Food such as soybeans, turnips, and rutabagas can affect people with thyroid disorders by:

• A. Suppressing thyroid hormone
• B. Decreasing the hypothermia of the person with hypothyroidism
• C. Supplementing the diet of a person with hypothyroidism
• D. Counteracting the effect of iodide therapy

Answer: (A)

Goitrogenic foods can interfere with thyroid hormone production by limiting the thyroid’s ability to use iodine, which is essential for making T4 and T3. In people with thyroid disorders, especially when iodine intake is not ample, these compounds reduce thyroid hormone synthesis, leading to lower circulating levels and potentially worsened hypothyroid symptoms. Soybeans and vegetables like turnips and rutabagas are classic examples of foods that have this effect. This does not directly cause hypothermia, does not provide thyroid hormone to supplement therapy, and does not reliably counteract iodide therapy. Therefore, the best answer is that these foods suppress thyroid hormone production.