scholarly journals Naturally occurring iodine in humic substances in drinking water in Denmark is bioavailable and determines population iodine intake

2008 ◽  
Vol 99 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Stig Andersen ◽  
Klaus M. Pedersen ◽  
Finn Iversen ◽  
Steen Terpling ◽  
Peter Gustenhoff ◽  
...  

Iodine intake is important for thyroid function. Iodine content of natural waters is high in some areas and occurs bound in humic substances. Tap water is a major dietary source but bioavailability of organically bound iodine may be impaired. The objective was to assess if naturally occurring iodine bound in humic substances is bioavailable. Tap water was collected at Randers and Skagen waterworks and spot urine samples were collected from 430 long-term Randers and Skagen dwellers, who filled in a questionnaire. Tap water contained 2 μg/l elemental iodine in Randers and 140 μg/l iodine bound in humic substances in Skagen. Median (25; 75 percentile) urinary iodine excretion among Randers and Skagen dwellers not using iodine-containing supplements was 50 (37; 83) μg/24 h and 177 (137; 219) μg/24 h respectively (P < 0·001). The fraction of samples with iodine below 100 μg/24 h was 85·0 % in Randers and 6·5 % in Skagen (P < 0·001). Use of iodine-containing supplements increased urinary iodine by 60 μg/24 h (P < 0·001). This decreased the number of samples with iodine below 100 μg/24 h to 67·3 % and 5·0 % respectively, but increased the number of samples with iodine above 300 μg/24 h to 2·4 % and 16·1 %. Bioavailability of iodine in humic substances in Skagen tap water was about 85 %. Iodine in natural waters may be elemental or found in humic substances. The fraction available suggests an importance of drinking water supply for population iodine intake, although this may not be adequate to estimate population iodine intake.


1999 ◽  
pp. 400-403 ◽  
Author(s):  
KM Pedersen ◽  
P Laurberg ◽  
S Nohr ◽  
A Jorgensen ◽  
S Andersen

The iodine intake level of the population is of major importance for the occurrence of thyroid disorders in an area. The aim of the present study was to evaluate the importance of drinking water iodine content for the known regional differences in iodine intake in Denmark and for the iodine content of infant formulas. Iodine in tap water obtained from 55 different locations in Denmark varied from <1.0 to 139 microg/l. In general the iodine content was low in Jutland (median 4.1 microg/l) with higher values on Sealand (23 microg/l) and other islands. Preparation of coffee or tea did not reduce the iodine content of tap water with a high initial iodine concentration. A statistically significant correlation was found between tap water iodine content today and the urinary iodine excretion measured in 41 towns in 1967 (r=0.68, P<0.001). The correlation corresponded to a basic urinary iodine excretion in Denmark of 43 microg/24h excluding iodine in water and a daily water intake of 1.7 l. The iodine content of infant formulas prepared by addition of demineralized water varied from 37 to 138 microg/l (median 57 microg/l, n=18). Hence the final iodine content would depend heavily on the source of water used for preparation. We found that iodine in tap water was a major determinant of regional differences in iodine intake in Denmark. Changes in water supply and possibly water purification methods may influence the population iodine intake level and the occurrence of thyroid disorders.



2002 ◽  
pp. 663-670 ◽  
Author(s):  
S Andersen ◽  
SB Petersen ◽  
P Laurberg

OBJECTIVE: The iodine intake level is important for the occurrence of thyroid disorders in a population. We have previously found that iodine in drinking water is related to iodine excretion but whether iodine is present as iodide or bound in other molecules remains unknown. DESIGN: We measured iodine in drinking water from 22 locations in Denmark. Six locations were selected by iodine content for further tap water analysis (Skagen 140 micro g/l, Samsoe 56 micro g/l, Nykoebing S. 50 micro g/l, Nakskov 40 micro g/l, Ringsted 38 micro g/l, Copenhagen 19 micro g/l). METHODS: HPLC size exclusion before (Skagen) and after (all sites) freeze drying and measurement of absorbance (280 nm) and iodine in fractions, and fluorescence spectroscopy of bulk organic matter in Skagen drinking water. RESULTS: Iodine content was unaltered after 3 Years (P=0.2). All samples contained organic molecules with characteristics similar to humic substances. Most iodine eluted with humic substances (Skagen 99%, Ringsted 98%, Nykoebing S. 90%, Copenhagen 90%, Samsoe 75%, Nakskov 40%). Changing pH and ionic strength and preincubation with iodide indicated that iodine was bound in humic substances. Humic substances may affect thyroid function but differ with geology. Geological and geochemical data agree with tap water humic substances having been released from marine deposits. Iodine is abundant in the marine environment and marine deposits are particularly rich in iodine. Correlation analysis (r=0.85, P=0.03) conform to iodine in drinking water, suggesting marine humic substances at the source rock. CONCLUSION: Iodine in Danish drinking water varied considerably. In drinking water with a high iodine content, the iodine mainly eluted with humic substances derived from marine source rock. We hypothesize that iodine in drinking water in general suggests coexisting humic substances of marine origin.



