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

A causal inference study exploring the impact of iron status on the risk of thyroid cancer based on two-sample mendelian randomization

BACKGROUND & AIMS

Thyroid cancer is prone to early lymph node metastasis.This study investigated the influence of iron status on thyroid cancer risk and its mediating role in the relationship between thyroid cancer incidence and thyroid cancer-related exposure factors.

METHOD

Utilizing iron status-related Single Nucleotide Polymorphisms as instrumental variables, the research analyzed summary data on iron status and thyroid cancer from Genome-Wide Association Studies following the Two-sample Mendelian randomization guidelines, primarily using the Inverse-variance weighted method, with Mendelian randomization-Egger method, weighted median method, simple mode, and weighted mode as supplementary analyses. The reliability and robustness of the results were assessed using the Leave-one-out analysis and Cochran's Q Test.

RESULTS

The findings indicate that the iron status has a vital causal relationship with the occurrence of thyroid cancer. The Inverse-variance weighted model results revealed Iron || id:ieu-a-1049: OR = 1.409, 95%CI = (1.043, 1.904), P < 0.05; Ferritin || id:ieu-a-1050: OR = 2.029, 95% CI = (1.081, 3.808), P < 0.05; Transferrin Saturation || id:ieu-a-1051: OR = 1.337, 95%CI = (1.058, 1.690), P < 0.05. The reliability and robustness of these results were further supported by the Leave-one-out analysis and Cochran's Q Test (P > 0.05).

CONCLUSION

The study establishes a certain causal link between iron status and thyroid cancer, indicating that transferrin saturation, serum ferritin and serum iron are associated with thyroid cancer incidence.

Inter-island variability in trace elements and trophic ecology of Brown Booby (Sula leucogaster) in the South Atlantic

This study investigates essential (Mg, Ca, Fe, Mn, Cu, Zn, Se, Ni) and non-essential (Li, Be, Cr, Rb, Sr, Cs, Cd, Sn, Ba, and Pb) element concentrations and stable isotope (δ13C, δ15N, δ34S) compositions in feathers of Brown Boobies (Sula leucogaster) from three distinct Atlantic islands: the Archipelagos of Saint Peter and Saint Paul (SPSP), Abrolhos, and Cagarras. We aimed to investigate the ecological and environmental factors influencing these seabird populations and assess potential variations in contaminant exposure and dietary habits based on location, sex, and maturity stages. Our finding revealed significant geographical differences in trace element concentrations. The Brown Boobies from Cagarras had higher concentrations (mean ± SD, μg g-1) of Fe (29 ± 20) and Mn (0.82 ± 0.82) than those from Abrolhos (Fe: 21 ± 20; Mn: 0.24 ± 0.09) and SPSP (Fe: 15 ± 16; Mn: 0.21 ± 0.06). Tin concentrations were also higher in Cagarras (Sn: 0.02 ± 0.01) than in SPSP (Sn: 0.01 ± 0.01). Our analyses revealed significant differences in Li, Mg, Rb, and Zn concentrations between adults and juveniles. However, there were no sex-related differences in element concentrations within each locality. SIBER analyses revealed distinct dietary differences among the three Brown Boobies populations, with the Cagarras seabirds occupying a higher trophic position compared to the SPSP population. This study highlights the importance of considering different populations to understand contaminant exposure and ecological dynamics in Brown Boobies along the South Atlantic. The Cagarras population shows significantly higher contaminant levels, likely due to proximity to anthropogenic activities. These results highlight the necessity for ongoing monitoring to evaluate long-term effects on the more impacted population and to ensure seabird health and sustainability in the Atlantic Ocean.

