Iodine Deficiency and Supplementation in Pregnancy

Assessment of iodine nutritional status and gestational thyroid function reference ranges during the first trimester of pregnancy in Taiwan

BACKGROUND

Iodine nutrition is critical for fetal neurodevelopment in the first trimester of pregnancy, a period associated with dramatic changes in thyroid function. The aim of this study was to evaluate iodine nutritional status and thyroid function reference ranges in the first trimester in Taiwan.

METHODS

Pregnant women aged 20 years and above in the first trimester were recruited in Taipei Veterans General Hospital, Taiwan from March 2019 to July 2022. Each participant provided a spot urine sample for measurement of urinary iodine concentration (UIC) and a blood sample for checkup of thyroid function and thyroid autoantibodies. A simple food frequency questionnaire was also completed.

RESULTS

A total of 209 women with a mean age of 32.9 ± 4.4 years were enrolled. The median UIC was 160.9 μg/L (interquartile range [IQR]: 105.0-246.2 μg/L), indicating overall iodine sufficiency. The gestational thyroid function reference ranges were: thyroid stimulating hormone (TSH) (median: 0.93 [0.007-2.9] µIU/mL), free T4 (1.3 [0.93-2.2] ng/dL), free T3 (3.0 [2.3-5.0] ng/dL), total T4 (9.9 [6.4-16.9] ng/dL), and total T3 (135 [88-231] ng/dL). If the nonpregnant reference range of serum TSH was used, eight women (4.8%) would be misclassified as having subclinical hyperthyroidism, and two women (1.2%) with subclinical hypothyroidism would be missed. In multivariate analysis, nulliparous (adjusted odds ratio [OR] from model 1-3: 2.02, 2.05, 2.02; 95% CI, 1.08-3.77, 1.10-3.81, 1.11-3.66; p = 0.027, 0.023, 0.022, respectively) and multivitamin nonusers (adjusted OR from model 1-3: 1.86, 1.85, 1.78; 95% CI, 1.04-3.34, 1.03-3.32, 1.004-3.71; p = 0.038, 0.039, 0.049, respectively) had increased odds of having lower UIC levels <150 μg/L.

CONCLUSION

The iodine nutritional status in the first trimester is adequate in Taiwan; however, certain subgroups such as nulliparous and multivitamin nonusers are still at risk for iodine deficiency. Gestational thyroid function reference ranges are needed for correct diagnosis of thyroid dysfunction in pregnancy.

Potential Micronutrient Deficiencies in the First 1000 Days of Life: The Pediatrician on the Side of the Weakest

PURPOSE OF REVIEW

This study is to examine potential micronutrient deficiencies and any need for supplementation in children following specific diet plans in the first 1000 days of life.

RECENT FINDINGS

Optimal nutrition in the first 1000 days of life has a lifelong positive impact on child development. Specific intrauterine and perinatal factors, pathological conditions, and dietary restrictions can represent potential risk factors for micronutrient deficiencies in the first 1000 days of life, which can have negative systemic consequences. Preterm and low-birth-weight infants are intrinsically at risk because of immature body systems. Children affected by cystic fibrosis are prone to malnutrition because of intestinal malabsorption. The risk of micronutrient deficiency can increase in various situations, including but not limited to children following selective dietary regimens (vegetarian and vegan diets and children affected by specific neuropsychiatric conditions) or specific dietary therapies (children affected by food allergies or specific metabolic disorders and children following restricted diet as a part of therapeutic approach, i.e., ketogenic diet for epilepsy). In light of this situation, the micronutrient status in these categories of children should be investigated in order to tailor strategies specific to the individual's metabolic needs, with a particular focus on deficiencies which can impair or delay the physical and cognitive development of children, namely, vitamin B12, vitamin D and folic acid, as well as oligo-elements such as iron, zinc, calcium, sodium, magnesium, and phosphorus, and essential fatty acids such as omega-3. Identification of micronutrient deficiency in the first 1000 days of life and timely supplementation proves essential to prevent their long-term consequences.

