Trace elements and the thyroid

Multi-element analysis of metals in human pathological and unchanged thyroid glands - pilot study

Disturbances in the homeostasis of the elemental composition of thyroid tissue may have serious metabolic and health consequences. It is believed that the accumulation of some metals or the deficiency of others may even cause lethal tumours. Due to the fact that metallomics most often uses human serum to analyse macro and microelements as well as trace elements, it was decided to use material that is more difficult to obtain, but also adds credibility to the research - thyroid tissue samples biopsy. The experiments were conducted on 17 patients diagnosed with: nodular (10) and colloidal goitre (2), chronic thyroiditis (2), follicular adenoma (2) and papillary carcinoma (1). They were recruited by collecting a tumour fragment, control fragment and serum from each of them. The content of Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Zn was examined using ICP-OES (Inductively Coupled Plasma - Optical Emission Spectrometers). Simultaneously, biochemical methods were used to determine the markers of inflammation, glycation and peroxidation: malondialdehyde, pentosidine, reactive free amine content, compounds with thiol groups and galectin 3 in the sera of the examined patients. Three statistically significant correlations were identified: Ca-Mg and Cu-Zn in control tissues (p < 0.05) and Cr-Mn in pathological tissues (p < 0.05). A comparison of individual groups of patients shows that there are some potentail tendencies to increase or decrease in the concentration of certain elements or markers of inflammation and glycation, therefore we discuss potential relationships between a given parameter and a thyroid disorder. The pilot study is an introduction to a deeper analysis aimed at tracing the pathomechanism of the development of thyroid diseases, so that the risk of developing these diseases can be effectively minimized.

Thyroid dysfunction due to trace element deficiency-not only selenium but also zinc

INTRODUCTION

Levels of serum selenium (Se) and zinc (Zn) decrease when total parental nutrition (TPN) is administered without trace element supplementation for just a few weeks. These trace elements are involved in thyroid hormone metabolism and their deficiencies cause thyroid dysfunction. However, there have been few reports on the details of its clinical course.

CASE PRESENTATION

A 50-year-old man presented with thyroid dysfunction due to Se and Zn deficiency. He had an approximately 70-cm residual small intestine after undergoing intestinal resection and he received TPN without trace element supplementation for one and a half months. Blood tests revealed high levels of thyroid-stimulating hormone (TSH) and free thyroxine (FT4) and low levels of free triiodothyronine (FT3). An abnormal pattern of thyroid function led to suspicion of Se deficiency. Se supplementation raised FT3 levels and lowered FT4 levels to within their respective reference ranges; however, subclinical hypothyroidism persisted with transient TSH elevation. We suspected that Zn deficiency also contributed to the hypothyroidism and, therefore, initiated Zn supplementation, which resulted in normalization of thyroid function.

DISCUSSION

Although thyroid dysfunction has been reported in many studies conducted on Se and Zn deficiencies, hormonal patterns vary between reports. Further accumulation of cases, including detailed data on nutritional status, would be of benefit to elucidate the clinical reality.

CONCLUSION

It is important to consider Se and Zn deficiencies when TSH and FT4 levels are elevated. It should also be noted that transient TSH elevation may be observed with Se supplementation.

Magnesium Is a Vital Ion in the Body-It Is Time to Consider Its Supplementation on a Routine Basis

The importance of maintaining proper magnesium intake and total body magnesium content in preserving human health remains underappreciated among medical professionals and laymen. This review aimed to show the importance of hypomagnesemia as a modifiable risk factor for developing disease processes. We searched the PubMed database and Google Scholar using the keywords 'magnesium', 'diabetes', 'cardiovascular disease', 'respiratory disease', 'immune system', 'inflammation', 'autoimmune disease', 'neurology', 'psychiatry', 'cognitive function', 'cancer', and 'vascular calcification'. In multiple contexts of the search terms, all reviews, animal experiments, and human observational data indicated that magnesium deficiency can lead to or contribute to developing many disease states. The conclusions of several in-depth reviews support our working hypothesis that magnesium and its supplementation are often undervalued and underutilized. Although much research has confirmed the importance of proper magnesium supply and tissue levels, simple and inexpensive magnesium supplementation has not yet been sufficiently recognized or promoted.

The effect of micronutrient on thyroid cancer risk: a Mendelian randomization study

Background

The effect of micronutrients on thyroid cancer has been studied in observational studies, however, the cause of relationships has not yet been determined. Thyroid cancer was the subject of a Mendelian randomization (MR) analysis of micronutrients. Aimed to determine whether micronutrient intake has a causal impact on the chance of developing thyroid cancer.

Methods

We used a Mendelian randomization (MR) analysis with two samples. Our circulation levels of Cu, Ir, Zn, Ca, VD, and VC were reflected by genetic variations reported from GWAS in individuals of European ancestry. For the GWAS outcome of thyroid cancer. Sensitivity studies that included MR-Egger, weighted median/mode tests, and a more open selection of variations at a genome-wide sub-significant threshold were added to our inverse-variance weighted (IVW) MR study.