Effects of Trace Elements on Endocrine Function and Pathogenesis of Thyroid Diseases-A Literature Review

The thyroid gland is an endocrine organ whose hormones enable the proper functioning of the organism. The normal function of this organ is influenced by internal and external factors. One of the external factors is trace elements. Trace elements in appropriate concentrations are necessary for the proper functioning of the thyroid. Fe, Cu, Mn, I, Zn, and Se are part of the enzymes involved in oxidative stress reduction, while Cd, Hg, and Pb can increase ROS production. Cu and Fe are necessary for the correct TPO synthesis. An imbalance in the concentration of trace elements such as Fe, Cu, Co, I, Mn, Zn, Ag, Cd, Hg, Pb, and Se in thyroid cells can lead to thyroid diseases such as Graves' disease, Hashimoto's thyroiditis, hypothyroidism, autoimmune thyroiditis, thyroid nodules, thyroid cancer, and postpartum thyroiditis. Lack of adequate Fe levels may lead to hypothyroidism and cancer development. The thyroid gland's ability to absorb I is reversibly reduced by Co. Adequate levels of I are required for correct thyroid function; both deficiency and excess can predispose to the development of thyroid disorders. High concentrations of Mn may lead to hypothyroidism. Furthermore, Mn may cause cancer development and progression. Insufficient Zn supplementation causes hypothyroidism and thyroid nodule development. Cd affecting molecular mechanisms may also lead to thyroid disorders. Hg accumulating in the thyroid may interfere with hormone secretion and stimulate cancer cell proliferation. A higher risk of thyroid nodules, cancer, autoimmune thyroiditis, and hypothyroidism were linked to elevated Pb levels. Se deficiency disrupts thyroid cell function and may lead to several thyroid disorders. On the other hand, some of the trace elements may be useful in the treatment of thyroid diseases. Therefore, the effects of trace elements on the thyroid require further research.

Association of dietary manganese intake and the IL1R1 rs3917225 polymorphism with thyroid cancer risk: a prospective cohort study in Korea

Dietary Mn intake may have a beneficial effect in reducing cancer risk; however, its association with thyroid cancer (TC) risk remains inadequately understood. Additionally, Mn was associated with inflammation markers. Thus, we examined whether dietary Mn intake emerges a protective role against TC and whether this preventative effect has an interaction with IL1 receptor type 1 (IL1R1) rs3917225. The prospective study was designed at National Cancer Center in Korea between October 2007 and December 2020 including 17 754 participants. We identified TC cases by following participants until December 2020. Mn intake was collected using a semiquantitative food frequency questionnaire (SQFFQ). Genotyping was performed to determine IL1R1 rs3917225. The hazard ratios (HR) and 95 % confidence interval (CI) were calculated with a Cox proportional hazards model. We ascertained 108 incident TC cases throughout follow-up duration. Dietary Mn intake was found to be inversely associated with TC risk (HR (95 % CI)=0·64 (0·44, 0·95)). However, IL1R1 rs3917225 seemed to modify this association; the protective effect was limited to G-allele carriers (HR = 0·30 (0·11, 0·86), P interaction=0·028). A higher dietary Mn was suggested to be a protective factor against TC. Additionally, we drew a potential biological interaction between Mn intake and IL1R1 rs3917225 with a greater effect among individuals with a minor allele. This implies that when considering the cancer-preventive role of Mn, it is important to account for the influence of inflammatory gene participation.

Association between vitamin C intake and thyroid function among U.S. adults: a population-based study

Background

Although some evidence suggests a role for vitamin C intake in thyroid diseases, the complex interplay between vitamin C intake and thyroid function remains incompletely understood. The objective of this study was to explore the relationship between vitamin C intake and serum thyroid function in the United States adults.

Methods

A total of 5,878 participants from the National Health and Nutrition Examination Survey (NHANES) between 2007 and 2012 were included in this study. Weighted multivariate linear regression models, subgroup analyses, and interaction terms were used to assess the association between vitamin C intake, evaluated as a continuous and categorical variable, and thyroid function. Additionally, restricted cubic spline (RCS) regression was employed to assess any nonlinear relationship that may exist between vitamin C intake and thyroid function.