Effects of selenium and iodine on Kashin-Beck disease: an updated review

Kashin-Beck disease (KBD) is an endochondral osteogenesis disorder characterised by epiphysis damage and secondary deformable arthropathy induced by multiple external factors, among which selenium (Se) and iodine deficiency are important influencing factors. Iodine deficiency is usually accompanied by a low Se content in the soil in the KBD areas of China. Se can reverse oxidative damage to chondrocytes. In addition, Se is related to the bone conversion rate and bone mineral density. Low Se will hinder growth and change bone metabolism, resulting in a decrease in the bone conversion rate and bone mineral density. Thyroid hormone imbalance caused by thyroid dysfunction caused by iodine deficiency can damage bone homeostasis. Compared with Se deficiency alone, Se combined with iodine deficiency can reduce the activity of glutathione peroxidase more effectively, which increases the vulnerability of chondrocytes and other target cells to oxidative stress, resulting in chondrocyte death. Clinical studies have shown that supplementation with Se and iodine is helpful for the prevention and treatment of KBD.

The research landscape concerning environmental factors in neurodevelopmental disorders: Endocrine disrupters and pesticides-A review

In recent years, environmental epidemiology and toxicology have seen a growing interest in the environmental factors that contribute to the increased prevalence of neurodevelopmental disorders, with the purpose of establishing appropriate prevention strategies. A literature review was performed, and 192 articles covering the topic of endocrine disruptors and neurodevelopmental disorders were found, focusing on polychlorinated biphenyls, polybrominated diphenyl ethers, bisphenol A, and pesticides. This study contributes to analyzing their effect on the molecular mechanism in maternal and infant thyroid function, essential for infant neurodevelopment, and whose alteration has been associated with various neurodevelopmental disorders. The results provide scientific evidence of the association that exists between the environmental neurotoxins and various neurodevelopmental disorders. In addition, other possible molecular mechanisms by which pesticides and endocrine disruptors may be associated with neurodevelopmental disorders are being discussed.

Iodized Salt May Not Be Sufficient to Guarantee an Adequate Iodine Intake in Pregnant Women

Adequate iodine intake is of crucial importance in pregnancy to meet the thyroid hormone needs of both mother and fetus. In the present study, undertaken as a part of the surveillance actions following the introduction in Italy of a national salt iodination program in 2005, the iodine intake was investigated in 123 pregnant women and 49 control women living in the same area of central Italy. All the participants were screened for urinary iodine concentration (UIC), serum level of thyrotropin, free-thyroxine, free-triiodothyronine, and thyroid volume. Moreover, they were provided with a questionnaire on the use of iodine-containing salt or supplements. Control women had a median UIC of 102 µg/L, consistent with an iodine sufficiency, while in pregnant women the median UIC value was 108 µg/L, lower than the endorsed UIC of 150 µg/L. In addition, pregnant women showed a significantly increased median thyroid volume compared to controls. Interestingly, the median UIC did not differ between pregnant women not using iodine-containing salt or supplements and those regularly consuming iodized salt alone, while pregnant women with a daily intake of iodine-containing supplements had an adequate median UIC (168 µg/L). In conclusion, the data reported here showed that pregnant women and their fetuses are still exposed to the detrimental effects of iodine deficiency and that the consumption of iodine-containing supplements should be recommended in pregnancy.

Iodine status and supplementation in pregnancy: an overview of the evidence provided by meta-analyses

Iodine supplementation during pregnancy in areas with mild-moderate deficiency is still a matter of debate. The present study aimed at systematically reviewing currently available evidences provided by meta-analyses with the aim to further clarify controversial aspects regarding the need of iodine supplementation in pregnancy as well as to provide guidance on clinical decision-making, even in areas with mild-moderate deficiency. Medline, Embase and Cochrane search from 1969 to 2022 were performed. For the purpose of this review, only studies containing meta-analytic data were selected. A total of 7 meta-analyses were retrieved. Four meta-analyses evaluated the relationship between iodine status during pregnancy and neonatal and maternal outcomes suggesting the existence of a U-shaped correlation between iodine status and several maternal and neonatal consequences, especially if iodine status is evaluated at the beginning of pregnancy. Three meta-analyses evaluating the results of intervention trials failed to provide straightforward conclusions on the benefits of iodine supplementation in pregnant women in areas with mild-moderate iodine deficiency. Although evidence coming from meta-analyses suggests a role of iodine status during pregnancy in determining maternal and child outcomes, results of meta-analyses of intervention trials are still controversial. Several factors including, degree of iodine deficiency, and pooling studies conducted in areas with different iodine intake, may account for the lack of benefits reported by meta-analyses of intervention trials. More high-quality, randomized, controlled trials including information on timing, dose and regimen of iodine supplementation are needed to further elucidate this issue.