Results

Using the IVW approach, we did not find evidence that any of the micronutrients to thyroid cancer (Cu: odds ratio [OR = 0.88, p = 0.41]; Zn: odds ratio [OR = 0.87, p = 0.40]; Ir: odds ratio [OR = 1.18, p = 0.39]; Ca: odds ratio [OR = 1.12, p = 0.43]; VC: odds ratio [OR = 0.95, p = 0.22]; VD: odds ratio [OR = 0.89, p = 0.04]). The heterogeneity (p > 0.05) and pleiotropy (p > 0.05) testing provided confirmatory evidence for the validity of our MR estimates.

Conclusion

This study does not provide evidence that supplementation with micronutrients including Cu, Ir, Zn, Ca, VD, and VC can prevent thyroid cancer.

Metal-induced autoimmunity in neurological disorders: A review of current understanding and future directions

Autoimmunity is a multifaceted disorder influenced by both genetic and environmental factors, and metal exposure has been implicated as a potential catalyst, especially in autoimmune diseases affecting the central nervous system. Notably, metals like mercury, lead, and aluminum exhibit well-established neurotoxic effects, yet the precise mechanisms by which they elicit autoimmune responses in susceptible individuals remain unclear. Recent studies propose that metal-induced autoimmunity may arise from direct toxic effects on immune cells and tissues, coupled with indirect impacts on the gut microbiome and the blood-brain barrier. These effects can activate self-reactive T cells, prompting the production of autoantibodies, inflammatory responses, and tissue damage. Diagnosing metal-induced autoimmunity proves challenging due to nonspecific symptoms and a lack of reliable biomarkers. Treatment typically involves chelation therapy to eliminate excess metals and immunomodulatory agents to suppress autoimmune responses. Prevention strategies include lifestyle adjustments to reduce metal exposure and avoiding occupational and environmental risks. Prognosis is generally favorable with proper treatment; however, untreated cases may lead to autoimmune disorder progression and irreversible organ damage, particularly in the brain. Future research aims to identify genetic and environmental risk factors, enhance diagnostic precision, and explore novel treatment approaches for improved prevention and management of this intricate and debilitating disease.

Effects of exposing Japanese quail eggs to a low dose of gamma radiation and in ovo feeding by two sources of trace elements on embryonic development activities

The present study investigated the influence of exposing quail eggs to low-dose gamma radiation (GR) and in ovo feeding with 2 sources of a mixture of trace elements (Zn, Fe, and Cu), including sulfate (TES) and loaded with montmorillonite (TEM), on embryonic development activities and prehatch quality. A total of 960 eggs on the seventh day of incubation were randomly divided into 6 groups (160 eggs/group) with 4 replicate of 40 eggs in each. A 3 × 2 factorial arrangement experiment was performed and included 3 sources in ovo feeding with a mixture of trace elements (Zn, Fe, and Cu), including 0 mg/egg, 50 mg TES/egg, and 50 mg TEM/egg with egg irradiation using 0 and 0.2 Gy from GR. Eggs injected with 50 mg TEM/egg and exposed to 0.2 Gy from GR (TEM/GR) was significantly (P ≤ 0.05 and 0.01) higher in hatchability, hatch body weight, and relative organ weight (liver, gizzard, proventriculus, heart, and intestine). The obtained results indicated significant (P ≤ 0.05) decreased in the serum concentration of malondialdehyde (MDA) in TEM/GR group. There was significant (P ≤ 0.05) increased of catalase (CAT) activity and the concentrations of growth hormone (GH) and insulin-like growth factor-1 (IGF-1) in TEM/GR group; however; total antioxidant capacity (T-AOC) was significant (P ≤ 0.05) increased in CT/GR group. Serum concentrations of immunoglobulin M (IgM) (P ≤ 0.05) and tumor necrosis factor-alpha (TNF-α) were increased in the TEM/CR group; the concentration of transforming growth factor beta (TGF-β) significant (P ≤ 0.05) increased in the TEM/GR group; and interleukins (IL6 and IL10) showed no significant differences among the groups. Our results showed increase in thyroxine and myostatin concentrations with TES/CR and CT/GR of our study groups, respectively. The relative mRNA expression levels of the GH, IGF-1, and Fas cell surface death receptor (FAS) genes were significantly (P ≤ 0.05 and 0.01) upregulated in the liver tissue of the TEM/GR group compared with the other groups. In conclusion, TEM/GR was the best treatment for improving prehatch quality, increasing serum antioxidant enzyme activities, and promoting the expression of growth and immune genes in fertilized quail eggs.

Are the elements zinc, copper, magnesium, and rubidium related to nutrition and iodine deficiency in pregnant Bulgarian women from iodine deficient region?

OBJECTIVE

Trace elements are essential for the biochemistry of the cell. Their reference values have been found to differ considerably in pregnant women stratified by age, place of residence, anthropometric status, and length of pregnancy. In optimal amounts, these elements reduce the risk of pregnancy complications. Subclinical hypothyroidism in pregnancy is associated with adverse maternal and neonatal outcomes. The aim of the study was to determine the effects of zinc (Zn), copper (Cu), magnesium (Mg), and rubidium (Rb) on pregnant women in an iodine deficiency region and find the relationship with the thyroid status and nutrition.