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.



1988 ◽  
Vol 117 (3) ◽  
pp. 333-338 ◽  
Author(s):  
Gerhard Hintze ◽  
Dieter Emrich ◽  
Klaus Richter ◽  
Hanne Thal ◽  
Horst Thal ◽  
...  

Abstract. The availability of iodinated salt containing 20 mg of iodine as iodate/kg salt consumed on a voluntary basis enabled us to investigate its effect on goitre prevalence and iodine excretion in urine in a longitudinal, prospective, randomized study over 4 years. With this salt, under the assumption of a consumption of 5 g salt per day and person, an additional intake of 100 μg of iodine can be achieved. The study was performed on initially 334 children (168 boys, 166 girls) at the age of 10 years living in an area of iodine deficiency. After 4 years, 286 children still participated in the study. Initially, goitre prevalence as assessed by palpation was found to be 30.5% (37.4% in girls and 23.8% in boys). Neck circumference was found to be significantly higher in children with goitre compared with those without (30.2 ± 1.4 vs 29.4 ± 1.4 cm; P < 0.001). Iodine excretion in the urine was significantly lower in children with goitre compared with those without (40.4 ± 16.7 μg/g creatinine vs 46.1 ± 24.9 μg/g creatinine; x ± sd; P < 0.05). The children were randomly assigned to two different groups: group A (N = 146) was asked to use iodinated salt, group B (N = 188) non-iodinated salt. Over the 4 years, a continuous increase in iodine excretion in urine could be demonstrated in group A. After 1 year, it was significantly higher than in the control group that used non-iodinated salt. After 4 years, the mean iodine excretion in children using iodinated salt was 60.1 ± 24.1 μg/g creatinine in contrast to 45.1 ± 18.6 μg/g in the control group (x ± sd; P< 0.0001). However, no decrease in goitre prevalence could be documented: after 4 years, 23.8% of the children belonging to the group using iodinated salt and 22.5% of those in the group taking non-iodinated salt had a goitre. From these observations we conclude: 1. The voluntary use of a commercially available iodinated salt containing 20 mg iodate/kg leads to a significant increase in iodine intake, measured by urinary iodine excretion. Even after 4 years, the value is far below the daily iodine intake recommended by the WHO. No decrease in goitre frequency could be assessed. 2. An increase in iodine ingestion can be achieved either by increasing the iodine content of the salt or by application of iodine by alternative measures. The safest way would be to use iodinated salt exclusively, i.e. also in the food industry and restaurants. An increase in the iodine content of the salt and its continuous voluntary use would lead to a large variation in iodine intake. A higher risk of adverse reaction, e.g. iodine-induced thyrotoxicosis, cannot be excluded in susceptible persons.



2007 ◽  
Vol 99 (4) ◽  
pp. 813-818 ◽  
Author(s):  
Stig Andersen ◽  
Jesper Karmisholt ◽  
Klaus M. Pedersen ◽  
Peter Laurberg

