Effects of Zinc and Selenium Supplementation on Thyroid Function in Overweight and Obese Hypothyroid Female Patients: A Randomized Double-Blind Controlled Trial

Effect of daily zinc supplementation for 12 weeks on serum thyroid auto-antibody levels in children and adolescents with autoimmune thyroiditis - a randomized controlled trial

OBJECTIVES

To assess the effect of daily zinc supplementation for 12 weeks on thyroid auto-antibodies - thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb), and oxidative stress in children with autoimmune thyroid disease (AITD) compared to standard therapy.

METHODS

This open-labeled, parallel, randomized controlled trial was done in a tertiary care teaching institute in south India. Children aged 3-18 years with AITD were randomized to receive 25 mg elemental zinc daily for 12 weeks or standard therapy alone. The change in thyroid function tests (thyroid stimulating hormone, free T3, free T4), thyroid auto-antibody (TPOAb, TgAb) titers, oxidative stress markers (glutathione peroxidase, malondialdehyde, superoxide dismutase, and total antioxidant capacity) were compared.

RESULTS

Forty children, 20 in each arm, were recruited in the study. We observed a female-to-male ratio of 7:1. Median duration of disease was 2 (0.25, 4.25) years. A total of 37 (92.5 %) children were hypothyroid, two hyperthyroid, and one euthyroid at enrolment. A total of 13 children (32.5 %) had associated co-morbidities, most commonly type 1 diabetes mellitus and systemic lupus erythematosus, three (7.5 %) each. We did not find any significant change in thyroid function tests, thyroid auto-antibody titers, and oxidative stress markers. However, the requirement of levothyroxine dose was significantly increased in the control arm, compared to the zinc group (p=0.03). Only four (20 %) children had minor adverse effects like nausea, metallic taste, and body ache.

CONCLUSIONS

Zinc supplementation did not have any effect on thyroid auto-antibodies and oxidative stress. Zinc-supplemented children did not require escalation in levothyroxine dose.

The Effects of the Paleo Diet on Autoimmune Thyroid Disease: A Mixed Methods Review

The aim of this systematic review was to examine the characteristics of Paleolithic diet (PD) interventions designed for adult patients with autoimmune thyroid disease (AITD) in order to determine if diet elements have the potential to successfully reduce thyroid antibodies (Ab) such as thyroglobulin (Tg), thyroid peroxidase (TPO), and thyroid stimulating hormone receptor (TSHR), and improve thyroid hormones (thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH)) or resolve AITD pathogenesis. Randomized controlled trials (RCTs) with an adult population of 18 years and older, diagnosed with Hashimoto's thyroiditis (HT) or Graves' disease (GD) (Basedow's), who were placed on a diet of Paleolithic or ancestral nature, and achieved reduction of AITD Abs, improvement of thyroid hormones, and, or resolution of AITD were searched. Various electronic databases were used. Bias was assessed using critical appraisal tools from the Scottish Intercollegiate Guidelines Network (SIGN) and Joanna Briggs Institute (JBI). Studies were excluded according to exclusion criteria and results analyzed. One randomized controlled trial (RCT), a pilot study, and six case studies were found. In total, eight AITD studies focusing on Paleolithic or ancestral interventions were located. In highlight, females were the predominant gender. Case studies solely focused on AITD with protocols ranging from 8-60 weeks. All studies showed clinical improvements, one had significant improvement, two showed AITD resolution. After structured evaluation of nutritional interventions utilizing the PD on the effects of AITD, it was concluded foods of ancestral nature along with the addition of specific supplements, food components, exercise and mindfulness meditation, and exclusion of modern day foods have a considerable impact on thyroid Ab and hormones. The relevant studies suggest while this dietary protocol can be useful in clinical practice, larger-scale studies need to be conducted. Key teaching pointsThere are currently no dietary interventions recommended for the treatment of autoimmune thyroid disease. The Paleo diet has been documented to improve AITD antibodies and thyroid hormones in both Hashimoto's thyroiditis and Graves' disease.The Paleo diet can provide a natural source of nutrients similar to supplemental nutrients that have shown positive results on AITD.The paleo diet provides specific macronutrient percentages that may be beneficial in reducing AITD antibodies, while improving thyroid hormones.Methylation supplementation may be useful in AITD cases.

Nutrient synergy: definition, evidence, and future directions

Nutrient synergy refers to the concept that the combined effects of two or more nutrients working together have a greater physiological impact on the body than when each nutrient is consumed individually. While nutrition science traditionally focuses on isolating single nutrients to study their effects, it is recognized that nutrients interact in complex ways, and their combined consumption can lead to additive effects. Additionally, the Dietary Reference Intakes (DRIs) provide guidelines to prevent nutrient deficiencies and excessive intake but are not designed to assess the potential synergistic effects of consuming nutrients together. Even the term synergy is often applied in different manners depending on the scientific discipline. Considering these issues, the aim of this narrative review is to investigate the potential health benefits of consuming different nutrients and nutrient supplements in combination, a concept we define as nutrient synergy, which has gained considerable attention for its impact on overall well-being. We will examine how nutrient synergy affects major bodily systems, influencing systemic health. Additionally, we will address the challenges associated with promoting and conducting research on this topic, while proposing potential solutions to enhance the quality and quantity of scientific literature on nutrient synergy.

Interaction Between Dietary Selenium and Zinc Intakes on Hypothyroidism

This study assessed the independent association of dietary selenium and zinc intakes with the risk of hypothyroidism and interaction effect between dietary selenium and zinc intakes with the risk of hypothyroidism in Americans. The data of this cross-sectional study was from the National Health and Nutritional Examination Survey (NHANES) 2007-2012. The outcome was defined as new-onset hypothyroidism. Weighted univariate and multivariate logistic regression and the subgroup analyses based on gender and body mass index (BMI) were conducted to evaluate the association between the dietary selenium and zinc intakes and new-onset hypothyroidism. Odds ratio (OR) and 95% confidence interval (CI) were calculated. A total of 6402 participants were included with 131 (2.05%) developed a hypothyroidism in this study. Compared with participants with high zinc intake, those with low zinc intake had a higher risk of new-onset hypothyroidism (OR = 1.74, 95% CI: 1.05-2.90). Moreover, we also found a significant interaction between dietary selenium level intake and dietary zinc level intake on new-onset hypothyroidism risk (OR = 5.99, 95% CI: 1.77-20.23). There was an interaction between dietary selenium and zinc intakes on the risk of new-onset hypothyroidism, especially the significant effect for adults with women or overweight. The findings indicated that improving the levels of dietary zinc and selenium intake may be beneficial in preventing of new-onset hypothyroidism.

