-
1.
Effect of probiotics or prebiotics on thyroid function: A meta-analysis of eight randomized controlled trials.
Shu, Q, Kang, C, Li, J, Hou, Z, Xiong, M, Wang, X, Peng, H
PloS one. 2024;19(1):e0296733
-
-
-
Free full text
Plain language summary
The gut microbiome is thought to play a role in thyroid disorders, mediated by regulating iodine uptake, degradation and enterohepatic cycling of thyroid hormones, and differences in microbiome composition between patients with thyroid disorders and healthy individuals have been observed. The aim of this systematic review and meta-analysis was to evaluate the effect of pro-, pre- and synbiotics on thyroid function (thyroid stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) and thyroid stimulating hormone receptor antibody (TRAb)) in patients with and without thyroid disorders. 8 randomised controlled trials including 367 participants were included in the review and meta-analysis. Neither pro-, pre- nor synbiotics had a significant effect on TSH, fT4 or fT3 but pre- and probiotics lead to a significant reduction in TRAb in patients with Graves’ disease.
Abstract
BACKGROUND Microbiome-directed therapies are increasingly utilized to optimize thyroid function in both healthy individuals and those with thyroid disorders. However, recent doubts have been raised regarding the efficacy of probiotics, prebiotics, and synbiotics in improving thyroid function. This systematic review aimed to investigate the potential relationship between probiotics/prebiotics and thyroid function by analyzing the impact on thyroid hormone levels. METHODS We conducted a comprehensive systematic review and meta-analysis of randomized controlled trials that investigated the effects of probiotics, prebiotics, and synbiotics on free triiodothyronine (fT3), free thyroxine (fT4), thyroid stimulating hormone (TSH), and thyroid stimulating hormone receptor antibody (TRAb) levels. We searched for articles from PubMed, Scopus, Web of Science, and Embase up until April 1st, 2023, without any language restriction. Quantitative data analysis was performed using a random-effects model, with standardized mean difference (SMD) and 95% confidence interval as summary statistics. The methods and results were reported according to the PRISMA2020 statement. RESULTS A total of eight articles were included in this review. The meta-analysis showed no significant alterations in TSH (SMD: -0.01, 95% CI: -0.21, 0.20, P = 0.93; I2: 0.00%), fT4 (SMD: 0.04, 95% CI: -0.29, 0.21, P = 0.73; I2: 0.00%) or fT3 (SMD: 0.45, 95% CI: -0.14, 1.03, P = 0.43; I2: 78.00%), while a significant reduction in TRAb levels was observed (SMD: -0.85, 95% CI: -1.54, -0.15, P = 0.02; I2: 18.00%) following probiotics/prebiotics supplementation. No indication of publication bias was found. CONCLUSIONS Probiotics/prebiotics supplementation does not influence thyroid hormone levels, but may modestly reduce TRAb levels in patients with Graves' disease.
-
2.
Selenium Supplementation in Patients with Hashimoto Thyroiditis:A Systematic Review and Meta-Analysis of Randomized Clinical Trials.
Huwiler, VV, Maissen-Abgottspon, S, Stanga, Z, Mühlebach, S, Trepp, R, Bally, L, Bano, A
Thyroid : official journal of the American Thyroid Association. 2024
-
-
-
Free full text
-
Plain language summary
Hashimoto Thyroiditis (HT) is a disease of the thyroid gland, which can result in insufficient production of thyroid hormone. Thyroid hormone is responsible for numerous functions within the body, such as weight regulation and energy production. Selenium is a nutrient that is used in the body to make thyroid hormones and low levels have been seen in patients with HT. Selenium supplementation has been researched previously, but inconsistent results have been shown. This systematic review and meta-analysis of 35 and 32 randomised control trials respectively, aimed to determine the effect of selenium supplementation on HT. The results showed that selenium supplementation favourably influenced thyroid hormones and oxidative stress, without affecting inflammation, but only if individuals were not receiving thyroid hormone replacement therapy. Adverse events were similar between the supplementation and control groups. It was concluded that selenium supplementation is a safe and effective therapy for individuals with HT who are not receiving hormone replacement therapy. This study could be used by healthcare professionals to recommend selenium supplementation as a way to balance thyroid hormones and alleviate the effects of HT.