METHODS

We evaluated the iodine status of 61 healthy pregnant women from an iodine deficient region in Bulgaria. Thyroid stimulating hormone (TSH) and thyroxin free (FT4) levels were measured using ELISA.

RESULTS

We found elevated levels of copper that differed the most between the first and second trimesters; Cu and TSH were found to be positively correlated (р < 0.05). Lower Cu levels were found in pregnant women consuming pulses more than 2-3 times a week (р = 0.033). The women consuming fish more than 2-3 times a week had higher levels of Rb. We found a pronounced iodine deficiency in more than half of the examined women in the first to third trimesters, without any effect of pregnancy on the ioduria (р=0.834). All second and third trimester cases were associated with severe ioduria (< 150 µg/L).

CONCLUSION

The high Cu levels were associated with subclinical hypothyroidism (SCH) and less pulse consumption during pregnancy in an iodine deficiency endemic area. SCH was found in 24% of the pregnant women in such an area while in 13% of them SCH had progressed to overt hypothyroidism.

Association between Heavy Metals and Trace Elements in Cancerous and Non-cancerous Tissues with the Risk of Colorectal Cancer Progression in Northwest China

Alterations in heavy metals and trace element levels may be associated with various cancers. However, the role of this interaction in colorectal cancer (CRC) progression is unclear. In recent years, Principal Component Analysis (PCA) and Bayesian Kernel Machine Regression (BKMR) models have provided new ideas for analyzing the effects of metal mixtures on CRC progression. Herein, we assessed the differences in the levels of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), selenium (Se), and zinc (Zn) in tumors and adjacent healthy tissues, to investigate the relationship between heavy metals/trace elements and CRC progression. Surgical samples of CRC and noncancerous tissues were collected, and trace metal levels were analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Logistic regression, PCA, and BKMR models were used to investigate the relationship between heavy metals and trace elements and the degree of tumor differentiation and lymph node metastasis in CRC. Cancer tissues showed lower As, Cd, Co, and Cr concentrations, and higher Se concentrations than healthy tissues (P < 0.05). In addition, CRC patients with poorly differentiated tumors and/or positive lymph node metastases had lower levels of Cd, Zn, Cu, and Se (P < 0.05). Logistic regression showed that single metal concentration was negatively correlated with CRC progression. PCA and BKMR models also showed that the metal mixture concentration was negatively correlated with CRC progression, with Cd contributing the most. Overall, changes in heavy metal and trace element levels may be related to the development of CRC; however, further mechanistic studies are required.

Assessment of Individual and Mixed Effects of Six Minerals on Thyroid Hormones in Chinese Pregnant Women

The biosynthesis of thyroid hormones is essential for brain and neurological development. It requires iodine as a key component but is also influenced by other nutrients. Evidence for the combined nutrient status in relation to thyroid hormones during pregnancy is limited. We aimed to investigate the joint associations of iodine, selenium, zinc, calcium, magnesium and iron with maternal thyroid functions in 489 pregnant women from Hangzhou, China. Serum levels of six essential minerals and thyroid function parameters were measured during the first antenatal visit. Linear regression, quantile g-computation and Bayesian kernel machine regression were used to explore the individual and joint relationships between the six minerals and thyroid hormones. Linear regression analyses revealed that calcium was positively associated with free triiodothyronine (FT3). Zinc was positively associated with free thyroxine (FT4). Iodine was negatively associated with thyroid-stimulating hormone (TSH) and positively associated with FT3 and FT4. The quantile g-computation and BKMR models indicated that the joint nutrient concentration was negatively associated with TSH and positively associated with FT3 and FT4. Among the six minerals, iodine contributed most to thyroid function. The findings suggested that maintaining the appropriate concentration of minerals, either as individuals or a mixture, is important for thyroid health during pregnancy.

Serum levels of heavy metals in patients with Bell's palsy: a case-control study

PURPOSE

The exact etiology of Bell's palsy (BP) remains unknown, while its potential etiopathology includes neuritis and inflammation-related demyelination as in optic neuritis. It has been reported that disruption of heavy metal homeostasis may be associated with the inflammatory process of optic neuritis; therefore, heavy metals may be involved in the pathogenesis of facial nerve neuritis. In this study, we aimed to investigate serum levels of heavy metals including essential elements [iron (Fe), zinc (Zn), copper (Cu), cobalt (Co), and manganese (Mn)], and nonessential elements [lead (Pb) and cadmium (Cd)] in patients with BP.

METHODS

The study included 25 patients with BP and 31 healthy volunteers. For each participant, serum levels of essential and nonessential elements were measured using the atomic absorption spectrophotometer method.

