Thyroid disorder diets often depend on the type of thyroid condition, states Cleveland Clinic. For example, people with hypothyroidism, a condition caused when the thyroid does not make enough of the thyroid hormone, should avoid soy, while those with hyperthyroidism are not as affected by soy.
For those with hypothyroidism, goitrogens, such as kale, broccoli and cauliflower, can prevent the thyroid from getting enough iodine. However, Cleveland Clinic states that the benefits of these vegetables outweigh their risks, and patients should consume them as normal.
For those with hyperthyroidism, a condition where the thyroid makes too much of the thyroid hormone, the University of Maryland Medical Center recommends eliminating suspected food allergens, such as lactose and gluten; avoiding refined foods, such as pasta and white flour; and reducing the intake of red meats by replacing them with more lean meats. Those with hyperthyroidism should also supplement their diet with foods rich in antioxidants, such as blueberries, cherries and tomatoes, and foods high in B-vitamins and iron.
Other foods that can negatively influence the thyroid include those high in sugar and fat content, as they can hinder the body's absorption of thyroid medication. In general, a diet high in protein, calcium and magnesium aids thyroid function.