The interaction between selenium status, sex hormones, and thyroid metabolism in adolescent girls in the luteal phase of their menstrual cycle

Minerals and the Menstrual Cycle: Impacts on Ovulation and Endometrial Health

The role of minerals in female fertility, particularly in relation to the menstrual cycle, presents a complex area of study that underscores the interplay between nutrition and reproductive health. This narrative review aims to elucidate the impacts of minerals on key aspects of the reproductive system: hormonal regulation, ovarian function and ovulation, endometrial health, and oxidative stress. Despite the attention given to specific micronutrients in relation to reproductive disorders, there is a noticeable absence of a comprehensive review focusing on the impact of minerals throughout the menstrual cycle on female fertility. This narrative review aims to address this gap by examining the influence of minerals on reproductive health. Each mineral's contribution is explored in detail to provide a clearer picture of its importance in supporting female fertility. This comprehensive analysis not only enhances our knowledge of reproductive health but also offers clinicians valuable insights into potential therapeutic strategies and the recommended intake of minerals to promote female reproductive well-being, considering the menstrual cycle. This review stands as the first to offer such a detailed examination of minerals in the context of the menstrual cycle, aiming to elevate the understanding of their critical role in female fertility and reproductive health.

The dynamic change of urinary selenium concentration during pregnancy and influencing factors: A longitudinal study

BACKGROUND

Selenium concentration of one spot urine sample cannot reflect selenium status during whole pregnancy. Studies on variations of urinary selenium concentration at different stages of pregnancy are limited.

AIM

To assess variations of urinary selenium concentrations during three trimesters of pregnancy and to explore the influencing factors.

METHODS

This study included 2613 pregnant women from a birth cohort study (Wuhan, China) enrolled between October 2014 and October 2016. Selenium concentrations of urine samples collected at three trimesters were measured. We used a generalized linear mixed effects model to observe the changes in urinary selenium concentration during pregnancy and its influencing factors.

RESULTS

The median value (range) of gestational weeks at urine sample collection was 11 (9-14), 24 (15-27), and 34 (28-41) respectively. Urine selenium concentration varied across trimesters (geometric mean: 16.34, 17.65 and 18.83 μg/g creatinine, respectively), with an upward trend (β = -0.145, 95%CI: -0.164, -0.126) (β = -0.066, 95%CI: -0.083, -0.048). The concentrations of urinary selenium increased with the increasing of educational level [β (95%CI): ≤ 9 years = -0.105 (-0.163, -0.047); 10-12 years = -0.086(-0.126, -0.047); > 12 years = reference]. Pregnant women who rarely or only took multivitamins in the first trimester [β (95% CI): rarely = -0.076 (-0.144, -0.007); only in the first three months of pregnancy = -0.104 (-0.170, -0.038); always = reference], or were not exposed to passive smoking during pregnancy（β = -0.093, 95% CI: - 0.173, - 0.014), or exercised three to four days per week for the first three months before delivery（β = -0.074, 95% CI: - 0.140, - 0.008) had lower urinary selenium concentrations. Pregnant women who took calcium supplements after the third month of pregnancy had higher urinary selenium levels（β = 0.114, 95% CI: 0.059, 0.169).

CONCLUSIONS

Urine selenium concentrations of pregnant women showed an upward trend across trimesters. Educational level, calcium or multivitamin supplementation, passive smoking, and physical exercise might impact urine selenium levels.

Does selenium fortification of kale and kohlrabi sprouts change significantly their biochemical and cytotoxic properties?

BACKGROUND

The sprouts of Brassica vegetables are known from their nutritional and chemopreventive values. Moreover, sprouts fortification with some trace elements, like selenium, may increase their importance in human diet. Thus, the aim of our study was to examine if selenium enrichment of kale and kohlrabi sprouts may influence their biochemical properties (phenolic acids and L-tryptophan content, antioxidant potential) or cytotoxic activity. Additional aim of the study was to evaluate the profile of selenium compounds and to describe the multidimensional interactions between the mentioned parameters.

