Can kale cause hypothyroidism? Here’s what you should know

Woman holding a stack of kale

At the top of the list of the many health benefits of kale, and other cruciferous vegetables like broccoli and cabbage is their anti-inflammatory and anticarcinogenic properties. These, however, might be overlooked sometimes due to their reported thyroid-related risks.

So, is it true? Is it possible that kale–that trendy, acclaimed “superfood,” chock full of vitamins, fiber, and calcium–could have negative health effects, particularly on your thyroid gland?

With thyroid disease affecting 20 million people in the U.S., as strange as it may sound, there is a theory out there that says kale, and cruciferous veggies, when eaten in large doses, could be a cause of hypothyroidism.

But before you toss your daily kale smoothie into the garbage, read on to learn more and hear what our experts have to say about the link between eating kale and your thyroid health.

How can kale affect your thyroid?

Kale is a cruciferous vegetable, and so are some of your other favorite (or not so favorite) plant foods including:

  • Arugula
  • Cabbage
  • Broccoli
  • Cauliflower
  • Watercress
  • Turnips
  • Brussel sprouts
  • Collard greens

Cruciferous vegetables are also what’s known as goitrogenic foods.  Goitrogenic foods contain substances called goitrin and thiocyanates which, in very high amounts, can interfere with the body’s ability to absorb the nutrient iodine.  

Without proper iodine nutrition, the thyroid gland is unable produce the right amount of thyroid hormone.

This could potentially result in an underactive thyroid, or hypothyroidism, according to endocrineweb.com.

What experts say

Joseph Mosquera, MD is saludmóvil’s founder and chief medical officer.  

Dr. Mosquera is also one of the country’s leading experts in integrative medicine, a discipline which adheres to the theory that food is medicine.  We asked him about the confusion over kale causing hypothyroidism, and here’s his take:

“Although excessive and obsessive ingestion of cruciferous veggies like kale may contribute [to hypothyroidism], the science on this is scanty, and the benefits clearly outweigh the risks when eating these in moderation.”

So, how much kale is safe to eat every day? Continue reading! 

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Naomi Pestana
Naomi Pestana

Naomi Pestana is an Emmy award-winning journalist with over 15 years in the television news industry. She is passionate about her family, Montessori education, and living green, organically, and toxic-free.