A. According to the National Institutes of Healths Office of Dietary Supplements, excess iodine might interact with anti-thyroid medications such as methimazole, used to treat hyperthyroidism. Taking high doses of iodine with anti-thyroid medications could cause your body to produce too little thyroid hormone. Dairy products such as milk, yogurt and cheese, along with products made from grains (like breads and cereals), are the major sources of iodine in American diets. One cup of low-fat yogurt, for example, contains 75 micrograms of iodine, or 50% of the Daily Value (DV, 150 micrograms). One cup of reduced-fat milk contains 56 micrograms (37%) and one ounce of cheddar cheese has 12 micrograms (8%). You can also reduce iodine intake by buying non-iodized salt: 1.5 grams of iodized salt (about one-quarter teaspoon) contains 71 micrograms of iodine (47% of the DV). Be aware, too, that many multivitamin/mineral supplements contain iodine in the forms of potassium iodide or sodium iodide.