Seaweed is rich in iodine, an essential component for the formation of thyroid hormones. Iodine deficiency is still a problem in the 21st century despite iodination programmes. Without sufficient iodine in the diet, we risk a decline in brain development and growth in fetuses and children. This key micronutrient is essential for the formation for thyroid hormones. Using a non-essential amino acid, tyrosine, organification generates the key thyroid hormone (thyroxine, a pro-hormone). Both thyroxine and its biologically active form, triiodothyronine, are essential for growth and development.