Kale And Thyroid: Learn WHY Cruciferous Veg Can Suppress Your Thyroid

Introduction To Raw Cruciferous Vegetables And Thyroid: How Do Cruciferous Vegetables Affect The Thyroid

If you are taking important steps to support normal thyroid function you may want to avoid consuming large amounts of cruciferous vegetables, especially in their raw state. This is because they contain goitrogens, which can interfere with thyroid hormone production and potentially contribute to thyroid problems such as an underactive thyroid.

Cruciferous vegetables include broccoli, cabbage, kale, and Brussels sprouts. If you are concerned that removing too many of this type of leafy greens from your diet may result in iodine deficiency, an alternative source from sea vegetables such as seaweed can improve iodine intake.

One popular way that people like to consume cruciferous veggies, is by putting fresh kale in a daily green smoothie. Caution should be taken with this if you have a thyroid disorder.

What are Cruciferous Veggies?

Cruciferous vegetables are a group of vegetables that belong to the Cruciferae, or mustard family. They were originally named due to the shape of their flowers which have four equal sized petals in the shape of a crucifix.

The Most Common Cruciferous Vegetables

The most commonly consumed cruciferous vegetables include; kale, broccoli, cauliflower, Brussels sprouts, bok choy, broccolini, Chinese cabbage, kohlrabi, radish, mustard greens, collard greens, choy sum, horseradish, turnips, rocket, and wasabi.

Goitrogens In Foods Are Linked to Thyroid Dysfunction

Cruciferous vegetables are termed ‘goitrogens’ as they block proper thyroid function. 

The word ‘goitrogen’ is derived from the word ‘goitre’, a condition in which the thyroid gland becomes enlarged.

Goitrogenic foods may not necessarily cause a goitre, but they do have the potential to block proper thyroid activity by interfering with iodine uptake in the thyroid. In addition, their goitrogenic effect is more significant when iodine stores are low.

The Kale Green Smoothie Fad

For health-conscious people kale is a popular ingredient in green smoothies. The problem is, kale is a powerful thyroid suppressor, especially when consumed raw. Consuming kale on a regular basis can therefore trigger a range of hypothyroid symptoms.

The popularity of kale green smoothies has also led to a rise in the consumption of raw kale, which can have a particularly negative impact on people who have pre-existing thyroid conditions or susceptibility to them. In addition, many people are also unaware of the impact that consuming large amounts of kale can have on their health, as it’s a relatively new fad. Therefore, it’s important to be mindful of the amount and type of kale you are consuming. If you are concerned about your health, it’s best to consult a doctor before increasing your consumption of kale.

Kale is NOT a Superfood

The Environmental Working Group (EWG) have raised serious concerns regarding kale.

  • The level, and type of pesticide residues on kale has expanded significantly in recent years.
  • Conventional kale farming relies heavily on the use of several synthetic pesticides, including Dacthal. The Environmental Protection Agency (EPA) classified this pesticide as a possible cancer causing chemical back in 1995.
  • All pesticides are potential thyroid disrupting chemicals (TDCs).
  • Kale is now placed third on the EWGs Dirty Dozen™ 2019 annual ranking of the fruits and vegetables with the worst amount of pesticide residues.

Your Take Home Message? Mix It Up.

Once your thyroid hormones return to optimal levels a small amount of cooked, or lightly steamed cruciferous vegetables may be a healthy addition to your daily diet, especially when you also consume iodine rich foods to top up levels of this essential mineral.

There is one caveat…you should definitely avoid consuming kale in any way other than a small amount every now and then!


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