Abstract
Background: Hashimoto thyroiditis (HT) is the most common cause of hypothyroidism in iodine-sufficient areas. Selenium is an essential trace element required for thyroid hormone synthesis and exerts antioxidant effects. Therefore, it may be of relevance in the management of HT. Methods: We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of selenium supplementation on thyroid function (thyrotropin [TSH], free and total thyroxine [fT4, T4], free and total triiodothyronine [fT3, T3]), thyroid antibodies (thyroid peroxidase antibodies [TPOAb], thyroglobulin antibodies [TGAb], thyrotropin receptor antibody [TRAb]), ultrasound findings (echogenicity, thyroid volume), immune markers, patient-reported outcomes, and adverse events in HT. The study protocol was registered on PROSPERO (CRD42022308377). We systematically searched MEDLINE, Embase, CINHAL, Web of Science, Google Scholar, and the Cochrane CENTRAL Register of Trials from inception to January 2023 and searched citations of eligible studies. Two independent authors reviewed and coded the identified literature. The primary outcome was TSH in patients without thyroid hormone replacement therapy (THRT); the others were considered secondary outcomes. We synthesized the results as standardized mean differences (SMD) or odds ratio (OR), assessed risk of bias using the Cochrane RoB 2 tool, and rated the evidence using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach. Results: We screened 687 records and included 35 unique studies. Our meta-analysis found that selenium supplementation decreased TSH in patients without THRT (SMD -0.21 [confidence interval, CI -0.43 to -0.02]; 7 cohorts, 869 participants; I2 = 0%). In addition, TPOAb (SMD -0.96 [CI -1.36 to -0.56]; 29 cohorts; 2358 participants; I2 = 90%) and malondialdehyde (MDA; SMD -1.16 [CI -2.29 to -0.02]; 3 cohorts; 248 participants; I2 = 85%) decreased in patients with and without THRT. Adverse effects were comparable between the intervention and control groups (OR 0.89 [CI 0.46 to 1.75]; 16 cohorts; 1339 participants; I2 = 0%). No significant changes were observed in fT4, T4, fT3, T3, TGAb, thyroid volume, interleukin (IL)-2, and IL-10. Overall, certainty of evidence was moderate. Conclusions: In people with HT without THRT, selenium was effective and safe in lowering TSH, TPOAb, and MDA levels. Indications for lowering TPOAb were found independent of THRT.
-
3.
Incidence and Determinants of Spontaneous Normalization of Subclinical Hypothyroidism in Older Adults.
van der Spoel, E, van Vliet, NA, Poortvliet, RKE, Du Puy, RS, den Elzen, WPJ, Quinn, TJ, Stott, DJ, Sattar, N, Kearney, PM, Blum, MR, et al
The Journal of clinical endocrinology and metabolism. 2024;109(3):e1167-e1174
-
-
-
Free full text
-
Plain language summary
With increasing age, circulating levels of thyroid stimulating hormone (TSH) generally rise, accompanied by a higher prevalence of subclinical hypothyroidism. Subclinical hypothyroidism is defined as an elevated TSH level while the serum free T4 (fT4) concentration is within the normal range. The aim of this study was to investigate the incidence of spontaneous normalisation of TSH levels and identify determinants of normalisation in a large group of adults aged 65 years and older with (persistent) subclinical hypothyroidism. This study was a longitudinal study that pooled data from 2 randomised, double-blind, placebo-controlled parallel-group clinical trials. Results showed that 60.8% of the older adults with biochemical subclinical hypothyroidism based on at least 1 elevated TSH measurement, TSH levels had returned to the normal range without intervention after a median follow-up of 1 year. Subsequently, TSH levels had still normalised after 1 year in 39.9% of older adults with persistent subclinical hypothyroidism. Younger age, female sex, lower initial TSH level, higher normal initial fT4 level, the absence of thyroid peroxidase antibodies, and a second measurement in summer were independent determinants for TSH normalisation. Authors concluded that since TSH levels spontaneously normalised in a large proportion of older adults with subclinical hypothyroidism, a third measurement is recommended before considering treatment.
