Effects of the Sex Factor on Mouse Iodine Intake: Interactions between the Gut Microbiota Composition and Metabolic Syndromes

Iodine plays a key role in maintaining thyroid homeostasis, which is influenced by hormones through almost all nucleated cells and is essential for growth and metabolism. The most common kinds of thyroid dysfunction, hypothyroidism and hyperthyroidism, are markedly related to iodine intake. In addition, the prevalence and incidence of hypothyroidism and hyperthyroidism are much higher in women than in men. However, the association between thyroid homeostasis and the gut microbiota is not yet completely clear, especially when comparing women and men. In this study, differences in the gut microbiota compositions, metabolic syndromes, and molecular mechanisms of female and male mice were investigated after iodine supplementation. The gut microbiota in male mice was changed more than that of female mice. The abundances of Muribacium intestinale, Barnesiella, Alloprevotella, Enterococcus, Desulfovibrionaceae, and Clostridium were significantly increased in female mice. This finding indicates that the high risk of thyroid disease in women could be related to the gut microbiota composition.