Autoimmune Thyroid Disorders: The Mediterranean Diet as a Protective Choice

Autoimmune thyroid diseases are on the rise worldwide, and such a rapid increase is mainly driven by environmental factors related to changed lifestyles in "modern" societies. In this context, diet seems to play a crucial role. An unhealthy high-energy diet, rich in animal fat and proteins, salt and refined sugars (the so-called "Western diet") negatively influences the risk of autoimmunity by altering the immune balance and the gut microbiota composition, enhancing oxidative stress and promoting inflammation. In contrast, the Mediterranean diet represents a unique model of healthy eating, characterized by a high intake of food from vegetable sources, a low consumption of saturated fats in favor of unsaturated fats (mainly, olive oil), a moderate consumption of fish (typically, the small oily fishes) and dairy products, as well as a moderate consumption of wine at meals, and a low intake of meat. Thanks to its nutritional components, the Mediterranean Diet positively influences immune system function, gut microbiota composition, and redox homeostasis, exerting anti-oxidants, anti-inflammatory, and immunomodulatory effects. The present review was aimed at exploring the existing knowledge on the correlations between dietary habits and thyroid autoimmunity, to evaluate the role of the Mediterranean diet as a protective model.

Thyroid hormones and minerals in immunocorrection of disorders in autoimmune thyroid diseases

Thyroid hormones and essential elements iodine (I), selenium (Se), iron (Fe), copper (Cu), zinc (Zn), calcium (Ca), magnesium (Mg), etc. play an important role in the work of many organs and systems of the body, including the immune system and the thyroid gland, and a violation of their supply can be the cause of pathological changes in them. In pathology, the interaction between thyroid hormones (TG), minerals and the immune system is disturbed. The review of the literature examines the immunomodulatory role of TG, minerals, their properties, and their participation in the pathogenesis of autoimmune thyroid diseases (AITD). The study of the relationship between the excess or deficiency of minerals and AITD is described. The basis of the development of AITD - Hashimoto's thyroiditis (HT), Graves' disease (GD), Graves' ophthalmopathy (GO) is the loss of immune tolerance to thyroid antigens - thyroid peroxidase (TPO), thyroglobulin (Tg) and thyroid-stimulating hormone receptor (TSH-R). Immune-mediated mechanisms - production of autoantibodies to thyroid antigens and lymphocytic thyroid infiltration - are involved in the pathogenesis of AITD. Insufficiency of regulatory T cells (Treg) and regulatory B cells (Breg), imbalance between Th17-lymphocytes and Treg-lymphocytes, abnormal production of pro-inflammatory cytokines has a significant influence on the progression of AITD. With AITD, the balance between oxidants and antioxidants is disturbed and oxidative stress (OS) occurs. The lack of modern effective pharmacological therapy of AITD prompted us to consider the mechanisms of influence, possibilities of immunocorrection of pathogenetic factors using TG, micro/macronutrients. In order to develop a more effective treatment strategy, as well as approaches to prevention, a critical analysis of the ways of immunotherapeutic use of dietary supplements of I, Se, Zn, Mg and other minerals in AITD was carried out.

The Effects of Zinc and Selenium Co-Supplementation on Resting Metabolic Rate, Thyroid Function, Physical Fitness, and Functional Capacity in Overweight and Obese People under a Hypocaloric Diet: A Randomized, Double-Blind, and Placebo-Controlled Trial

Evidence of the effectiveness of zinc (Zn) and selenium (Se) on resting metabolic rate (RMR) and physical function parameters in people with overweight and obesity is scarce, while the effects of zinc and selenium on thyroid function and body composition are still a topic of debate and controversy. The aim of this randomized, double-blind, and placebo-controlled trial was to examine the effects of a hypocaloric diet and Se-Zn co-supplementation on RMR, thyroid function, body composition, physical fitness, and functional capacity in overweight or obese individuals. Twenty-eight overweight-obese participants (mean BMI: 29.4 ± 4.7) were randomly allocated (1:1) to the supplementation group (n = 14, 31.1 ± 5.5 yrs, 9 females) and the placebo group (n = 14, 32.1 ± 4.8 yrs, 6 females). The participants received Zn (25 mg of zinc gluconate/day) and Se (200 mcg of L-selenomethionine/day) or placebo tablets containing starch for eight weeks. The participants of both groups followed a hypocaloric diet during the intervention. RMR, thyroid function, body composition, cardiorespiratory fitness (VO₂max), and functional capacity (sit-to-stand tests, timed up-and-go test, and handgrip strength) were assessed before and after the intervention. A significant interaction was found between supplementation and time on RMR (p = 0.045), with the intervention group's RMR increasing from 1923 ± 440 to 2364 ± 410 kcal/day. On the other hand, no interaction between supplementation and time on the thyroid function was found (p > 0.05). Regarding the effects of Zn/Se co-administration on Se levels, a significant interaction between supplementation and time on Se levels was detected (p = 0.004). Specifically, the intervention group's Se serum levels were increased from 83.04 ± 13.59 to 119.40 ± 23.93 μg/L. However, Zn serum levels did not change over time (90.61 ± 23.23 to 89.58 ± 10.61 umol/L). Even though all body composition outcomes improved in the intervention group more than placebo at the second measurement, no supplement × time interaction was detected on body composition (p > 0.05). Cardiorespiratory fitness did not change over the intervention. Yet, a main effect of time was found for some functional capacity tests, with both groups improving similarly over the eight-week intervention period (p < 0.05). In contrast, a supplement x group interaction was found in the performance of the timed up-and-go test (TUG) (p = 0.010), with the supplementation group improving more. In conclusion, an eight-week intervention with Zn/Se co-supplementation combined with a hypocaloric diet increased the RMR, TUG performance, and Se levels in overweight and obese people. However, thyroid function, Zn levels, body composition, and the remaining outcomes of exercise performance remained unchanged.