The iodine intake level in a population is determined in cross-sectional studies. Urinary iodine varies considerably and the reliability of studies of iodine nutrition and the number of samples needed is unsettled. We performed a longitudinal study of sixteen healthy men living in an area of mild to moderate iodine deficiency. Iodine and creatinine concentrations were measured in spot urine samples collected monthly for 13 months. From these data we calculated the number of urine samples needed to determine the iodine excretion level for crude urinary iodine and for 24 h iodine excretion estimated from age- and gender-specific creatinine excretions. We found that mean urinary iodine excretion varied from 30 to 87 μg/l (31 to 91 μg/24 h). Sample iodine varied from 10 to 260 μg/l (20 to 161 μg/24 h). Crude urinary iodine varied more than estimated 24 h iodine excretion (population standard deviation 32v. 26; individual standard deviation 29v. 21; Bartlett's test,P < 0·01 for both). The number of spot urine samples needed to estimate the iodine level in a population with 95 % confidence within a precision range of ± 10 % was about 125 (100 when using estimated 24 h iodine excretions), and within a precision range of ± 5 % was about 500 (400). A precision range of ± 20 % in an individual required twelve urine samples or more (seven when using estimated 24 h iodine excretions). In conclusion, estimating population iodine excretion requires 100–500 spot urine samples for each group or subgroup. Less than ten urine samples in an individual may be misleading.



1936 ◽  
Vol 36 (2) ◽  
pp. 182-203 ◽  
Author(s):  
C. E. Hercus ◽  
H. D. Purves

VI. Summary1. Some improvements in the determination of small quantities of iodine in biological substances are described.2. The thesis that a low iodine intake is prerequisite for goitre production is supported.3. A survey of determinations by various authors of the daily urinary iodine excretion in goitrous and non-goitrous regions leads to the conclusion that the critical level of iodine intake sufficient to suppress goitre is between 120 and 160γ per day.4. Determinations of urinary iodine excretion in New Zealand and in the non-goitrous islands of Samoa are presented which show that in the parts of New Zealand investigated the iodine intake is at a low or goitrous level.5. The result in New Plymouth, Taranaki, shows that a high content of iodine in the soil does not necessarily assure an adequate iodine intake.6. The progress of prophylaxis by iodised salt in New Zealand is reviewed, and from consumption data it is concluded that iodised salt constitutes approximately only 30 per cent, of the domestic salt consumption of New Zealand.7. To ensure a more general use of iodised salt it is recommended that the regulations be amended to provide that:(a) Ordinary domestic salt shall be iodised.(b) Non-iodised salt shall be sold only in packages labelled “Non-iodised” and with the addition “ The use of this salt exposes the user to the risk of developing goitre”.8. The results obtained hitherto with the use of iodised salt are briefly reviewed and attention drawn to some apparent failures even when iodised salt has been used for all domestic purposes. These failures are attributed to the standard for iodised salt being too low.9. It is concluded that for New Zealand a supplementation of at least 100γ per day is necessary to afford complete protection against goitre.10. To provide the necessary amount of supplementation the iodine content of iodised salt in New Zealand requires to be raised. We recommend therefore that either(a) If the domestic salt only is to be iodised the standard be fixed at from 5 to 6 parts of potassium iodide (KI) per 250,000 of salt, or(b) If iodised salt is to be used in the manufacture of bread, butter, bacon and other salted foods, the standard be fixed at from 3 to 4 parts of potassium iodide (KI) per 250,000 of salt.11. In New Zealand cabbage has not shown any marked goitrogenic activity as tested on rabbits.12. Turnip roots showed sporadically a goitrogenic activity comparable with that found for the most active samples of cabbage in other countries.13. In tests of Brassica seeds on rats, goitrogenic activity was found in rape seed, cabbage seed, steamed white mustard seed, and steamed black mustard seed.14. The activity of rape seed was destroyed by steaming.We have pleasure in acknowledging the financial help which we have received from the Sir John Roberts Endowment for Medical Research, from the Sir H. L. Ferguson Fund and from the Honorary Staff of the Dunedin Hospital, and for the co-operation of a large number of our colleagues in New Zealand and Samoa in the collection of specimens.



