Question

A person that has a diet deficient in iodine begins to experience weight gain, low blood pressure, and an intolerance to cold. The person also has a goiter (i.e. enlarged thyroid gland).

A). What causes the weight gain, low blood pressure, and intolerance to cold?

B). Why does this person have a goiter?

C). How is iodine typically introduced in the diet?

Answer 1

A. The weight gain, low blood pressure, and intolerance to cold is all caused by deficiency of thyroid hormones T3 and T4 or hypothyroidism. Iodine is an important component of Thyroxine (T4) and its active form Triiodothyronine (T3). Iodine is mostly absorbed from food as the body cannot synthesize it. Thyroid hormones are produced in the thyroid gland and are stimulate metabolism in the body. Lack of these hormones will decrease metabolism, thereby causing storage of calories as fat. This causes the weight gain. As the body is producing less energy due to decreased metabolism, the person will start feeling cold. Thyroid hormones are regulators of blood pressure and their lack will cause the low blood pressure in the patient.

B. The hypothyroidism causes the body to increase the production of thyroid stimulating hormone. TSH stimulates thyroid hormone production in the thyroid gland. However, as there is iodine deficiency, T3 and T4 cannot be formed efficiently despite increasing TSH. TSH will stimulate hypertrophy in thyroid gland, resulting in goiter (enlarged thyroid).

C. Iodine is mainly present in soil and thus, can be ingested in the body via food. It is also present in water and salt in trace amounts naturally. However, iodine deficiency can cause metabolic issues due to thyroid hormone deficiency. In order to treat iodine deficiency, iodine is incorporated in salt and is known as iodized salt. Some foods are rich in iodine. These include sea fish such as tuna, Haddock and cod, dairy products such as milk, cheese as well as eggs and meat. Food can contain Supplements containing iodine can also be taken to cure iodine deficiency.