Original article Selenium status and its relationship with thyroid hormones in obese women Larissa Cristina Fontenelle a, * , Mayara Monte Feitosa a , Tayn  ah Emannuelle Coelho Freitas a , Juliana Soares Severo a , Jennifer Beatriz Silva Morais a , Gilberto Simeone Henriques b , Francisco Erasmo Oliveira c , Jos  e Machado Moita Neto d , Dilina do Nascimento Marreiro a a Department of Nutrition, Federal University of Piauí, Campus Ministro Petr^ onio Portella, Teresina, Piauí, 64049-550, Brazil b School of Nursing, Department of Nutrition, Federal University of Minas Gerais, 6627 Av. Pres. Ant^ onio Carlos, Belo Horizonte, Minas Gerais, 31270-901, Brazil c Med Imagem Clinical Laboratory, Rua Paissandu 1862, Centro Sul, CEP, Teresina, Piauí, 64001-120, Brazil d Department of Chemistry, Federal University of Piauí, Campus Ministro Petr^ onio Portella, Teresina, Piauí, 64049-550, Brazil article info Article history: Received 30 September 2020 Accepted 17 October 2020 Keywords: Selenium Nutritional status Obesity Thyrotropin Thyroxine Triiodothyronine summary 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 under- stood. 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 ¼ 35) and a control group with women of normal weight (n ¼ 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 concen- trations 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. © 2020 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved. 1. Introduction Obesity is a chronic disease characterized by excessive body fat accumulation resulting from positive energy balance and the interaction between environmental and genetic factors [1]. This condition leads to adipocyte hypertrophy with a consequent dysfunction of adipose tissue, development of metabolic disorders, and disturbances in the endocrine system [2,3]. In this context, several studies have demonstrated alterations in thyroid hormone levels in obese individuals without a diagnosis of Abbreviations: BMI, body mass index; EAR, Estimated Average Requirement; fT3, free triiodothyronine; fT4, free thyroxine; ICP-OES, inductively coupled plasma optical emission spectrometry; SelP, selenoprotein P; TgAb, thyroglobulin autoan- tibody; TPOAb, thyroid peroxidase autoantibody; TSH, thyrotropin. * Corresponding author. Laboratory of Experimental Nutrition, Department of Nutrition, Federal University of Piauí, Campus Ministro Petr^ onio Portella, Teresina, Piauí, 64049-550, Brazil. E-mail addresses: larissacris.f@hotmail.com (L.C. Fontenelle), mayarafeitosa@ hotmail.com (M.M. Feitosa), taynahcoelho@outlook.com (T.E.C. Freitas), ju_ ssevero@hotmail.com (J.S. Severo), jenniferbeatriz.morais@gmail.com (J.B.S. Morais), gilberto.simeone@gmail.com (G.S. Henriques), erasmo@ medimagem.com.br (F.E. Oliveira), jmoita@pq.cnpq.br (J.M. Moita Neto), dilina. marreiro@gmail.com (D.N. Marreiro). Contents lists available at ScienceDirect Clinical Nutrition ESPEN journal homepage: http://www.clinicalnutritionespen.com https://doi.org/10.1016/j.clnesp.2020.10.012 2405-4577/© 2020 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved. Clinical Nutrition ESPEN xxx (xxxx) xxx Please cite this article as: L.C. Fontenelle, M.M. Feitosa, T.E.C. Freitas et al., Selenium status and its relationship with thyroid hormones in obese women, Clinical Nutrition ESPEN, https://doi.org/10.1016/j.clnesp.2020.10.012