Several minerals and trace elements are essential for normal thyroid hormone metabolism, e.g., iodine, iron, selenium, and zinc. Coexisting deficiencies of these elements can impair thyroid function. Iron deficiency impairs thyroid hormone synthesis by reducing activity of heme-dependent thyroid peroxidase. Iron-deficiency anemia blunts and iron supplementation improves the efficacy of iodine supplementation. Combined selenium and iodine deficiency leads to myxedematous cretinism. The normal thyroid gland retains high selenium concentrations even under conditions of inadequate selenium supply and expresses many of the known selenocysteine-containing proteins. Among these selenoproteins are the glutathione peroxidase, deiodinase, and thioredoxine reductase families of enzymes. Adequate selenium nutrition supports efficient thyroid hormone synthesis and metabolism and protects the thyroid gland from damage by excessive iodide exposure. In regions of combined severe iodine and selenium deficiency, normalization of iodine supply is mandatory before initiation of selenium supplementation in order to prevent hypothyroidism. Selenium deficiency and disturbed thyroid hormone economy may develop under conditions of special dietary regimens such as long-term total parenteral nutrition, phenylketonuria diet, cystic fibrosis, or may be the result of imbalanced nutrition in children, elderly people, or sick patients.
iron selenium deficiency thyroid hormone metabolism, iodine deficiency thyroid peroxidase iron dependence, selenium selenoprotein thyroid gland protection, combined iodine selenium deficiency myxedematous cretinism, iron deficiency anemia iodine supplementation efficacy, trace element mineral thyroid function public health, glutathione peroxidase deiodinase thioredoxin reductase thyroid, Zimmermann Köhrle selenium iodine thyroid, selenium supplementation hypothyroidism risk iodine deficiency, micronutrient deficiency thyroid hormone synthesis impairment
PMID 12487769 12487769 DOI 10.1089/105072502761016494 10.1089/105072502761016494 Zimmermann et al. 2002, Zimmermann 2002
Cite this article
Zimmermann, M. B., & Köhrle, J. (2002). The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health. Thyroid : official journal of the American Thyroid Association, 12(10), 867-878. https://doi.org/10.1089/105072502761016494
Zimmermann MB, Köhrle J. The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health. Thyroid. 2002;12(10):867-878. doi:10.1089/105072502761016494
Zimmermann, Michael B., and Josef Köhrle. "The impact of iron and selenium deficiencies on iodine and thyroid metabolism: biochemistry and relevance to public health." Thyroid : official journal of the American Thyroid Association, vol. 12, no. 10, 2002, pp. 867-878.
Keywords
Animals, Humans, Iodine/metabolism, Iron Deficiencies, Nutrition Disorders/metabolism, Public Health, Selenium/deficiency, Thyroid Gland/chemistry/metabolism, Iodine, Selenium
Velmahos AH et al., 2026·Journal of Restorative Reproductive Medicine·
Open Access
To evaluate the extent to which a history of infertility is associated with adherence to specific diets among reproductive-aged females. Cross-sectional analysis Between 2017–2023, 7,227 North American female pregnancy planners aged 21-45 years enrolled in PRESTO (Pregnancy Study Online), a preconception cohort study. Participants completed self-administered baseline questionnaires during preconception. Exposure: Infertility history, defined as: 1) self-reported 12-month clinical infertility, 2) history of visiting a clinician for an infertility work-up, and/or 3) clinician-identified cause of infertility (e.g., ovulatory or tubal). Adherence to specific diets, including vegetarian, vegan, Mediterranean, Paleo, Weight Watchers®, ketogenic, dairy free, gluten free, Atkins®, South Beach®, Zone®, raw foods, or other at baseline. Multivariable log-binomial regression models estimated the prevalence ratios (PRs) and 95% confidence intervals (CIs), adjusted for age, income, and body mass index (BMI). The percentage of participants with a history of infertility was 26% based on the 12-month clinical infertility definition, 30% based on visiting a physician for infertility evaluation, and 26% based on an infertility diagnosis following a physician visit. Overall adherence to any particular diet was low (4.6% vegetarian, 2.8% ketogenic, 1.7% Weight Watchers®, 1.4% Mediterranean, 1.3% vegan, 0.8% Paleo, and all other diets: <0.8%); 86.6% reported not adhering to any particular diet. A history of 12-month clinical infertility was associated with lower adherence to vegetarian (PR=0.78; 95% CI: 0.60-1.03), Paleo (PR=0.43; 95% CI: 0.19-0.98), and Weight Watchers® (PR=0.55; 95% CI: 0.34-0.91) diets. An infertility history involving a medical work-up was associated with a higher prevalence of adherence to a ketogenic diet (PR=1.56; 95% CI: 1.17-2.09). Participants whose infertility was attributed to ovulatory or tubal causes were nearly two times more likely to adhere to a ketogenic diet (PR=2.01; 95% CI: 1.38-2.94; PR=2.22; 95% CI: 1.09-4.49, respectively). The cross-sectional design cannot establish temporality or causality. Data on dietary patterns and infertility history were self-reported, which can introduce misclassification. Generalizability may be limited because participants were pregnancy planners not using fertility treatments; participants were also more likely to be non-Hispanic White and of higher socioeconomic status than the general population. The ketogenic diet was more prevalent among females with an infertility history, while vegetarian, Paleo, and Weight Watchers® diets were less prevalent. These associations mirror the results of studies evaluating the reverse relationship, suggesting that some patients with infertility seek information for behavioral modifications via evidence-based medicine.
