Your thyroid gland is a structure in your neck that helps regulate use of the energy in various foods in your diet, as well as normal brain development in fetuses and newborn children. Kelp, also called Atlantic kelp or bladderwrack, is a form of seaweed. It contains a mineral called iodine, which can significantly alter your normal thyroid function.
Background
Your thyroid gland produces its effects by secreting two primary hormones: thyroxine, commonly called T4; and triiodothyronine, commonly called T3. T3 has a greater effect on your body, while T4 stays in your body longer and can be chemically converted to T3. Your thyroid gland also secretes a hormone related to T3, called reverse T3, and another unrelated hormone called calcitonin; these substances don't alter your body's energy usage. Hormone secretion in your thyroid gland is triggered by a pituitary gland hormone called thyroid-stimulating hormone, or TSH; in turn, TSH release is triggered by interactions between your pituitary gland and a part of your brain called the hypothalamus.
Iodine and Thyroid Function
You need small amounts of iodine to produce T3 and T4 and maintain your normal thyroid function. If you don't get enough iodine, you can develop an underactive thyroid disorder called hypothyroidism, as well as an enlargement of your thyroid gland called goiter. Potential symptoms of hypothyroidism include unwanted weight gain, fatigue, depression and lack of mental concentration. People with abnormally high output of thyroid hormones can develop a condition called hyperthyroidism, which has potential symptoms that include unexpected weight loss, nervousness, abnormal heat sensitivity and heart palpitations.
Kelp Uses and Effects
All seafood contains significant amounts of iodine, and kelp is the most common iodine-rich sea vegetable, according to the U.S. National Library of Medicine's MedlinePlus. However, any given batch of kelp can have varying iodine content. Kelp supplements are sometimes used by doctors to treat thyroid-related conditions that include an underactive thyroid gland, iodine deficiency and goiter. Although it may seem counterintuitive, very high iodine intake can trigger the onset of reduced thyroid function. If you have hypothyroidism or hyperthyroidism, the iodine in kelp can significantly worsen your related symptoms. For this reason, MedlinePlus strongly recommends that you avoid kelp consumption if you have thyroid problems.
Considerations
Most of the iodine in the average American diet comes from iodized table salt. Other commonly available sources of the mineral include dairy products and plant-based foods grown in soil that has significant iodine content. If you take medications for hyperthyroidism, kelp consumption can amplify their effects and lead to an unwanted reduction in your thyroid function. In fact, any oral intake of kelp can potentially endanger your health, MedlinePlus explains. Before you consider using kelp for any reason, seek your doctor's explicit consent. Consult your doctor for more information on the connections between iodine intake and the health of your thyroid gland.
