If a client has a low dietary intake of iodine, which hormone is most profoundly affected?

The hormone that is most profoundly affected by a low dietary intake of iodine is thyroid hormones. Iodine is an essential mineral required for the synthesis of thyroid hormones, specifically thyroxine (T4) and triiodothyronine (T3). These hormones are crucial for regulating metabolism, growth, and development. When iodine intake is insufficient, the production of T3 and T4 decreases, leading to various physiological issues, including hypothyroidism, which can result in symptoms such as fatigue, weight gain, and cold intolerance.

Cortisol, insulin, and estrogen are not directly influenced by iodine levels in the diet. Cortisol is a steroid hormone produced by the adrenal glands and is involved in the response to stress and metabolism but does not rely on iodine for its synthesis. Insulin, produced by the pancreas, regulates blood glucose levels and is unrelated to iodine. Estrogen is a sex hormone primarily associated with reproductive functions and does not depend on iodine for its production. Therefore, insufficient iodine intake primarily impacts the synthesis of thyroid hormones.