Iodine for hypothyroidism: friend or foe?

Iodine for hypothyroidism is a controversial topic, with experts at both ends of the spectrum arguing for and against its use. But if you have hypothyroidism, or know someone who does, it’s important to understand that iodine is often No a preferred form of treatment, and in many cases can worsen your condition.

Before we delve into why this is so, you are probably wondering about all the Okay things you’ve heard about iodine, so let us explain…

Your thyroid needs iodine to function.

Your body does not make iodine on its own, which means you must get it through food. If you don’t get enough, you won’t be able to make enough thyroid hormone.

Your thyroid depends on iodine to make two hormones, triiodothyronine (T3) and thyroxine (T4). The numbers in these hormone names are actually a marker for how many iodine atoms are attached, with T4 containing 4-atom molecules then releasing one to convert to T3, the active form of the hormone.

An estimated 2 billion people worldwide, including 266 million school-age children, have insufficient iodine intake,[1] and the resulting iodine deficiency is, in fact, the most common cause of hypothyroidism (underactive thyroid) worldwide.

If you have an iodine-deficient diet, eating iodine-rich foods like seaweed and even supplementing with iodine can quickly help remedy the problem…but it’s important to realize that in the United States iodine deficiency is No one of the main causes of hypothyroidism and, in many cases, treating the condition with iodine is a major health disaster.

Iodine deficiency is NOT a major cause of hypothyroidism in the US.

Iodine levels in food vary widely depending on the concentration of iodine in soil and seawater. Because of this, it can be difficult to get enough iodine from your diet alone, especially if you live in an area with iodine-deficient soil. To remedy this, the United States adds iodine to most table salt, which means you not only get additional iodine when you salt your food, but also when you eat processed foods, which are typically heavily salted with iodized salt.

Many animal feeds in the United States are also supplemented with iodine, and as a result, dairy products are also good dietary sources of this nutrient.

However, there have been signs that iodine intake in the United States has decreased, possibly due to more people reducing their salt intake, but data from the latest available study, the National Health and Nutrition 2003-2004, suggests most Americans still get enough.[2]

Therefore, in the United States, iodine deficiency is not considered a major cause of hypothyroidism, except in specific risk groups, such as those who do not consume iodized salt (including from processed foods), fish or seaweed, or women who are pregnant.

That said, cases of hypothyroidism are widespread in the United States, affecting nearly 4% of the population, [3] including 13 million who have not been diagnosed and do not know they have the condition. [4]

If iodine deficiency isn’t the problem, then what is?

The most common cause of hypothyroidism in the United States

Hypothyroidism in the United States is often the result of an autoimmune disease called Hashimoto’s thyroiditis, or Hashimoto’s disease, which causes the immune system to mistakenly attack and destroy the thyroid.

The disease usually begins with inflammation of the thyroid gland (thyroiditis) which, over time, affects the thyroid’s ability to produce enough hormones, eventually leading to an underactive thyroid, or hypothyroidism.

The exact causes of Hashimoto’s disease are unknown, but it is likely the result of a combination of factors including:

• A virus or bacteria that triggers the response.
• Genetics/family history
• Sex (women are more likely to have Hashimoto’s)
• Other environmental factors

However, and this is an important point, excess iodine can also worsen the condition.

Increased Iodine May Worsen Hypothyroidism

There’s no arguing that iodine is a crucial nutrient for your body…but in the case of hypothyroidism, more isn’t always better.

Studies show that giving iodine to people who had adequate or excessive iodine intake could trigger hypothyroidism and autoimmune thyroiditis.

Research also suggests that iodine actually increases the activity of the enzyme thyroid peroxidase (TPO), and increased antibodies against this enzyme are common in Hashimoto’s patients. It is the interaction between the TPO enzyme and the antibodies that leads to inflammation and destruction of the thyroid. In other words, too much iodine can cause Hashimoto’s disease. worse.

Remember, since most cases of hypothyroidism in the United States are due to Hashimoto’s disease, NOT iodine deficiency, this study could apply to you…

Be very careful if your doctor automatically recommends iodine for hypothyroidism

Many health professionals in the United States do not understand the complexities of thyroid function and will routinely recommend iodine supplementation for people with hypothyroidism. Unfortunately, this approach will be detrimental to some.

If you truly are deficient in iodine, then you need to supplement or increase your dietary intake. But if not, the extra iodine is most likely just triggering or worsening thyroid disorders.

So if your health care professional recommends iodine supplementation without any real evidence that you have a deficiency, that’s a red flag to watch out for. A second opinion from a doctor who understands the complex role of iodine in hypothyroidism, and who can discuss its benefits versus risks with you, is likely warranted.

References

1. Food and Nutrition Bulletin 2008 Sep;29(3):195-202.
2. Thyroid. 2008 November; 18(11): 1207-14.
3. Thyroid. 2007 December; 17(12): 1211-23.
4. Archives of Internal Medicine 2000;160:526-534.