Abstract
CONTEXT With age, the prevalence of subclinical hypothyroidism rises. However, incidence and determinants of spontaneous normalization remain largely unknown. OBJECTIVE To investigate incidence and determinants of spontaneous normalization of TSH levels in older adults with subclinical hypothyroidism. DESIGN Pooled data were used from the (1) pretrial population and (2) in-trial placebo group from 2 randomized, double-blind, placebo-controlled trials (Thyroid Hormone Replacement for Untreated Older Adults With Subclinical Hypothyroidism Trial and Institute for Evidence-Based Medicine in Old Age thyroid 80-plus thyroid trial). SETTING Community-dwelling 65+ adults with subclinical hypothyroidism from the Netherlands, Switzerland, Ireland, and the United Kingdom. PARTICIPANTS The pretrial population (N = 2335) consisted of older adults with biochemical subclinical hypothyroidism, defined as ≥1 elevated TSH measurement (≥4.60 mIU/L) and a free T4 within the laboratory-specific reference range. Individuals with persistent subclinical hypothyroidism, defined as ≥2 elevated TSH measurements ≥3 months apart, were randomized to levothyroxine/placebo, of which the in-trial placebo group (N = 361) was included. MAIN OUTCOME MEASURES Incidence of spontaneous normalization of TSH levels and associations between participant characteristics and normalization. RESULTS In the pretrial phase, TSH levels normalized in 60.8% of participants in a median follow-up of 1 year. In the in-trial phase, levels normalized in 39.9% of participants after 1 year of follow-up. Younger age, female sex, lower initial TSH level, higher initial free T4 level, absence of thyroid peroxidase antibodies, and a follow-up measurement in summer were independent determinants for normalization. CONCLUSION Because TSH levels spontaneously normalized in a large proportion of older adults with subclinical hypothyroidism (also after confirmation by repeat measurement), a third measurement may be recommended before considering treatment. TRIAL REGISTRATION ClinicalTrials.gov, NCT01660126 and Netherlands Trial Register, NTR3851.
-
4.
The Influence of Nutritional Intervention in the Treatment of Hashimoto's Thyroiditis-A Systematic Review.
Osowiecka, K, Myszkowska-Ryciak, J
Nutrients. 2023;15(4)
-
-
-
Free full text
Plain language summary
Hashimoto’s thyroiditis is an autoimmune disorder characterized by the presence of antibodies in the thyroid gland such as thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies. Immune-mediated inflammatory responses eventually lead to the progressive destruction of the gland and impaired thyroid function. The disease has a strong genetic disposition but is also influenced by environmental factors, including diet. Hence diet has been considered a complementary tool to manage thyroid function and disease progression by harnessing the benefits of certain nutrients and anti-inflammatory properties. This systematic review examined the effects of nutrients and dietary interventions on Hashimoto’s disease in current literature. Using antibody levels, thyroid hormone levels and body weight to measure outcomes. The review included 9 studies, all of which compared the intervention group to the control groups. The trials included looked at gluten-free, lactose-free and energy-restricted diets, with or without selected nutrients and foods supplements (ie. Nigella sativa, iodine). The intervention duration ranged from 3 weeks to 12 months. Despite the small number of trials, the data from those studies included in this review showed promising results. Improvements in disease parameters were observed in diets that were energy deficient, eliminated gluten, lactose and goitrogens or added Nigella sativa. Iodine restrictions did not show any improvements. In the discussion section, the authors presented the results in the wider context and the findings from other studies. Ultimately there appears to be a wide variance in outcomes, usually ranging from beneficial to neutral. The authors contributed to such variability due to the complexity of the condition and many influencing factors. Often participants in trials have highly variable thyroid status and function, and differences in regular dietary intakes of nutrients critical to thyroid health can easily distort the results. Hence much more specific research is needed to make firmer conclusions. Whereby no clear conclusions in larger groups could be drawn, potential benefits of dietary interventions in Hashimoto's disease may be much more apparent in clinical settings with personalized approaches that account for such individual variances.
