Iodine: it’s elementary, my dear watson

Iodine: it’s elementary, my dear watson

Key Findings

  • Iodine is an essential trace element required to keep all body systems working at peak capacity and to protect against disease.
  • Iodine primarily affects levels of thyroid hormone, but it also has a role in the immune system, in cognitive function and in pregnancy.
  • Dietary iodine comes from seafood (including seaweeds), green leafy vegetables, eggs and raw dairy products.

A powerful chemical

Nearly every organ and tissue in the body contains iodine, an essential trace element. It is necessary for the proper functioning of nearly every biological system, as well as for the prevention of several diseases, including cancer.

However, iodine is an essential nutrient that the body cannot produce on its own. Because of this, we need a balanced diet that contains enough iodine-rich plants and animals. The most plentiful supply of iodine comes from plants and animals that live in the sea. The recommended daily amount (RDA) for men and women age 14 and over is 150 micrograms (mcg) per day.

It all starts with the thyroid

Iodine’s most important job is to help the thyroid gland produce its hormones. The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), contain iodine in their chemical structures. They travel throughout the body to regulate the body’s basal metabolic rate (BMR). BMR is the sum of the numerous energy-related processes in the body, including heart rate, blood pressure, organ efficiency, digestive enzymes, food absorption and conversion to energy, the sleep–wake cycle, growth of brain and bones, and many other processes.

Other functions of iodine

Besides its role in maintaining normal thyroid function, iodine also has an important role in sustaining the body’s immune system. As a scavenger of free hydroxyl radicals, it promotes antioxidant activity that strengthens the body’s defenses. It also assists in promoting the self-destruction of malignant cells. This aspect of iodine’s action is particularly amazing because it helps your body destroy the mutated cancer cells while leaving the healthy cells intact. The anti-cancer properties of iodine are particularly important in the treatment of thyroid cancer.

Iodine also helps the body produce perspiration and saliva and plays a role in treatment of breast conditions, including fibrosis, turgidity, soreness and fibrocystic disease. When it comes to having healthy hair, iodine is particularly beneficial in developing robust follicles and building strong, smooth and fast-growing hair.

Finally, iodine’s role in a healthy pregnancy cannot be overstated. It helps the mother avoid high blood pressure and helps the baby develop a healthy brain to avoid future motor-function and learning problems.

Best sources of iodine

Which foods provide the most iodine? Just ask Poseidon, God of the Sea. Marine plants and animals are some of the best providers of iodine because they absorb the element from seawater. Iodine-containing plants include brown seaweed kelp, nori, kombu and wakame. Wild-caught fish that are good sources of iodine include cod, haddock, salmon, halibut, shrimp, deep-water whitefish and many others.

Iodized salt provides iodine, but some other foods also contain iodine (listed in alphabetical order):

  • Canned tuna and sardines
  • Cage-free eggs
  • Lima beans
  • Raw, unpasteurized dairy products
  • Spinach
  • Summer squash
  • Swiss chard
  • Whole grains

Supplementation may be necessary for those who don’t eat seafood regularly. Potassium iodide and sodium iodide are two forms of iodine found in supplements, and they may also be included in multivitamins. When making decisions about supplements, your doctor or a trained holistic practitioner can help you assess whether these supplements are right for you.


The essential trace element iodine supports the thyroid. The thyroid, in turn, regulates the body’s basal metabolic rate (BMR), which affects everything from blood pressure and food absorption to sleep cycles and development of the central nervous system and skeleton. In addition, iodine strengthens the immune system, aids in the elimination of malignant cells, helps in development of the brain and promotes a healthy pregnancy for mother and child. Iodine is primarily found in seafood and marine plants like kelp and seaweed but is also present in green leafy vegetables, beans, and dairy products. If you think you have an iodine deficiency and need iodine supplementation to keep your body in a healthy state, seek the advice of a doctor.