Estimation of appropriate dietary intake of iodine among lactating women in China based on iodine loss in breast milk

OBJECTIVE

Data on iodine loss in breast milk, which are critical for establishing the appropriate dietary iodine intake for lactating women, is currently limited. A study was conducted to assess iodine loss in breast milk among Chinese lactating women to estimate the appropriate dietary intake of iodine.

METHODS

A total of 54 pairs of healthy, lactating women and their infants aged 0-6 months were recruited from Tianjin and Luoyang cities in China. A 4 days infant weighing study was conducted to assess iodine loss in the breast milk of lactating women. Mothers were required to weigh and record their infants' body weights before and after each feeding for a 24 h period from 8:00 am to 8:00 am. During the weighing study, 2812 breast milk samples and 216 24-h urine samples were collected from each lactating mother for four consecutive days. In addition, a 3 days 24 h dietary record, including salt weighing and drinking water samples collecting, was performed by each lactating mother to determine dietary iodine intake during the weighing study.

RESULTS

The average dietary iodine intake of lactating women was 323 ± 80 μg/d. The median breast milk iodine concentration and 24 h urinary iodine concentration of lactating women were 154 (122-181) and 135 (104-172) μg/L, respectively. The mean volume of breast milk and the mean iodine loss in the breast milk of lactating women were 711 ± 157 mL/d and 112 ± 47 μg/d, respectively. The appropriate dietary intake of iodine among lactating Chinese women is approximately 260 µg/d.

CONCLUSIONS

Based on the iodine loss in breast milk (110 μg/d) found in this study, and the estimated average requirement of iodine for adults, the appropriate dietary intake of iodine among lactating Chinese women is 260 µg/d, which is higher than the 240 μg/d recommended by the China Nutrition Science Congress in 2013.

Half of expectant women in Montenegro show iodine deficiency, indicating that supplementation during pregnancy is necessary

OBJECTIVE

In this study, iodine level in pregnant women of Montenegro and their needs for supplementation were investigated.

METHODS

A urinary iodine concentration (UIC) study of 326 pregnant women between September and December 2017 in three regions of Montenegro was performed. UIC was related to creatinine (UI/Cr ratio).

RESULTS

The median UIC (133 ± 5 μg/L) was indicative of iodine deficiency, as the WHO recommended UIC is 150-249 μg/L. The UI/Cr ratio (160 ± 6 μg/g creatinine) was just above the WHO/UNICEF/IGN recommendation. Approximately 50% of the surveyed women had a lower UIC than that recommended.

CONCLUSION

Iodine deficiency is present in pregnant women in Montenegro. Monitoring the UIC during routine analyses in pregnant women in Montenegro is recommended, along with iodine supplementation for individuals that need it.

[Neonatal thyrotropin - indicatior of monitoring of iodine deficiency severity. What's level is considered a «cutoff point»?]

BACKGROUND

The issues of monitoring the effectiveness of iodine deficiency prevention programs are an important component in the process of iodine elimination. Neonatal thyrotropin (TSH) has been used as a criterion for the severity of iodine deficiency since 1994, however, the question of the "cut-off point" of the neonatal TSH level has been widely discussed in the recent literature.

AIM

Evaluate the criterion for neonatal hyperthyroidism above 5 mIU/l from the perspective of monitoring iodine deficiency and establish a «cut-off point» on the model of healthy pregnant women with adequate iodine status.

MATERIALS AND METHODS

A prospective study was conducted in a population of pregnant women in the city of Tyumen, with the formation of observation groups according to the level of iodine excretion in the urine - the main group (with adequate iodine status throughout the entire gestation period) and the comparison group (women with iodine levels less than 150 μg/l). The results of neonatal screening for congenital hypothyroidism in children of women participating in the study were evaluated. The frequency of neonatal TSH above 5mIU/l was assessed in the observation groups. ROC-analysis was performed and a «cut-off point» of the level of neonatal TSH was established as an indicator of iodine deficiency.

RESULTS

The median urinary iodine concentration in the population of pregnant women in Tyumen was 159.05 μg/l, the incidence of goiter was 0.38%, the incidence of neonatal hyperthyroidism above 5 mIU/l was 2.88%, which characterizes adequate iodine intake in the pregnant population women. The frequency of neonatal TSH above 5 mIU/l in newborns from women from the main group was 1.47%, and in the comparison group - 9.3% (p = 0.076). ROC analysis revealed a threshold value of neonatal TSH of 2.77 mIU/l at the cut-off point, which corresponded to the highest value of the Youden index. Urinary iodine concentrations greater than 150 μg/l were predicted for nTSH values below this value.

