Despite many claims, no specific diet has been shown to improve thyroid function in people with hyperthyroidism, according to Mayo Clinic. However, elements critical to thyroid function are more plentiful in some foods, while others contain substances that interfere with the thyroid and thyroid medications, as listed by WebMD.
The thyroid needs iodine for good functioning. Common iodized table salt contains iodine, and most people get ample amounts from this product, as noted by WebMD. Sea salt and some other table salts are not iodized. Fish and shrimp also tend to be good sources of iodine.
Magnesium is another critical element for proper thyroid performance. Green, leafy vegetables, including spinach and lettuce, contain magnesium. Another excellent magnesium source is nuts, such as cashews, almonds and pumpkin seeds. Brazil nuts contain magnesium and also provide selenium, a third element that helps maintain thyroid health, as noted by WebMD.
Goitrogens interfere with the uptake of iodine by the thyroid. Common sources of goitrogens include kale, cabbage, broccoli, cauliflower and Brussels sprouts. Goitrogens promote thyroid problems in people who have low levels of iodine, notes WebMD. Soy products hinder proper hormone production by the thyroid if iodine levels are insufficient. When consumed in excess, the lipoic acid found in organ meats such as liver disrupts thyroid function and lessens the effects of thyroid medicines.