North Macedonia. Using cluster sampling, 1,200 children were recruited, and 1,191 children participated (response rate: 99.2%). Iodine status was assessed through urinary iodine concentration (UIC), and iodine availability through iodine content in household salt requested from participants. SES was assessed using standardized Family Affluence Score (FAS). No statistically significant correlation was found between FAS and iodine in salt. Median regression revealed no significant associations of middle vs. low FAS (β=0.00; 95%-confidence interval (CI)=[−0.61, 0.62]; p=0.999) or high vs. low affluence (β=0.48; 95%CI=[−1.37, 0.41]; p=0.291) with iodine content in household salt. UIC levels were significantly lower in middle FAS children compared to low FAS children (β=-16.4; 95%CI=[−32.3,-0.5]; p=0.043). No statistically significant differences in UIC were found between children with high and low affluence (β=-12.5; 95%CI=[−35.5, 10.5]; p=0.287), possibly due to lowered statistical power for this comparison. Universal salt iodization (USI) proves to be cost-effective measure for appropriate iodine intake in healthy children and adults, irrespective of their social status. It can thus be concluded that USI contributes to reducing health inequalities related to iodine status among population of different social strata.


Nutrients ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1529
Author(s):  
Roberto Iacone ◽  
Paola Iaccarino Idelson ◽  
Pietro Formisano ◽  
Ornella Russo ◽  
Cinzia Lo Noce ◽  
...  

Monitoring the population iodine status is essential for iodine deficiency eradication. This study assessed the average dietary iodine intake and the iodine status of a random sample of the Italian general adult population. The study population included 2378 adults aged 35–79 years (1229 men and 1149 women) from all 20 Italian regions, participating in the Osservatorio Epidemiologico Cardiovascolare/Health Examination Survey 2008–2012 (OEC/HES), and were examined for iodine intake in the framework of the MINISAL-GIRCSI Programme. Dietary iodine intake was assessed by the measurement of 24 h urinary iodine excretion. The median daily iodine intake of the whole population was lower (96 µg/d, interquartile range 51–165) than the daily adequate iodine intake according to both EFSA and WHO recommendation (150 µg/d), with a significantly lower value among women (85 µg/d) compared with men (111 µg/d). Iodine intake diminished with age and increased with BMI (body mass index) in male but not in female participants, without achieving the adequate intake in any sex, age, or BMI category. In this random sample of Italian general adult population examined in 2008–2012, iodine intake still remained lower than the recommended values despite the implementation of a strategy of iodoprophylaxis based on salt iodization in 2005. These data represent a valuable reference for future monitoring of iodine status in our country.


Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.


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