Physiological Benefits of Novel Selenium Delivery via Nanoparticles

Dietary selenium (Se) intake within the physiological range is critical to maintain various biological functions, including antioxidant defence, redox homeostasis, growth, reproduction, immunity, and thyroid hormone production. Chemical forms of dietary Se are diverse, including organic Se (selenomethionine, selenocysteine, and selenium-methyl-selenocysteine) and inorganic Se (selenate and selenite). Previous studies have largely investigated and compared the health impacts of dietary Se on agricultural stock and humans, where dietary Se has shown various benefits, including enhanced growth performance, immune functions, and nutritional quality of meats, with reduced oxidative stress and inflammation, and finally enhanced thyroid health and fertility in humans. The emergence of nanoparticles presents a novel and innovative technology. Notably, Se in the form of nanoparticles (SeNPs) has lower toxicity, higher bioavailability, lower excretion in animals, and is linked to more powerful and superior biological activities (at a comparable Se dose) than traditional chemical forms of dietary Se. As a result, the development of tailored SeNPs for their use in intensive agriculture and as candidate for therapeutic drugs for human pathologies is now being actively explored. This review highlights the biological impacts of SeNPs on growth and reproductive performances, their role in modulating heat and oxidative stress and inflammation and the varying modes of synthesis of SeNPs.

Zn and Se abrogate heavy metal mixture induced ovarian and thyroid oxido-inflammatory effects mediated by activation of NRF2-HMOX-1 in female albino rats

The thyroid is vital for the proper functioning of the female reproductive system since it regulates the metabolism and development of ovary. This is an evaluation of the essential trace elements ETE on the heavy metals mixture HMM mediated oxido-inflammatory effects in the ovary and thyroid of female albino rats. Eight groups (5 female rats /group) were treated as follows for 60 days: Group 1: Deionized water only; Group 2: (Pb, Hg, Mn and Al); Group 3: HMM + ZnCl₂, 0.80 mg/kg; Group 4: HMM + Na₂SeO₃, 1.50 mg/kg; Group 5: HMM + ZnCl₂, 0.80 mg/kg and Na₂SeO₃, 1.50 mg/kg combined. On day 60 animals were euthanized, ovary and thyroid were harvested and used for, MDA, NO, antioxidants, TNF-α, IL-6, HMOX-1, Caspase-3, NF-KB, NRF2, HM and histopathology. There was significant bioaccumulation of Pb, Al, Hg and MN; elevated IL-6 and TNF-α, MDA and NO, caspase-3 and NRF2, NFKB and HMOX-1 with significant decrease in antioxidants in the HMM only group in comparison to the control. Co-treatment with ETE reversed most of these effects. ETE may ameliorate HMM -induced ovarian and thyrotoxicity in female albino rats by blunting oxido-inflammatory activities.

Thyroid, Diet, and Alternative Approaches

BACKGROUND

Increasingly, patients are asking their physicians about the benefits of dietary and alternative approaches to manage their diseases, including thyroid disease. We seek to review the evidence behind several of the vitamins, minerals, complementary medicines, and elimination diets that patients are most commonly using for the treatment of thyroid disorders.

SUMMARY

Several trace elements are essential to normal thyroid function, and their supplementation has been studied in various capacities. Iodine supplementation has been implemented on national scales through universal salt iodization with great success in preventing severe thyroid disease, but can conversely cause thyroid disorders when given in excess. Selenium and zinc supplementation has been found to be beneficial in specific populations with otherwise limited generalizability. Other minerals, such as vitamin B12, low-dose naltrexone, and ashwagandha root extract, have little to no evidence of any impact on thyroid disorders. Avoidance of gluten and dairy has positive impacts only in patients with concomitant sensitivities to those substances, likely by improving absorption of levothyroxine. Avoidance of cruciferous vegetables and soy has little proven benefit in patients with thyroid disorders.

CONCLUSION

While many patients are seeking to avoid conventional therapy and instead turn to alternative and dietary approaches to thyroid disease management, many of the most popular approaches have no proven benefit or have not been well studied. It is our responsibility to educate our patients about the evidence for or against benefit, potential harms, or dearth of knowledge behind these strategies.

Relationships Between Maternal Selected Metals (Cu, Mg, Zn and Fe), Thyroid Function and Blood Glucose Levels During Pregnancy

The aim of this study were to understand the intake of selected metals (copper (Cu), zinc (Zn), iron (Fe) and magnesium (Mg)) during pregnancy; to detect serum Cu, Mg, Zn and Fe levels in pregnant women; to analyze the relationships among the selected metals, maternal thyroid function and fasting blood glucose (FBG) levels; to investigate the impact of the selected metals and maternal thyroid function on the risk of gestational diabetes mellitus (GDM); and to provide clinical value for the rational intake of the selected metals and iodine during pregnancy to ensure normal fetal development. The population was recruited from pregnant women presenting to the obstetrics outpatient clinic of Shanxi Provincial People's Hospital (February 2021 to April 2022). Selected metal, thyroid hormone (TH (free thyroxine (FT4), free tri-iodothyronine (FT3), and thyroid-stimulating hormone (TSH)) and FBG levels were measured in pregnant women during early, middle and late pregnancy. Covariance analysis was used to analyze the overall trends in selected metal, TH and FBG levels during pregnancy, and binary logistic regression models were used to assess the impacts of the selected metals and thyroid function on the risk of GDM. In addtion, the potential mediation effects of thyroid functions were explored in the mediation analyses. A total of 65 pregnant women were included in this study. Regression models showed that maternal Mg and Cu levels were positively associated with the risk of GDM, conversely, logFT4 was negatively associated with the risk of GDM. Mediation analyses suggested that the associations between the selected metals (Zn, Cu and Mg) and GDM might be mediated by FT3 levels, and that the Cu-GDM and Zn-GDM association could be explained by FT4 levels. Additionally, the Zn-GDM association could also potentially be mediated by the FT3/FT4 ratio. Our findings suggest that Mg, Cu and FT4 levels may act as influencing factors for the development of GDM, and maternal FT3, FT4 and the FT3/FT4 ratio might be the potential mediators of the associations between the selected metals and GDM risk during pregnancy.

