Iodine: A necessary nutrient, and not just for our thyroid –

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Iodine: A necessary nutrient, and not just for our thyroid

How I realized iodine is an important nutrient for our reproductive organs

Greta Thunberg isn't the only one to recognize a health condition as a blessing (or as she refers to it as a superpower). 

I don't want to spend a ton of time on my back story, but considering my diagnosis with Hashimoto's (also known as autoimmune thyroiditis) has helped me tremendously with planning new formulations for Return to Eden Cosmetics, I wanted to use this blog post to tell you about my journey to diagnosis... and my journey to regaining my health (and my appetite).

In 2016, I started gaining weight.  Not a lot of weight, but definitely enough for me to notice.  My weight steadily increased over the next two years while my appetite kept plummeting in spite of absolutely no change in my exercise regimen or diet. 

I saw four different doctors during this time period, and their recommendations ranged from keeping a food journal to accepting the weight gain because I'd reached that magic age where my metabolism changed overnight (to which I asked "Like a light switch?" to which she replied "Yes." Needless to say, I haven't been back to see that doctor).

In 2018, I started having yet another symptom...a slight full feeling in the right side of my neck. So, I scheduled an appointment with yet another doctor hoping he might give me a different answer than the previous four. 

And, that's how I was diagnosed with autoimmune thyroiditis.  This doctor actually listened to me and was smart enough to test my thyroid antibodies. 

For those of you who don't know, it is possible to have normal thyroid hormone levels (TSH, T3, T4, free T3, and free T4), and STILL have an autoimmune thyroid condition. 

The body can make a number of different antibodies that can attack the thyroid.  In my case, my anti-thyroid peroxidase antibody (anti-TPO antibody) levels were high, but all of my thyroid hormone levels were normal.

Diagnosed, so now what?

Because all my thyroid hormone levels were (and still are) normal, Western medicine couldn't offer me much help.  I, of course, didn't let that stop me from trying to figure out how to feel better and get those anti-TPO levels down. You see, by and large Western medicine (or at least the doctors practicing it) hasn't yet caught up to Western science, so I headed to Google Scholar to figure out how to heal myself.

That's why I'm an amateur "expert" on immunology today (check out Immunology 101: Balancing T helper cells and T regulatory cells if you're interested in reading more about what I learned regarding adaptogens and immune modulation).

Diet and dietary supplements presented over and over as I researched how to make my immune system stop attacking my thyroid gland. 

I incorporated daily highly bioavailable selenium into my supplement program and stopped taking all supplements containing iodine because so many articles contra-indicated iodine intake with Hashimoto's. 

Boy was that a mistake!

Within a month of eliminating supplemental iodine from my diet, I developed a painful breast cyst.  Back to Google Scholar where I found out that iodine is a necessary nutrient not just for thyroid health but also for breasts, ovaries, and prostate.

Iodine and Breast Health

A large body of scientific literature shows that iodine can reverse fibrocystic breast disease and also prevent and treat breast cancer. 

While some of these studies simply look at the increased incidence of breast cancer and the decreased intake of iodine and assume causality, there are plenty of studies out there looking at animal models, human breast cells in petri dishes (in vitro), and human studies to evaluate iodine's impact on breast health.

One study in a paper published late in 2016 shows compelling results that iodine inhibits growth of breast cancer cells and induces cell death of breast cancer cells1.  While this study was conducted in vitro (petri dish of particular types of breast cancer cells treated with iodine), at least three human trials show that fibrocystic breast tissue is reduced or eliminated, and researchers believe fibrocystic breast disease is a precursor to breast cancer2

Why exactly iodine is so beneficial for breast health is still being researched, but it seems to play a multi-functional role in maintaining healthy breasts by:

  1. Desensitizing estrogen receptors in the breasts
  2. Reducing estrogen production in overactive ovaries
  3. Increasing progesterone production
  4. Triggering cell cycle differentiation.  This is important because cancer cells typically display characteristics of undifferentiated cells.
  5. Decreasing peroxidation of lipids, which are oil soluble compounds like fatty acids and oil soluble hormones.  Basically, iodine acts as an anti-oxidant.
Wondering which hormones are oil soluble?  Estrogen, progesterone, testosterone, cortisol, and aldosterone are a few oil soluble hormones.


Iodine and Ovarian Health

Several studies show that the symptoms of Polycystic Ovarian Syndrome (PCOS) are relieved by supplementing with iodine, namely iodine helped restore normal menstruation3.  Now, this may be due to subclinical (undetectable by blood tests) or undiagnosed hypothyroidism3,4, but the ovaries have the highest concentration of iodine than any other organ in the body except for the thyroid3

Studies haven't yet figured out the role of iodine in ovaries, but it appears the ovaries can convert T4 (a thyroid hormone) to T3 (another thyroid hormone)5

For all women out there who are pregnant or want to become pregnant, iodine deficiency has also been tied to fetal development and mental development of babies, toddlers, and children6,7,8

Iodine and Testicular Health

It's a little harder to find whether the testicles have iodine receptors, but what is clear is that men who are treated with radioactive iodine for thyroid cancer tend to experience problems with sperm damage that is directly related to the dose of radioactive iodine received during the course of treatment9

This phenomenon indicates that there are thyroid receptors in the testicles or that thyroid hormones (T3 and T4), which incorporate iodine into their structures as shown in the image below, are necessary for normal testicular function, and when radioactive iodine is present in the body, testicular health is impacted.

structure of thyroid hormones T3, T4, reverse T3

Structures of the thyroid hormones T3 and T4.

