scholarly journals Excess iodine intake: sources, assessment, and effects on thyroid function

Author(s):  
Jessica Farebrother ◽  
Michael B. Zimmermann ◽  
Maria Andersson
Thyroid ◽  
1990 ◽  
Vol 1 (1) ◽  
pp. 69-72 ◽  
Author(s):  
ORLO H. CLARK

Thyroid ◽  
2018 ◽  
Vol 28 (9) ◽  
pp. 1198-1210 ◽  
Author(s):  
Jessica Farebrother ◽  
Michael B. Zimmermann ◽  
Fatma Abdallah ◽  
Vincent Assey ◽  
Ralph Fingerhut ◽  
...  

1987 ◽  
Vol 116 (1_Suppl) ◽  
pp. S70-S76 ◽  
Author(s):  
Lewis E. Braverman ◽  
Terri Paul ◽  
Walter Reinhardt ◽  
Michael C. Appel ◽  
Elsie M. Allen

Abstract. Spontaneous LT and elevated serum anti-Tg occur in the diabetes prone BB/W rat, but thyroid function is essentially normal in the rats with LT. Prolonged low dose MMI decreases the incidence of LT in BB/W rats. The administration of excess iodine beginning at 30 days of age markedly accelerates the occurrence of LT and anti-Tg at 90 days of age. Low iodine intake decreases the incidence of LT. Excess iodine intake did not induce LT in W-line, Wistar-Furth, and SpragueDawley rats. This suggests that iodine induced LT occurs only in genetically susceptible rats. Despite the increased incidence of LT during iodine administration, thyroid function remains essentially normal. This is in contrast to the frequent induction of hypothyroidism following iodine administration to euthyroid patients with Hashimoto's thyroiditis. In order to decrease thyroid reserve, rats were hemiTX at 30 days of age. The administration of iodine markedly increased the incidence of LT and serum anti-Tg, increased the weight of the remaining lobe, and induced hypothyroidism as determined by significantly lower serum T4 and T3 concentrations and elevated serum TSH concentrations. Excess iodine administration to hemi-TX W-line rats (genetically equivalent, non-diabetes, non-LT prone BB/W rats) did not induce LT but did induce hypothyroidism, suggesting that BB/W and W-line rats are susceptible to iodine induced hypothyroidism, perhaps unrelated to the induction of LT. Excess iodine did not induce LT or affect thyroid function in hemi-TX Wistar-Furth and Sprague-Dawley rats.


2021 ◽  
pp. 1-30
Author(s):  
Ying Sun ◽  
Xin Du ◽  
Zhongyan Shan ◽  
Weiping Teng ◽  
Yaqiu Jiang

Abstract Iodine is an important element in thyroid hormone biosynthesis. Thyroid function is regulated by the hypothalamic-pituitary-thyroid axis (HPT). Excessive iodine leads to elevated thyroid stimulating hormone (TSH) levels, but the mechanism is not yet clear. Type 2 deiodinase (Dio2) is a selenium-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 randomized into five groups and administered different iodine dosages (folds of physiological dose): normal iodine (NI), 3-fold iodine (3HI), 6-fold iodine (6HI), 10-fold iodine (10HI), and 50-fold iodine (50HI). Rats were euthanized 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 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.


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.


2015 ◽  
Vol 11 (1) ◽  
pp. 43 ◽  
Author(s):  
Aleksey Vasil'evich Kiyaev ◽  
Nadezhda Mikhailovna Platonova ◽  
Fatima Magomedovna Abdulhabirova ◽  
Ekaterina Anatolyevna Troshina ◽  
Grigoriy Anatol'evich Gerasimov

2013 ◽  
Vol 60 (5) ◽  
pp. 273-275
Author(s):  
Soralla Civantos ◽  
Emilia Cancer ◽  
Juan José Gorgojo ◽  
Gloria Cánovas ◽  
Azucena Rodríguez
Keyword(s):  

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1574
Author(s):  
Eva Duborská ◽  
Martin Urík ◽  
Martin Šeda

Iodine is an essential trace element for both humans and animals. It is essential to produce important hormones by the thyroid gland. In most inland areas, the soils are iodine deficient and its amount is insufficient to produce agricultural crops with adequate iodine content to cover the recommended daily intake. In connection with the occurrence of iodine deficiency disorders (IDDs), it has been the subject of intensive research in the past. However, following the introduction of iodized table salt in the food industry, problems related to IDD were not solved and studies on iodine mobility and bioavailability from soils are rare even today and have remained insufficiently investigated. In many countries, mainly in Europe, the prescription rate of medicaments used to treat goiter is still high. Thus, there are a considerable amount of studies looking for alternative methods for iodine supplementation in foodstuffs among the use of iodized table salt. In most cases, the subject of these studies are agricultural crops. This mini review presents the consequences of inadequate and excess iodine intake, the current status of iodine supplementation and the most recent alternative methods of the application of iodine in agriculture and its effect on the quality of used plant species.


2018 ◽  
Vol 1446 (1) ◽  
pp. 117-138 ◽  
Author(s):  
Brenda A.Z. Abu ◽  
Wilna Oldewage‐Theron ◽  
Richmond N.O. Aryeetey

Author(s):  
Nam H. Cho ◽  
Hoon Sung Choi ◽  
Kyung Won Kim ◽  
Hyung-Lae Kim ◽  
Soo-Youn Lee ◽  
...  

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