Author(s):  
Dinesh P. Sharma ◽  
Amitkumar Maheshwari ◽  
Chandan Chakrabarti ◽  
Darshan J. Patel

Abstract Aim Iodine deficiency disorder (IDD) is the cause of preventable brain damage, mental retardation, and stunted growth and development in children. This study aimed to detect the prevalence of IDD in Kachchh district, Gujarat, by testing urinary iodine excretion levels and iodine intake of salts in school-going children. Methods A cross-sectional study was conducted and the level of iodine deficiency was assessed in 223 school children of both sexes, aged 6 to 12 years from four talukas, that is, subdivisions, of the Kachchh district by estimating urinary iodine using Sandell–Kolthoff reaction along with iodine content in edible salt samples by MBI kit (STK-Spot testing kit, MBI Kits International, Chennai, TN, India). Results The median urinary iodine level was found to be 194 μg/L, indicating no biochemical iodine deficiency in the region. In the study areas, 1% of the population showed a level of urinary iodine excretion < 50 μg/L. About 83% salt samples had iodine level more than 15 ppm and the iodine content in salt samples less than 15 ppm was only about 17%, indicating the salt samples at households contain iodine in adequate level. Conclusion There is a need of periodic surveys to assess the change in magnitude of IDD with respect to impact of iodized salt intervention.Furthermore, to strengthen National Iodine Deficiency Disorders Control Program, factors should be identified. There is also a need to prevent and reimpose the ban on the sale of noniodized salts in Gujarat.



2020 ◽  
pp. 1-6
Author(s):  
Johannes Riis ◽  
Klaus M. Pedersen ◽  
Mathias B. Danielsen ◽  
Gustav V. B. Sørensen ◽  
Martin G. Jørgensen ◽  
...  

Abstract Iodine intake affects the occurrence of thyroid disorders. However, the association of iodine intake with longevity remains to be described. This led us to perform a 20 years’ follow-up on participants from the Randers–Skagen (RaSk) study. Residents in Randers born in 1920 (n 210) and Skagen born in 1918–1923 (n 218) were included in a clinical study in 1997–1998. Mean iodine content in drinking water was 2 µg/l in Randers and 139 µg/l in Skagen. We collected baseline data through questionnaires, performed physical examinations and measured iodine concentrations in spot urine samples. Income data were retrieved from Danish registries. We performed follow-up on mortality until 31 December 2017 using Danish registries. Complete follow-up data were available on 428 out of 430 of participants (99·5 %). At baseline, the median urinary iodine concentration was 55 µg/l in Randers and 160 µg/l in Skagen residents. Participants were long-term residents with 72·8 and 92·7 % residing for more than 25 years in Randers and Skagen, respectively. Cox regression showed that living in Skagen compared with Randers was associated with a lower hazard ratio (HR) of death in both age- and sex-adjusted analyses (HR 0·60, 95 % CI 0·41, 0·87, P = 0·006), but also after adjustment for age, sex, number of drugs, Charlson co-morbidity index, smoking, alcohol and income (HR 0·60, 95 % CI 0·41, 0·87, P = 0·008). Residing in iodine-replete Skagen was associated with increased longevity. This indicates that long-term residency in an iodine-replete environment may be associated with increased longevity compared with residency in an iodine-deficient environment.



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.



1990 ◽  
Vol 29 (03) ◽  
pp. 113-119
Author(s):  
C. R. Pickardt ◽  
K. Horn ◽  
G. Bechtner ◽  
C. Vaitl ◽  
C. M. Kirsch ◽  
...  

Global TcTU was determined in 568 patients without any specific thyroid drug intake - 54 with normal thyroid, 274 with goitre and euthyroidism and 240 with thyroid autonomy. 57 patients with autonomy and overt hyperthyroidism were the only group with TcTU values significantly higher than normals. Common to all groups was a large scatter of the TcTU values. In 332, the effects of individual iodine supply were studied by measuring the iodine concentration in spot urine samples. There was a significant inverse correlation between the TcTU values and the urinary iodine excretion in the groups of normal thyroids and of goitres with euthyroidism. In the group with autonomy an effect of iodine supply could only be seen in cases of greatly increased urinary iodine excretion, resulting in very low TcTU values. Out of 20 patients with autonomy and iodine contamination, only 4 showed overt hyperthyroidism. The large scatter of TcTU values in all groups may be explained by the persistent iodine deficiency as well as by the frequent exposure to unknown amounts of iodine in patients with thyroid disease. Therefore, the spontaneous TcTU alone cannot identify a small group of patients with autonomy and high risk of iodine-induced hyperthyroidism, from a very large group of patients with goitre.



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