Results

After adjusting for covariates, our research found a significant inverse correlation between vitamin C intake and total thyroxine (TT4) (β= -0.182, P= 0.006). Using subgroup analyses, the association was more pronounced among subjects with lower alcohol consumption(β= -0.151, P=0.013, P for interaction = 0.043). In RCS regression, the correlation between vitamin C and TT4 exhibited a distinct reversed L-shaped curve pattern in total participants (P for nonlinear = 0.005) and male adults (P for nonlinear = 0.014). Additionally, we found an inverted U-shaped curve pattern in the relationship between vitamin C intake and FT4 (P for nonlinear = 0.029), while an U-shaped curve relationship was observed between vitamin C consumption and the FT3/FT4 ratio (P for nonlinear = 0.026).

Conclusion

The findings of our study have illustrated a notable correlation between vitamin C intake and thyroid function. A high level of vitamin C intake is associated with a decreased in TT4 levels among American adults, and the association was more pronounced among subjects with lower alcohol consumption. Furthermore, our analysis revealed a nonlinear correlation between the intake of vitamin C and the levels of TT4, FT4, and FT3/FT4 ratio. Our findings support the rationale for making food-based dietary recommendations and maybe provide guidance for diet guidelines with thyroid dysfunction to a certain extent in the future.

Selected Trace Elements and Their Impact on Redox Homeostasis in Eye Health

Oxidative stress plays a crucial role in the pathogenesis of various ocular degenerative diseases, leading to structural and functional changes in eye tissues. This imbalance between reactive oxygen species (ROS) and antioxidants significantly contributes to conditions such as age-related macular degeneration, diabetic retinopathy, cataracts, and glaucoma. Both enzymatic and nonenzymatic antioxidants are vital for maintaining ocular health by neutralizing ROS and restoring cellular redox balance. Essential trace elements, including iron, zinc, copper, and selenium, are fundamental for the proper functioning of these antioxidant systems. Iron is indispensable for enzymatic activity and cellular energy production, zinc supports numerous proteins involved in visual functions and antioxidant defense, copper is essential for various enzymatic reactions preventing oxidative stress, and selenium is critical for the activity of antioxidant enzymes such as glutathione peroxidase (GPX) and thioredoxin reductase (TrxR). This review summarizes current research on the complex interactions between oxidative stress and trace elements in ocular diseases, highlighting the therapeutic potential of antioxidant supplementation to mitigate oxidative damage and improve eye health. By integrating insights from studies on oxidative stress, trace elements, and eye physiology, this article underscores new diagnostic and therapeutic strategies that could lead to more effective prevention and treatment of ocular diseases, aiming to enhance clinical outcomes and guide future research in optimizing therapeutic strategies for eye health.

Zinc and Ferritin Levels and Their Associations with Functional Disorders and/or Thyroid Autoimmunity: A Population-Based Case-Control Study

Population zinc and iron status appear to be associated with an increased risk of thyroid function abnormalities and thyroid autoimmunity (AITD). In the present study, we aimed to determine whether zinc and/or iron levels (assessed by ferritin levels) were associated with the presence of AITD and with alterations in thyroid function. A population-based case-control study (n = 1048) was conducted (cases: n = 524; controls: n = 524). Participants were measured for blood concentrations of zinc and ferritin, TSH, FT4, FT3, and thyroid autoantibodies. No significant differences were found in relation to ferritin levels between cases and controls. Among cases, the prevalence of low zinc levels in those with hypothyroidism (both subclinical and overt) was 49.1% [odds ratio (OR) of low zinc levels: 5.926; 95% CI: 3.756-9.351]. The prevalence of low zinc levels in participants with hyperthyroidism (both subclinical and overt) was 37.5% [OR of low zinc levels: 3.683; 95% CI: 1.628-8.33]. The zinc value that best discriminated the highest frequency of AITD was 70.4 µg/dL [sensitivity: 0.947, 1-specificity: 0.655, specificity: 0.345]. The highest frequency of AITD was calculated based on a zinc value <70 µg/dL (relative to a normal value), with this frequency being significantly higher in cases than in controls [OR: 9.3; 95% CI: 6.1-14.3 (p = 0.001)]. In conclusion, the results of our study suggest that zinc deficiency is associated with an increased frequency of functional thyroid disorders and thyroid autoimmunity.

