Hashtag, I've just remembered something. There are foods you can eat which can affect your thyroid. For hyperthyroidism, low iodine foods are good, high iodine intake is not so good.
It is highly recommended by doctors and endocrinologist to avoid iodine, saturated fats, caffeine, sugar, wheat and diary products. At the same time the goitrogens (these are foods containing chemical compounds that block iodine absorption) should be increased. These are foods that inhibit the uptake of iodine work on the same principle as some of the antithyroid drugs, inhibiting thyroid hormone synthesis, release or action.
Goitrogens include foods of the Brassica family including broccoli (eaten raw), kale, kohlrabi, Brussel sprouts, turnips, cauliflower (eaten raw), rape and mustard. Non Brassica with goitrogenic properties include horseradish, cress and radish. Levels of goitrogens are highest in the seeds of those plants. Other goitrogens include sweet potatoes, millet, peaches and cabbage. Herbs and seeds which could help are: members of the mint family, including mint(s), borage, basil, oregano, marjoram, mustard greens, pears, almonds and spinach, lemon balm, rosemary, lavender and hyssop.
Sweetcorn is good too.
Lean turkey meat is good due to high levels of vitamin B.
Foods rich in vitamin D and zinc are also good for those with hyperthyroidism (because deficiencies of these can often go with hyperthyroidism). This would have shown up in blood tests.
It is also suggested to cut down on red meat (see if that helps) and gluten/wheat.
My friend (the one who had the thyroidectomy) was put on this diet by her doctor before her operation. it did seem to help a little.