RESULTS

Serum levels of essential elements were significantly lower in the patient group compared to the control group (p < 0.001, for each). Serum levels of Pb increased in the patient group compared to the control group although no significant difference was achieved (p = 0.105). In contrast, serum Cd levels increased significantly in the patient group compared to the control group (p < 0.001).

CONCLUSION

Our findings suggest that decreased essential and increased nonessential elements may be associated with BP and thus, serum concentrations of these elements should be taken into account in BP. Studies are warranted to determine the role of these elements in treatment of BP.

Dietary Patterns and Hypothyroidism in U.S. Adult Population

The thyroid gland produces hormones that are essential for various body functions. Hypothyroidism is defined as insufficient thyroid hormone production. Several studies have found associations between specific micronutrients and overall thyroid function; however, the amount of evidence regarding the relationship between dietary patterns and hypothyroidism among the U.S. population is limited. Data from three cycles of National Health and Nutrition Examination Surveys (NHANES), 2007-2008, 2009-2010, and 2011-2012, were used (n = 8317). Subjects with serum thyroid stimulating hormone >4.5 mIU/L or on levothyroxine were considered to have hypothyroidism. Age, sex, race/ethnicity, body mass index, and several lifestyle factors were considered as covariates. Three patterns were extracted using factor analysis. These were labeled as fat-processed grains-sugars-meats (FPSM), oils-nuts-potatoes-low-fat meats (ONPL), and fruits-whole grains-vegetables-dairy (FWVD) patterns. In a weighted multiple logistic regression, FPSM and ONPL were inversely associated with hypothyroidism (OR, 0.75; 95% CI, 0.57-1; p = 0.049 and OR, 0.81; 95% CI, 0.67-0.97; p = 0.025, respectively). However, FWVD demonstrated no association with hypothyroidism (p = 0.63). In conclusion, FPSM and ONPL patterns but not FWVD patterns were associated with hypothyroidism in U.S. adults. Nutrient deficiencies and their interactions may be linked to hypothyroidism.

Global scientific trends on thyroid disease in early 21st century: a bibliometric and visualized analysis

Background

Bibliometrics has been used to analyze the literature in the field of thyroid disease studies in the early 21st century, indicating the changes in current international study trends.

Methods

In this study, a bibliometric analysis of data retrieved from the Web of Science (WoS) database was conducted, and the publication trends and thematic evolution in the field of thyroid disease research from January 1, 2000, to November 16, 2022, were analyzed. A total of 69283 articles related to thyroid diseases were evaluated for their characteristics, including annual publication volume, countries, journals, institutions, authors, keywords, and references. VOSviewer was utilized to perform the analysis of co-authorship, co-citation, co-occurrence and descriptive.

Results

The annual publication volume of thyroid disease research literature showed a fluctuating upward trend from 2000 to 2021, exceeding 5,000 articles for the first time in 2021. The United States (16120 counts, 678255 cities) ranks first in terms of publication volume and citation. Thyroid (n=3201) and Journal of Clinical Endocrinology&Metabolism (n=140399) are the most prolific and cited journals, respectively. The organization with the highest publication volume and citation frequency is Harvard University (1011 counts, 59429 cities), Miyauchi Akira (n=422), Schlumberger, and Martin (n=24839) possess the highest publication volume and citation frequency, respectively. Co-occurrence analysis of 307 keywords with frequencies of more than 20 resulted in 6 clusters (1): Thyroid dysfunction and diseases (2); mechanism of occurrence and development of thyroid cancer (3); autoimmune thyroiditis (4); scope and postoperative management of thyroid surgery (5); fine needle aspiration of thyroid nodules (6); radioactive iodine therapy for thyroid cancer. Active monitoring, thermal ablation, Lenvatinib, and long noncoding RNA refer to the latest keywords. Discussing the six clusters helps scholars to determine the scope and direction of studies.

Conclusion

Over the past two decades, the literature related to thyroid diseases has increased year by year, with closer collaboration between countries, institutions, and authors. In this study, the global trends, research hotspots, emerging subjects, and basic knowledge of literature related to thyroid diseases were respectively elucidated, which will facilitate researchers in this field to seek better development.

Emerging Insights and Global Trends in the Relationship between Selenium and Thyroid Diseases: A Bibliometric Analysis

OBJECTIVE

Selenium, a significant trace element needed by the human body, is closely related to thyroid. Therefore, this study aimed to explore the status of selenium and thyroid diseases, analyze emerging insights, and predict future trends.

METHODS

Literature on selenium and thyroid included in the core database of Web of Science from January 1992 to October 2022 was retrieved. CiteSpace and VOSviewer software were used for visual analysis in terms of publication, author, country, institution, co-citation, and keywords.

RESULTS

A total of 1,142 works of literature were included after the screening, and the annual publication showed a fluctuating upward trend. The country and the institution with the highest publication volume were the United States and Charité Universitätsmedizin Berlin, respectively. In terms of authors, Schomburg L has formed a cooperative network and has published the largest number of papers and made great contributions in this field. The biggest cluster of keywords was trace elements, and the hot keywords in recent years were oxidative stress, Hashimoto's thyroiditis, cadmium, copper, etc. Conclusion: This paper analyzes the current status, insights, and trends of the studies on selenium and thyroid diseases by the method of bibliometrics and delivers ideas and methods for subsequent research in this field. The therapeutic effect of selenium on Hashimoto's thyroiditis is controversial and needs further research, and oxidative stress is also a research hotspot in this field. The crossstudy of multiple trace elements and diseases may be the development trend in the future.