Effects of magnesium picolinate, zinc picolinate, and selenomethionine co-supplementation on reproductive hormones, and glucose and lipid metabolism-related protein expressions in male rats fed a high-fat diet

This study aimed to examine the impacts of the magnesium picolinate (MgPic), zinc picolinate (ZnPic), and selenomethionine (SeMet) alone or as a combination on blood metabolites, oxidative enzymes, reproductive hormones, and glucose and lipid metabolism-related protein expressions in Wistar rats fed a high-fed diet (HFD). The rats were fed either a control, HFD, or HFD supplemented with a single (MgPic, ZnPic, SeMet) or two or three organic mineral combinations. Body weights, visceral fat, serum glucose, insulin, total cholesterol, triglycerides, leptin, malondialdehyde (MDA) concentrations as well as liver sterol regulatory element-binding protein-1c (SREBP-1c), liver X receptor alpha (LXRα), ATP citrate lyase (ACLY), fatty acid synthase (FAS), and nuclear factor kappa B (NF-κB) levels increased, while serum testosterone, follicle-stimulating hormone (FSH), luteinizing hormone (LH), sex hormone-binding globulin (SHBG), and insulin-like growth factor (IGF-1) concentrations along with liver nuclear factor erythroid 2-related factor 2 (Nrf2) levels declined in HFD rats (P < 0.05). Supplementing each organic mineral, but particularly the combination of HFD + MgPic + ZnPic + SeMet reversed the responses with various degrees. None of the organic elements alone or as a combination of two exerted a prominent effect on parameters measured. Although not additive or synergistic, the combination of all organic minerals added to HFD (HFD + MgPic + ZnPic + SeMet) provided the greatest responses.

Factors influencing the levothyroxine dose in the hormone replacement therapy of primary hypothyroidism in adults

Levothyroxine (LT4) is a safe, effective means of hormone replacement therapy for hypothyroidism. Here, we review the pharmaceutical, pathophysiological and behavioural factors influencing the absorption, distribution, metabolism and excretion of LT4. Any factor that alters the state of the epithelium in the stomach or small intestine will reduce and/or slow absorption of LT4; these include ulcerative colitis, coeliac disease, bariatric surgery, Helicobacter pylori infection, food intolerance, gastritis, mineral supplements, dietary fibre, resins, and various drugs. Once in the circulation, LT4 is almost fully bound to plasma proteins. Although free T4 (FT4) and liothyronine concentrations are extensively buffered, it is possible that drug- or disorder-induced changes in plasma proteins levels can modify free hormone levels. The data on the clinical significance of genetic variants in deiodinase genes are contradictory, and wide-scale genotyping of hypothyroid patients is not currently justified. We developed a decision tree for the physician faced with an abnormally high thyroid-stimulating hormone (TSH) level in a patient reporting adequate compliance with the recommended LT4 dose. The physician should review medications, the medical history and the serum FT4 level and check for acute adrenal insufficiency, heterophilic anti-TSH antibodies, antibodies against gastric and intestinal components (gastric parietal cells, endomysium, and tissue transglutaminase 2), and Helicobacter pylori infection. The next step is an LT4 pharmacodynamic absorption test; poor LT4 absorption should prompt a consultation with a gastroenterologist and (depending on the findings) an increase in the LT4 dose level. An in-depth etiological investigation can reveal visceral disorders and, especially, digestive tract disorders.

The Effects of Zinc and Selenium Supplementation on Body Composition and Thyroid Function in Individuals with Overweight or Obesity: A Systematic Review

People with obesity have been found to have lower zinc (Zn) and selenium (Se) circulatory levels and abnormal thyroid function than people with normal weight. Studies about the effects of Zn and Se supplementation on body composition and thyroid function of overweight-obese people showed inconsistent results. A systematic review of randomized controlled trials was conducted to determine the effects of Ζn supplementation, Se supplementation, and their combination on body composition and thyroid function of individuals with overweight or obesity. Databases of PubMed, ScienceDirect, and Cochrane, were searched from inception to February 27, 2022, to identify relevant articles. For the assessment of the methodological quality of the studies, the Jadad scale was used. After screening the articles, thirteen studies were finally included and were analyzed using the strength of the evidence approach. Regarding the effectiveness of Zn supplementation on body composition, moderate evidence was found, while the effects of Se were found to be mixed. Zn supplementation was found to affect the thyroid function of people with overweight or obesity by increasing their free triiodothyronine (FT3) levels. However, this result is based only on one study among hypothyroid patients. At this point, the effectiveness of Zn, Se, and their combination, on the body composition and the thyroid function of people with overweight or obesity cannot safely be determined because of the controversial results, small number, and the limitations of the identified studies. The results of this systematic review must be interpreted with caution due to the limitations detected.

Protective Effects of Selenium and Zinc Against Nickel Chloride-Induced Hormonal Changes and Oxidative Damage in Thyroid of Pregnant Rats

Nickel chloride (NiCl₂) is a heavy metal that may affect the function of the thyroid. Selenium (Se) and zinc (Zn) are essential trace elements involved in thyroid hormone metabolism. However, little is reported about thyrotoxicity during gestation. The current study aimed to investigate the protective effects of selenium and zinc against NiCl₂-induced thyrotoxicity in pregnant Wistar rats. Female rats were treated subcutaneously (s.c.) on the 3rd day of pregnancy, with NaCl 0.9% and served as control, NiCl₂ (100 mg/kg body weight (BW)) alone, or in association with Se (0.3 mg/kg, s.c.), ZnCl₂ (20 mg/kg, s.c.), or both of them simultaneously. Oxidative stress parameters, thyroid biomarkers, and histopathological examination were evaluated. Results showed that NiCl₂ exposure caused a significant decrease in maternal body weight and an increase in absolute and relative thyroid weight compared to the controls. NiCl₂ administration also led to decreased plasma triiodothyronine (T3) and thyroxine (T4) with a concomitant significant increase in thyroid-stimulating hormone (TSH) levels when compared to that of control. In addition, an overall pro-oxidant effect was associated with a decrease in the reduced glutathione (GSH) and nonprotein thiol (NPSH) contents and the enzymatic activity of glutathione peroxidase (GPx) and superoxide dismutase (SOD), and an increase in malondialdehyde (MDA). These biochemical disturbances were confirmed by histological changes. However, the co-treatment of Se and/or ZnCl₂ attenuates NiCl₂-induced changes. Our findings suggested that Se and ZnCl₂ ameliorated NiCl₂-induced thyrotoxicity in pregnant Wistar rats by exhibiting antioxidant effects.

