The most common form of hypothyroid is Hashimoto’s thyroiditis -an autoimmune disorder where the body is producing antibodies to the thyroid and leads to decreased production of thyroid hormones. The most common cause of hyperthyroid is Graves’ disease—this is also an autoimmune disorder, but in Graves’ disease, the antibodies stimulate thyroid hormone production and you get too much.
Some thyroid disorders occur after or during pregnancy, after viral or bacterial infections or after long periods of stress . Both hypo- and hyper-thyroid occurs predominantly in women starting at the ages of 30-40. Some cases of Graves’ disease have been associated with heavy metals and prescription drugs.
T4 and T3 are the main thyroid hormones. Iodine is a critical nutrient for the proper functioning of the thyroid gland. (the numbers 4 and 3 represent the number of iodine atoms per molecule of hormone.)
Thyroid disease is diagnosed by both physical symptoms and lab results.