Abstract
Diet can be a complementary treatment for Hashimoto's disease by affecting thyroid function and anti-inflammatory properties. It is still unclear which dietary strategy would be the most beneficial. The aim of this systematic review is to examine all the data currently available in the literature on the effects of nutritional intervention on biochemical parameters (anti-thyroid antibody and thyroid hormones levels) and characteristic symptoms in the course of Hashimoto's thyroiditis. This systematic review was prepared based on PRISMA guidelines. Articles in PubMed and Scopus databases published up to November 2022 were searched. As a result of the selection, out of 1350 publications, 9 were included for further analysis. The nutritional interventions included the following: elimination of gluten (3 articles) or lactose (1 article), energy restriction with or without excluding selected foods (n = 2), consumption of Nigella sativa (n = 2), or dietary iodine restriction (n = 1). The intervention duration ranged from 21 days to 12 months and included individuals with various thyroid function. Of the nine studies, three studies were female only. An improvement was observed during an energy deficit and after the elimination of selected ingredients (e.g., gluten, lactose, or goitrogens), as well as after the intervention of Nigella sativa. These interventions improved antibody levels against peroxidase (anti-TPO), (thyrotropin) TSH, and free thyroxine (fT4). No improvement was seen on the iodine-restricted diet. Varied outcomes of analyzed dietary interventions may be due to the heterogeneous thyroid condition, high variability between patients, and differences in habitual intake of critical nutrients (e.g., iodine, selenium, and iron) in different populations. Therefore, there is a great need for further experimental studies to determine whether any nutritional interventions are beneficial in Hashimoto's disease.
-
5.
Are probiotics, prebiotics, and synbiotics beneficial in primary thyroid diseases? A systematic review with meta-analysis.
Zawadzka, K, Kałuzińska, K, Świerz, MJ, Sawiec, Z, Antonowicz, E, Leończyk-Spórna, M, Abadi, AK, Trofimiuk-Müldner, M, Bała, MM
Annals of agricultural and environmental medicine : AAEM. 2023;30(2):217-223
-
-
-
Free full text
Plain language summary
Irregularities in intestinal microbial composition are thought to be correlated with thyroid dysfunction. Supplementation of prebiotics, probiotics and synbiotics are gaining momentum in recent times in improving health in general. This systematic review of randomised controlled trials was conducted to summarise the up-to-date evidence on the therapeutic potential of prebiotics, probiotics and synbiotics in the treatment of thyroid disease. The meta-analysis did not show beneficial effects on thyroid hormone balance, BMI or levothyroxine dosage reduction. Supplementation with Lactobacillus and Bifidobacterium resulted in improvement in constipation and a statistically non-significant reduction in thyroid-stimulating hormone in adult participants with hypothyroidism. Further robust long-term studies are required to evaluate the efficacy of prebiotics, probiotics and synbiotics in thyroid disease treatment as the availability of the number of studies included in this systematic review was limited. However, healthcare professionals can use the review to understand the current evidence in this area and the correlation between gut microbial alterations and thyroid disease.
Abstract
INTRODUCTION AND OBJECTIVE A number of studies indicate the presence of a thyroid-gut axis and the important influence of the gut microbiota on thyroid function. As prebiotics, probiotics and synbiotics show therapeutic potential in the treatment of intestinal dysbiosis, the aim of this review is to evaluate the efficacy of their supplementation in primary thyroid diseases. REVIEW METHODS Electronic databases (Ovid MEDLINE, Embase, CENTRAL), registers of clinical trials, and grey literature up to 6 October 2022 were searched for randomised controlled trials (RCTs) meeting pre-specified inclusion criteria. The protocol was registered in PROSPERO (CRD42021235054). BRIEF DESCRIPTION OF THE STATE OF KNOWLEDGE After screening 1,721 references, two RCTs were identified, which included 136 hypothyroid participants in total. Meta-analysis of the results after eight weeks of supplementation with predominantly Lactobacillus and Bifidobacterium strains indicated a clinically and statistically nonsignificant decrease in TSH (MD -0.19 mIU/L; 95% CI -0.43 to 0.06; I2= 0%), and no effect on fT3 levels (MD 0.01 pg/mL; 95% CI-0.16 to 0.18; I2= 0%). Data from single studies indicated no significant change in the levels of fT4, thyroid auto-antibodies, BMI, levothyroxine doses, and severity of symptoms measured with validated scales. Only constipation scores showed significant improvement (MD -8.71 points in the Faecal Incontinence Questionnaire; 95% CI -15.85 to -1.57; I2= 0%). SUMMARY Low-certainty evidence from two randomised trials, suggests that routine administration of probiotics, prebiotics or synbiotics may result in little to no benefit in patients with primary hypothyroidism.
-
6.