Long COVID-19 in Children: From the Pathogenesis to the Biologically Plausible Roots of the Syndrome

Long Coronavirus disease-19 (COVID-19) refers to the persistence of symptoms related to the infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). This condition is described as persistent and can manifest in various combinations of signs and symptoms, such as fatigue, headache, dyspnea, depression, cognitive impairment, and altered perception of smells and tastes. Long COVID-19 may be due to long-term damage to different organs-such as lung, brain, kidney, and heart-caused by persisting viral-induced inflammation, immune dysregulation, autoimmunity, diffuse endothelial damage, and micro thrombosis. In this review, we discuss the potential and biologically plausible role of some vitamins, essential elements, and functional foods based on the hypothesis that an individual's dietary status may play an important adjunctive role in protective immunity against COVID-19 and possibly against its long-term consequences.

Effect of Selenium-Enriched Yeast Supplementation on Serum Thyroid-Stimulating Hormone and Anti-Thyroid Peroxidase Antibody Levels in Subclinical Hypothyroidism: Randomized Controlled Trial

Background

In the subclinical hypothyroidism, T4 or T3 levels are normal and thyroid-stimulating hormone (TSH) is slightly high. Selenium deficiency can lead to thyroid dysfunction. The present study aims to investigate the effect of selenium supplementation on the thyroid hormone and anti-thyroid peroxidase antibody (anti-TPO AB) levels.

Materials and Methods

In this double-blinded, randomized, placebo-controlled clinical trial, 42 patients with subclinical hypothyroidism were randomly assigned to receive 200 μg selenium or placebo for 8 weeks. In the both groups, the serum TSH and anti-TPO antibody levels were measured and assessed before and after the intervention.

Results

After the interventions, the mean serum TSH reduction in the intervention and placebo groups was -10.98 ± 33.31 and -3.20 ± 38.36, respectively, which were not statistically significant. However, the mean serum anti-TPO Ab concentration increased in the intervention and placebo groups (109.81 ± 51.49% vs. 173.17 ± 96.26%), between which the difference was not statistically significant (P >0.05) despite a slight increase in the mean anti-TPO level in the intervention group.

Conclusion

The results of the current study indicated that selenium supplementation has no significant effect on serum anti-TPO Ab and TSH levels in the patients with subclinical hypothyroidism. Studies with larger sample size and with different doses of selenium are needed to reach more precise results.

Maternal essential metals, thyroid hormones, and fetal growth: Association and mediation analyses in Chinese pregnant women

BACKGROUND

Essential metals play critical roles in fetal growth and development, but results from human studies are inconsistent. Additionally, whether maternal thyroid hormone (TH) levels mediate the associations between essential metals and fetal growth remains unknown.

METHODS

Data for analysis were extracted from the Information System of Guangdong Women and Children Hospital between January 2017 and December 2019. Maternal levels of essential metals [copper (Cu), zinc (Zn), magnesium (Mg), and iron (Fe)] and THs were measured at the second trimester. Multivariate linear models were introduced to evaluate the potential associations between maternal essential metals, thyroid functions, and fetal growth, and the possible mediation effects of thyroid functions were explored in the median analyses.

RESULTS

A total of 4186 mother-infant pairs were included in the present study. Maternal Fe levels were found to significantly increase birth weight in 272.91 g (95 % CI: 15.59, 530.22) among anemia group. Maternal Cu levels were positively associated with increased free triiodothyronine/free thyroxine ratio (FT3/FT4). Negative associations of Fe and Mg levels with thyroid-stimulating hormone (TSH) concentrations were observed, accompanied with the positive associations in relation to FT3, FT4 and FT3/FT4 ratio. Mediation analyses suggested that 72.01 % of the associations between Fe levels and birth length might be mediated by FT3 levels. Additionally, 25.85 % of the Cu-birth length association and 44.53 % of the Fe-birth length association could be explained by FT3/FT4 ratio.

CONCLUSION

Our findings suggest that maternal Cu, Mg, and Fe levels can alter TH concentrations, and maternal FT3 and FT3/FT4 ratio might be potential mediators on the developmental effects of Cu and Fe levels.

Relation Between Zinc and Thyroid Hormones in Humans: a Systematic Review

The aim of this study was to systematically evaluate the relation between zinc and the thyroid hormones in humans. The search for articles was conducted using the Pubmed, Scopus, Cochrane Central Register of Controlled Trials (CENTRAL), and ScienceDirect databases on October 21 and 22, 2019, by two authors independently. The recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were followed in the conduct of this review. The Cochrane Collaboration tool was used to assess the risk of bias of the trials included in this review. After the screening of the articles, eight studies that assessed the effects of zinc supplementation on thyroid hormone concentrations and ten studies that assessed the relationship between blood zinc concentrations and thyroid hormones were included in this systematic review. Although cross-sectional and case-control studies have shown a relationship between zinc deficiency and thyroid, the data from this systematic review provides inconclusive evidence with respect to the effects of zinc supplementation on thyroid hormone concentrations due to the divergence of the research found by the authors that only reports findings in patients suffering from some kind of disease, which cannot be generalized to the average human population.

The Association between the Dietary Inflammatory Index and Thyroid Function in U.S. Adult Males

Thyroid function has a close link with inflammation. However, it is still unknown whether the dietary inflammatory potential is associated with thyroid function. We aimed to assess the relationship among them using the data from the National Health and Nutrition Examination Survey (NHANES). This study was a cross-sectional study, where weighted multivariable linear regression, subgroup analyses, and interaction terms were employed. Thyroid function was assessed by eight indexes, including total and free T4 and T3, Tg, TgAb, TPOAb, and TSH. A total of 2346 male participants aged ≥20 years with an average age of 50.74 ± 17.68 years were enrolled. The mean DII score among participants was −0.46 ± 1.73, ranging from −4.12 to 4.41, and mean total thyroxine (T4) was 7.61 ± 1.51 μg/dL. We found a positive association between DII and total T4 (β = 0.07; p = 0.0044). Using subgroup analysis, this association became stronger in both the iodine-deficient and obese group (iodine-deficient group: β = 0.15, p < 0.0001; obese group: β = 0.14, p < 0.0001). In conclusion, men adhering to a more pro-inflammatory diet appeared to have higher total T4 levels. However, these hormone variations were still within the normal clinical range and more well-designed studies are still needed to validate the causal relationship between DII and thyroid function.

