Iron plays an important role in thyroid hormone metabolism; thus, iron deficiency anemia may lead to alterations in resting metabolic rate (RMR). Based on this premise, two iron-deficient-anemic female athletes, 18 (A 1) and 21 (A2) years of age, were supplemented with 23 mg/day of elemental iron to assess its effects on iron and thyroid hormone status and RMR at 0, 8, and 16 weeks. Anemia was clinically corrected in both subjects (hemoglobin: Al = 11.0 to 13.0 to 12.6 g/dL and A2 = 11.5 to 13.9 to 12.6 g/dL, 0 to 8 to 16 weeks, respectively). Serum ferritin (SF) concentration also improved in both subjects (Al: 5.0 to 11.0 to 15.0 ng/dL and A2: 5.0 to 16.0 to 20.0 ng/dL; 0 to 8 to 16 weeks, respectively); however, 16 weeks of iron supplementation did not fully replete iron stores. A2 increased dietary iron and ascorbic acid intakes from 8 to 16 weeks, possibly accounting for her higher SF concentrations. RMR and total thyroxine changed over time: Al increased while A2 decreased in these variables. Although clinical correction of iron deficiency anemia occurred after 16 weeks of low-level iron supplementation, RMR and thyroid hormone metabolism were oppositely affected in the two subjects.
Penny Harris Rosenzweig and Stella L. Volpe
Kathryn H. Myburgh, Claire Berman, Illana Novick, Timothy D. Noakes and Estelle V. Lambert
We studied 21 ballet dancers aged 19.4 ± 1.4 years, hypothesizing that undernu-trition was a major factor in menstrual irregularity in this population. Menstrual history was determined by questionnaire. Eight dancers had always been regular (R). Thirteen subjects had a history of menstrual irregularity (HI). Of these, 2 were currently regularly menstruating, 3 had short cycles, 6 were oligomenorrheic, and 2 were amenorrheic. Subjects completed a weighed dietary record and an Eating Attitudes Test (EAT). The following physiological parameters were measured: body composition by anthropometry, resting metabolic rate (RMR) by open-circuit indirect calorimetry, and serum thyroid hormone concentrations by radioimmunoassay. R subjects had significantly higher RMR than HI subjects. Also, HI subjects had lower RMR than predicted by fat-free mass, compared to the R subjects. Neitherreported energy intake nor serum thyroid hormone concentrations were different between R and HI subjects. EAT scores varied and were not different between groups. We concluded that in ballet dancers, low RMR is more strongly associated with menstrual irregularity than is currentreported energy intake or serum thyroid hormone concentrations.
Kirsty J. Elliott-Sale, Adam S. Tenforde, Allyson L. Parziale, Bryan Holtzman and Kathryn E. Ackerman
al., 2013 ). Thyroid Hormones The thyroid hormones triiodothyronine (T3) and thyroxine (T4) are important for growth, reproduction, and metabolism. Both thyroid excess and deficiency can stunt growth and inhibit reproductive function ( Martin et al., 2008 ). In response to periods of low EA, the
W. Daniel Schmidt, Gerald C. Hyner, Roseann M. Lyle, Donald Corrigan, Gerald Bottoms and Christopher L. Melby
This study examined resting metabolic rate (RMR) and thermic effect of a meal (TEM) among athletes who had participated in long-term anaerobic or aerobic exercise. Nine collegiate wrestlers were matched for age, weight, and fat-free weight with 9 collegiate swimmers. Preliminary testing included maximal oxygen consumption, maximal anaerobic capacity (MAnC) for both the arms and the legs, and percent body fat. On two separate occasions, RMR and TEM were measured using indirect calorimetry.
Andrea S. Hartmann, Florian Steenbergen, Silja Vocks, Dirk Büsch and Manuel Waldorf
(65.48) 1 (0.60) 1 (0.60) 3 (1.79) 3 (1.79) AAS 18 (10.71) 142 (84.52) 1 (0.60) 2 (1.19) 2 (1.19) 3 (1.79) Ephedrine 51 (30.36) 97 (57.74) 8 (4.76) 6 (3.57) 3 (1.79) 3 (1.79) Thyroid hormones 33 (19.64) 120 (71.43) 2 (1.19) 3 (1.79) 6 (3.57) 4 (2.38) Nitric oxide/Arginine 47 (27.98) 99 (58.93) 7 (4
Margaret C. Morrissey, Michael R. Szymanski, Andrew J. Grundstein and Douglas J. Casa
). UCP3 and thyroid hormone involvement in methamphetamine-induced hyperthermia . Biochemical Pharmacology, 68 ( 7 ), 1339 – 1343 . 10.1016/j.bcp.2004.03.049 Tansey , E.A. , & Johnson , C.D. ( 2015 ). Recent advances in thermoregulation . Advances in Physiology Education, 39 ( 3 ), 139 – 148
Julien Louis, Fabrice Vercruyssen, Olivier Dupuy and Thierry Bernard
, and thyroid hormones on the age-related decline in resting metabolic rate . Metabolism, 41 ( 8 ), 915 – 921 . PubMed ID: 1640872 10.1016/0026-0495(92)90177-C Res , P.T. , Groen , B. , Pennings , B. , Beelen , M. , Wallis , G.A. , Gijsen , A.P. , . . . Van Loon , L.J. ( 2012
Dana M. Lis, Daniel Kings and D. Enette Larson-Meyer
grown in iodine-poor soil (e.g., parts of the United Kingdom, United States, and New Zealand; Krajcovicova-Kudlackova et al., 2003 ). Although many plant foods such as cruciferous vegetables, sweet potatoes, and soybeans naturally contain “goitrogens,” which impair the synthesis of thyroid hormone
Nicole C.A. Strock, Kristen J. Koltun, Emily A. Southmayd, Nancy I. Williams and Mary Jane De Souza
(i.e., growth and reproduction). This results in suppression of metabolism, energy expenditure, and thyroid hormones ( Wade et al., 1996 ), contributing to the development of exercise-associated menstrual disturbances ( Loucks et al., 1998 ). Exercise-associated menstrual disturbances can range in
Margo Mountjoy, Jorunn Sundgot-Borgen, Louise Burke, Kathryn E. Ackerman, Cheri Blauwet, Naama Constantini, Constance Lebrun, Bronwen Lundy, Anna Melin, Nanna Meyer, Roberta Sherman, Adam S. Tenforde, Monica Klungland Torstveit and Richard Budgett
athletes striving for leanness . Clinical Journal of Sport Medicine, 23 ( 3 ), 197 – 201 . PubMed ID: 23275346 doi:10.1097/JSM.0b013e31827a8809 10.1097/JSM.0b013e31827a8809 Harber , V.J. , Petersen , S.R. , & Chilibeck , P.D. ( 1998 ). Thyroid hormone concentrations and muscle metabolism in