Do Dietary Supplements Affect Inflammation, Oxidative Stress, and Antioxidant Status in Adults with Hypothyroidism or Hashimoto's Disease?-A Systematic Review of Controlled Trials.
Kubiak, K, Szmidt, MK, Kaluza, J, Zylka, A, Sicinska, E
Antioxidants (Basel, Switzerland). 2023;12(10)
-
-
-
Free full text
Plain language summary
A deficiency of the thyroid hormone causes hypothyroidism (HT), whereas Autoimmune thyroiditis (AIT) is mainly an organ-specific autoimmune condition. Both HT and AIT are characterised by low-grade inflammation and inflammation in the thyroid gland. Dietary supplements may offer health benefits; however, previous research findings are inconclusive. This systematic review evaluated twenty-two controlled studies to understand the effectiveness of dietary supplements in reducing inflammation and oxidative stress and improving antioxidant and thyroid parameters in patients with HT or AIT. The efficacy of dietary supplements in improving thyroid health and reducing inflammation and oxidative stress was inconclusive due to the low quality of the included studies and the limited number of available studies. Selenium supplements might be beneficial in improving thyroid parameters and inflammation in patients with HT or AIT. Even though the therapeutic benefits of dietary supplements in treating thyroid disease were inconclusive, healthcare professionals can use them to address the common nutritional deficiencies in people with HT and AIT. Further, large, long-term, robust studies are required to assess the therapeutic utility of different dietary supplements in promoting the health of the thyroid gland.
Abstract
This systematic review aims to summarise the results of controlled trials on dietary supplements (DS) usage and inflammation, oxidative stress, antioxidant status, and thyroid parameter improvement in hypothyroidism (HT)/Hashimoto's thyroiditis (AIT) patients. The study protocol was registered with PROSPERO (no. CRD42022365149). A comprehensive search of the PubMed, Scopus, and Web of Science databases resulted in the identification of nineteen randomised controlled trials and three non-randomised studies for the review; three studies examined the effect of supplementation with vitamin D, twelve studies-with selenium, and seven studies-with other DS. Based on very limited evidence, the lack of influence of vitamin D supplementation on inflammatory parameters was found, while no studies have examined oxidative stress and antioxidant status parameters, and only one provided results for a single thyroid parameter after an intervention. Some evidence was found proving that selenium supplementation may decrease inflammation and improve thyroid parameters, but reaching a conclusion about its influence on oxidative stress and antioxidant status is not possible because of the insufficient number of studies. Additionally, due to examining other DS (e.g., multicomponent, Nigella sativa, and genistein) only in single studies, conclusions cannot be drawn. Further long-term, high-quality randomised controlled trials are necessary to better understand the influence of DS on inflammation, oxidative stress, and antioxidant status, as well as their potential to improve thyroid gland function in HT/AIT patients.
-
7.
How to keep your mitochondria healthy for better energy
Dr Ruscio is a Doctor of Natural Medicine, Doctor of Chiropractic, clinical researcher and author. His podcast, Dr Ruscio Radio presents cutting edge information in health, nutrition and functional medicine distilled into practical advice that can be used to improve our health.
2023
Abstract
Dr Ruscio chats to Ari Whitten to unpack mitochondrial health, introducing the concept that mitochondria are not just energy producers but are also involved in cellular defence, protecting the body by dialling down energy production if they feel threatened. Subsequently, intervening upstream with implementation of diet and lifestyle changes may help shut off this defence response so that mitochondria can focus on energy production. They review the myriad of connections between nutrition, lifestyle factors and mitochondrial function, including body composition/fat, gut health, blood sugar regulation, and sleep (particularly circadian rhythm and melatonin). Mitochondrial testing and supplementation are discussed, as well as fasting to support mitochondrial health, and ways to potentially mitigate mitochondrial loss with ageing via hormetic stress.
-
8.
How chronic stress can impact your adrenals and thyroid
Dr Ruscio explores the evidence around different types of probiotic drinks, their wide ranging effects on gut, cardiovascular, metabolic, and immune system health, and how their efficacy may be impacted by storage and processing. He also does a comparison between the effectiveness of probiotic drinks, probiotic supplements and probiotic food, with respect to their viability and delivery system within the body.
