The nutritional difficulty of thyroid resistance is in converting T4 (inactive thyroid hormone) to T3 (active thyroid hormone) or difficulty absorbing it. There are many causes of thyroid resistance that include everything from diet, to environment and toxins. The causes of thyroid resistance can include an anti-thyroid diet, low or absent foods that support good thyroid function, plus the many dietary, environmental and natural substances that inhibit thyroid function and stress. (Read More)