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Iodine is an essential trace mineral in the diet that it important for thyroid function.
The thyroid gland uses iodine to make two hormones – thyroxine (T4) and triiodothyronine (T3) – that are involved in regulating metabolism throughout the body.
If you get too little iodine in your diet, you may develop low levels of thyroid hormones (hypothyroidism), enlarged thyroid (goiter) and experience fatigue and a lack of energy.
Other symptoms of iodine deficiency disorders (IDD) can include weight gain, poor skin and hair quality, changes in mood, infertility, impaired cognitive function and a persistent feeling of being cold.
If you get too much iodine in your diet, you may be at risk of autoimmune thyroid disorders like Graves disease and Hashimoto’s thyroiditis, overactive thyroid (hyperthyroidism) and possibly thyroid cancer. [1]
Deficiencies in this mineral are more common than having too much. If you believe that you have a thyroid condition, continue reading to determine whether iodine supplementation is appropriate for you.
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Weight Loss- Important for thyroid hormones & metabolism
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- Essential nutrient with multiple roles in the body
Top Iodine Products* ❯Iodine and Thyroid Hormone Production
The thyroid gland plays an important role in setting the basal metabolic rate of your body.
Increasing thyroid activity speeds up many different bodily functions and cellular reactions whereas decreasing thyroid activity causes many processes to slow down.
The thyroid gland synthesizes hormones that regulate energy production, body temperature, heart rate, respiration and other important biological and neurological functions.
Every cell in the body is affected by thyroid hormones. Along with the amino acid tyrosine, iodine is the main constituent of the T3 and T4 thyroid hormones.
According to Endotext, “Iodine is an indispensable component of the thyroid hormones, comprising 65% of T4’s weight, and 58% of T3’s. The thyroid hormones are the only iodine-containing compounds with established physiologic significance in vertebrates.”. [1]
If iodine is lacking in the diet, then the thyroid gland may become unable to synthesize adequate amounts of these hormones. This can result in hypothyroidism, the formation of a goiter and a wide range of physiological symptoms.
Iodine and Hypothyroidism
When the thyroid gland is not producing sufficient amounts of T3 and T4 to meet the body’s needs, hypothyroidism may be diagnosed.
The most common symptom of an underactive thyroid is inadequate thyroid hormone production. Other common markers include increased secretion of TSH (thyroid stimulating hormone) and overstimulation of the thyroid gland.
Another common sign of hypothyroidism is goiter, which refers to the swelling of the thyroid gland. According to Dr. Joseph Mercola, the thyroid gland swells when iodine levels are low.
It increases in size in an attempt to trap more iodine from the circulating blood that surrounds this gland. This swelling is temporary and the gland typically reverts to normal size after sufficient levels of iodine are achieved in the diet.
Some additional signs of hypothyroidism to look for include:
- Becoming more sensitive to cold temperatures;
- Weight gain and/or resistance to losing weight;
- Pain, swelling and/or stiffness in joints;
- Increased blood cholesterol;
- Irregular menstruation;
- Depression;
Other signs that your thyroid may be sluggish include fatigue, hoarseness, weak muscles, slow heart rate, thinning hair and dry skin. Poor memory, puffy face, constipation and achy muscles are also associated with hypothyroidism.
Ensuring adequate dietary intake of iodine and/or using a supplement can help to prevent or reverse hypothyroidism. Consult with your doctor to determine whether an iodine deficiency is causing your symptoms and what the best dosage to take is.
Iodine and Hypothyroidism
There is some concern that increasing your iodine intake too much can cause hyperactivity of the thyroid gland.
When the thyroid gland is overly active and manufactures too much thyroxine (T4) and triiodothyronine (T3), symptoms of hyperthyroidism can develop.
According to Dr. Group, although it can occur in rare cases, getting too much iodine is not a common cause of overactive thyroid (hyperthyroidism).
This disorder is most commonly caused by a condition where the immune system attacks the thyroid gland called Graves disease.
Other common causes of hyperthyroidism include another autoimmune disorder called Hashimoto’s thyroiditis, overuse of medicinal iodine in hospitals and inflammation of the thyroid gland that causes excessive T4 production.
Additional rare causes for hyperthyroidism include use of antiarrhythmic drugs like Amiodarone, overuse of synthetic thyroid hormones like Synthroid and consumption of beef that is contaminated with bovine thyroid tissue.
Dr. Group says that these causes for hyperthyroidism are significantly more prevalent than excessive iodine intake.
Some of the most common signs of hyperthyroidism include:
- Weight loss or inability to gain weight;
- Poor attention span;
- Hyperactivity;
- Irritability;
- Anxiety;
People with overactive thyroids may also be intolerant to heat and often feel fatigued. In rare cases, cardiac shock and death have resulted from hyperthyroidism. [2]
Iodine RDA and UL
The US RDA (Recommended Dietary Allowance) for iodine is 150 micrograms (mcg) each day. This is the amount that the Food and Drug Administration recommends you consume in your diet every day to meet the majority of people’s needs.
The upper tolerable level (UL) for iodine is 1100 mcg/day. This is the amount that the FDA says is safe to consume daily without negative effects.
In some countries such as Japan, the average diet provides many times more iodine than these dosages without adverse effects. Epidemiological research suggests that iodine intake from foods of as much as 13,800 mcg daily has caused no adverse health effects. [3]
The RDA for iodine is the amount that health authorities determined to be sufficient for preventing goiter in the 1900’s. However, some health professionals believe that the recommended daily intake should be higher to meet optimal health needs.
They claim that exposure to toxic chemicals such as bromine, chlorine and fluoride has increased significantly in the modern age. These substances compete with iodine for uptake into the thyroid gland.
To compensate for this increased exposure, these health professionals believe that the current RDA is not sufficient to promote optimal well-being and is only sufficient to prevent goiter.
You should seek medical advice about using iodine supplements to support thyroid function as it pertains to your health state.
There are certain side effects and interactions you should be aware of before beginning to supplement your diet with iodine-rich foods or taking this mineral in pill capsule or liquid form.
- Miot F, Dupuy C, Dumont J, et al. Chapter 2 Thyroid Hormone Synthesis And Secretion. [Updated 2015 Sep 2]. In: De Groot LJ, Chrousos G, Dungan K, et al., editors. Endotext [Internet]. South Dartmouth (MA): MDText.com, Inc.; 2000-.
- Hjørringgaard J1, Birkelund T, Ravn HB. [Cardiac arrest and cardial insufficiency as result of thyrotoxicosis]. Ugeskr Laeger. 2013 Apr 1;175(14):962-3.
- Patrick L1 Iodine: deficiency and therapeutic considerations. Altern Med Rev. 2008 Jun;13(2):116-27.
Article last updated on: July 4th, 2018 by Nootriment