METHODS

Selenium content in the sprouts was evaluated by double-channel atomic fluorescence spectrometer AFS-230 with the flow hydride-generation system. Separation of selenium species in water soluble fraction was performed by size-exclusion LC-ICP-MS. The identification and quantification of phenolic acids and L-tryptophan was performed by HPLC. For antioxidant activity DPPH and FRAP methods were used. Cytotoxic activity of the sprouts extracts on a panel of human metastatic carcinoma cells was evaluated by MTT test.

RESULTS

Selenium content in the fortified sprouts was several orders of magnitude higher than in the unfortified ones. Only small percentage of supplemented selenium (ca. 10 %) was incorporated into the sprouts as seleno-L-methionine, while the other detected selenium species remained unidentified. Selenium fortification differently stimulated the production of phenolic acids (sinapic, chlorogenic, isochlorogenic and caffeic acid) in the tested sprouts, depending on the particular species, selenium dose and the investigated compound. PCA analysis revealed strong correlation between antioxidant parameters and phenolic acids and L-tryptophan, while Se correlated only with caffeic acid. The sprouts extracts (≥1 mg/mL) showed cytotoxic potency to all the studied cancer cell lines (SW480, SW620, HepG2, SiHa), regardless the selenium supplementation.

CONCLUSION

Se-fortified kale and kohlrabi sprouts are good candidates for functional food ingredients. Moreover, these results indicate that the sprouts enriched with sodium selenite show higher nutritional value, without significant changes in their cytotoxic activity.

Dietary minerals, reproductive hormone levels and sporadic anovulation: associations in healthy women with regular menstrual cycles

Although minerals are linked to several reproductive outcomes, it is unknown whether dietary minerals are associated with ovulatory function. We hypothesised that low intakes of minerals would be associated with an increased risk of anovulation. We investigated associations between dietary mineral intake and both reproductive hormones and anovulation in healthy women in the BioCycle Study, which prospectively followed up 259 regularly menstruating women aged 18-44 years who were not taking mineral supplements for two menstrual cycles. Intakes of ten selected minerals were assessed through 24-h dietary recalls at up to four times per cycle in each participant. Oestradiol, progesterone, luteinising hormone (LH), follicle-stimulating hormone (FSH), sex-hormone-binding globulin and testosterone were measured in serum up to eight times per cycle. We used weighted linear mixed models to evaluate associations between minerals and hormones and generalised linear models for risk of anovulation. Compared with Na intake ≥1500 mg, Na intake <1500 mg was associated with higher levels of FSH (21·3 %; 95 % CI 7·5, 36·9) and LH (36·8 %; 95 % CI 16·5, 60·5) and lower levels of progesterone (-36·9 %; 95 % CI -56·5, -8·5). Na intake <1500 mg (risk ratio (RR) 2·70; 95 % CI 1·00, 7·31) and Mn intake <1·8 mg (RR 2·00; 95 % CI 1·02, 3·94) were associated with an increased risk of anovulation, compared with higher intakes, respectively. Other measured dietary minerals were not associated with ovulatory function. As essential minerals are mostly obtained via diet, our results comparing insufficient levels with sufficient levels highlight the need for future research on dietary nutrients and their associations with ovulatory cycles.

Selenium status parameters in patients with polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age. To date, no systematic study of interactions between selenium status parameters (SSPs: serum selenium concentration, plasma glutathione peroxidase, GPX3, plasma selenoprotein P, SELENOP), sex hormones, thyroid function parameters, and other laboratory parameters in patients with PCOS has been undertaken. Therefore we aimed to compare such parameters in women with PCOS and in the control groups, and to investigate the multidimensional interactions between various parameters in PCOS patients and in controls. The subjects were diagnosed either with PCOS (n=28, 25.4±5.2 y) or with PCOS+Hashimoto disease (n=13, 27.3±5.6 y). Female patients having normal menses were recruited into the first control group (n=70, 26.8±7.3 y) or to the second control group comprising women only with Hashimoto disease (n=10, 26.2±6.9 y). No apparent differences in SSPs between control subjects and patients with PCOS, also complicated with Hashimoto disease, were identified, though such differences were noticeable for total testosterone (tT), sex hormone binding globulin, free androgen index, dehydroepiandrosterone sulfate (DHEAS), and insulin profile. The correlation between tT and DHEAS was found the strongest. The other group of mutually highly and positively correlated parameters consisted of GPX3, follicle stimulating hormone, free triiodothyronine and free thyroxine. All the latter parameters correlated negatively with vitamin D3. SSPs took part in interactions with thyroid hormones, sex hormones and some other parameters, but only for GPX3 such interactions were statistically significant. The significance of these findings remains open for further investigation, particularly in patients with PCOS and/or Hashimoto disease.

