Affiliations: Human and Animal Physiology Group, Wageningen
University, Wageningen, The Netherlands | Department of Endocrinology and Metabolic Diseases,
Leiden University Medical Center, Leiden, The Netherlands
Note: [] Address for correspondence: Daan van der Heide, Human and Animal
Physiology Group, Wageningen University, Wageningen, The Netherlands. Tel.: +31
317 483000; Fax: +31 317 484077; E-mail: daan.vanderheide@WUR.nl
Abstract: The most potent natural plant-derived compounds that can affect
thyroid function, thyroid hormone secretion and availability to tissues is the
group of flavonoids, i.e. plant pigments. They are present in our daily food,
such as vegetables, fruits, grains, nuts, wine, and tea. Epidemiological
studies suggest beneficial effects on health of flavonoids, which are commonly
attributed to their activity as antioxidants. Experimental studies in
vitro, however, showed inhibition of organification in thyroid cells and
follicles by several flavonoids. Studies in vivo and vitro with
synthetic and natural flavonoids showed displacement of T_4
from transthyretin leading to disturbances in thyroid hormone availability in
tissues. Radioactive labeled flavonoids appeared to be eliminated rapidly from
the body mainly through excretion in the feces. In pregnant rats synthetic
flavonoids cross the placenta and accumulate in the fetal compartment,
including the fetal brain. Therefore, a high intake of flavonoids is
contraindicated. In conclusion: flavonoids show strong interference with many
aspects of thyroid hormone synthesis and availability.
Keywords: flavonoids, thyroid hormone, fetal development
Journal: BioFactors, vol. 19, no. 3-4, pp. 113-119, 2003
