Naturally occurring compounds called ‘goitrogens’ can disrupt normal thyroid function and hormone balance by blocking how the thyroid absorbs and uses iodine. 

When an iodine deficiency occurs in the thyroid, it results in an enlarged thyroid gland (aka goiter).

Some foods contain goitrogens and can interfere with the production and balance of thyroid hormones. 

Foods that contain goitrogens include: 

  • Cassava (also known as manioc or yuca)

  • Lima beans

  • Sweet potatoes

  • Cruciferous vegetables, like cabbage, kale, cauliflower, broccoli, brussels sprouts bok choy, and turnips

  • Soybeans and soy products

  • Millet

Vegetables offer a lot of health benefits in the form of vitamins, minerals, antioxidants, and fibre.  There’s no real need to avoid these goitrogen-containing foods unless you’ve been diagnosed with an under-active thyroid and/or iodine deficiency and prefer to be cautious.

But even then, goitrogens are usually only a problem if eaten in excess – and you’d have to eat A LOT of those foods to take in enough goitrogens to effect your thyroid function and create a goiter.

Goitrogens are also inactivated by heat, so simply cooking the above foods makes them pretty harmless to your thyroid. 

Cooking cruciferous vegetables, like broccoli and cauliflower, is particularly beneficial for most people’s digestion as well. It helps reduce the amount of bloating and gas you may experience when you eat these foods. 

Tips to maintain good thyroid health: 

● Include good sources of iodine in your diet, such as naturally mineralised Himalayan pink salt or Celtic sea salt, fish, and seaweed.

● Eating a varied diet guarantees you won’t take in too many goitrogens. Plus, eating a variety of foods ensures you get a variety of nutrients!

● Cook your sweet potatoes and cruciferous vegetables to reduce their goitrogen content.

If you’re concerned about the health of your thyroid or are currently managing an over- or underactive thyroid, be sure to ask your healthcare professional to regularly test your thyroid levels and consider speaking with a qualified nutrition professional regarding your diet.


Hyperthyroidism - Good & Bad

Food contains minerals which affect the thyroid.  As the hyperthyroidism is corrected, the foods on the avoid list will be tolerated better.
Also, a list of the foods that bother you can be a great help in determining what nutrient deficiencies you have and need to correct.

Beans                   Crab             Lobster             Nuts            Shrimp  

Dairy - Excessive calcium to magnesium ratio increases rapid heart rate and tremors.
Garlic - Excessive zinc depletes copper.
Iodine containing foods -  Until copper is built up.
Licorice -  May be a toxic to the adrenals and thereby interfere with the sodium/potassium pump.  
Tinned foods, especially fish like tuna - bisphenol-A (an estrogen mimic) from varnish inside the can, increases heavy metal accumulation like mercury and cadmium which accumulate in fish and other sea foods.
Fruits, at least for a while - depletes copper
High carbohydrate diet- causes thyroid hormone increase to burn up excess calories.
Too many green leafy vegetables - high in cadmium
Rice - high in cadmium
Canola oil - interferes with normal thyroid functioning


Zinc--depletes copper so you need to limit zinc until copper is built up.
Iron--depletes copper so you need to limit it at the beginning, but it's essential for making hemoglobin so try to slowly introduce it after a few weeks of copper supplementation.
Manganese--Assists iron metabolism and a known copper antagonist. Introduce again if you go hypo.
Grape seed extract
Proanthrocyanadins--from grape seed or pine bark.
Ephedra--found in weight loss and energy supplements.
Tyrosine--the amino acid that is the basis of thyroxine.
Arginine --stimulates growth hormone production which seems to stimulate thyroid hormone production.
Ornithine--same as Arginine
Licorice--depletes MAO which breaks down thyroid hormones after use.
Colostrum--seems to significantly increase hyper symptoms and may induce a thyroid storm.