CONCLUSION

Analysis of databases of neonatal screening for congenital hypothyroidism makes it possible to effectively, quickly and at minimal cost annually assess the iodine status in the population. The established «cut-off point» of neonatal TSH in the model of healthy pregnant women with adequate iodine intake in our work is 2.77 mIU/l, the absence of statistically significant differences in the incidence of neonatal hyperthyroidism above 5 mIU/l from women with different iodine status during pregnancy indicate the need to revise the existing threshold of 5 mIU/l and may be an incentive to conduct large-scale studies in regions with different iodine supply.

The relationship between different iodine sources and nutrition in pregnant women and adults

Background

Different iodine supplement measures emerge along with the economy development in China. The article objectives are to compare and explore the relationship between iodine sources and nutrition of pregnant women and adults.

Methods

A total of 2,145 pregnant women and 1,660 adults were investigated by multi-stage random method. Questionnaire was used to collect basic information and the consumption of food, water, and iodine preparations. Household salt and individual urine and blood samples were collected, and thyroid function and morphology of pregnant women were measured.

Results

The median urinary iodine concentration (MUIC) of pregnant women (164.49 μg/L) was lower than adults (187.30 μg/L, p < 0.05). Iodine supplement with IS (iodized salt) was the main measure for pregnant women and adults, and the difference was mainly on the consumption of iodine preparations between pregnant women (5.19%) and adults (0.85%). Moreover, adults' dietary iodine intake from food (100.6 μg/day), IS (140.8 μg/day), and drinking water (6.0 μg/day) was higher than those of pregnant women (86.5, 107.2, and 3.5 μg/day, respectively). Compared with iodine supplement with IS, ISFP (IS + iodine-rich food + iodine preparations) could reduce the risk of iodine deficiency for pregnant women. The MUICs for pregnant women and adults of iodine supplements with IF (iodine-rich food) and ISF (IS + iodine-rich food) were lower. For pregnant women, thyroid nodule (11.90%) and peroxidase antibody (TPOAb) positive (9.32%) were high prevalent thyroid diseases, and habitation (urban/rural), gestation, annual income, and drinking water type would affect them.

Conclusion

Pregnant women and adults had adequate iodine nutrition in four provinces. Their iodine supplement measures were different, the consumption of iodine preparations in pregnant women was higher, and their dietary iodine intake was lower than adults. ISFP was an effect measure for pregnant women to supplement iodine.

The Role of Iodine for Thyroid Function in Lactating Women and Infants

Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.

Effect of Moderate-to-Severe Iodine Deficiency in Early Pregnancy on Subclinical Hypothyroidism: A Longitudinal Study in an Iodine-Sufficient Region in China

Objective

To investigate iodine status among pregnant women in an iodine-sufficient region in China after the implementation of revised universal salt iodization (USI) standards in 2012 and assess the association between urinary iodine concentrations (UIC) in early pregnancy and the incidence of subclinical hypothyroidism (SCH) in euthyroid women negative for antithyroid Ab during different trimesters.

Methods

We measured the iodine status of 1,264 pregnant women, and performed follow-up assessment of thyroid function at 20 and 30 weeks of gestation among a cohort of 250 euthyroid women. We assessed the association of UIC in the 1st trimester with the incidence of SCH in subsequent trimesters. UIC and serum free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) were measured.

Results

The median UIC was 135.95 μg/L among 1,264 women. Serum FT4 level was significantly higher in the group of UIC 150 to 249 μg/L compared with other UIC groups (P &lt; 0.001). TSH was significantly higher in the UIC more than or equal to 250 μg/L group than the UIC 150 to 249 g/L group (P = 0.043). Of the 250 euthyroid women negative for antithyroid Ab (TSH value of 2.5–3.55 mU/L) in the 1st trimester, pregnant women with UIC lower than 100 μg/L in the 1st trimester exhibited a significantly increased risk of SCH (odds ratio [OR] = 2.47; 95% confidence interval [CI] = 1.22–5.71; P = 0.012, according to the Chinese Medical Association criteria; OR = 5.22, 95% CI = 1.73–6.09, P = 0.004, according to ATA criteria) during the latter half of pregnancy compared with the UIC 150 to 249 μg/L group.

