Iodine is a micronutrient required for thyroid hormone production. Adequate (but not excessive) levels of iodine, a trace element found mostly in the soil and water of coastal areas, are required for the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3), which play key roles in our many metabolic systems. The major concerns regarding the global and growing scope of iodine deficiency are related to goiter, neurocognitive impairments, and lastly, hypothyroidism.
In its severest form, the threat represents mental retardation and cretinism.
The association between seaweed, a high source of iodine, and goiter was noted in Chinese records dating back to 3600 BC and was also written about by Hippocrates. Iodine, however, was not discovered until the 19th century, with its formal discovery announced in 1896.
Iodine supplementation, primarily through the fortification of table salt, did not begin until the early 1920s. Although iodized salt in the U.S. is fortified at 45 mg iodide/kg, 47 of 88 table salt brands recently sampled contained less than the FDA’s recommended range of 46–76 mg iodide/kg. Today, most salt intake is from processed foods that use the non-iodinated form of salt, and the message of iodine supplementation has seemingly been lost in the history books.
This is of particular concern today in light of the American Heart Association announcing its new and lowered hypertension guidelines. This means that more people will be classified as hypertensive with corresponding lifestyle recommendations of limiting sodium advised. High blood pressure should be treated earlier with lifestyle changes at 130/80 mm Hg rather than 140/90 – based on new American Heart Association (AHA) guidelines for the detection, prevention, management, and treatment of high blood pressure.
With the restriction of sodium, the first thing that leaves the table is the salt shaker, and along with it, the iodine.
Many people are not even aware that the salt they buy should have iodine in it, and some are not even aware they have a choice.
Although a 2012 study noted that recent national studies suggest the general population is overall iodine sufficient, salt iodization in the U.S. is not universal, and certain subsets of the population including pregnant and lactating women and their offspring may be at risk for mild to moderate iodine deficiency. This is compounded by the previously mentioned decline in the definition of hypertension and salt restriction as well as the limited knowledge about iodine, its function, and where it comes from.
What Are Iodine Requirements?
The 2011 Dietary Recommended Intakes Are:
- 1-8 years old: 90 micrograms (mcg)/ day
- 9-13 years old- 120 micrograms (mcg)/ day
- 14+ years old – 150 mcg/day
- Pregnant or breastfeeding – 290 mcg/day
What Foods Are High in Iodine?
- Seaweed: whole or 1 sheet: 16 – 2,984 mcg.
- Baked cod – 3 ounces: 99 mcg
- Cranberries – 1 ounce: 90 mcg
- Plain low-fat yogurt – 1 cup: 75 mcg
- Egg: 24 mcg
- Dried prunes – 5 prunes: 13 mcg
Role of Iodine in the Body
- Iodine helps keep metabolism stable through its key role in thyroid hormone metabolism. Iodine helps the body use calories for energy rather than being deposited as fat and is a main determinant of the basal metabolic rate.
- Iodine is involved in the cancer process. Iodine boosts cellular immunity and the cellular death of mutated cells while protecting healthy cells. Inadequate iodine intake will result in increased TSH stimulation, increased thyroid cell responsiveness to TSH, increased thyroid cell EGF-induced proliferation, decreased TGF b 1 production, and increased angiogenesis– all phenomena related to promotion of tumor growth. However, other studies have related excessive iodine intake to cancer incidence. The take-home message is that iodine balance is key: not too much, and not too little.
- Cognitive status can be severely impaired by iodine deficiency. Iodine deficiency is generally recognized as the most common preventable cause of mental retardation.
- Iodine’s role in the prevention of neurodegenerative disorders is one reason why the World Health Organization recommends increased iodine supplementation during pregnancy and breastfeeding. The impact of iodine deficiency on growth rate, learning problems, motor function, and cretinism are undeniable.
- Healthy hair and skin are dependent on an adequate iodine intake.
- Adequate iodine prevents goiter (a swelling of the thyroid gland), which leads to thyroid dysregulation.
The roles for iodine noted above are just a few of the major roles iodine plays in body homeostasis and optimal functioning. Hopefully, it can be seen that iodine deficiency is a crucial concern and one that may need to be revisited here in the United States.
If you’re looking for Thyroid Specialist in Rancho Cucamonga, come to Core Integrated Health of Inland Empire.