Sex-Specific Associations of Five Serum Essential Metal Elements with Thyroid Nodules in Euthyroid Adults: a Cross‑sectional Study

The association between the serum essential metal elements (magnesium, iron, copper, zinc, and calcium) and thyroid nodules is still inconsistent. The current study aims to investigate the relationship of metal elements with thyroid nodules and their malignant tendency. A total of 6480 Chinese euthyroid adults were included in our study. We collect basic information through questionnaires and medical checkups. We diagnose thyroid nodules by ultrasound and detect serum trace metal concentrations by using an automatic biochemical analyzer. Binary and multinomial logistic regressions were used to investigate the associations. As a result, we found that serum copper concentrations were positively associated with thyroid nodules in the second, third, and fourth quartiles, compared to the first quartile (P = 0.024, P = 0.016, P = 0.032) in women and P for trend is 0.038. There is a significant sex-specific association between copper concentrations and thyroid nodules (P for interaction = 0.009). The results of the multinomial logistic regression analyses indicate high serum calcium and magnesium concentrations emerged as consistent risk factors for thyroid nodules in both genders, whereas low zinc was a sex-specific factor. We also observed significant sex interactions in the relationships of magnesium (P for interaction = 0.043) with thyroid nodules with malignant tendency among participants with thyroid nodules. In conclusion, our study suggests that gender is an important factor when studying the association between serum metals and thyroid nodules. The imbalance of selected metal elements (calcium, copper, zinc, and magnesium) may relate to thyroid nodules and their malignant tendency, and future prospective studies are needed to further confirm the associations.

Crossroads between Skin and Endocrine Glands: The Interplay of Lichen Planus with Thyroid Anomalies

In this narrative review, we aimed to overview the interplay between lichen planus (LP) and thyroid conditions (TCs) from a dual perspective (dermatologic and endocrine), since a current gap in understanding LP-TC connections is found so far and the topic is still a matter of debate. We searched PubMed from Inception to October 2023 by using the key terms "lichen planus" and "thyroid", (alternatively, "endocrine" or "hormone"). We included original clinical studies in humans according to three sections: LP and TC in terms of dysfunction, autoimmunity, and neoplasia. Six studies confirmed an association between the thyroid dysfunction (exclusively hypothyroidism) and LP/OL (oral LP); of note, only one study addressed cutaneous LP. The sample size of LP/OLP groups varied from 12-14 to 1500 individuals. Hypothyroidism prevalence in OLP was of 30-50%. A higher rate of levothyroxine replacement was identified among OLP patients, at 10% versus 2.5% in controls. The highest OR (odd ratio) of treated hypothyroidism amid OLP was of 2.99 (p < 0.005). Hypothyroidism was confirmed to be associated with a milder OLP phenotype in two studies. A single cohort revealed a similar prevalence of hypothyroidism in LP versus non-LP. Non-confirmatory studies (only on OLP, not cutaneous LP) included five cohorts: a similar prevalence of hypothyroidism among OLP versus controls, and a single cohort showed that the subjects with OLP actually had a lower prevalence of hypothyroidism versus controls (1% versus 4%). Positive autoimmunity in LP/OLP was confirmed in eight studies; the size of the cohorts varied, for instance, with 619 persons with LP and with 76, 92, 105, 108, 192, 247, and 585 patients (a total of 1405) with OLP, respectively; notably, the largest control group was of 10,441 individuals. Four clusters of approaches with respect to the autoimmunity in LP/OLP were found: an analysis of HT/ATD (Hashimoto's thyroiditis/autoimmune thyroid diseases) prevalence; considerations over the specific antibody levels; sex-related features since females are more prone to autoimmunity; and associations (if any) with the clinical aspects of LP/OLP. HT prevalence in OLP versus controls was statistically significantly higher, as follows: 19% versus 5%; 12% versus 6%; and 20% versus 9.8%. A single study addressing LP found a 12% rate of ATDs. One study did not confirm a correlation between OLP-associated clinical elements (and OLP severity) and antibody values against the thyroid, and another showed that positive TPOAb (anti-thyroperoxidase antibodies) was more often found in erosive than non-erosive OLP (68% versus 33%). Just the reverse, one cohort found that OLP subjects had a statistically significantly lower rate of positive TPOAb versus controls (9% versus 15%). Five case-control studies addressed the issue of levothyroxine replacement for prior hypothyroidism in patients that were diagnosed with OLP (no study on LP was identified); three of them confirmed a higher rate of this treatment in OLP (at 8.9%, 9.7%, and 10.6%) versus controls. In conclusion, with regard to LP/OLP-TC, we note several main aspects as practical points for multidisciplinary practitioners: OLP rather than LP requires thyroid awareness; when it comes to the type of thyroid dysfunction, mostly, hypothyroidism should be expected; female patients are more prone to be associated with ATDs; a potential higher ratio of OLP subjects taking levothyroxine was found, thus a good collaboration with an endocrinology team is mandatory; and so far, OLP individuals have not been confirmed to be associated with a higher risk of thyroid nodules/cancer.