Beneficial effects of Se/Zn co-supplementation on body weight and adipose tissue inflammation in high-fat diet-induced obese rats

This research investigated the effect of co-supplementation of selenium with zinc on weight control and the inflammatory and oxidative status in relation to obesity. Male Wistar rats (N = 32) were randomly divided into four groups after induction of obesity model: 1) "Zn" was supplemented with zinc sulfate (15 mg/kg BW), 2) "Se" supplemented with selenium as sodium selenate (0.5 mg/kg BW), 3) "Zn + Se" which received Zn (15 mg/kg BW) + Se (0.5 mg/kg BW), and 4) "HFD" as the control group. The intervention was done for eight weeks. At the end of treatment, serum and tissue level of Zn, Se, SOD, GSH-Px, MDA, leptin, TNF-α, and IL-6 was evaluated. Weight and food intake were significantly reduced in the Se group(p < .001), while in the Zn group, weight gain due to obesity was prevented compared to the control group (p = .48). There was a significant and stronger increase in SOD, GSH-Px levels and a remarkable decrease in MDA, leptin, TNF-α, and IL-6 in the group receiving the combination of two supplements than either alone(p < .001). Leptin had a positive correlation with inflammatory factors and lipid peroxidation marker and showed an inverse relationship with Zn and Se levels and anti-oxidative enzymes(p < .05). The analysis showed the mediating role of leptin in the effects of zinc. Co-supplementation of selenium and zinc may have a synergistic effect in reduction of oxidative and inflammatory markers. Regarding the effect of zinc on inflammatory factors and lipid peroxidation, leptin can play a mediating role.

Selenium status and its relationship with thyroid hormones in obese women

BACKGROUND AND AIMS

Studies have been conducted with the purpose of elucidating thyroid gland dysfunction in obesity, however the contributing factors for such dysfunction are not yet fully understood. Selenium is notable for its role in thyrocyte protection against oxidative damage and control of thyroid hormone synthesis. In addition, subjects with obesity may exhibit alterations in the selenium homeostasis. Therefore, the present study aimed to examine the selenium status and its relationship with serum thyroid hormone levels in obese women.

METHODS

This cross-sectional study included 69 euthyroid women, aged between 18 and 50 years, who were divided in two groups: an obese group (n = 35) and a control group with women of normal weight (n = 34). Selenium intake was assessed by three-day diet records and analyzed using NutWin software version 1.5. Plasma, erythrocyte, and urinary selenium levels were determined using inductively coupled plasma optical emission spectrometry. Testing for thyroid hormones and thyroid autoantibodies was performed based on chemiluminescence.

RESULTS

The median dietary selenium content was adequate according to the recommendations, with no statistical difference between groups. Obese women had reduced plasma and erythrocyte selenium levels compared to the control group, although selenium concentration in erythrocytes was adequate within the normal range for both groups. There was no significant difference between the urinary selenium concentrations in the subjects; however, the mineral clearance was higher in the obese group. Free triiodothyronine (fT3) and free thyroxine (fT4) levels were higher in obese women with class II obesity when compared to the control group. There was a negative correlation between plasma selenium and serum fT4 levels.

CONCLUSIONS

Obese women showed impairment in selenium homeostasis, however, this fact did not seem to adversely affect thyroid metabolism.

Minerals: An Untapped Remedy for Autoimmune Hypothyroidism?

For decades, the focus of managing autoimmune hypothyroidism has been on thyroxine replacement. Correcting lab parameters such as thyroid stimulating hormone (TSH) has been a primary goal. The increasing prevalence of Hashimoto’s thyroiditis (HT) continues to impact the quality of life in patients. We believe a holistic approach to this disease entity, considering its underlying complex etiopathogenesis, would benefit patients. Nutraceuticals are combinations of essential nutrients and are becoming a part of novel medical treatments despite the lack of regulation. This review aims to present a concise summary of recent developments regarding minerals such as zinc, selenium, magnesium, iron, and their potential clinical benefit as nutraceuticals in patients with HT. We have explored the potential benefits and associations of these minerals in HT and thyroid function. We reviewed relevant articles, metanalyses, and clinical trials in literature platforms such as PubMed, PubMed Central, and Google Scholar. Significant data found in the literature suggesting a potential health benefit of these minerals in HT though there were many studies to the contrary. Many trials demonstrated the restoration of residual symptoms, reversal of HT-associated thyroid morphological changes, and improvement in thyroid functions. Many of these trials lack statistical power due to the small sample sizes, and their external validity may be questionable due to unaccounted confounding factors. In our opinion, to support an evidence-based holistic clinical approach, further scientific evidence is needed. The association of these elements in thyroid function necessitates more large scale pragmatic trials to elucidate the benefits of nutraceuticals in HT.

Trace Element Status and Hypothyroidism: A Systematic Review and Meta-analysis

The relationship between thyroid hormones metabolism and trace element levels has biological plausibility; however, previous reports that compared trace element levels in patients with hypothyroidism and healthy individuals yielded conflicting results. Therefore, the aim of this meta-analysis was to investigate the association between selected trace elements (i.e., selenium (Se), zinc (Zn), iron (Fe), manganese (Mn), copper (Cu), lead (Pb)), and magnesium (Mg) concentrations in patients with hypothyroidism and healthy controls. Electronic databases, including PubMed, Scopus, Embase, and Science Direct, were searched systematically until September 2019. Thirty-two observational studies were included in the final analyses. Hedges' g tests were used to estimate effect sizes, as trace element concentrations were reported using different measurement units across the studies. Selenium (Hedges' g = - 0.52; 95% CI = [- 1.05, - 0.002]; P = 0.049) and Zn (Hedges' g = - 0.86; 95% CI = [- 1.66, - 0.06]; P = 0.035) concentrations were significantly lower, whereas Pb concentrations were significantly higher (Hedges' g = 0.34; 95% CI = [0.10, 0.59]; P = 0.006) in patients with hypothyroidism compared with healthy controls. There were no differences in the concentrations of Fe, Cu, Mn, and Mg between the groups. Patients with hypothyroidism exhibited lower Se and Zn and increased Pb concentrations compared with healthy controls. High-quality studies with larger sample sizes are required to explicate the link between trace element status and hypothyroidism.

