Britannica Sources used in this answer

How does iodine help regulate metabolism through thyroid hormones?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

USDA MyPlate dietary guidelines — human nutrition MyPlate, a revised set of dietary guidelines introduced by the U.S. Department of Agriculture (USDA) in 2011, divides the four basic food groups (fruits, grains, protein, and vegetables) into sections on a plate, the size of each section representing the relative dietary proportions of each food group. The small blue circle shown at the upper right illustrates the inclusion and recommended proportion of dairy products in the diet.

Iodine is a fundamental dietary element required for the synthesis of thyroid hormones, specifically thyroxine and triiodothyronine. These hormones cannot be produced without iodine, which is concentrated by the thyroid gland and attached to tyrosine residues to form the active hormone structures.12

Once secreted, these hormones regulate metabolism by entering target cells and binding to nuclear receptors. This process influences the transcription of DNA, leading to the synthesis of various proteins and enzymes that control cellular activity. Specifically, triiodothyronine regulates the utilization of nutrients and oxygen consumption within mitochondria, the sites of energy production.13

By modulating these cellular processes, thyroid hormones stimulate carbohydrate utilization, lipid metabolism, and the dissipation of energy as heat. Furthermore, they support critical physiological functions, including heart rate, nervous system activation, and normal growth and development. Because iodine is the essential building block for these regulatory hormones, adequate intake is vital for maintaining metabolic health and preventing conditions like goitre or hypothyroidism.32