Cadmium exposure and thyroid hormone disruption: a systematic review and meta-analysis

INTRODUCTION

This meta-analysis aimed to analyze the effect of cadmium (Cd) exposure on thyroid hormone disruption.

CONTENT

Databases including PubMed, Embase, Cochrane Library, and Scopus were searched for studies published up to December 14, 2022. Studies evaluating the association between Cd exposure (blood Cd [BCd] or urine Cd [UCd]) and thyroid function (thyroid-stimulating hormone [TSH], free thyroxine [FT4], total triiodothyronine [TT3]) or thyroid autoimmunity (thyroglobulin antibody [TgAb] or thyroperoxidase Ab [TPOAb]) were included.

SUMMARY AND OUTLOOK

This systematic review included 12 cross-sectional studies. Cd exposure showed a neutral association with TSH (pooled correlation=0.016, 95 % confidence interval [CI]=-0.013 to 0.045, p=0.277), FT4 (pooled correlation=0.028, 95 % CI=-0.005 to 0.061, p=0.098), and thyroid autoimmunity (pooled odds ratio=1.143, 95 % CI=0.820-1.591, p=0.430). However, Cd exposure showed a positive association with TT3 (pooled correlation=0.065, 95 % CI=0.050-0.080, p<0.001), which was consistent with the BCd and UCd subgroup analyses (pooled correlation=0.053 and 0.081, respectively, both p<0.001). Cd exposure was not associated with TSH, FT4, or thyroid autoimmunity but tended to increase with TT3.

Trace elements dyshomeostasis in liver and brain of weanling mice under altered dietary selenium conditions

BACKGROUND

A balanced diet containing selenium (Se) and other trace elements is essential for normal development and growth. Se has been recognized as an essential trace element; however, its interaction with other elements has not been fully investigated. In the present study, sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), copper (Cu), zinc (Zn), Se and rubidium (Rb), were analysed in liver and brain regions under altered dietary Se intake in weanling mice to identify major discriminatory elements.

METHODS

The study investigated the effects of different levels of Se intake on the elemental composition in liver and brain tissues of weaned mice. After 24 weeks of feeding with Se adequate, deficient, and excess diets, elemental analysis was performed on the harvested tissues using Inductively coupled plasma mass spectrometry (ICP-MS). Statistical analysis that included analysis of covariance (ANCOVA), correlation coefficient analysis, principal component analysis, and partial least squares discriminant analysis were performed.

RESULTS

The ANCOVA showed statistically significant changes and correlations among the analysed elements under altered dietary Se status. The multivariate analysis showed differential changes in elements in liver and brain regions. The results suggest that long-term dietary Se alternations lead to dyshomeostasis in trace elements that are required in higher concentrations compared to Se. It was observed that changes in the Fe, Co, and Rb levels were similar in all the tissues studied, whereas the changes in Mg, Cr, and Mn levels were different among the tissues under altered dietary Se status. Additionally, the changes in Rb levels correlated with the dietary Se intake but had no relation with the tissue Se levels.

CONCLUSIONS

The findings suggest interactions between Mg, Cr, Mn, Fe, Co, and Se under altered Se status may impact cellular functions during postnatal development. However, the possible biological significance of alterations in Rb levels under different dietary Se paradigms needs to be further explored.

Occurrence of 8 trace elements in Rhizoma Cibotii from China and exposure assessment

The contamination of trace elements in Chinese edible herbs has attracted worldwide concern over the world. The objective of the present study was to investigate the occurrence and exposure assessment of eight trace elements in Rhizoma Cibotii from China. For this purpose, the method of inductively coupled plasma mass spectrometry was employed to detect the contamination levels of target trace elements in 58 Rhizoma Cibotii samples. The results demonstrated that the trace elements of Cr, Ni, Cu, Zn, and Pb were detected in all analyzed samples; the occurrence frequencies of As, Se, and Cd were 98.3%, 96.6%, and 98.3%, respectively. The highest mean levels were found in Zn (17.32 mg/kg), followed by Pb (8.50 mg/kg) and Cu (3.51 mg/kg). For a further step, one-way ANOVA was used to compare the difference of eight elements levels among groups, and Pearson's correlation analysis was used to explore the correlation between elements in Rhizoma Cibotii. A strong positive correlation between Zn and Cd was observed by Pearson's correlation analysis, which indicated that the possible presence of Cd contamination in Rhizoma Cibotii. Based on the contamination levels, the mean exposure of individual element and the health risks of eight trace elements in Rhizoma Cibotii were estimated by health risk assessment models. The calculated HQ values were less than 1, indicating that the contamination of trace elements in Rhizoma Cibotii did not pose significant health risks to human. In conclusion, the study provided baseline information on the contamination levels of trace elements in Rhizoma Cibotii. Moreover, it is necessary to monitor the trend of trace elements levels in Rhizoma Cibotii, which will be useful for ingredient control and human health protection.