The Role of Selected Elements in Oxidative Stress Protection: Key to Healthy Fertility and Reproduction

Oxidative stress and its relationship to fertility and reproduction is a topic of interest in medicine, especially in the context of the effects of trace elements and micronutrients. Oxidative stress occurs when there is an excess of free radicals in the body, which can lead to cell and tissue damage. Free radicals are reactive oxygen species (ROS) that can be formed as a result of normal metabolic processes, as well as under the influence of external factors such as environmental pollution, UV radiation, and diet. Oxidative stress has a significant impact on fertility. In men, it can lead to DNA damage in sperm, which can result in reduced semen quality, reduced sperm motility and increased numbers of defective sperm, and free radical damage to sperm cell membranes causing a reduction in the number of available sperm. In women, oxidative stress can affect the quality of female reproductive cells, which can lead to problems with their maturation and with embryo implantation in the uterus and can also affect ovarian function and disrupt hormonal regulation of the menstrual cycle. A proper balance of trace elements and micronutrients is key to protecting against oxidative stress and maintaining reproductive health. Supplementation with appropriate elements such as zinc, selenium, copper, manganese, chromium, and iron can help reduce oxidative stress and improve fertility. This work discusses the effects of selected elements on oxidative stress parameters specifically in terms of fertility and reproduction.

The Role of Nutrition on Thyroid Function

Thyroid function is closely linked to nutrition through the diet-gut-thyroid axis. This narrative review highlights the influence of nutritional components and micronutrients on thyroid development and function, as well as on the gut microbiota. Micronutrients such as iodine, selenium, iron, zinc, copper, magnesium, vitamin A, and vitamin B12 influence thyroid hormone synthesis and regulation throughout life. Dietary changes can alter the gut microbiota, leading not just to dysbiosis and micronutrient deficiency but also to changes in thyroid function through immunological regulation, nutrient absorption, and epigenetic changes. Nutritional imbalance can lead to thyroid dysfunction and/or disorders, such as hypothyroidism and hyperthyroidism, and possibly contribute to autoimmune thyroid diseases and thyroid cancer, yet controversial issues. Understanding these relationships is important to rationalize a balanced diet rich in essential micronutrients for maintaining thyroid health and preventing thyroid-related diseases. The synthetic comprehensive overview of current knowledge shows the importance of micronutrients and gut microbiota for thyroid function and uncovers potential gaps that require further investigation.

Correlation of Zinc and Copper Levels In Mothers and Cord Blood of Neonates With Prematurity and Intrauterine Growth Pattern

Background Trace elements like zinc and copper are indispensable for human growth and development, exerting significant influence on a multitude of physiological processes. Acting as pivotal components for transcription factors and catalytic cofactors for enzymes, these elements play essential roles in cellular differentiation and maturation Objective The objective of this study was to study serum zinc and copper levels in mothers and neonates in relation to prematurity and intrauterine growth retardation (IUGR). Methods This was a cross-sectional study that included 100 mothers who met the inclusion criteria. Maternal history was recorded, and gestational age was estimated using the New Ballard scoring system. Maternal and cord blood samples were taken for zinc and copper analysis. Results The comparison of maternal copper and zinc levels between term and preterm neonates revealed a statistically significant difference with both trace elements found in less concentration in preterm when compared to the term patients (p= 0.03 for Zinc; 0.0001 for copper). We also report a statistically significant difference in maternal and cord blood copper and zinc levels in cases with IUGR compared to normal neonates. Conclusion The findings show that maternal zinc and copper levels are critical for the intrauterine growth of the fetus and for appropriate gestational age.