Conclusion

Moderate-to-severe iodine deficiency (UIC lower than 100 μg/L) in the 1st trimester was associated with a significantly higher risk of SCH during the 2nd or 3rd trimesters among euthyroid pregnant women who had negative for antithyroid Ab. Women with SCH during pregnancy require regular UIC tests to maintain appropriate iodine status.

Assessment of Iodofolic Supplementation on Thyroid Function in Pregnant Women with Iodine Sufficient Status and their Infants in Birjand

BACKGROUND

Maintaining iodine at sufficient levels is necessary throughout the pregnancy to prevent adverse outcomes in infants. This study aimed to assess iodofolic supplementation's impact on thyroid function in women at the end of the third trimesters of gestation.

METHODS

This case-control study was conducted on 130 pregnant women in the Birjand, east of Iran, during the period from August 2017 to February 2019. We assessed iodofolic supplementation effect in the women at the first trimesters of gestation and followed them at the end of the third trimesters and also their infants on days 3-5. Serum samples were obtained from women and infants for measuring levels of thyroid-stimulating hormone (TSH). Urinary iodine concentration (UIC) was also determined at the end of the third trimester.

RESULTS

The median serum TSH concentration in the folic acid consumed group (3.26 ± 1.91) did not significantly differ from another group (2.98 ± 1.41), (p = 0.68). There is also no considerable difference in the mean serum TSH concentration between infants born from mothers who consumed folic acid in the first trimester of pregnancy and another group (p = 0.50). The TSH concentration in all infants was below 5 μM/L. The significant difference in the mean of UIC was also not observed between pregnant women in the folic acid consumed group (188.02 ± 105.38) and iodofolic consumed group (225.77 ± 130.26), (p = 0.13).

CONCLUSION

Iodine intake in our study was sufficient according to the WHO recommendation and idofolic supplementation was not emphasized.

Investigation on spatial variability and influencing factors of drinking water iodine in Xinjiang, China

Background and objectives

Xinjiang is one of the areas in China with extremely severe iodine deficiency. The health of Xinjiang residents has been endangered for a long time. In order to provide reasonable suggestions for scientific iodine supplementation and improve the health and living standards of the people in Xinjiang, it is necessary to understand the spatial distribution of iodine content in drinking water and explore the influencing factors of spatial heterogeneity of water iodine content distribution.

Methods

The data of iodine in drinking water arrived from the annual water iodine survey in Xinjiang in 2017. The distribution of iodine content in drinking water in Xinjiang is described from three perspectives: sampling points, districts/counties, and townships/streets. ArcGIS was used for spatial auto-correlation analysis, mapping the distribution of iodine content in drinking water and visualizing the distribution of Geographically Weighted Regression (GWR) model parameter. Kriging method is used to predict the iodine content in water at non-sampling points. GWR software was used to build GWR model in order to find the factors affecting the distribution of iodine content in drinking water.

Results

There are 3293 sampling points in Xinjiang. The iodine content of drinking water ranges from 0 to 128 μg/L, the median is 4.15 μg/L. The iodine content in 78.6% of total sampling points are less than 10 μg/L, and only that in the 3.4% are more than 40 μg/L. Among 1054 towns’ water samples in Xinjiang, 88.9% of the samples’ water iodine content is less than 10 μg/L. Among the 94 studied areas, the median iodine content in drinking water in 87 areas was less than 10 μg/L, those values in 7 areas were between 10–40 μg/L, and the distribution of water iodine content in Xinjiang shows clustered. The GWR model established had found that the effects of soil type and precipitation on the distribution of iodine content in drinking water were statistically significant.

Conclusions

The iodine content of drinking water in Xinjiang is generally low, but there are also some areas which their drinking water has high iodine content. Soil type and precipitation are the factors affecting the distribution of drinking water iodine content, and are statistically significant (P<0.05).

Iodine: Its Role in Thyroid Hormone Biosynthesis and Beyond

The present review deals with the functional roles of iodine and its metabolism. The main biological function of iodine concerns its role in the biosynthesis of thyroid hormones (THs) by the thyroid gland. In addition, however, further biological roles of iodine have emerged. Precisely, due to its significant action as scavenger of reactive oxygen species (ROS), iodine is thought to represent one of the oldest antioxidants in living organisms. Moreover, iodine oxidation to hypoiodite (IO⁻) has been shown to possess strong bactericidal as well as antiviral and antifungal activity. Finally, and importantly, iodine has been demonstrated to exert antineoplastic effects in human cancer cell lines. Thus, iodine, through the action of different tissue-specific peroxidases, may serve different evolutionarily conserved physiological functions that, beyond TH biosynthesis, encompass antioxidant activity and defense against pathogens and cancer progression.

