scholarly journals Nutritional iodine status and obesity

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Mariacarla Moleti ◽  
Maria Di Mauro ◽  
Giuseppe Paola ◽  
Antonella Olivieri ◽  
Francesco Vermiglio

AbstractIodine is an essential component of the thyroid hormones, thyroxine and triiodothyronine. Its availability strictly depends on iodine content of foods, which may vary from very low to very high. Inadequate iodine intake (deficiency or excess) may affect thyroid function resulting in hypothyroidism or hyperthyroidism. Based on median urinary iodine concentrations, epidemiological criteria have been established for the categorization and monitoring of nutritional iodine status of a population (or subgroups of populations). Additional methods for iodine intake assessment include measurement of thyroid size (by thyroid palpation or ultrasonography) and of biochemical parameters, such as neonatal thyroid stimulating hormone, thyroglobulin and thyroid hormones.Recent studies carried out in overweight/obese children and adults provide evidence that body mass index (BMI) may significantly influence the above indicators, thus theoretically affecting the epidemiological evaluation of nutritional iodine status in populations.In this short review, we analyze current knowledge on the effects of overweight and obesity on indicators of adequacy and monitoring of iodine status, namely urinary iodine excretion and thyroid volume and echogenicity.Data on urinary iodine excretion in overweight/obese children are divergent, as both increased and reduced levels have been reported in overweight/obese children compared to normal-weight controls.Whether gastrointestinal surgery may affect iodine absorption and lead to iodine deficiency in patients undergoing bariatric surgery has been evaluated in a limited number of studies, which excluded iodine deficiency, thus suggesting that supplements usually recommended after bariatric surgery do not need to include iodine.Albeit limited, evidence on thyroid volume and obesity is consistent with a direct relationship between thyroid volume and BMI, irrespective of nutritional iodine status. Finally, a higher frequency of thyroid hypoechoic pattern has been described in overweight/obese children. This finding has been recently related to an increased adipocyte infiltration and thyroid parenchyma imbibition mediated by inflammatory cytokines and should be considered when the frequency of thyroid hypoechoic pattern is used as non-invasive marker to indirectly assess thyroid autoimmunity in monitoring Universal Salt Iodization programs. Further studies, specifically addressing the role of schoolchildren body mass index as a factor potentially influencing iodine intake indicators are needed.

Author(s):  
Yozen Fuse ◽  
Yoshiya Ito ◽  
Yoshimasa Shishiba ◽  
Minoru Irie

Abstract Context Japan has been regarded as a long-standing iodine sufficient country without iodine fortification; however, data on nationwide iodine status is lacking. Objective This study aimed to characterize the iodine status in Japan. Methods From 2014 through 2019 a nationwide school-based survey was conducted across all districts in Japan. Urinary iodine concentration (UIC), creatinine (Cr) concentration and anthropometry were assessed in healthy school-aged children (SAC) aged 6 to 12 years. Their iodine status is regarded as generally representative of the nation's iodine status. Results A total of 32,025 children participated. The overall median UIC was 269 μg/L which was within the WHO’s adequacy range. There was a regional difference in UIC values within 14 regions, and the lowest and highest median UIC were found in Tanegashima Island (209 μg/L) and Nakashibetsu, Hokkaido (1,071 μg/L), respectively. The median UIC ≥ 300 μg/L was observed in 12 out of 46 regions. By using estimated 24-h urinary iodine excretion (UIE), the prevalence of SAC exceeding the upper tolerable limit of iodine for Japanese children was from 5.2 to 13.7%. The UIC values did not change with age, BSA and BMI percentile, while the Cr concentration simultaneously increased suggesting the effect of urinary creatinine on UI/Cr and estimated 24-h UIE values. Conclusions The iodine intake of Japanese people is adequate, but in some areas it is excessive. The incidence and prevalence of thyroid disorders associated with iodine intake should be obtained especially in the areas where high amounts of iodine are consumed.