2023
Abstract
Dr Ruscio reviews the impact that chronic stress can have on our adrenal and thyroid health and the underlying mechanisms. He explores the internal factors that influence our cortisol levels such as gut health and nutrient insufficiency/caloric restriction, but also the external factors such as unresolved daily stressors that place a burden on the hypothalamus-pituitary-adrenal (HPA) axis. Identifying the root cause of chronic stress and looking at ways to improve our response to stress may be the single most important way to support adrenal health, but he also touches upon the evidence for adaptogenic herbs such as Ashwagandha and Rhodiola.
-
9.
Associations between Dynamic Vitamin D Level and Thyroid Function during Pregnancy.
Wang, H, Wang, HJ, Jiao, M, Han, N, Xu, J, Bao, H, Liu, Z, Ji, Y
Nutrients. 2022;14(18)
-
-
-
Free full text
Plain language summary
Thyroid hormones play a vital role in regulating metabolism. Adequate thyroid hormone levels are also critical during pregnancy for optimal fetal growth and development. The foetus is dependent on maternal thyroid hormones until its own thyroid gland matured in the second half of pregnancy. Furthermore, pregnancy impacts thyroid function leading to an increased demand for thyroid hormones. Thyroid disease has been associated with Vitamin D deficiency. During pregnancy, both thyroid disorders and Vitamin D deficiency can have adverse effects on pregnancy and pregnancy outcomes, hence a potential link between Vitamin D status and thyroid function has been postulated. To fill the gaps in previous research, this retrospective cohort study aimed to explore the associations between Vitamin D status and thyroid function throughout the pregnancy, in each trimester. The analysis of hospital data collected in Beijing demonstrated an association between Vitamin D levels and thyroid function throughout pregnancy. Such interlink appeared to be dynamic and changed depending on the stage of pregnancy. The author's findings affirmed that maintenance of adequate Vitamin D levels supports normal thyroid function which is an important nutritional strategy for a healthy pregnancy.
Abstract
Optimal Vitamin D (VitD) status and thyroid function are essential for pregnant women. This study aimed to explore associations between dynamic VitD status and thyroid function parameters in each trimester and throughout the pregnancy period. Information on all 8828 eligible participants was extracted from the Peking University Retrospective Birth Cohort in Tongzhou. Dynamic VitD status was represented as a combination of deficiency/sufficiency in the first and second trimesters. Thyroid function was assessed in three trimesters. The associations between VitD and thyroid function were assessed by multiple linear regression and generalized estimating equation models in each trimester and throughout the pregnancy period, respectively. The results indicated that both free thyroxine (fT4; β = 0.004; 95%CI: 0.003, 0.006; p < 0.001) and free triiodothyronine (fT3; β = 0.009; 95%CI: 0.004, 0.015; p = 0.001) had positive associations with VitD status in the first trimester. A VitD status that was sufficient in the first trimester and deficient in the second trimester had a lower TSH (β = -0.370; 95%CI: -0.710, -0.031; p = 0.033) compared with the group with sufficient VitD for both first and second trimesters. In conclusion, the associations between VitD and thyroid parameters existed throughout the pregnancy. Maintaining an adequate concentration of VitD is critical to support optimal thyroid function during pregnancy.
-
10.
The relationship between different iodine sources and nutrition in pregnant women and adults.
Sun, R, Fan, L, Du, Y, Liu, L, Qian, T, Zhao, M, Che, W, Liu, P, Sun, D
Frontiers in endocrinology. 2022;13:924990
-
-
-
Free full text
Plain language summary
Iodine is one of the essential trace elements in human body, which can only be obtained from the diet. Pregnant women are a special population, and their iodine intake needs to not only meet their own health needs but also to supply the growth of the foetus. The main aim of this study was to compare the iodine supplement measures and dietary contribution between pregnant women and adults. This study is based on a multi-stage random sampling method with a total of 2,128 pregnant women and 1,493 adults. Results show that iodine nutrition of pregnant women and adults was adequate in the four provinces included in the study. The largest difference of iodine levels between these provinces was the use of iodine during food preparation and the amount of dietary iodine intake. Additionally, the dietary iodine intake of pregnant women was less than the recommended nutrition intake. Authors conclude that various factors may affect thyroid disease prevalence in pregnant women, such as habitation (urban/rural) and gestation. Furthermore, it is important to coordinate the relationship between iodine nutrition and low sodium diet.
Abstract
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.