Thyroid disease or dysfunction can explain a wide variety of symptoms, yet it is notoriously under-diagnosed. The American Thyroid Association estimates that over 12% of the US population will develop thyroid disease during their lifetime, and that as many as 60% of people with thyroid disease are not aware of it.  Thyroid function can be affected by deficiencies, particularly of the elements iodine and selenium, of excesses of bromine, arsenic, mercury and cadmium, which are toxic to the body when we are overexposed. These elements are present in the food we eat, air we breathe, and water we drink and are tasteless and odorless, so they are impossible to detect without testing.