When people think of the importance of iodine, they mostly think of thyroid health. But iodine goes way beyond just an important part of thyroid health. 

The thyroid gland has the most iodine receptors of any other part of the body. It is through these iodine receptors that the iodine enters the cells to work its magic. There is no doubt that iodine is essential for thyroid health. But there are other body parts for which iodine is just as important. Breast tissue, and any part of the female reproduction system needs a lot of iodine for optimum health. For men, prostate needs a lot of iodine. The following article discusses the importance of iodine, symptoms of iodine deficiency, food sources of iodine and the best way to test to determine if you are iodine deficient.

Symptoms of iodine deficiency

Most of the symptoms of iodine deficiency mimic the symptoms of hypothyroidism, because the thyroid gland is so dependent on iodine. But there are other symptoms not related to thyroid to watch out for. Below is a list of possible iodine deficiency symptoms.

  • Goitre (swelling of the thyroid)
  • Fatigue 
  • Brain fog 
  • Thinning hair 
  • Dry skin 
  • Unexpected weight gain
  • Cold hands and feet (and feeling colder in general) 
  • Poor memory and concentration 
  • Fibrocystic breasts
  • Heavy or irregular periods
  • Uterine fibroids
  • Anxiety
  • Depression
  • Insomnia 

Thyroid and iodine

As mentioned above, the thyroid gland has the most amount of iodine receptors in the body. 70 – 80% of the body’s supply of iodine is used in the thyroid gland. Iodine is essential for the conversion of thyroid hormones T4 (Thyroxine) to T3 (Triiodothyronine). T4 is largely inactive, but T3 is the active thyroid hormone, essential for a healthy body metabolism. If not enough iodine is available, the body cannot convert the largely inactive T4 to the active T3, leading to hypothyroid symptoms such as brain fog, weight gain, hair falling out, constipation, fatigue, heavy periods and much more. 

Breast tissue and iodine

In women, breast tissue has the second largest amount of thyroid receptors. The most obvious sign of low iodine in the breast tissue is Fibrocystic breasts, where the breast tissue can feel lumpy, thick and tender due to cysts developing. Iodine can be “painted” onto the breasts which will help reduce the cysts.  

Female reproductive system and iodine

Second to thyroid, the female reproductive system (which includes breast tissue) utilises the most iodine. This is why female reproduction cancers such as Breast, Ovarian, Uterine and Endometrial are linked to low iodine. Studies have shown that being even mildly deficient in iodine can cause a significant decrease in the ability to conceive. One of the symptoms of iodine deficiency is heavy and prolonged periods. Iodine is required for the production of progesterone and the break down of oestrogen. It is also essential for ovulation. Uterine fibroids are another symptom of iodine deficiency.    

Pregnancy and iodine 

Iodine deficiency can cause serious problems for developing foetuses. Iodine deficiency during pregnancy is associated with an increased risk of miscarriage, stillbirth, low birth weight and congenital abnormalities. Iodine is essential for the baby’s growth and brain development and even a mild iodine deficiency is associated with neurological and cognitive impairment in children.  

Prostate and iodine

For men, the prostate has the second most amount of iodine receptors after the thyroid. Research has shown that low iodine intake increases the risk of BPH (Benign Prostatic Hyperplasia, or enlarged prostate) and prostate cancer. Japanese, who have a high dietary intake of iodine, have much lower levels of prostate cancer compared to the United States. 

Cancer and iodine

Iodine has potent antioxidant, anti-inflammatory and anticancer effects. Iodine deficiency has been linked to Thyroid, Stomach, Breast, Ovarian, Uterine, Endometrial, Colorectal and Prostate cancer. 

Clearly, cancer is a multifactorial disease (like all disease) so an iodine deficiency is not likely to be the sole cause of cancer, but as an easily remedied modifiable risk factor, iodine deficiency can be ignored only at the peril of cancer and other disease. 

Why are so many people low in iodine?

Iodine is found in soil and the ocean. Unfortunately, with modern farming practises, the soil is depleted of iodine (as it is with most other nutrients) which is one of the reasons iodine deficiency is common. Another one being the fact that most people don’t eat much fish or sea vegetables. But the most important cause of low iodine are the halides – fluoride, chlorine and bromine, in particular bromine. The molecular structure of these halides is very similar to iodine (which is another halide) and as a result they compete with iodine in the body, attaching to the iodine receptors. Bromine is the “strongest” of these halides and therefore has the most impact on iodine levels. The bromine “pushes” iodine out of the body.   