Effects of Zinc Supplementation on Cardiometabolic Risk Factors: a Systematic Review and Meta-analysis of Randomized Controlled Trials

The prevalence of cardiometabolic risk factors has been increasing worldwide. The results of reported studies on the effects of zinc supplementation on cardiometabolic risk factors are unequivocal. This systematic review and meta-analysis of randomized controlled trials was conducted to evaluate the effects of zinc supplementation on cardiometabolic risk factors. A systematic search was conducted through international databases (PubMed/Medline, Institute of Scientific Information, and Scopus) until December 2018 to include all randomized controlled trials (RCT), quasi-RCT, and controlled clinical trials which assessed the effect of zinc supplementation on cardiometabolic risk factors including lipid profile, glycemic indices, blood pressure, and anthropometric indices. Random- or fixed-effects meta-analysis method was used to estimate the standardized mean difference (SMD) and 95% confidence interval (CI). A total of 20 studies were included in the meta-analysis, which included a total of 1141 participants in the intervention group. Meta-analysis showed that zinc supplementation significantly decreased plasma levels of triglyceride (SMD - 0.66, 95% CI - 1.27, - 0.06), very-low-density lipoprotein (SMD - 1.59, 95% CI - 2.86, - 0.31), and total cholesterol (SMD - 0.65, 95% CI - 1.15, - 0.15). Similarly, zinc supplementation significantly decreased fasting blood glucose (SMD - 0.52, 95% CI - 0.96, - 0.07) and HbA1c (SMD - 0.64, 95% CI - 1.27, - 0.02). The effects of zinc supplementation on blood pressure and anthropometric indices were not statistically significant (P > 0.05). Zinc supplements had beneficial effects on glycemic indices and lipid profile. Thus, it appeared that zinc supplementation might be associated with a decrease in cardiometabolic risk factors contributing to a reduction in risk of atherosclerosis.

Zinc Supplementation and Body Weight: A Systematic Review and Dose-Response Meta-analysis of Randomized Controlled Trials

The aim of this study was to determine the effect of zinc supplementation on anthropometric measures. In this systematic review and dose-response meta-analysis, we searched PubMed, Scopus, ISI Web of Science, and the Cochrane Library from database inception to August 2018 for relevant randomized controlled trials. Mean differences and SDs for each outcome were pooled using a random-effects model. Furthermore, a dose-response analysis for zinc dosage was performed using a fractional polynomial model. Quality of evidence was evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. Twenty-seven trials (n = 1438 participants) were included in the meta-analysis. There were no significant changes in anthropometric measures after zinc supplementation in the overall analysis. However, subgroup analyses revealed that zinc supplementation increased body weight in individuals undergoing hemodialysis (HD) [3 trials, n = 154 participants; weighted mean difference (WMD) = 1.02 kg; 95% CI: 0.38, 1.65 kg; P = 0.002; I2 = 11.4%] and decreased body weight in subjects who are overweight/obese but otherwise healthy (5 trials, n = 245 participants; WMD = -0.55 kg; 95% CI: -1.06, -0.04 kg; P = 0.03; I2 = 31.5%). Dose-response analyses revealed a significant nonlinear effect of supplementation dosage on BMI (P = 0.001). Our data suggest that zinc supplementation increases body weight in patients undergoing HD and decreases body weight in individuals who are overweight/obese but otherwise healthy, although after normalization for study duration, the association observed in subjects who are overweight/obese disappeared. Although more high-quality studies are needed to reach a definitive conclusion, our study supports the view that zinc may be associated with body weight.

Evaluation of Qualitative Dietary Protocol (Diet4Hashi) Application in Dietary Counseling in Hashimoto Thyroiditis: Study Protocol of a Randomized Controlled Trial

The current state of knowledge related to diet in Hashimoto thyroiditis (HT) is far from satisfactory, as many HT subjects experience several disorders and report reduced quality of life. There are three aims of the study: (1) to develop a qualitative dietary protocol (QDP; 'Diet4Hashi') as a simple, graphic-text tool dedicated to TH subjects, (2) to evaluate the use of the QDP in dietetic counseling compared to conventional dietetic counseling (CDC) in HT women, and (3) to assess the impact of both the QDP and the CDC on the diet quality, quality of life, adiposity, and metabolic parameters of HT women. The QDP is based on subject self-monitoring supported with a graphic-text tool to help them in food selection and adequate food frequency consumption, while the CDC on oral explanation and printed sample menus were provided by a dietician. The QDP contains two lists: (A) foods recommended for consumption and (B) foods with limited consumption, along with indicated consumption frequency per day/week/month. Both approaches include the same dietary recommendations for HT extracted from the literature but differ in subject-dietician cooperation. To summarize the evidence regarding dietary recommendations in HT, the PubMed, Embase, and Cochrane Library databases (to March 2019) and the bibliographies of key articles were searched. The study is designed as a dietary intervention lasting six months in two parallel groups: experimental and control. In the experimental group, the QDP will be applied, while in the control group, the CDC will be applied. In total, the study will include a baseline of 100 women with diagnosed HT. The subjects will be randomly allocated into the experimental/control groups (50/50). Data related to diet quality and other lifestyle factors, nutrition knowledge, quality of life, thyroid function, body composition, blood pressure, serum fasting glucose, and lipid profile at baseline and after a six-month follow-up will be collected. This study was conducted to develop a dietary protocol (Diet4Hashi) that is easy to follow for HT subjects, and it will contribute to providing valuable data that are useful to dieticians and physicians. It is anticipated that this graphic-text qualitative dietary protocol, by improving food selection and diet quality, may reduce adiposity and improve metabolic parameters and the quality of life of HT women.