Determination of Serum Zinc and Phosphorus Levels in Patients with Hypothyroidism

Various studies reported that serum zinc (Zn) and phosphorus (P) levels altered in patients with hypothyroidism and vice versa, but results were found inconsistent. It was aimed to find the association between serum Zn and P in patients with hypothyroidism. In this case-control study, a total of 100 subjects (50 newly diagnosed patients of hypothyroidism and 50 controls) were enrolled aged between 25 and 60 years. Biochemical parameters such as thyroid profile, serum Zn, and P were estimated in each subject. A p < 0.05 was considered statistically significant. The mean level of body mass index (BMI), thyroid-stimulating hormone (TSH), and serum P was found significantly elevated in cases compared to controls (p < 0.001). However, the mean level of total triiodothyronine (T3), thyroxine (T4), and serum Zn was found significantly reduced in cases compared to controls (p < 0.001). The serum Zn has shown a significant negative correlation with T3 and BMI among cases (r =  - 0.313 p < 0.05, r =  - 0.338 p < 0.05, respectively). However, serum P has shown a significant positive correlation with TSH and BMI among cases (r = 0.310 p < 0.05, r = 0.449 p < 0.01, respectively). Regression analysis indicated that serum Zn significantly predicted hypothyroidism (p < 0.00). Similarly, serum P significantly predicted hypothyroidism (p < 0.007). Results showed that serum Zn levels were significantly reduced and serum P levels were significantly elevated in cases compared to controls. The serum Zn and serum P both significantly associated with hypothyroidism.

Determination of calcium, iron, and selenium in human serum by isotope dilution analysis using nitrogen microwave inductively coupled atmospheric pressure plasma mass spectrometry (MICAP-MS)

In this study, we demonstrate the applicability of nitrogen microwave inductively coupled atmospheric pressure mass spectrometry (MICAP-MS) for Ca, Fe, and Se quantification in human serum using isotope dilution (ID) analysis. The matrix tolerance of MICAP-MS in Na matrix was investigated, revealing that high Na levels can suppress the signal intensity. This suppression is likely due to the plasma loading and the space charge effect. Moreover, 40Ca and 44Ca isotopic fractionation was noted at elevated Na concentration. Nine certified serum samples were analyzed using both external calibration and ID analysis. Overestimation of Cr, Zn, As, and Se was found in the results of external calibration, which might result from C-induced polyatomic interference and signal enhancement, respectively. Further investigations performed with methanol showed a similar enhancement effect for Zn, As, and Se, potentially supporting this assumption. The mass concentrations determined with ID analysis show metrological compatibility with the reference values, indicating that MICAP-MS combined with ID analysis can be a promising method for precise Ca, Fe, and Se determination. Moreover, this combination reduces the influence of matrix effects, broadening the applicability of MICAP-MS for samples with complex matrixes.

Mineral patterns in hair: A decisive factor between reproducible and repeat breeder dairy cows

Reproduction, especially impregnation, is a critical aspect of dairy cow management that directly influences herd milk productivity. We conducted a noninvasive hair mineral assay to compare the mineral profiles of two dairy cow groups: reproducible and repeat breeder, by investigating the levels of 11 essential minerals (Ca, Mg, Na, K, Fe, Cu, Mn, Zn, Cr, Se, and P) and 6 toxic elements (Hg, Pb, Cd, Al, As, and Ni) in both groups. We also conducted principal component and correlation matrix analyses to compare hair mineral patterns between the groups. Compared to their reproducible counterparts, repeat breeder cows had lower levels of Na, K, and Se. However, Fe, Cd, Al, and As levels were higher in repeat breeders than in their reproducible counterparts. The correlation matrix showed notable correlation patterns for each group. Ca, K, and Na levels were positively correlated in reproducible cows, whereas repeat breeder cows showed positive correlations only between Ca and K levels. Se showed positive correlations with Zn only in the reproducible cow group. Negative correlations were not found in the reproducible group, whereas the repeat breeder group exhibited 7 negative correlations. Despite the limitations of hair mineral analysis, this study provided useful insights into the reproductive potential of dairy cows. These findings aid in easing the prediction of repeat breeder occurrences in herds and are expected to facilitate timely mineral supplementation and other interventions to improve overall herd reproduction in dairy farms.