Iron deficiency and thyroid dysfunction among sudanese women in first trimester of pregnancy: a cross-sectional study

BACKGROUND

Pregnant women are more susceptible to iron deficiency (ID), and it can lead to several maternal and perinatal adverse effects. There are some published data on the effect of ID on thyroid function, but none of the studies were conducted in sub-Saharan African countries including Sudan. This study was conducted to investigate association between ID (ferritin < 15 µg/L) and thyroid functions [thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4)] among Sudanese women in the first trimester of pregnancy.

METHOD

A cross-sectional study was conducted in Saad Abuelela Maternity Hospital, Sudan. Obstetric/sociodemographic characteristics were gathered through questionnaires. Hemoglobin, serum ferritin, TSH, FT3, and FT4 were measured in all pregnant women. Continuous variables were compared with either independent sample t-test if they were normally distributed, or with Mann-Whitney U- test if they were not-normally distributed. Spearman correlations were performed between the continuous variables.

RESULTS

In total, 127 pregnant women with mean [standard deviation (SD)] age of 27.0 (5.5) years and gestational age of 10.5 (3.0) weeks, respectively, were enrolled in this study. Forty-seven (37.0%) of these 127 women had ID. While the median [interquartile range (IQR)] of the parity, TSH, and FT3 were not different between women with ID and women without ID, the median (IQR) of FT4 was significantly lower in women with ID compared with women without ID [1.020 (0.910‒1.120) vs. 1.095 (0.990‒1.217) pmol, P = 0.014]. Serum ferritin was inversely correlated with FT3, (r = -0.225, P = 0.011). There was no significant correlation between serum ferritin, TSH, and FT4.

CONCLUSIONS

Iron deficiency was common during the first trimester of pregnancy and was associated with thyroid dysfunctions. Therefore, ID should be evaluated to avoid thyroid dysfunction.

Association between female circulating heavy metal concentration and abortion: a systematic review and meta-analysis

Objective

This study aimed to evaluate the association between blood heavy metal (zinc (Zn), copper (Cu), lead (Pb), and cadmium (Cd)) concentrations and spontaneous abortion (SA) and recurrent pregnancy loss (RPL) and explore the possible endocrine dysfunction associated with it.

Methods

A literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases up to April 2023. The overall effects were expressed as the standard mean difference (SMD). Subgroup analysis was performed according to the type of abortion (SA or RPL). Stata 16.0 was utilized for data analysis.

Results

Based on the integrated findings, abortion women showed significantly lower Zn (SMD = -1.05, 95% CI: -1.74 to -0.36, p = 0.003) and Cu concentrations (SMD = -1.42, 95% CI: -1.97 to -0.87, p <0.001) and higher Pb (SMD = 1.47, 95% CI: 0.89-2.05, p <0.001) and Cd concentrations (SMD = 1.15, 95% CI: 0.45-1.85, p = 0.001) than normal pregnant women. Subgroup analysis showed that Zn and Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with RPL, whereas Cu deficiency and Cd and Pb exposure were significantly (p <0.05) associated with SA.

Conclusion

Zn and Cu deficiencies and Pb and Cd exposure were associated with abortion. Endocrine dysfunction, such as insulin resistance, vitamin D insufficiency, and abnormal thyroid and sex hormone concentrations, is thought to be involved in heavy metal-related abortion.

Effect of Trace Metal Ions on the Conformational Stability of the Visual Photoreceptor Rhodopsin

Trace metals are essential elements that play key roles in a number of biochemical processes governing human visual physiology in health and disease. Several trace metals, such as zinc, have been shown to play important roles in the visual phototransduction process. In spite of this, there has been little research conducted on the direct effect of trace metal elements on the visual photoreceptor rhodopsin. In the current study, we have determined the effect of several metal ions, such as iron, copper, chromium, manganese, and nickel, on the conformational stability of rhodopsin. To this aim, we analyzed, by means of UV-visible and fluorescence spectroscopic methods, the effects of these trace elements on the thermal stability of dark rhodopsin, the stability of its active Metarhodopsin II conformation, and its chromophore regeneration. Our results show that copper prevented rhodopsin regeneration and slowed down the retinal release process after illumination. In turn, Fe³⁺, but not Fe²⁺, increased the thermal stability of the dark inactive conformation of rhodopsin, whereas copper ions markedly decreased it. These findings stress the important role of trace metals in retinal physiology at the photoreceptor level and may be useful for the development of novel therapeutic strategies to treat retinal disease.

