A patient with hypothyroidism should avoid all foods that interfere with thyroid function, including vegetables from the cabbage family, soybeans, peanuts, kale and spinach. In hypothyroidism, the thyroid gland does not produce enough thyroid hormone, causing the body's metabolism to slow down, according to the University of Maryland Medical Center.
Hypothyroidism may be due to Hashimoto's thyroiditis, post-therapeutic hypothyroidism or goiter, according to UMMC. Hashimoto's thyroiditis is a condition where antibodies from the blood mistake the thyroid gland as a threat and begin to destroy it. Treatment for hyperthyroidism often involves removal or destruction of part or all of the thyroid gland, which can result in hypothyroidism. Goiter develops due to a lack of iodine in the diet. It is uncommon in developed countries due to the addition of iodine to salt.
Doctors treat patients with hypothyroidism using medication, including either a synthetic hormone or one from the desiccated thyroid glands of pigs, according to UMMC. Use of this medication requires regular blood tests to monitor the amount of the hormone in the body. Lifestyle changes, such as avoiding certain foods, can help to reduce symptoms. Caffeine, tobacco, alcohol and iron supplements may affect how the body reacts to thyroid medications.