2007 ◽  
Vol 10 (12A) ◽  
pp. 1596-1599 ◽  
Author(s):  
Fereidoun Azizi

AbstractObjective: To describe studies evaluating urinary iodine excretion during pregnancy and lactation in women living in cities with adequate or more than adequate iodine intake.Design: Cross-sectional study conducted between 1996 and 1998 in pregnant women and a study of lactating women conducted in 2003.Settings and Subjects: Pregnant women attending prenatal clinics in four cities in the Islamic Republic of Iran. Urinary iodine excretion and thyroid volume was measured in 403 women. In a second study, 100 lactating women from Taleghani Hospital in Gorgan, Iran were evaluated for thyroid size, and both urinary and breast milk iodine concentrations were determined.Results: In Rasht city, 84% of pregnant women had a urinary iodine concentration of ≥ 200 μg l-1, while in the other cities this percentage ranged from 45 to 55%. When data were combined for the cities of Ilam, Isfahan and Tehran, where women have an adequate or more than adequate median urinary iodine concentration, 51% of pregnant women had a urinary iodine concentration less than that recommended during pregnancy. In Rasht, where the median urinary iodine concentration indicates an excessive iodine intake, 15.4% of pregnant women had a urinary iodine concentration < 200 μg l-1. The mean urinary iodine concentration in lactating women was 250 μg l-1, and 16% of women had a urinary iodine concentration < 100 μg l-1. Grade 1 goitre was present in 8% of lactating women, and another 8% had grade 2 goitre.Conclusions: Findings of this study call for further attention to iodine intake during pregnancy and lactation. The currently recommended intake of iodine through universal salt iodisation may not be adequate for pregnant and lactating women, and supplementation during pregnancy and lactation should be further considered in light of the latest recommendations.


Author(s):  
Nilratan Majumder ◽  
Balaram Sutradhar ◽  
Saradindu Riang ◽  
Shib Sekhar Datta

Background: Due to excess metabolic demand of iodine in pregnancy, pregnant women and lactating mother and their neonates are most vulnerable of iodine deficiency disorder. Urinary iodine excretion is a good marker of recent dietary iodine intake. Thus, present study was conducted to assess the iodine status and median urinary iodine excretion (UIE μg/lit) among pregnant and non-pregnant women of Tripura.Methods: Tribal and Bengali pregnant and non-pregnant women from Bokafa and Jolaibari Block of South Tripura district were included in the study. Urinary iodine excretion was done using simple micro plate method. Salt iodine was estimated using iodometric titration. All the tests were performed at CNRT Lab, ICMR, India.Results: Total number of subjects included in this study was 1071. Total number of urine samples collected from pregnant and non-pregnant women was 538 and 533 respectively. Median value of UIE in pregnant and non-pregnant women of Tripura was 155.0µg/L and 130.0µg/L. In pregnant women percentage prevalence of severe (<20µg/L), moderate (20-49µg/L) and mild iodine deficiency (50-149µg/L) was found in 4.1%, 15.1% and 29.6% subjects. In case of non-pregnant women severe (<20µg/L), moderate (20-49µg/L) and mild iodine deficiency (50-99µg/L) was found in 0.6%, 9.6%, 27.8% subjects respectively. The overall prevalence of iodine deficiency was found in 48.8% pregnant women, compared to 38.0% non-pregnant subjects.Conclusions: Efforts towards universal salt iodization need to be stepped-up in Sub-Himalayan region (NE part of India) and pregnant and lactating mothers may be targeted with alternate iodine supplements (Colloidal Iodine).


2019 ◽  
Vol 15 (4) ◽  
pp. 146
Author(s):  
Widya Ayu Kurnia Putri ◽  
Dodik Briawan ◽  
Hidayat Syarief ◽  
Leily Amelia

Iodine status in school-age children determined from iodine urine excretion and iodine intakeBackground: School-age children are more at risk if they experience deficiencies and excess iodine. The concentration of iodine in urine is a good biomarker for assessing iodine intake, 90% of iodine intake will be excreted through urine. Objective: This study aimed to analyze the iodine status of school-age children based on urinary iodine excretion (UIE) and iodine intake.Method: The study design used a cross-sectional study on 44 healthy school-aged children in Bogor Regency. Subject selection was done purposively in healthy 5th-grade elementary school students. The data taken in this study was urine iodine excretion concentration and food recall (1x24 hours). Data were analyzed using descriptive analysis and Pearson correlation test.Results: Median iodine excretion concentration in urine was 157 μg/l and the average daily iodine intake of children was 83.29 mg/day. Conclusion: The concentration of iodine excretion in the urine of the children is in the category of sufficient iodine as recommended by WHO / UNICEF / ICCID while the daily intake of iodine for children is still in the less category. The results showed that there was no association of iodine daily intake with iodine excretion concentration in urine(p=0.469).