The Role of Selenitetriglycerides in Enhancing Antioxidant Defense Mechanisms in Peripartum Holstein-Friesian Cows

The transition period in high-yielding dairy cows is a critical phase marked by an elevated risk of oxidative stress. This study evaluated the effect of oral selenitetriglyceride supplementation on oxidative stress management in periparturient cows. A controlled experiment was conducted on 12 cows, divided into two groups: the experimental group (STG) received selenitetriglycerides (0.5 mg Se/kg BW), while the control group (CON) was given a placebo, starting 12 days before calving until the calving day. Blood and liver tissue samples were collected at predetermined intervals around the time of parturition. The study observed a significant increase in serum selenium levels and NEFA stabilization in the STG group compared with the control. Antioxidant parameters indicated elevated GSH-Px and CAT concentrations in the STG group. Liver gene expression analysis revealed a significant increase in SOD2 mRNA levels in the STG group (FC = 4.68, p < 0.01). Conversely, GSH-Px3 expression significantly decreased (FC = 0.10, p < 0.05) on the 7th day postpartum in the CON group. However, SOD1, SOD3, and CAT expressions remained stable in both groups. These findings highlight the beneficial role of selenitetriglycerides in enhancing antioxidant capacity and influencing specific gene expressions associated with oxidative stress management in dairy cows during the peripartum period.

Nutrition and thyroid disease

PURPOSE OF REVIEW

The aim of this review was to determine, based on the most recent findings, the involvement of trace elements and vitamins critical for thyroid function and combating thyroid disease.

RECENT FINDINGS

Nutritional guidance is pivotal to reducing the risk of thyroid disease and to managing it when it arises, this meaning the prescription of diets rich in such micronutrients as iodine, selenium, iron, zinc, and vitamins B12, D3, and A. Most of the above micronutrients are good antioxidants, building up an anti-inflammatory profile, reducing thyroid autoantibodies and body fat, and improving thyroid function. Diets are increasingly being prescribed, especially for those suffering from Hashimoto's thyroiditis. Notable among prescribed diets is the Mediterranean diet. Rich in critical elements, it benefits patients at the immune endocrine and biomolecular levels.

SUMMARY

Importantly, it is likely that widespread adherence to the Mediterranean diet, together with a reduction of meat consumption and potential elimination of gluten and lactose may improve inflammation and have an impact on public health while possibly diminishing thyroiditis symptoms. It is hoped that this review can direct policymakers towards undertaking cost-effective interventions to minimize deficiency of essential minerals and vitamins and thus protect both general and thyroid health.

Assessment of the Impact of Nutritional Intervention with the Probiotic Lactiplantibacillus plantarum 299v on Nutritional Status and Quality of Life of Hashimoto's Thyroiditis Patients-A Randomized Double-Blind Study Protocol

The current treatment for the autoimmune disease of hypothyroidism (AIDH) is based on pharmacotherapy with levothyroxine. A non-pharmacological supplementary element of therapy could be the implementation of an individualized balanced diet and probiotics. Lactiplantibacillus plantarum 299v (Lp299v), with its anti-inflammatory effects, may also support the therapy. However, the number of studies on personalized dietary interventions with probiotics in AIDH is limited, and no clear conclusions can be drawn from the results so far. Therefore, this trial will analyze the effect of Lp299v supplementation in conjunction with nutrition education on the quality of life and nutritional status of patients with Hashimoto's. Methods: This double-blind, 12-week intervention study will include 100 female patients with AIDH. They will be divided into two groups: (1) individual personalized nutrition education + Lp299v and (2) individual personalized nutrition education + placebo. Before and after the education intervention, selected elements in the diet, eating behavior, quality of life, nutritional status (anthropometric parameters, body composition), blood pressure, and anti-TPO (antibodies against thyroid peroxidase) titer will be assessed. Hypothesis: It is expected that this study will provide deeper knowledge on the validity of using proper nutritional principles and Lp299v in AIDH. Specifically, the impact on the subjective assessment of the quality of life, selected elements in the diet, and the state of nutrition and health will be assessed.