Dietary factors and luteal phase deficiency in healthy eumenorrheic women

STUDY QUESTION

Are prospectively assessed dietary factors, including overall diet quality, macronutrients and micronutrients, associated with luteal phase deficiency (LPD) in healthy reproductive aged women with regular menstrual cycles?

SUMMARY ANSWER

Mediterranean Diet Score (MDS), fiber and isoflavone intake were positively associated with LPD while selenium was negatively associated with LPD after adjusting for age, percentage body fat and total energy intake.

WHAT IS KNOWN ALREADY

LPD may increase the risk of infertility and early miscarriage. Prior research has shown positive associations between LPD and low energy availability, either through high dietary restraint alone or in conjunction with high energy expenditure via exercise, but few studies with adequate sample sizes have been conducted investigating dietary factors and LPD among healthy, eumenorrheic women.

STUDY DESIGN, SIZE, DURATION

The BioCycle Study (2005-2007) prospectively enrolled 259 women from Western New York state, USA, and followed them for one (n = 9) or two (n = 250) menstrual cycles.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Women aged 18-44 years, with self-reported BMI between 18 and 35 kg/m(2) and cycle lengths between 21 and 35 days, were included in the study. Participants completed baseline questionnaires, four 24-h dietary recalls per cycle and daily diaries capturing vigorous exercise, perceived stress and sleep; they also provided up to eight fasting serum samples during clinic visits timed to specific phases of the menstrual cycle using a fertility monitor. Cycles were included for this analysis if the peak serum luteal progesterone was >1 ng/ml and a urine or serum LH surge was detected. Associations between prospectively assessed diet quality, macronutrients and micronutrients and LPD (defined as luteal duration <10 days) were evaluated using generalized linear models adjusting for age, percentage body fat and total energy intake.

MAIN RESULTS AND THE ROLE OF CHANCE

LPD occurred in 41 (8.9%) of the 463 cycles from 246 women in the final analysis. After adjusting for age, percentage body fat and total energy intake, LPD was positively associated with MDS, adjusted odds ratio (aOR): 1.70 (95% confidence interval [CI]: 1.17, 2.48), P = 0.01. In separate macro- and micronutrient adjusted models, increased fiber and isoflavone intake showed modest positive associations with LPD: fiber (per g), aOR: 1.10 (95% CI: 0.99, 1.23), P = 0.07; and isoflavones (per 10 mg), aOR: 1.38 (95% CI: 0.99, 1.92), P = 0.06. In contrast, selenium (per 10 mcg) was inversely associated with LPD, aOR: 0.80 (95% CI: 0.65, 0.97), P = 0.03. Additional adjustments for relevant lifestyle factors including vigorous exercise, perceived stress and sleep did not appreciably alter estimates.

LIMITATIONS, REASONS FOR CAUTION

The number of LPD cycles was limited, and thus these findings are exploratory. We relied on participant self-report of their medical history to apply exclusion criteria; it is possible that we admitted to the study women with a gynecologic or medical disease who were unaware of their diagnosis.

WIDER IMPLICATIONS OF THE FINDINGS

Our study suggests that diet quality may be associated with LPD among healthy eumenorrheic women. As LPD may contribute to infertility and early miscarriage, further research is warranted to elucidate how dietary factors, such as MDS, may influence LPD. The inverse association we found with selenium is supported by previous research and deserves further investigation to determine whether this finding has pathophysiologic and therapeutic implications.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Intramural Research Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health. No competing interests declared.

