Most people connect iodine intact with thyroid conditions. Indeed, in order to make thyroid hormone, you must have an adequate amount of iodine in your body. However, iodine does much more. Iodine deficiency is linked to fatigue, breast cancer, fibrocystic breast disease, obesity, cognitive impairment, heart disease and psychiatric disorders.

Unfortunately, there is a growing amount of evidence that iodine deficiency is more common than we thought (1). Today, nearly 74% of normal, “healthy” adults may no longer consume enough iodine in their diet (2, 3). This is a fourfold increase in this deficiency over the past 40 years. Most Americans get their salt from iodized salt, but with us all reducing our salt intake, we are inadvertently creating an epidemic of iodine deficiency (3, 4).

So what are the symptoms of iodine deficiency? Iodine is essential to life. It is necessary for development of the brain, thyroid gland, breast and many other organs. You need iodine to just function day to day, call your metabolism. Lack of iodine thus affects all parts of our body and our ability to function.

The US recommended dietary allowance (RDA) for iodine ranges from 150-290 mcg to 1,100 mcg per day depending on the source (5, 6, 7). However, Japanese consume 5,280 to 13,800 mcg per day with no harmful effects yet with many benefits, including a decrease in breast cancer (8, 9).

Thyroid gland health

Most people connect iodine with the thyroid gland. Lake of thyroid hormone (hypothyroidism) slows your metabolism and result in a plethora of symptoms including fatigue, decreased mentation, gaining weight, and malaise (10, 11). Many of these problems, including cognitive impairment, may be reversible with iodine or thyroid hormone replacement (12, 13).

Too much thyroid (hyperthyroidism) can also cause fatigue because it revs up your metabolism. You’re thus using up too many calories resulting in you being tired. One way to find out which problem you have is to take your pulse. Too low a pulse would be indicative of low thyroid while too high a pulse would suggest too high thyroid (14). However, only adequate blood testing will really let you know.

Breast health

There is a growing amount of evidence that a deficiency is linked to an increase in fibrocystic breast disease and breast cancer (14, 15, 16). Japanese women consume an iodine-rich diet, intaking 25 time more Iodine than Americans (17). Japanese women also have one-third less breast cancers than American women (18), a difference that disappears in Japanese women who immigrate to the US where they much less iodine (19).

You may have complained of breast tenderness off and on. This may have been from inflammation of fibrocystic changes seen in many women. I deprived of iodine, breast tissue develops fibrocystic changes (20, 21). These changes can be reversed by high doses of iodine equivalent to 5,000 mcg per day in humans (22). Indeed, women with breast tenderness due to iodine deficiency can be adequately treated using high doses of iodine (23). Thus, consider taking high dose iodine (3,000-6,000 mcg per day) when breast tenderness from fibrocystic changes is a problem for you (18).

Cardiovascular health

Iodine supplementation has been used as a natural remedy for high blood pressure and heart disease (cardiovascular disease) (24). Lack of iodine can increase the risk of death from a heart condition (24, 25, 26). Lack of iodine results in low thyroid conditions, which weaken the heart (27) and increase risk of obesity with its associated cardiovascular disease (28).

Thus, restoring adequate thyroid function and iodine levels improves heart health, and may help reverse multiple cardiovascular risk factors including adverse lipid profiles (29).

Stomach cancer

Like the breast and thyroid gland, the stomach contains a rich concentration of iodine. Studies have linked a decrease in iodine to higher rates of stomach cancers (30). Patients with low iodine had 2.5 times more stomach cancers (31).

Thus, increasing your iodine intake may reduce your risk of stomach cancer (


If you have problems with weight gain, low energy, fatigue, depression, poor mental clarity, these may be due to an iodine deficiency state. After all, iodine deficiency rates have increased fourfold over the past 40 years and 75% of healthy American adults may be deficient in iodine.

Taking iodine supplementation may improve these while they may also improve your heart health and decrease the risk of you developing some cancers. They may also improve the breast tenderness that many women suffer from due to fibrocystic changes of the breast.



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