Quality Traits and Nutritional Value of Pork and Poultry Meat from Animals Fed with Seaweeds

Seaweeds have caught the attention of the scientific community in recent years. Their production can mitigate the negative impact of anthropogenic activity and their use in animal nutrition reduces the dependency on conventional crops such as maize and soybean meal. In the context of monogastric animals, novel approaches have made it possible to optimise their use in feed, namely polysaccharide extraction, biomass fermentation, enzymatic processing, and feed supplementation with carbohydrate-active enzymes (CAZymes). Their bioactive properties make them putative candidates as feed ingredients that enhance meat quality traits, such as lipid oxidation, shelf-life, and meat colour. Indeed, they are excellent sources of essential amino acids, polyunsaturated fatty acids, minerals, and pigments that can be transferred to the meat of monogastric animals. However, their nutritional composition is highly variable, depending on species, harvesting region, local pollution, and harvesting season, among other factors. In this review, we assess the current use and challenges of using seaweeds in pig and poultry diets, envisaging to improve meat quality and its nutritional value.

Prevalence of goiter and iodine deficiency in indigenous pregnant women from five nonmetropolitan areas of Colombia 2019

Objective: To assess the prevalence of goiter and iodine deficiency in indigenous pregnant women coming from five non-metropolitan areas in Colombia. Materials and methods: Descriptive cross-sectional cohort study that included pregnant women of any gestational age with no pregnancy-related conditions, seen in community health centers or in their homes. Patients with comorbidities at the time of pregnancy and those who were receiving iodine supplementation were excluded. Simple random sampling was used. The sociodemographic and obstetric characteristics, urinary iodine concentration and the presence of goiter were measured in accordance with the World Health Organization methodology. A descriptive analysis was performed. Results: Of 189 indigenous pregnant women who were candidates to enter the study, 2 declined participation, and 62 had exclusion criteria, and 125 were included in the final analysis. The mean urinary iodine concentration was 184.4 μg/L (min-max: 12.0-390.0). A total of 42 women (33.6%) had iodine deficiency (< 100 μg/L), and goiter (grade 1-2) was found in 43 (34.4%). No grade 3 or 4 goiter was identified. Conclusions: A high prevalence of goiter and iodine deficiency was found in indigenous pregnant women living in non-metropolitan areas. There is a need to assess maternal and perinatal effects and to implement nutritional interventions.

Iodine Content in Meal Replacements in the United States

OBJECTIVE

Iodine is essential for thyroid hormone production. The recommended dietary allowance for iodine in nonpregnant adults is 150 μg/d. However, most product labels do not list the iodine content. Meal replacements are not required to contain specific vitamins and minerals. Nevertheless, they are often marketed as good and convenient sources of a balanced nutrition. In this study, we aimed to assess the iodine content in meal replacements to determine how they may contribute to iodine deficiency or excess.

METHODS

Twenty seven meal replacements from supermarkets in the Boston area were collected. The iodine concentration of each meal replacement was measured spectrophotometrically. Iodine content in meal replacements were compared according to form (liquid, bar, and powder) and type (vegan and nonvegan).

RESULTS

The overall mean ± SD iodine content was 49.7 ± 125.4 μg/serving. However, 1 meal replacement was an outlier and had 671.9 μg iodine per serving. Mean iodine content differed between forms and was highest for liquids (mean ± SD: 37.4 ± 6.5 μg/serving). Nonvegan meal replacements had a higher mean iodine content than vegan meal replacements (mean ± SD: 31.6 ± 15.78 μg/serving).

CONCLUSION

All of the meal replacements contained detectible amounts of iodine regardless of whether it was listed on their labels (41% did not list iodine). Overall, the meal replacements in this study were found to be good sources of iodine. However, consumers should be aware that packaging labels may not accurately reflect the amount of iodine present.

