People with thyroid problems, or hypothyroidism, should avoid eating soy-based foods, high-fat foods, gluten and cruciferous vegetables, according to Everyday Health. Soy contains high amounts of phytoestrogen, which can have a negative impact on proper thyroid function.
Cruciferous vegetables, including broccoli, Brussels sprouts, bok choy, cauliflower and cabbage, may reduce hormone production in the thyroid gland, states Everyday Health. The recommended amount of cruciferous vegetables is limited to 5 ounces a day, particularly in people with an iodine deficiency. Iodine is essential to the thyroid gland, and cruciferous vegetables block its ability to absorb enough of the essential mineral.
Gluten is a protein found in many foods made with whole grains such as wheat, barley and rye, and it is known to interfere with thyroid hormone replacement medications, explains Everyday Health. Whole grains are good sources of fiber, which support other symptoms of hypothyroidism, including bowel irregularity. People taking thyroid medications should time their intake several hours from eating gluten-based foods.
Foods high in fat interfere with thyroid medications and the ability to produce hormones, notes Everyday Health. People should reduce or avoid fried foods and dishes containing butter, margarine, mayonnaise and fatty cuts of meat. Fat and sugar add excess calories that can quickly lead to weight gain, particularly in people with a slow thyroid metabolism. Additionally, people suffering from hypothyroidism should limit their sodium intake to 1,500 milligrams per day. Thyroid patients have a higher risk for high blood pressure, and excess sodium increases the risk.