title: Genistein aglycone does not affect thyroid function: results from a three-year, randomized, double-blind, placebo-controlled trial.
abstract: OBJECTIVE
  Genistein aglycone positively affects postmenopausal symptoms. However, questions about its long-term safety on the thyroid gland still remain.
  
  
  METHODS
  The parent study was a randomized, double-blind, placebo-controlled trial involving 389 osteopenic, postmenopausal women for 24 months. A subcohort (138 patients) continued therapy for an additional year.
  
  
  METHODS
  Patients received ambulatory care.
  
  
  METHODS
  Participants received 54 mg of genistein aglycone daily (n = 71) or placebo (n = 67), plus calcium and vitamin D(3) at therapeutic doses. Circulating thyroid hormones (TSH, free T(3), free T(4)) and autoantibodies (thyroid peroxidase, thyroglobulin, and thyroid microsomal antigen) were assessed in 40 genistein and 37 placebo subjects who completed 3 yr. Thyroid hormone receptor (THRalpha and THRbeta) and retinoid receptor (RARalpha, RARgamma, and RXRalpha) expression from peripheral blood monocytes was also evaluated at baseline, 12, 24, and 36 months in all 3-yr completers.
  
  
  RESULTS
  Genistein administration over 3 yr did not affect serum thyroid hormones or autoantibodies. In addition, there were no differences in THRalpha, THRbeta, RARalpha, RARgamma, or RXRalpha mRNA expression between groups.
  
  
  CONCLUSIONS
  These data suggest that genistein aglycone intake does not significantly increase the risk of clinical or subclinical hypothyroidism at the dose of 54 mg/d.
authors.affiliation: Department of Clinical and Experimental Medicine and Pharmacology, Section of Pharmacology, University of Messina, 98125 Messina, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Bitto
authors.forename: Francesca
authors.initials: F
authors.lastname: Polito
authors.forename: Marco
authors.initials: M
authors.lastname: Atteritano
authors.forename: Domenica
authors.initials: D
authors.lastname: Altavilla
authors.forename: Susanna
authors.initials: S
authors.lastname: Mazzaferro
authors.forename: Herbert
authors.initials: H
authors.lastname: Marini
authors.forename: Elena Bianca
authors.initials: EB
authors.lastname: Adamo
authors.forename: Rosario
authors.initials: R
authors.lastname: D'Anna
authors.forename: Roberta
authors.initials: R
authors.lastname: Granese
authors.forename: Francesco
authors.initials: F
authors.lastname: Corrado
authors.forename: Silvia
authors.initials: S
authors.lastname: Russo
authors.forename: Letteria
authors.initials: L
authors.lastname: Minutoli
authors.forename: Francesco
authors.initials: F
authors.lastname: Squadrito
mesh_terms: D000368:Aged; D015992:Body Mass Index; D004032:Diet; D004311:Double-Blind Method; D005260:Female; D019833:Genistein / Q000009:adverse effects* / Q000097:blood; D006801:Humans; D018828:Immunoglobulins, Thyroid-Stimulating / Q000097:blood; D008055:Lipids / Q000097:blood; D008875:Middle Aged; D017698:Postmenopause / Q000502:physiology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011988:Receptors, Thyroid Hormone / Q000096:biosynthesis / Q000378:metabolism; D047488:Retinoid X Receptors / Q000096:biosynthesis / Q000378:metabolism; D013960:Thyroid Function Tests; D013961:Thyroid Gland / Q000187:drug effects*; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood; D014284:Triiodothyronine / Q000097:blood
chemical_list: D018828:Immunoglobulins, Thyroid-Stimulating; D008055:Lipids; D012333:RNA, Messenger; D011988:Receptors, Thyroid Hormone; D047488:Retinoid X Receptors; D014284:Triiodothyronine; D013972:Thyrotropin; D019833:Genistein; D013974:Thyroxine