Bromine, the nastiest of the iodine depleting chemicals – where is it found? 

Years ago, bakers used to use iodine to clean out the baking equipment (iodine is a potent anti microbial agent). Because bromine is cheaper, it is used now. Potassium Bromate is also used as a dough conditioner in baked goods. Bromine is used as a fire retardant in plastics, fabrics, foam, computers, mobile phones, with very high levels found in cars. It is used in pesticides, insecticides, certain medications, some citrus flavoured soft drinks, hair dye – the list goes on!  It is impossible to avoid bromine totally. I recently purchased a new car, and although I tried my hardest to remember to wind down the windows every time I drove it, I would often forget. I recently had my bromine levels tested and they are much higher than I am comfortable with. 

How can we increase our iodine levels?

We need to ensure that we have as limited exposure to bromine as possible. Avoid processed foods, eat organic food to eliminate the ingestion of pesticides, remove as much plastic from your life as possible, wherever possible drive with the car windows down, use organic personal care products. Never use hair dye – henna only.  

Iodised salt is not a good way to increase iodine levels. Firstly, most of the iodine is lost over time, and iodised table salt contains anti caking agents (which contain aluminium amongst other nasty chemicals) which are not good for us. 

Eating more seafood and sea plants is a great way to increase iodine levels. Other foods that contain iodine are asparagus, cod, garlic, lima beans, eggs, dairy, beef liver, chicken, mushrooms, oyster, sunflower seeds, but it needs to be noted that there are only tiny amounts of iodine in most of these foods (other than the sea plants). Drinking filtered water (make sure the filter can eliminate fluoride as well as chlorine and bromide), not eating processed foods, and taking iodine as a supplement are other ways to increase iodine levels 

Supplementing with iodine is of course the best way to increase levels. But this needs to be done with caution. I use high dose iodine in my clinic, but it is not as simple as taking iodine. It needs to be taken with certain co factors and there are some situations where taking iodine is actually dangerous. Because of this, supplementing in high doses needs to be done with the guidance of an iodine experienced practitioner. When increasing iodine through food, the food also contains the co factors needed. The problem with trying to increase iodine with only food is that once someone is low in iodine, higher doses than found in food are needed to bring levels up to optimum, in particular if there is a lot of bromine in their system.  

How much iodine do we need?

The recommended dietary intake of iodine in western countries is shockingly low – 150 mcg per day, 220mcg for pregnant women and 270mcg for breastfeeding. The Japanese have much higher levels of iodine in their diet, but it is very difficult to obtain accurate information. Depending on which research you look at, the Japanese consume between 3mg – 12mg of iodine per day. Even if you take the 3mg intake, that is 20 times more the recommended daily intake in western countries. The 12mg is 80 times more. Whichever research you trust, it is clear that western country’s recommended intake of iodine is woefully low. Japanese have always had a lower risk of breast cancer, prostate cancer and thyroid problems (due no doubt to their higher intake of iodine). When Asian people move to western countries and adopt the western style of eating, these health problems increase to western levels. 

Testing for iodine

Most Doctors will test for iodine though a urinary spot iodine test. This is a totally inaccurate test, and in my opinion is actually dangerous. If bromine levels are high, the bromine will push the iodine out of the body leading to apparently “good” levels of iodine according to these tests. It is essential to also test for bromine in any iodine test. I use a 24 hour urinary iodine loading test which is the gold standard of iodine testing. With this test, a dose of iodine is given and urine is collected over a 24 hour period. The amount of iodine excreted in the urine is then measured. The principle of this test is that the body will only absorb as much iodine as is needed. So the more iodine that is excreted, the more optimum your iodine levels are. 

In my clinic, I deal with a lot of thyroid issues. I have never had a client with thyroid issues with optimum iodine levels. Although I do not normally test clients for iodine if they don’t have thyroid problems (the test comes at a cost), I firmly believe that most of the population is low in iodine. 

By Andrea Southern, Naturopath, Clinical Nutritionist, Herbalist.