Relationship between Serum Selenium Level and Self-Reported History of Kidney Stone

A relationship may exist between selenium and kidney calculi, but there is a lack of research in this field at present. Our study explored the relationship between the serum selenium level and a medical history of adult kidney calculi. We utilized data from the National Health and Nutrition Examination Survey conducted between 2011 and 2016. Participants self-reported their history of kidney stones, while serum selenium levels were measured using inductively coupled plasma dynamic reaction cell mass spectrometry. Our findings indicate a negative correlation between serum selenium levels and the risk of kidney stone history. In the multiple-adjusted model, the lowest serum selenium level group had a higher risk than the other groups. The odds ratio (95% confidence interval) of ever having kidney stones for the highest serum selenium level group was 0.54 (0.33-0.88). In the results of stratified analysis, this relationship was still significant in the groups of women and those 40-59 years. We also found that as a nonlinear dose-response relationship between serum selenium levels and the history of kidney stones disease. In our research, we found that people with higher serum selenium levels had a lower risk of having a history of kidney stones. We concluded that selenium may have a protective effect on kidney stones. In the future, more population studies are needed to explore the relationship between selenium and kidney stones.

Nutritional Assessment of the Symptomatic Patient on a Plant-Based Diet: Seven Key Questions

Plant-based diets, both vegan and vegetarian, which emphasize grains, vegetables, fruits, legumes, nuts, and seeds are increasingly popular for health as well as financial, ethical, and religious reasons. The medical literature clearly demonstrates that whole food plant-based diets can be both nutritionally sufficient and medically beneficial. However, any person on an intentionally restrictive, but poorly-designed diet may predispose themselves to clinically-relevant nutritional deficiencies. For persons on a poorly-designed plant-based diet, deficiencies are possible in both macronutrients (protein, essential fatty acids) and micronutrients (vitamin B12, iron, calcium, zinc, and vitamin D). Practitioner evaluation of symptomatic patients on a plant-based diet requires special consideration of seven key nutrient concerns for plant-based diets. This article translates these concerns into seven practical questions that all practitioners can introduce into their patient assessments and clinical reasoning. Ideally, persons on plant-based diets should be able to answer these seven questions. Each serves as a heuristic prompt for both clinician and patient attentiveness to a complete diet. As such, these seven questions support increased patient nutrition knowledge and practitioner capacity to counsel, refer, and appropriately focus clinical resources.

The Role of Selected Trace Elements in Oxidoreductive Homeostasis in Patients with Thyroid Diseases

Impaired levels of selenium (Se), zinc (Zn), copper (Cu), iron (Fe), manganese (Mn) and iodine (I) in the organism may adversely affect the thyroid endocrine system. These trace elements play a role in the fight against oxidative stress as components of enzymes. Oxidative-antioxidant imbalance is considered a possible factor in many pathological conditions, including various thyroid diseases. In the available literature, there are few scientific studies showing a direct correlation of the effect of supplementation of trace elements on slowing down or preventing the occurrence of thyroid diseases in combination with the improvement of the antioxidant profile, or through the action of these elements as antioxidants. Among the available studies, it has been shown that an increase in lipid peroxidation levels and a decrease in the overall antioxidant defense status occur during such thyroid diseases as thyroid cancer, Hashimoto's thyroiditis and dysthyroidism. In studies in which trace elements were supplemented, the following were observed: a decrease in the level of malondialdehyde after supplementation with Zn during hypothyroidism and reduction in the malondialdehyde level after Se supplementation with a simultaneous increase in the total activity status and activity of antioxidant defense enzymes in the course of autoimmune thyroiditis. This systematic review aimed to present the current state of knowledge about the relationship between trace elements and thyroid diseases in terms of oxidoreductive homeostasis.

Selenium, Iodine and Iron-Essential Trace Elements for Thyroid Hormone Synthesis and Metabolism

The adequate availability and metabolism of three essential trace elements, iodine, selenium and iron, provide the basic requirements for the function and action of the thyroid hormone system in humans, vertebrate animals and their evolutionary precursors. Selenocysteine-containing proteins convey both cellular protection along with H₂O₂-dependent biosynthesis and the deiodinase-mediated (in-)activation of thyroid hormones, which is critical for their receptor-mediated mechanism of cellular action. Disbalances between the thyroidal content of these elements challenge the negative feedback regulation of the hypothalamus-pituitary-thyroid periphery axis, causing or facilitating common diseases related to disturbed thyroid hormone status such as autoimmune thyroid disease and metabolic disorders. Iodide is accumulated by the sodium-iodide-symporter NIS, and oxidized and incorporated into thyroglobulin by the hemoprotein thyroperoxidase, which requires local H₂O₂ as cofactor. The latter is generated by the dual oxidase system organized as 'thyroxisome' at the surface of the apical membrane facing the colloidal lumen of the thyroid follicles. Various selenoproteins expressed in thyrocytes defend the follicular structure and function against life-long exposure to H₂O₂ and reactive oxygen species derived therefrom. The pituitary hormone thyrotropin (TSH) stimulates all processes required for thyroid hormone synthesis and secretion and regulates thyrocyte growth, differentiation and function. Worldwide deficiencies of nutritional iodine, selenium and iron supply and the resulting endemic diseases are preventable with educational, societal and political measures.