Role of Dietary Supplements in Thyroid Diseases.

BACKGROUND: Thyroid hormones play a vital role in regulating our body's metabolism. Two important thyroid hormones released from the thyroid gland are tri-iodothyronine (T3) and tetra-iodothyronine (T4). Thyroid-stimulating hormone and thyroid regulating hormone control the T3 and T4 levels in our body. Increased TSH levels indicate hypothyroidism and decreased TSH levels indicate hyperthyroidism. Iodine is a crucial nutrient for the synthesis of thyroid hormones and is mostly obtained from our diet. Other essential nutrients for the thyroid hormones formation include selenium, iron, vitamin D, vitamin B12, etc. Dietary changes in these nutrients can result in alterations in thyroid function and structure. Although normally, the hormonal diseases cannot be cured, but we can improve their signs and symptoms using suitable dietary supplements. OBJECTIVE: The aim of the study was to thoroughly analyze the various benefits and risks associated with the use of dietary supplements for the prevention and treatment of various thyroid disorders, like hypothyroidism, as seen in Hashimoto's thyroiditis; hyperthyroidism, as seen in Graves' disease; sick euthyroidism and subclinical hypothyroidism. METHODS: Literature was searched using the search terms "dietary supplements+thyroid diseases" on Pubmed, Google Scholar, Scopus, Cochrane Library, and other search engines, and data were collected from 1967 to November, 2021, including research inputs from the authors. The literature was thoroughly searched, and deep knowledge was acquired on this topic, which was then sequentially organized and summarized using suitable tables and figures. CONCLUSION: After analyzing various studies on this topic, we arrived at the conclusion that although there are various claimed and observed health benefits of dietary supplements in the prevention and treatment of various thyroid disorders, still several studies have shown too many risks to be associated with the use of dietary supplements, and people using these products should be aware of these risks in order to use them very judiciously for the improvement of their thyroid status.