2014 ◽  
Vol 112 (10) ◽  
pp. 1715-1723 ◽  
Author(s):  
Sarah C. Bath ◽  
Michelle L. Sleeth ◽  
Marianne McKenna ◽  
Alan Walter ◽  
Andrew Taylor ◽  
...  

As intra-thyroidal iodine stores should be maximised before conception to facilitate the increased thyroid hormone production during pregnancy, women who are planning to become pregnant should ideally consume 150 μg iodine/d (US RDA). As few UK data exist for this population group, a cross-sectional study was carried out at the University of Surrey to assess the iodine intake and status of women of childbearing age. Total iodine excretion was measured from 24 h urine samples in fifty-seven women; iodine intake was estimated by assuming that 90 % of ingested iodine was excreted. The average iodine intake was also estimated from 48 h food diaries that the participants completed. The median urinary iodine concentration value (63·1 μg/l) indicated the group to be mildly iodine deficient by WHO criteria. By contrast, the median 24 h urinary iodine excretion value (149·8 μg/24 h) indicated a relatively low risk of iodine deficiency. The median estimated iodine intake, extrapolated from urinary excretion, was 167 μg/d, whereas it was lower, at 123 μg/d, when estimated from the 48 h food diaries. Iodine intake estimated from the food diaries and 24 h urinary iodine excretion were strongly correlated (r 0·75, P< 0·001). The intake of milk, eggs and dairy products was positively associated with iodine status. The iodine status of this UK cohort is probably a best-case scenario as the women were mostly nutrition students and were recruited in the winter when milk-iodine content is at its highest; further study in more representative cohorts of UK women is required. The present study highlights the need for revised cut-off values for iodine deficiency that are method- and age group-specific.


2003 ◽  
Vol 6 (1) ◽  
pp. 95-98 ◽  
Author(s):  
F Azizi ◽  
A Aminorroya ◽  
M Hedayati ◽  
H Rezvanian ◽  
M Amini ◽  
...  

AbstractObjective:Pregnancy is accompanied by profound alterations in thyroid economy and relative iodine deficiency. The aim of this study was to evaluate urinary iodine excretion of pregnant women in cities with adequate and more than adequate iodine intake.Methods:A cross-sectional study was performed on schoolchildren and pregnant women in four cities in the Islamic Republic of Iran. Urinary iodine excretion was measured for 438 schoolchildren and 403 pregnant women. In addition, in Isfahan City, thyroid volume was measured by sonography for 30 pregnant women in each trimester of pregnancy and for 90 non-pregnant women who also had urinary iodine measurement.Results:Median urinary iodine of schoolchildren was 31.2, 25.0, 20.2 and 19.3 μg/dl in Rasht, Isfahan, Ilam and Tehran, respectively. Corresponding values for pregnant women were 33.8, 21.2, 19.0 and 18.6μg/dl. The percentage of pregnant women with urinary iodine below 20μg/dl was 16, 45, 55 and 54, and below 10μg/dl was 1, 7, 7 and 13, in Rasht, Isfahan, Ilam and Tehran, respectively. In Isfahan, urinary iodine was significantly decreased in the third trimester of pregnancy, compared with controls. Mean thyroid volume was 7.8±3.1 ml and 7.8±2.8 ml in pregnant and non-pregnant women, respectively.Conclusion:Recommended values for dietary iodine through universal salt iodisation may not be adequate for pregnant women, and the specific problem of iodine and pregnancy should be considered further in the light of the latest recommendations.


2005 ◽  
Vol 44 (04) ◽  
pp. 137-142 ◽  
Author(s):  
A. Haase ◽  
M. Seyfarth ◽  
B. E. Wenzel ◽  
E. Richter ◽  
M. Baehre ◽  
...  

