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Useful News in Endocrinology: Things that Are Harmful to Your Thyroid Gland

Things that Are Harmful to Your Thyroid Gland

CT Scans and Contrast Die

First, a new study in the Archives of Internal Medicine (1) reveals that imaging studies which use Iodide as a contrast agent in CT scans and cardiac catheterizations increase the risk of over active thyroid (hyperthyroidism) by two to 2.5 times. The risk of severe low thyroid states (severe hypothyroidism) in increased 3-fold. Doctors and patients should take these risks into consideration when ordering these tests, as these tests use anywhere between 90 to several hundred-thousand times the recommended daily dose of iodine (150 micrograms).

What to do if you need a CT scan?

Commentaries on the article suggested that if you need a CT scan or cardiac catheterization, by all means do it; however, if the tests might not be necessary, the risks and benefits should be carefully weighed taking this new information into account, as well as your risks of developing thyroid dysfunction (e.g., family history, thyroid nodules, goiter). You should be more educated about symptoms of hyper and hypothyroidism and be more observant for the emergence of the problems, and be sure you can tolerate the treatment of either disorder (hyper or hypothyroidsm) should it develop.

BPA in Canned Foods and Drinks +

The FDA recently denied a request to ban a substance -BPA- which is used extensively in food and beverage containers (e.g., canned foods and drinks). This is despite growing evidence that BPA (bisphenol A) disrupts many hormonal systems. A recent study in rats published in the well- respected journal Endocrinology (2) showed that that BPA inhibits certain estrogen assisted memory storage functions and growth of neurons, two functions which are usually enhanced by certain estrogens. The doses used in the study were below the supposedly safe daily limit set by the Environmental Protection Agency. While this study is done on rats, and such studies do not necessarily transfer to people, there is enough reason to be wary of BPA.

How can you avoid BPA? 

  1. Limit your intake of canned foods and drinks as much as possible. BPA is found in polycarbonate plastics and epoxy resins.
  2. Read the labels. Polycarbonate plastics are often used in containers that store food and beverages, such as water bottles, and baby bottles and cups.
  3. Ask questions. They may also be used in toys and other consumer goods. Epoxy resins can be used to coat the inside of metal products, such as food cans, baby formula cans, bottle tops and water supply lines.
  4. Ask your dentist. Some dental sealants and composites also may contain BPA.
  5. Avoid taking thermal receipts such as those at gas stations. Certain thermal paper products, such as cash register receipts, may contain BPA. If you must take handle such paper products, wash your hands thoroughly before handling food, touching your lips, or another person.

(1) Rhee CM, Ban I, et al.: Association between iodinated contrast media exposure and incident hyperthyroidism and hypothyroidism. Arch Intern Med. 2012; 172(2): 153-159

(2) Inagaki T., Frankfurt M., et al.: Estrogen-induced memory enhancements are blocked by bisphenol A in adult female rats: Role of dendritic spines. Endocrinology, doi:10.1210/en.2012.1121.