Making the Connection: PCOS, Hormones, Thyroid & Iodine - PCOS Diva
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Making the Connection: PCOS, Hormones, Thyroid & Iodine


Guest Post by Dr. Margarita Ochoa-Maya, Functional Endocrinology and Woman’s Health





In the setting of hormonal imbalance, PCOS, fatigue, weight gain, and breast pain, iodine deficiency is particularly important and should be considered. It is also very important to identify iodine deficiency in the setting of an enlarged or underactive thyroid especially when the laboratory tests are not conclusive.

When a woman has PCOS, iodine is a topic of interest and should be part of the conversation as it is well known that the ovaries have the second highest concentration of iodine in the body. This has been confirmed by research. The contents of follicular fluid in the ovarian follicles are rich in thyroid hormone (T3) and iodine.

Traditionally, iodine has been discussed in the setting of thyroid disease. It is well known that iodine is necessary for thyroid hormone balance and production. With newer research, iodine is now important since having low levels of iodine in the body can be linked to breast and ovarian dysfunction and PCOS as well as thyroid imbalance and underactivity.

Iodine deficiency is claimed to be rare, particularly in the United States, but compelling data was recently reported by the Centers for Disease Control suggesting that some 2.2 million women nationwide could have low iodine and more than a third of women of childbearing age have measured insufficient iodine levels. Now that awareness is setting in, more testing is being done and iodine deficiency is becoming more common. This may be due to the fact that iodine is decreasing in the average American diet.

Iodine is an essential component of the thyroid hormones, thyroxine (T4) and tri-iodothyrnine (T3). Thyroid hormones are important as they regulate biochemical functions such as the production of complex proteins, the activity of enzymes and in general metabolism energy and weight.

What is Iodine and Where Does It Come From?

Iodine is a chemical element found in some foods naturally, and in some foods it has been added. It is also available as a dietary supplement. Iodine in small amounts in the human body is obtained primarily through the diet from the soil. Unfortunately, the soil in certain areas is deficient, primarily in high mountainous regions such as the Himalayas, the European Alps, and the Andes where the iodine has been washed away due to glaciation and flooding. Vegetables and food that come from these areas are usually low in iodine. In areas where iodine is low in the soil and iodine is not added to the water supply, the primary source of dietary iodine are saltwater fish, seaweed, and trace amounts in grains.

In the United States, iodine has been voluntarily supplemented in ‘iodized’ table salt (70 mcg/g). It was thought that salt would be the perfect medium since it is used across the board and in every diet type and cultures as well as in different socioeconomic levels. It is also very inexpensive to supplement iodine in the salt; it costs an average of $0.04 per person. Keep in mind that this supplementation is voluntary, and as production costs are cut, so is voluntary supplementation. Other food supplements that include iodine may have it due to indirect supplementation. For example, eggs and chicken have iodine due to the supplementation of the feed. Cows and cattle, in general, also get supplemental dietary iodine to prevent hoof rot and to increase fertility; therefore, milk and other milk products may be another source of iodine. Yet if this supplementation does not happen, a decrease in the iodine content of the food will be a consequence.

  1. Low iodine content in food in areas low in iodine
  2. Low iodine content in food due to over farming and the industrialization of the food industry
  3. A decreased consumption of iodine-rich products for health reasons
  4. Decreased iodized salt consumption due to hypertension
  5. Decreased consumption of eggs due to elevated cholesterol
  6. Decreased consumption of fish due to cost and availability

The recommended dietary intake of iodine was developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences). The recommendations are just guidelines and they vary by age, gender and pregnancy state. These include:

Age Male Female Pregnancy Lactation
Birth to 6 months 110 mcg* 110 mcg
7-12 months 130 mcg * 130 mcg *
1-3 years 90 mcg 90 mcg
4-8 years 90 mcg 90 mcg
9 – 13 years 120 mcg 120 mcg
14+ years 150 mcg 150 mcg 220 – 300 mcg** 290 mcg
*Adequate Intake

** WHO and UNICEF recommendations

The upper limit of iodine intake in adults is 1,100 mcg/day.

The National Health and Nutrition Examination Survey (NHANES), NHANES III, demonstrated that the median U.S. urinary iodine excretion decreased significantly in 1999 (145 mcg/d) compared to levels measured in the early 1970s (320mcg/d). NHANES also reported that certain subgroups such as pregnant women are at a very high risk for iodine deficiency and that their average intake of iodine is 125 mcg/d compared to what it should be, 300 mcg/d. This is furthermore encouraged and recommended by the World Health Organization (WHO), United Nations Children’s Fund (UNICEF) and the International Council for the Control of Iodine Deficiency Disorders (ICCIDD).

Internationally, 2.5 billion people worldwide are at risk for iodine deficiency disorder; and of these people, 30–70 percent will present with an enlarged thyroid, and 1–10 percent will have severe iodine deficiency. In the United States today, severe iodine deficiency with urinary iodine levels less than 50 mcg/l are found in 11.1 percent of the total population, 7.3 percent of pregnant women, and 16.8 percent of reproductive women. Please note that I believe that these figures could even be an underestimation of the problem due to lack of testing.