Sonographic evaluation of thyroid morphology during the normal estrous cycle in the Indo-Pacific bottlenose dolphin (Tursiops aduncus)

Physiologic changes occurring in the thyroid in response to the estrous cycle have been noted in companion animals. However, in bottlenose dolphins, the influence of different reproductive states on thyroid morphology remains unclear. Sonography was used to evaluate the variations of thyroid morphology for nine consecutive estrous cycles of four sexually mature, female Indo-Pacific bottlenose dolphins (Tursiops aduncus). The estrous cycle was divided into two phases for evaluation: the follicular and luteal phases. To compare changes associated with sex, thyroid volumes were measured in the different phases during the estrous cycle of female dolphins and were compared to the ultrasound examinations of the four male dolphins measured over a 2-mo period. In males, there was no significant difference in thyroid volume during the study period (P > 0.05). The thyroid volume measured in combining all estrous cycle phases of the female dolphins was significantly larger than that measured in the male dolphins (P < 0.05). A difference in thyroid volume during the estrous cycle was observed, with the thyroid volume during the follicular phase significantly smaller (P < 0.05) than that of the luteal phase, and is possibly related to the influence of female sex steroids. Thyroid volume variability during estrus should, therefore, be taken into account when examining the thyroid gland of female dolphins.

Hormonal factors and the risk of papillary thyroid cancer in the California Teachers Study cohort

BACKGROUND

Despite the increasing incidence of thyroid cancer, there is limited information on its etiology. The strikingly higher rates in young women, compared with men, suggest that sex steroid hormones may be involved in the development of this disease.

METHODS

We investigated the effects of menstrual, reproductive, and other hormonal factors on papillary thyroid cancer risk in the prospective California Teachers Study cohort. Among 117,646 women, 233 were diagnosed with invasive histologically confirmed papillary thyroid cancer after cohort enrollment and before January 1, 2008. Relative risks (RR) and 95% CIs were estimated by using Cox proportional hazards regression models.

RESULTS

Among younger women (age <45 years at baseline; approximately one-third of the cohort), but not older women, later age at menarche (age ≥14 years) was associated with increased risk (RR = 1.88, 95% CI: 1.13-3.13; p(interaction) by age = 0.06). Risk was also increased among young women who had longer (>30 days) adolescent menstrual cycles (RR = 1.78, 95% CI: 1.01-3.14) and whose last pregnancy had ended within five years of cohort enrollment (RR = 2.21, 95% CI: 1.13-4.34). Among older women (age ≥45 years at baseline), ever use of estrogen-only therapy was associated with a statistically nonsignificant increase in risk (RR = 1.69, 95% CI: 0.95-2.98).

CONCLUSIONS

The findings from this prospective analysis suggest that several factors related to delayed pubertal development and the transient effects of pregnancy may be particularly important in influencing risk in young women.

IMPACT

These results suggest the importance of future research into the role of progesterone and the estrogen-to-progesterone ratio.

Iodine, selenium, and other trace elements in urine of pregnant women

The purpose of this work was to determine trace element levels in urine and evaluate possible associations between urinary iodine concentration (UIC), other trace elements (Cr, Cu, Fe, Mn, Na, Se, Zn), toxic elements (Cd, Pb), anthropometrical measures (body weight and height), glycemic indices (serum insulin and glucose), and several parameters related to thyroid function (thyroid stimulating hormone, free thyroxine, antithyroid peroxidase antibodies, thyroid volume, and thyroid echogenicity) in pregnant women. One hundred sixty-nine participants were recruited. The whole study group, originating from Krakow region, comprised three subgroups belonging to three trimesters: I trimester (n = 28), II trimester (n = 83), and III trimester (n = 58). Trace elements were determined using inductively coupled plasma mass/(atomic emission) spectrometry. Partial least square model was used to reveal correlation structure between parameters investigated, as well as a possible causal relationship between dependent parameters and potentially explanatory parameters. Results obtained for trace and toxic elements in urine were comparable with results of other authors, although the study group was not homogenous. We confirmed (1) low iodine excretion in pregnant women, (2) the existence of statistically significant correlation between UIC and urinary selenium, and (3) lack of correlation between latter parameter and typical indices of thyroid function. Urinary selenium correlated with other urinary trace elements, but physiological significance of this finding remains uncertain. The fact that a large number of pregnant women fail to meet dietary recommendations for iodine is the major reason for concern.

