Foods You Think Are Healthy That Are Bad For the Thyroid


A normal person with a healthy thyroid can eat a wide range of foods without having to worry about the implications on their thyroid function, the production of thyroid hormones, and the impact of those thyroid hormones on their metabolism.

However, a person with a slow thyroid needs to be vigilant, because certain foods can worsen their symptoms. It does of course depend on the cause of their thyroid problem. But since most people with a slow thyroid (hypothyroidism) have a condition known as Hashimoto’s thyroiditis, they need to be careful of what they eat.

What is Hashimoto’s thyroiditis (HT)?

Hashimoto’s thyroiditis is not an actual malfunction of the thyroid gland. It is an autoimmune disorder in which the immune system has been given incorrect signals and thinks your thyroid is a foreign body like a virus. The immune system therefore attacks the thyroid and kills off thyroid cells to the point where not enough thyroid hormone is being produced. In this case, you would need to do all you can to stop the attack, best accomplishing by following an autoimmune/anti-inflammatory diet or a thyroid-specific diet, and by avoiding foods known to interfere with thyroid function. In this way, whatever healthy thyroid tissue you have left can do the job.


Iodine is essential for healthy thyroid function but if there is too much in the diet and too like healthy thyroid tissue, things can swing the other way and your thyroid can become overactive.

Most people consume iodine in iodized (iodine added) table salt. So staying away from the salt shaker can help. So too can staying away from fish like cod and seafood like shrimp. A little is good as a lean protein used as a substitute for red meat, for example, but it should be high quality and wild-caught, not farmed. Portion control will always be key in any healthy diet.


A person with a slow thyroid will often develop an enlarged thyroid that gets so large it starts to look like a hump near their Adam’s apple. It is known as a goiter (GOYT-err). Goitrogens (GOYT-row-gens) affect the thyroid.

They can affect thyroid hormone production in a number of different ways. So even though we are supposed to get up to 11 servings of fruits and vegetables per day, around 5.5 cups, some of these healthy food might be off the menu, or eaten only in moderation, that is no more than 8 servings per week of any of the foods on this list.

Foods to watch out for include:

  • Bamboo shoots in stir fries
  • Cassava (a starchy vegetable eaten as a staple in many developing nations)
  • Corn
  • Flax seed
  • Lima Beans
  • Rutabaga (Swedish Turnip)
  • Sweet Potatoes

Unfortunately, the entire class of cruciferous vegetables is also cause for concern, including some familiar “super foods” that carry a lot of nutritional benefits, such as broccoli and kale. Other to put on the limited list include:

  • Arugula in salads
  • Bok choy in stir fries
  • Brussels sprouts
  • Cabbage
  • Cauliflower
  • Radishes
  • Watercress

Soy and soy products

Soy has become hugely popular as a low fat and seemingly healthier alternative to dairy products. Soy milk, cheese, ice cream, tofu and edamame (soy beans in their pods) are everywhere. Tofu is used as a healthy meat substitute.

However, soy is under scrutiny in reference to the amount of hormones it has it in, substances known as phytoestrogens, or plant-based hormones, and another phytochemical called flavonoids. There is some concern that soy suppresses thyroid hormone production and also prevents thyroid hormone absorption if someone is taking a synthetic supplement.


If you have ever had a parakeet, you’ve fed it millet. In many developing nations, it is a staple. In the West, it is used as a ‘whole grain’ that is supposed to be healthy for us, but studies have linked it to goiter and slow thyroid. Watch your bread and cereals.

Leave a Reply