The role of nutrition on thyroid health and disease. Myths and facts

Purpose: This narrative review examines the role of essential nutritional factors in thyroid function, moving beyond the traditional focus on iodine supplementation. The specific aim was to explore the association between food intake, specific nutrients, dietary patterns, and thyroid diseases, with particular emphasis on autoimmune mechanisms. Methods: A structured literature search was conducted using online databases to identify relevant studies published over the past two decades. Articles investigating the relationship between nutrients, dietary patterns, thyroid function, and autoimmune thyroid disorders were selected and analyzed. Results: Evidence confirms the crucial role of iodine and selenium in thyroid hormone synthesis and redox balance. Iron and zinc support enzymatic activity and endocrine stability. Vitamin D has emerged as a potential immunoregulatory factor in autoimmune thyroid diseases. Additionally, certain macronutrients and bioactive compounds, including polyphenols and omega-3 fatty acids, demonstrate beneficial effects due to their anti-inflammatory, antioxidant, and immunomodulatory properties. Adherence to the Mediterranean diet has been associated with favorable thyroid outcomes. In contrast, Western-style dietary patterns high in fat, calories, and red meat may negatively affect thyroid health, while gluten-free or lactose-free regimens do not appear to provide significant benefits. Conclusions: Evidence-based nutritional strategies represent valuable adjunctive approaches in the prevention and clinical management of thyroid disorders. Adherence to a Mediterranean dietary pattern and reduced meat consumption may improve thyroid function and help protect against autoimmune diseases.