Declining fertility, overlooked mental health, and reduced life expectancy underscore the urgent need for renewed attention to men's health. A semen analysis, traditionally used to assess fertility, holds untapped potential as a tool for promoting lifestyle changes and preventing chronic diseases in men. Spermatogenesis is highly sensitive to environmental and lifestyle factors and can be an early indicator of overall health. Disruptions in this process can signal underlying systemic issues and predict long-term health risks, including cardiovascular disease and metabolic disorders. An increasing number of men seek to engage in preconception care, as fertility is closely tied to a man's sense of masculinity, identity and aspirations for fatherhood. In this context, a semen analysis can be a powerful motivator to encourage healthy behaviours and proactive health management. By incorporating semen analysis into primary care, health care providers can leverage men's desire for fatherhood as an entry point to discuss broader health concerns, such as mental well-being, nutrition and physical activity. This approach would address immediate reproductive health, and also promote long-term wellness, helping to reduce the burden of chronic disease in men.
Self-reported dietary intake varies across menstrual cycle phases, but objective assessments of dietary intake together with appetite and resting metabolic rate (RMR) are limited. This study aimed to assess differences in dietary intake, appetite, and RMR during two hormonally-distinct menstrual cycle phases in laboratory and free-living settings. Healthy premenopausal females with predictable normal-length menstrual cycles completed two study visits: one in the late-follicular and one in the mid-luteal phase. Menstrual cycle phases were assessed using urinary luteinizing hormone surge and prospective cycle days. Participants consumed a 2-day energyand macronutrient-balanced run-in diet prior to each visit. RMR was measured with indirect calorimetry, followed by appetite ratings before and after a standardized breakfast, and a food cravings questionnaire. Appetite was also tracked for 2.5 days post-visit in a free-living environment. Ad libitum energy and macronutrient intakes were measured using pre-weighed plus weighing of uneaten food at an in-laboratory lunch meal, as well as during the 2.5-day free-living period. Eighteen participants were included (age: 21 ± 4 years; body mass index: 21.2 ± 1.5 kg/m2). There were no differences between in-laboratory ad libitum energy or macronutrient intakes, appetite, or food cravings between phases. RMR did not differ between phases, although the mid-luteal phase RMR tended to be higher (104 ± 218 kcal/day higher; P = 0.074). No main or interaction effects for phase or time were observed for free-living dietary intake nor appetite ratings. Although RMR tended to be increased during the luteal phase, comprehensive appetite and energy intake assessments showed no significant cycle-phase differences in these 18 participants.
Are dietary patterns associated with age at menarche after accounting for BMI-for-age (BMIz) and height? We observed associations between both the Alternative Healthy Eating Index (AHEI) and the Empirical Dietary Inflammatory Pattern (EDIP) and age at menarche. Dietary patterns have been sparsely examined in relation to age at menarche and no studies have examined the association between the AHEI, a healthier diet, and EDIP, a pro-inflammatory diet, and menarche. STUDY DESIGN, SIZE, The Growing Up Today Study (GUTS) is a prospective cohort of children ages 9-14 years at study enrollment. GUTS enrolled in two waves with enrollment beginning in 1996 (GUTS1) and 2004 (GUTS2). For this analysis, GUTS1 and GUTS2 participants were followed through 2001 and 2008, respectively. PARTICIPANTS/MATERIALS, SETTING, We included 7530 participants who completed food frequency questionnaire(s) (FFQ) prior to menarche who then self-reported age at menarche during study follow-up. Cox proportional hazard models were used to calculate multivariable hazard ratios (HRs) and 95% CIs for the associations between two dietary patterns, the AHEI and EDIP, and age at menarche, with and without adjustment for time-varying BMIz and height. MAIN Six thousand nine hundred ninety-two participants (93%) reported menarche during the study period. On average, participants completed the baseline FFQ 1.75 years prior to menarche. Participants in the highest quintile of AHEI diet score (indicating a healthier diet) were 8% less likely to attain menarche within the next month compared to those in the lowest quintile (95% CI = 0.85-0.99; Ptrend = 0.03). This association remained after adjustment for BMIz and height (corresponding HR = 0.93; 95% CI = 0.86-1.00; Ptrend = 0.04). Participants in the highest quintile of the EDIP score (i.e. most inflammatory diet), were 15% more likely to attain menarche in the next month relative to those in the lowest quintile (95% CI = 1.06-1.25; Ptrend = 0.0004), and the association remained following adjustment for BMIz and height (corresponding HR = 1.15; 95% CI = 1.06-1.25; Ptrend = 0.0004). LIMITATIONS, Self-reported questionnaires are subject to some error; however, given our prospective study design it is likely this error is non-differential with respect to the outcome. Our findings of an association between both the AHEI and EDIP and age at menarche indicate that diet quality may play a role in age at menarche independent of BMI or height. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the Breast Cancer Research Foundation. The GUTS is supported by the National Institutes of Health U01 HL145386. C.P.D. was supported by National Institutes of Health T32 CA094880. The authors have no conflicts of interest to disclose. N/A.