Iodine levels in many parts of the world, including the USA have fallen more than 50 percent during the past 40 years. In our medical clinic we have found that over 50% of our patients are iodine deficient.

Could iodine deficiency be a factor in the epidemic of thyroid and breast disorders being observed in the USA today? These include autoimmune thyroid disorders such as Hashimoto’s disease, thyroid cancer and hypothyroidism, as well as fibrocystic breast disease and breast cancer.

Unfortunately, most U.S. doctors don’t regularly test for iodine deficiency.

Iodine deficiency should be suspected if you have –

  • Fatigue
  • Weight gain
  • Hair loss
  • Dry skin
  • Fluid retention and puffy limbs
  • Constipation
  • Thyroid nodules
  • Frequent infections
  • Lumpy tender breasts (fibrocystic breasts)

Chances are that most of us have an iodine deficiency because iodine is generally low in agriculture soils everywhere. Iodine can be found in seafood, but its levels vary depending upon the food eaten by the fish (a lot of seafood is farmed) and the amount of pollution in the oceans from which the seafood is harvested.

Thyroid hormone is made in the thyroid gland from iodine and tyrosine and selenium. Thyroid hormone is responsible for controlling the body’s metabolic rate, which is the rate at which calories are burned.  If thyroid hormone levels drop below normal, metabolism slows down, weight gain occurs and energy levels drop.  Conversely if thyroid hormone levels become too high, all body processes speed up into overdrive.


Why has the incidence of thyroid diseases, including thyroid cancer, increased so dramatically?

Researchers are looking at several factors-

  • Deficiencies of the minerals iodine and selenium
  • Exposure to radiation from medical procedures, mobile phones and computers etc
  • Working in certain industries – the manufacture of prefabricated wooden buildings, electric installations, working with fertilisers, oilseed and grain, working with toxic chemicals such as dry cleaning fluids, solvents, pesticides, glues, paints and plastics etc

There is only one piece of good news in all this – the survival rate of patients with thyroid cancer is over 90%.


Practical recommendations for keeping your thyroid and breast tissue healthy:

  • Ensure that you have a healthy diet, rich in nutrients required for healthy thyroid gland function.  These include iodine, selenium and vitamin D.
  • In the USA the majority of thyroid conditions are caused by an autoimmune disease; meaning the immune system is responsible for causing the thyroid to become either under active or over active.  Research has shown that gluten intolerance can be a triggering factor in autoimmune thyroid disease.  Gluten is a protein found in wheat, rye, oats and barley.  Many thyroid patients benefit from following a gluten free diet.
  • Ensure you have a healthy liver.  The liver is the main site of conversion of thyroid hormone (T4) into its more active form (T3).  A sluggish or fatty liver may impair the efficiency of this process.
  • Ensure your diet contains adequate levels of beneficial fatty acids, as found in oily fish (salmon, sardines, tuna, anchovies, mackerel), raw nuts and hemp and flax seeds, cold pressed vegetable and seed oils, avocadoes and organic coconut oil.  These fats can reduce inflammation in autoimmune thyroid disease, and improve the health of thyroid cells. You might need to take a supplement if you don’t get enough of these oils.
  • Minimize your exposure to the heavy metals mercury, cadmium and lead, as they can interfere with the manufacture of thyroid hormones.
  • Minimize your exposure to pesticides and insecticides, chemical anti-perspirants and deodorants and other toxic chemicals, as some have been linked with the formation of thyroid nodules, cancer and autoimmune thyroid disease.
  • Get your doctor to examine your thyroid gland for lumps, bumps or enlargement.
  • If you are fatigued, ask your doctor to do a blood test for thyroid function.

Essential nutrients for healthy thyroid and breast tissue


Iodine deficiency can be one cause of an under active thyroid gland (hypothyroidism).  Long term iodine deficiency can cause the thyroid gland to enlarge and form a swelling called a goiter.  Obtaining adequate iodine during pregnancy is vitally important for the healthy intellectual development of the infant.  Iodine deficiency in infanthood can lead to reduced IQ.

There are large areas of the world where soils are extremely deficient in iodine and one billion people are at risk of severe iodine deficiency. I have found that over 50% of my patients are deficient in iodine. The best way to test your body’s level of iodine is with a urine test which measures the concentration of iodine in your urine.

Iodine status of patient Urinary iodine concentration
Severe iodine deficiency Less than 20 mcg/Liter
Moderate iodine deficiency 20 to 49 mcg/Liter
Mild iodine deficiency 50 to 99 mcg/Liter
Not iodine deficient Over 100 mcg/Liter



Selenium is a mineral important for healthy thyroid function for several reasons.  Selenium is required for the production, activation and metabolism of thyroid hormone.  A healthy thyroid gland contains more selenium per gram than any other tissue in the body.

Selenium is required by the enzyme that converts T4 thyroid hormone into its active form, T3.  If you are deficient in selenium you will not be able to manufacture sufficient T3 and you may experience the symptoms of an under active thyroid gland, such as fatigue, easy weight gain, dry skin, dry hair, constipation, rapid ageing, depression and scalp hair loss.

A selenium deficiency can contribute to the development of autoimmune thyroid disease, such as Hashimoto’s disease, Graves’ disease and post partum thyroiditis.  Selenium has an anti inflammatory effect and can inhibit the production of antibodies against the thyroid gland in autoimmune thyroid disease.

Obtaining adequate selenium from diet alone is very difficult because very few foods are a rich source of selenium.  Brazil nuts, crab and salmon provide some selenium, however using a selenium supplement will ensure you receive optimal levels of this vital mineral.

Recommended supplemental dosage of selenium is: 200mcg daily


Vitamin D

Vitamin D helps to regulate cellular replication in a very important way. Specifically vitamin D helps cells to differentiate (become specialised), and inhibits cells from proliferating, or growing in an out of control way.  It is thought that these are the reasons why vitamin D deficiency increases the risk of various types of cancer.

Vitamin D deficiency increases the risk of autoimmune disease and cancer.  Surprisingly vitamin D deficiency is a common problem even in sunny countries.  A study conducted in 2001 detected mild or moderate vitamin D deficiency in more than one in three women during summer, and one in two in winter.  Those most at risk of deficiency include people with dark skin, women who practice veiling, people taking certain medications (such as anti-epileptic drugs), and people who spend most of their time indoors.  Sunscreen inhibits the manufacture of vitamin D.

Vitamin D deficiency is more common in women than men.  Inadequate levels of vitamin D may increase the risk of autoimmune thyroid disease and many types of cancer.  Prolonged sun exposure can be hazardous and inconvenient, and vitamin D is found in very few foods; therefore supplementing with vitamin D may be the best option.

Recommended supplemental dosage is: 1000 to 5000 IU daily

Thyroid Health capsules are available combining vitamin D, selenium and iodine all in one.


The above statements have not been evaluated by the FDA and are not intended to diagnose, treat or cure any disease.


Vitamin D Council
NEJM Volume 339:1156-1158 October 15, 1998 number 16
Pasco JA, Henry MJ, Nicholson GC, et al. Vitamin D status of women in the Geelong Osteoporosis Study: association with diet and casual exposure to sunlight. Med J Aust 2001; 175: 401-405.
Linus Pauling Institute Oregon State University