Pathophysiological Processes Associated with Hypothyroidism and the Protective role of Polyphenols: Current Insights

<jats:p>At present, thyroid-related disorders are increasing worldwide. In particular, hypothyroidism, which occurs when thyroid hormone levels fall below normal values, is one of the most frequently observed health problems among the population. Its main clinical manifestations include weight gain, fatigue, general weakness, chronic constipation, memory impairment, and cold intolerance. If hypothyroidism is not properly treated, it may lead to various metabolic disorders, such as diabetes mellitus and cardiovascular diseases. Although significant progress has been made in identifying the causes of hypothyroidism, understanding its clinical consequences, as well as in its diagnosis and treatment, a number of unanswered questions regarding its management still remain. Hypothyroidism is usually treated with synthetic pharmacological agents. However, long-term use of these drugs may cause adverse effects, including cardiac dysfunction, left ventricular hypertrophy, and oxidative stress–related liver damage1. Therefore, the development of new therapeutic approaches with no or fewer side effects that can improve thyroid function and alleviate hypothyroidism-induced pathophysiological processes in the body is of great importance. Plant-based preparations are often considered promising alternatives, as they usually have minimal or no adverse effects and provide valuable therapeutic potential for various metabolic disorders. This review aims to summarize the role of the thyroid gland and its hormones, the systemic changes observed in hypothyroidism, as well as the modulatory effects of polyphenols on thyroid function and hypothyroidism-associated metabolic syndromes.</jats:p>