Summary Aim: The extent of urinary iodine excretion (UIE) provides information about iodine supply and release. In the present study we investigated correlations between UIE and radioiodine uptake (RIU) as well as effects of radioiodine therapy on UIE in patients with autonomous goitre. Patients, methods: In 197 consecutive patients with thyroid autonomy, UIE was measured twice during radioiodine test (RITe) and correlated with RIU. In 98 of these patients, thyroglobulin and thyroid volume (V) were determined prior to therapy. Individual changes in urinary iodine excretion (ΔUIE) and TG (ΔTG) could be investigated four weeks (4W) and six months (6M) after radioiodine therapy. Additionally, ΔV was determined 6M after therapy. ΔUIE, ΔTG and ΔV were correlated with target dose and target volume. Results: Patients with higher iodine excretion exhibited significantly lower thyroidal radioiodine uptake values. Twofold increased UIE prior to therapy decreased radioiodine uptake by 25%. Compared with pretherapeutic values, UIE and TG were significantly increased four weeks after radioiodine therapy (p <0.001). Median values of both parameters were found to be doubled. The product of target dose and target volume was not only correlated with a decrease of thyroid volume 6M after therapy, but also with an increase of UIE and TG in the early phase after therapy. Conclusions: It was confirmed that UIE during RITe is a measure for iodine intake and can be used to investigate the competition between stable iodine and radioiodine. The increase of UIE and TG four weeks after therapeutic administration of radioiodine can be explained by disintegrated thyroid follicles. The therapy-induced iodine release may be one important cause for the development of hyperthyroidism in some patients during the first weeks after radioiodine therapy. It may contribute to the known decrease of radioiodine uptake after preapplications of 131I in various thyroid diseases.


1993 ◽  
Vol 129 (6) ◽  
pp. 497-500 ◽  
Author(s):  
F Aghini-Lombardi ◽  
A Pinchera ◽  
L Antonangeli ◽  
T Rago ◽  
GF Fenzi ◽  
...  

It is well established that iodine supplementation is effective in correcting iodine deficiency and reducing goiter prevalence. In Italy, legislation has allowed the production of iodized salt since 1972, but its consumption is on a voluntary basis. In the present study, the efficacy of legislative measures that made compulsory the availability of iodized salt in foodstores has been evaluated. Urinary iodine excretion and thyroid size, scored according to Pan American Health Organization recommendations, were determined prior to (1981) and 10 years after (1991) the introduction of legislative measures in the whole schoolchildren population residing in a restricted area of the Tuscan Appennines. Moreover, in 1991, thyroid volume was determined by ultrasonography. In 1981, mean urinary iodine excretion was 47.1±22.4 mg/kg creatinine (0.412 μmol/l) and goiter prevalence was 60%, indicating a moderate iodine deficiency. Eighty of the families subsequently used iodized salt on a regular basis; as a result of this excellent compliance, in 1991 the mean urinary iodine excretion increased to 129.7±73 mg/kg creatinine (1.24 μmol/l) and goiter prevalence dropped to 8.1%. The results of this study underline the effectiveness of iodine prophylaxis in correcting iodine deficiency and abating endemic goiter in schoolchildren, and suggest that implementation of measures that make compulsory the availability of iodized salt in foodstores overcomes the fact that there is no law governing the exclusive production and trading of iodized salt.


Nutrients ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 3955
Author(s):  
Do-Kyung Lee ◽  
Hunjoo Lee ◽  
Hyeyoung Lee ◽  
Taehyung Yoon ◽  
Seon-Joo Park ◽  
...  

Iodine is an essential component of thyroid hormones, but excessive iodine intake can lead to thyroid dysfunction. Traditionally, Korean mothers consume brown seaweed soup (miyeokguk), a high source of iodine, after childbirth. There is controversy regarding the effects of excessive postpartum iodine intake on the health of mothers and infants. Thus far, there have been no nationwide large-scale surveys regarding the status of iodine intake among postpartum women in Korea. Therefore, we conducted a nationwide survey of postpartum dietary iodine intake among Korean women. In total, 1054 Korean women aged ≥19 years, at less than 8 weeks postpartum, participated in this survey. Dietary data were collected using self-reported 2-day dietary records, along with before-and-after meal photos. To evaluate the correlation between dietary iodine and urinary iodine excretion (UIE), spot urine, and 24 h urine samples were collected from 98 and 29 participants, respectively. The mean daily iodine intake among all participants was 2945.6 μg, and it gradually decreased over time after childbirth. Dietary iodine intake was significantly correlated with 24 h UIE (r = 0.396, p < 0.05) and spot urine UIE (r = 0.312, p < 0.05). Follow-up studies are required to examine the influence of excessive postpartum iodine intake on thyroid health in mothers and their infants.


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