“To eat a healthy diet in general is going to support a healthy thyroid.” Instead of concentrating on a few specific foods, your diet should mostly consist of whole grains, low-fat dairy, fruits and vegetables and lean protein, she added. The claim: You should make sure you get enough iodine in your diet, or you might develop a goiter. The facts: In the past, a goiter — swelling in the neck caused by enlargement of the thyroid — was linked to diets deficient in iodine, but that hasn’t been a widespread phenomenon in the United States in decades.