Iodine Deficiency Increases Fat Contribution to Energy Expenditure in Male Mice

More than a billion people worldwide are at risk of iodine deficiency (ID), with well-known consequences for development of the central nervous system. Furthermore, ID has also been associated with dyslipidemia and obesity in humans. To further understand the metabolic consequences of ID, here we kept 8-week-old C57/Bl6 mice at thermoneutrality (~28°C) while feeding them on a low iodine diet (LID). When compared with mice kept on control diet (LID + 0.71 μg/g iodine), the LID mice exhibited marked reduction in T4 and elevated plasma TSH, without changes in plasma T3 levels. LID mice grew normally, and had normal oxygen consumption, ambulatory activity, and heart expression of T3-responsive gene, confirming systemic euthyroidism. However, LID mice exhibited ~5% lower respiratory quotient (RQ), which reflected a ~2.3-fold higher contribution of fat to energy expenditure. LID mice also presented increased circulating levels of nonesterified fatty acids, ~60% smaller fat depots, and increased hepatic glycogen content, all indicative of accelerated lipolysis. LID mice responded much less to forced mobilization of energy substrates (50% food restriction for 3 days or starvation during 36 hours) because of limited size of the adipose depots. A 4-day treatment with T4 restored plasma T4 and TSH levels in LID mice and normalized RQ. We conclude that ID accelerates lipolysis and fatty acid oxidation, without affecting systemic thyroid hormone signaling. It is conceivable that the elevated plasma TSH levels trigger these changes by directly activating lipolysis in the adipose tissues.

Insufficient iodine status in pregnant women as a consequence of dietary changes

Background

Historically, Iceland has been an iodine-sufficient nation due to notably high fish and milk consumption. Recent data suggest that the intake of these important dietary sources of iodine has decreased considerably.

Objective

To evaluate the iodine status of pregnant women in Iceland and to determine dietary factors associated with risk for deficiency.

Methods

Subjects were women (n = 983; 73% of the eligible sample) attending their first ultrasound appointment in gestational weeks 11–14 in the period October 2017–March 2018. Spot urine samples were collected for assessment of urinary iodine concentration (UIC) and creatinine. The ratio of iodine to creatinine (I/Cr) was calculated. Median UIC was compared with the optimal range of 150–249 μg/L defined by the World Health Organization (WHO). Diet was assessed using a semiquantitative food frequency questionnaire (FFQ), which provided information on main dietary sources of iodine in the population studied (dairy and fish).

Results

The median UIC (95% confidence interval (CI)) and I/Cr of the study population was 89 μg/L (42, 141) and 100 (94, 108) μg/g, respectively. UIC increased with higher frequency of dairy intake, ranging from median UIC of 55 (35, 79) μg/L for women consuming dairy products <1 time per week to 124 (98, 151) μg/L in the group consuming dairy >2 times per day (P for trend <0.001). A small group of women reporting complete avoidance of fish (n = 18) had UIC of 50 (21, 123) μg/L and significantly lower I/Cr compared with those who did not report avoidance of fish (58 (34, 134) μg/g vs. 100 (94, 108) μg/g, P = 0.041). Women taking supplements containing iodine (n = 34, 3.5%) had significantly higher UIC compared with those who did not take supplements (141 (77, 263) μg/L vs. 87 (82, 94), P = 0.037).

Conclusion

For the first time, insufficient iodine status is being observed in an Icelandic population. There is an urgent need for a public health action aiming at improving iodine status of women of childbearing age in Iceland.

Nutritional Gaps and Supplementation in the First 1000 Days

Optimized nutrition during the first 1000 days (from conception through the 2nd birthday) is critical for healthy development and a healthy life for the newborn. Pregnancy and the postpartum period are accompanied by physiological changes, increased energy needs, and changing requirements in the nutrients critical for optimal growth and development. Infants and toddlers also experience physiological changes and have specific nutritional needs. Food and nutrition experts can provide women of childbearing age with adequate dietary advice to optimize nutrition, as well as guidance on selecting appropriate dietary supplements. Considering the approaching 2020-2025 Dietary Guidelines for Americans (DGA) will be making specific recommendations for children, it is important to provide accurate scientific information to support health influencers in the field of nutrition. The purpose of this review is to summarize the nutrition and supplementation literature for the first 1000 days; to highlight nutritional and knowledge gaps; and to educate nutrition influencers to provide thoughtful guidance to mothers and families. Optimal nutrition during pregnancy through early childhood is critical for supporting a healthy life. Nutrition influencers, such as dietitians, obstetricians/gynecologists, and other relevant health professionals, should continue guiding supplement and food intake and work closely with expectant families and nutrition gatekeepers.