When iodine is scant, it can cause problems in the body:

  1. Thyroid enlargement or goiter
  2. Underactive thyroid (hypothyroidism)
  3. Decreased fertility rate
  4. Ovarian cysts
  5. Polycystic Ovarian Syndrome (PCOS)
  6. Breast cysts and breast tenderness
  7. Increased infant mortality
  8. Learning disabilities
  9. Mental retardation in children

Even though the correlation is still under active investigation, there is an association between thyroid cancer and areas of iodine deficiency as there is increased mortality due to more aggressive thyroid cancers in these areas.

How Can You Tell If You Are Iodine Deficient?

In order to check to see if there is a deficiency of iodine, you can test whether you have enough iodine on board. There is a home test where you can dip a clean ball of cotton in inexpensive red-tinged tincture of iodine from any drugstore. Paint a 2-inch circle of tincture of iodine on soft skin tissue, such as the inner arm or thigh. If the stain is absorbed within 1–3 hours, your body may need a higher iodine intake. If the yellow-orange stain takes more than 6 hours to disappear, you are likely to be iodine replete.

The next step is to ask your health care provider for a more accurate 24-hour urine collection where iodine is measured in the urine. There has been some correlation with the changes in the size of the thyroid gland and the changes in the thyroid labs. When the median urine iodine measures greater than 100 mcg/l, goiter is rarely present and the TSH is usually low normal as compared to when it is less than 20mcg/l when goiter is present in more than 30 percent and the TSH is elevated in more than 40 percent.

Where can we find iodine in the diet?

Sources of iodine in food come from seaweed such as kelp, nori, kombu, and wakame). Other good sources include seafood, dairy products- due to sanitizing agents and feed supplements for the animals (when tolerated), grain products and eggs. Iodine is present in human breast milk and some fortified formulas.

Iodized salt is a source of iodine in more than 70 countries. The salt iodization programs are meant to address the global iodine deficiency problems and have indeed helped address the issue. In the USA, salt manufacturers have been adding iodine to salt since the 1920s. According to the label, iodized salt contains approximately 45 mcg iodine per 1 gram of salt (45 mcg/ g iodized salt). However, the majority of salt intake in the USA comes from processed foods and the manufacturers almost always use NON-IODIZED SALT, therefore it is important to consider this. It is also important to note that a high sodium diet is unhealthy and may increase water retention, and elevate blood pressure.

Dietary supplements may contain iodine and as such it will state it on the label. The most common forms are potassium iodine and sodium iodine. More natural alternatives include supplements that have kelp (a seaweed). Potassium iodine is almost completely absorbed in humans and is the better of the synthetic replacement formulations.

Iodine deficiency and Hashimoto’s Thyroiditis

It is not a coincidence that iodine deficiency is linked to Hashimoto’s Thyroiditis. This condition is an AUTOIMMUNE DISEASE, and is commonly present in women and more so when a woman suffers from PCOS. The cause of Hashimoto’s Thyroiditis is multifactorial, but what is well known is that there is a specific antibody that attacks the thyroid called Thyroid Peroxidase Antibody (TPO Atb). Inadequate iodine will cause the thyroid gland to be weak as it does not have the main substrate – iodine, to produce thyroid hormones.

There have been several studies that state too much iodine is bad, and not enough iodine is bad. Most importantly it is necessary to consider a person’s gut health, food and food sensitivities, lifestyle and exercise habits in addition to the microbacterial environment.  What we do know is that Hashimoto’s Thyroiditis is more common in women and especially more prevalent when a woman has PCOS. So don’t forget to get your antibodies tested even if the basic thyroid function tests were thought of as ‘within the normal range.’  In future articles we can address these issues in more detail.

Lastly, when it comes to female hormones and PCOS and its relation to iodine, we can comfortably say that monitoring your iodine in the diet and assuring that you are getting the right amount in the diet helps fertility, mood and hormonal balance. Take notice though, because too much of a good thing can also be dangerous. Be sure to talk to your doctor before embarking in treatment.

This article does not intend to treat or diagnose disease it is meant to generate awareness and promote health education and prevention.


Originally from Medellin Colombia, Dr. Ochoa-Maya graduated from ‘Instituto de Ciencia de la Salud, CES’ and completed her Internal Medicine Residency at Boston City Hospital affiliated with Boston Medical Center in Boston, Massachusetts. She is Board Certified in Internal Medicine. She then completed a fellowship in Hypertension, Endocrinology and Metabolism at Brigham and Women’s Hospital affiliated with Harvard Medical School. She is Board Certified in endocrinology and metabolism.

Dr. Ochoa-Maya, MD, CDE, established Advanced Health and Wellbeing, PC in 2010. She has been practicing endocrinology since 1999 and has been an MD since 1994. Dr. Ochoa-Maya is well-known in southern New Hampshire, Massachusetts, Florida and Colombia, and Puerto Rico.

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