No association between zinc and thyroid activity in obese women

Obesity is characterized by changes in the metabolism of zinc and thyroid hormones. Studies have also shown the role of zinc in the function and metabolism of thyroid. The present study aimed to evaluate the relationship between serum concentrations of thyroid hormones, dietary zinc intake and zinc distribution in obese women. A case-control study was conducted enrolling 98 women aged between 20 and 50 years old who were divided into case group (BMI ≥ 35 kg/m²) and control group (BMI = 18.5-24.9 kg/m²). Patients underwent anthropometric measurements and analysis of dietary zinc intake, which was performed by a three-day food record. Zinc concentrations in plasma and erythrocytes were determined by inductively coupled plasma optical emission spectrometry. Serum concentrations of thyroid hormones and antibodies were determined by chemiluminescence. Mean values of dietary zinc intake were higher than recommended (10.37 ± 3.12 mg/day and 11.37 ± 4.36 mg/day for control and obeses, respectively). Obese women had reduced plasma (67.22 ± 5.96 μg/dL) and erythrocyte (37.16 ± 3.64 μg Zn/gHb) zinc concentrations when compared to the control group (plasma: 89.71 ± 13.33 μg/dL; erythrocyte: 42.68 ± 3.73 μg Zn/gHb) (p < 0.001). Serum TSH (control: 2.62 ± 1.29 μIU/mL; obeses: 3.08 ± 1.13 μIU/mL), Free T3 (control: 2.19 ± 0.63 pg/dL; obeses: 2.09 ± 0.34 pg/dL), and Free T4 (control: 1.12 ± 0.31 ng/dL; obeses: 1.09 ± 0.19 ng/dL) concentrations were within the normal range in both groups, without significant difference between them (p > 0.05). There was no correlation between thyroid hormone concentrations and zinc parameters (p > 0.05). Although obese women presented hypozincemia, they had normal levels of thyroid hormones and no correlation was found between the studied parameters.

Repeated Whole-Body Exposure to Low-Dose Radiation Combined With Topical Application of Basic Fibroblast Growth Factor and Zinc Accelerates Wound Healing in Diabetic Rats

We reported the acceleration of skin wound healing in diabetic rats by repeated exposure to low-dose radiation (LDR). Here, we explored whether the wound healing could be further improved when LDR was combined with a topical application of basic fibroblast growth factor (bFGF) or zinc. Wounds were established on the backs of type 1 diabetic rats induced by a single injection of streptozotocin. Rats were treated daily with normal saline (Diabetes), LDR, bFGF, zinc, or combined 3 treatments for 5 consecutive days with a 2-day break between each consecutive 5-day treatment. Changes in wound size, histopathology, and microvessel density were assessed on days 5, 10, and 15, respectively, once treatment is started. All treatment regimens significantly accelerated skin wound healing, tissue remodeling, and new vessel formation compared to diabetes group. However, the combined LDR plus bFGF and zinc provided a better beneficial effect on wound healing than either one of these treatments alone. Further, we found that the effects of LDR and bFGF were similar, whereas zinc alone induced a weaker response. Our results suggest that whole-body LDR plus the topical application of bFGF and zinc can further accelerate wound healing in diabetic rats.

Selenoproteins in human body: focus on thyroid pathophysiology

Selenium (Se) has a multilevel, complex and dynamic effect on the human body as a major component of selenocysteine, incorporated into selenoproteins, which include the selenocysteine-containing enzymes iodothyronine deiodinases. At the thyroid level, these proteins play an essential role in antioxidant protection and hormone metabolism. This is a narrative review based on PubMed/Medline database research regarding thyroid physiology and conditions with Se and Se-protein interferences. In humans, Se-dependent enzyme functions are best expressed through optimal Se intake, although there is gap in our knowledge concerning the precise mechanisms underlying the interrelation. There is a good level of evidence linking low serum Se to autoimmune thyroid diseases and, to a lesser extent, differentiated thyroid cancer. However, when it comes to routine supplementation, the results are heterogeneous, except in the case of mild Graves' orbitopathy. Autoimmune hypothyroidism is associated with a state of higher oxidative stress, but not all studies found an improvement of thyroid function after Se was introduced as antioxidant support. Meanwhile, no routine supplementation is recommended. Low Se intake is correlated with an increased risk of developing antithyroid antibodies, its supplementation decreasing their titres; there is also a potential reduction in levothyroxine replacement dose required for hypothyroidism and/or the possibility that it prevents progression of subclinical hypothyroidism, although not all studies agree. In thyroid-associated orbitopathy, euthyroidism is more rapidly achieved if the micronutrient is added to traditional drugs, while controls appear to benefit from the microelement only if they are deficient; thus, a basal assay of Se appears advisable to better select patients who need substitution. Clearly, further Se status biomarkers are required. Future introduction of individual supplementation algorithms based on baseline micronutrient levels, underlying or at-risk clinical conditions, and perhaps selenoprotein gene polymorphisms is envisaged.

Selenium Supplementation Alters Hepatic Energy and Fatty Acid Metabolism in Mice

Background

Human and animal studies have raised concerns that supplemental selenium can increase the risk of metabolic disorders, but underlying mechanisms are unclear.

Objective

We used an integrated transcriptome and metabolome analysis of liver to test for functional pathway and network responses to supplemental selenium in mice.

Methods

Male mice (8-wk-old, C57BL/6J) fed a standard diet (0.41 ppm Se) were given selenium (Na2SeO4, 20 μmol/L) or vehicle (drinking water) for 16 wk. Livers were analyzed for selenium concentration, activity of selenoproteins, reduced glutathione (GSH) redox state, gene expression, and high-resolution metabolomics. Transcriptomic and nontargeted metabolomic data were analyzed with biostatistics, bioinformatics, pathway enrichment analysis, and combined transcriptome-metabolome-wide association study (TMWAS).

Results

Mice supplemented with selenium had greater body mass gain from baseline to 16 wk (55% ± 5%) compared with controls (40% ± 3%) (P < 0.05); however, no difference was observed in liver selenium content, selenoenzyme transcripts, or enzyme activity. Selenium was higher in the heart, kidney, and urine of mice supplemented with selenium. Gene enrichment analysis showed that supplemental selenium altered pathways of lipid and energy metabolism. Integrated transcriptome and metabolome network analysis showed 2 major gene-metabolite clusters, 1 centered on the transcript for the bidirectional glucose transporter 2 (Glut2) and the other centered on the transcripts for carnitine-palmitoyl transferase 2 (Cpt2) and acetyl-CoA acyltransferase (Acaa1). Pathway analysis showed that highly associated metabolites (P < 0.05) were enriched in fatty acid metabolism and bile acid biosynthesis, including acylcarnitines, triglycerides and glycerophospholipids, long-chain acyl-coenzyme As, phosphatidylcholines, and sterols. TMWAS of body weight gain confirmed changes in the same pathways.

Conclusions

Supplemental selenium in mice alters hepatic fatty acid and energy metabolism and causes increases in body mass. A lack of effect on hepatic selenium content suggests that signaling involves an extrahepatic mechanism.