Iodine Intake and Other Bodily Functions

One study I came across while researching this post used mice to evaluate effects of iodine intake on triglyceride and cholesterol levels.  This study found that iodine deficiency correlated with higher low density lipoproteins (LDL, better known as the bad cholesterol), higher triglyceride levels, and higher total cholesterol. 

A second group of mice in this study were fed a diet with excess iodine.  After 8 months, the females in this group had lower total cholesterol levels, and the males in this group had lower triglyceride levels than the iodine deficient group10.

How much iodine should you take?

The Food & Nutrition Board recommends 150 micrograms per day for adults.  Nearly double that is recommended for pregnant women and lactating women11

The population of Japan consumes nearly 100 times the RDA for iodine3 and has a low incidence of hypothyroidism and breast cancer.  Studies using 3 to 6 milligrams (20 to 40 times the RDA) of iodine effectively treated fibrocystic breast disease12.  It is unclear whether the iodine intake in that study was consumed daily or over a duration of days or weeks.

And, here's where I should point out, I'm not a doctor, so I'm not telling you what you should do.  Here's what is working for me:

I have increased my daily intake of iodine to about 675 micrograms per day, and I am not having any symptoms of Hashimoto's or cystic breast pain as long as I stick to my gluten free diet and maintain my selenium (L-Selenomethionine) intake of between 50-100 micrograms a day - be cautious with selenium because too much is not a good thing. 

Since I've been gluten free, I've dropped 5 pounds, and more importantly, my appetite is back and I don't have a constant full feeling in the right side of my neck due to swollen lymph nodes (see the Other Reference (Autoimmune Thyroiditis) if you need some peer reviewed journal articles to get your doctor to pay attention to you on this symptom in particular).

I will talk about why gluten specifically is so bad for people with autoimmune thyroiditis in a future blog post, but I really wanted to use this post to talk about why iodine is such an important micronutrient.



2 Fluoride Interactions with Iodine and Iodide:  Implications for Breast Health

3Orthoiodosupplementation: Iodine sufficiency of the whole human body
Guy. E. Abraham M.D.1, Jorge D. Flechas M.D.2 and John C. Hakala

4 Prevalence of autoimmune thyroiditis in patients with polycystic ovary syndrome

5 Ovarian iodide uptake and triiodothyronine generation in follicular fluid: The enigma of the thyroid ovary interaction

6 Iodine, Iodine metabolism and Iodine deficiency disorders revisited

7Iodine during fetal development and the first years of life

8 Importance of thyroid hormones for normal pregnancy

9 Testicular Damage After Radioactive Iodine (I‐131) Therapy for Thyroid Cancer

10 The Impact of Dietary Iodine Intake on Lipid Metabolism in Mice

11 Fact Sheet for Health Professionals: Recommended Iodine Intake

12Iodine: Deficiency and Therapeutic Considerations

Other References (Iodine Specific)

Changes in Dietary Iodine Explains Increasing Incidence of Breast Cancer with Distant Involvement in Young Women

Optimum Levels of Iodine for Greatest Mental and Physical Health

Other References (Hashimoto's and Enlarged Lymph Nodes)

Hashimoto's Thyroiditis

The presentation of lymph nodes in Hashimoto’s thyroiditis on ultrasound

Shifting cervical lymphadenopathy in Hashimoto’s disease

Neck Lymph Nodes in Chronic Autoimmune Thyroiditis: The Sonographic Pattern

About the Author

Brandy Searcy sitting on a concrete bench underneath a green leafy tree in Edmonton, IL

Brandy Searcy is a pharmaceutical formulation development scientist with over a decade experience in skincare product development.  She holds a B.S. in chemical engineering from Georgia Tech and is self taught in many fields most notably skin anatomy and physiology and immune modulation (although she has formal training as well and was also raised by a registered nurse).  When she's not at her day job formulating pharmaceuticals, she's researching immunology to learn more about her own diagnosis with Hashimoto's, developing new skincare formulations, or spending time with her husband and two rescues in Southern California.

A lover of rescued dogs, she's had her share of heartbreak losses due to diseases from congestive heart failure to cancer for these beloved dogs.  As their caretaker, she learns more with every diagnosis in an effort to extend quality of life for as many days as possible because one more day is so worth it.  Brandy isn't just a health nut, dog lover, and formulation nerd,  she's also a wildlife advocate and an avid environmentalist.  

Just figuring out day by day how to leave no trace on the environment while doing everything she can to make the world better for those she crosses paths with, whether that's humans or other animals.

Brandy's LinkedIn Bio


  • How frustrating to go through a medical scare only to have a doctor be unable to give you a diagnosis. I know autoimmune disorders are hard to diagnose so thats great that you were able to isolate it and work on treating. Thanks for sharing your wealth of knowledge.

  • Thank you for sharing your journey! There’s so much information out there, it can be hard to keep track, much less know what’s “best.” Having links to your references is especially helpful!


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