Selenoenzymes, laboratory parameters, and trace elements in different types of thyroid tumor

This study was performed to investigate selenoenzyme activities and trace element concentrations in thyroid tissues, with reference to other parameters routinely used to characterize thyroid function. This was to reveal relevant parameters as possible additional markers of tumor grade, clinical course, and prognosis of thyroid disorders. The tissue samples were obtained during surgical treatment (total or near total thyroidectomy) of 122 patients with different types of thyroid tumor. For most of the investigated parameters in different groups of patients, we did not find statistically significant differences. In the majority of cases, thyroid benign or malignant tumors were not accompanied by significant derangement of the gland selenoenzymes and of either intrathyroidal or plasma concentration of selenium. Nevertheless, types I and II iodothyronine deiodinases were the most promising (among selenoenzymes) targets for diagnoses and possibly therapy of thyroid tumors. Higher activities of both enzymes in cases with Graves' disease, as compared with other thyroid lesions, suggest their involvement in the pathogenesis of this condition. Patients with struna nodosa had higher levels of thyroid Zn, Cu, and Pb as compared with papillary carcinoma subjects and also a higher level of Cu than follicular carcinoma cases. The above diagnostics may play a similar role to some of the general thyroid function indices, TSH, anti-TG, anti-TPO, and calcitonin, which can partially distinguish between various thyroid tumors. In conclusion, some of selenium status markers, when accompanied with general parameters, and trace elements can serve as factors with pathophysiologic relevance and be helpful in the identification of malignant disease. Multivariate statistical methods should be employed to tackle a broad array of thyroid tumor diagnostic data in a short time. Partial least squares model and other pattern recognition methods seem to be the most appropriate methods for that task. The miniaturization of all the steps of complex analytical procedure should be developed in a way to allow its completion as sensitive, robust, and efficient for use of the small quantity of material provided by fine-needle biopsy.

Selenium and hormone interactions in female patients with Hashimoto disease and healthy subjects

OBJECTIVE

To examine the correlation structure of parameters expressing selenium status, sex hormones secretion and thyroid function in a group of patients with Hashimoto disease and healthy female subjects.

METHOD

Partial Least Square modeling was applied to parameters under study.

RESULTS

The correlations between relevant parameters were confirmed. Selenoenzyme glutathione peroxidase (GPX3) an progesterone played the most significant roles among factors contributing to thyroid stimulating hormone and free thyroxine regulation. Additionally, a correlation between GPX3 and estradiol was also observed which is in agreement with results reported by other authors. Patients with Hashimoto disease had lower glutathione peroxidase activities than healthy subjects.

CONCLUSION

The integrated multivariate approach applied to a new group of patients dissimilar to the previous one, was validated by statistical adequacy as well ass meaningful interpretation.

Selenium status, sex hormones, and thyroid function in young women

The aim of the study was to identify those parameters characterising selenium status and sex hormones secretion, which are responsible for the changes in indicators of thyroid function, and to reveal the correlation structure of parameters expressing selenium status, sex hormones secretion and thyroid function, if any exist. The general approach in this work was essentially the same as in our previous report (cf. [Zagrodzki P, Ratajczak R, Wietecha-Posłuszny R. The interaction between selenium status, sex hormones, and thyroid metabolism in adolescent girls during the luteal phase of their menstrual cycle. Biol Trace Elem Res 2007; 120: 51-60]), but the study group and parameters' spectrum were different. Thirty-six women aged 23.5+/-0.6 years were investigated. The parameters of interest were: plasma selenium concentration (Se) and plasma glutathione peroxidase activity (GPX3) (indicators of selenium status); serum estradiol (E2), progesterone (P4), follicle-stimulating hormone (FSH), luteotropic hormone (LH), and age of menarche (indicators of sex hormones secretion); thyroid-stimulating hormone (TSH), free thyroxine (fT4), free triiodothyronine (fT3), anti-thyroid peroxidase antibodies in serum (anti-TPO), and thyroid volume (indicators of thyroid function). Our findings show that Se, GPX3, P4, LH, FSH, TSH and fT4 were interrelated. The pairs of parameters: GPX3 and P4; LH and FSH exhibited the strongest associations. The thyroid function parameters were mainly influenced by GPX3 and P4. Partial least-squares method corroborated our hypothesis about the existence of complex interactions among selenium status, sex hormones secretion, and thyroid function in healthy young women in the luteal phase.