Do fermented cruciferous vegetables like sauerkraut and kimchi hurt the thyroid? Does fermenting reduce goitrogens? –asks Angel S.
You see, many recognize that cruciferous veggies such as broccoli, cauliflower, and cabbage contain goitrogens — which at the least increase the body’s need for iodine or at the worst, damage the thyroid.
Cooking is known to reduce goitrogens. But does fermenting reduce goitrogens, too?
And if not, should someone with thyroid disease be eating fermented vegetables at all?
That’s what we’re tackling on this week’s #AskWardee.
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The Question: Does Fermenting Reduce Goitrogens?
Angel S. asks:
For someone with thyroid issues, does fermenting goitrogenic foods change the harmful properties so that they don’t have a negative affect? I love the effects of fermented foods, but as spring and summer are coming, I want to be wise with the foods I ferment. If broccoli, kohlrabi, cauliflower, etc. are still harmful for my thyroid even after fermenting, I will just freeze them.
My Answer:
Angel, you have just opened a can of worms. 😉
Seriously.
There’s a lot of debate over this on the Internet, even among more “learned” folks such as doctors, nutritionists, and degreed researchers.
The best I’m going to be able to do is explain the issues to you and leave it to you to make an informed decision with confidence.
The Goitrogen Issue
So cruciferous vegetables have goitrogenic properties. What’s the big deal with that?
When raw crucifers are chewed, or when microwaved and steamed crucifers are digested by intestinal bacteria, they release substances called goitrogens that increase the need for iodine when consumed in small amounts and can damage the thyroid gland when consumed in large amounts.
These goitrogens also inhibit the transfer of iodine into mother’s milk.
If someone is deficient in iodine, has thyroid issues, or is breastfeeding, paying attention to the goitrogen issue seems to be a good idea.
Namely, reducing goitrogens (or excess goitrogens) in the diet.
How To Reduce Goitrogens
As far as I can tell, cooking is the only way to reduce goitrogens — steaming or boiling.
Steaming crucifers until they are fully cooked reduces the goitrogens to one-third the original value on average. Since release of the goitrogens from steamed crucifers depends on intestinal bacteria, however, the amount released varies from person to person.
Boiling crucifers for thirty minutes reliably destroys 90 percent of the goitrogens. (Source.)
Fermenting does NOT reduce goitrogens, according to Chris Masterjohn (source):
Fermentation does not neutralize the goitrogens in crucifers.
Uh-oh!
Wait, though… there’s good news.
Can Someone With Thyroid Disease Eat Goitrogens?
Chris Masterjohn goes on to say:
When foods like sauerkraut are consumed as condiments, however, the small amount of goitrogens within them is not harmful if one’s diet is adequate in iodine.
So, while goitrogens may be harmful in large quantities, as long as your diet is adequate in iodine, fermented cruciferous vegetables are fine to eat in condiment-sized portions.
Do you know your iodine levels, Angel? That’s important to know in order for you to make a decision about whether or not to eat sauerkraut and the like. (Because too much iodine can be a problem, too.)
You might also be happy to hear from others who have decided to consume small amounts of cruciferous veggies (raw, cooked, and fermented), even with thyroid issues:
- Katie, the Wellness Mama — who does not have an iodine deficiency and chooses to eat those greens in moderation
- Sarah from Nourished and Nurtured — who suggests adding iodine-rich seaweed to her homemade sauerkraut
- Mickey from Autoimmune Wellness — who eats AIP (Auto Immune Protocol) goitrogenic foods in moderate amounts
More helpful articles related to supporting thyroid function:
- 5 Supplements To Consider Taking This Year
- Top 5 Supplements For Hashimoto’s
- 7 Foods That Nourish Your Thyroid
- 7 Foods That Are Making Your Thyroid Sick
- Why & How To Use MCTs {reduce belly fat & improve thyroid function!}
- Top 5 Herbs For Thyroid Support
- Free Traditional Cooking Video Series
Do you have thyroid disease? Do you still eat crucifers? What do you think? Do fermented cruciferous vegetables hurt the thyroid?
Disclaimer: I am not a medical professional. You are responsible for your own health and for the use of any remedies, treatments, or medications you use at home.
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Great info – thank you, thank you, Wardeh! God bless!
Hi there, what about broccoli sprouts? Would they pose a problem? Are they high in goitrogens? They have a nutritional profile much higher than regular broccoli, would the goitrogens then by any chance be different? Thank you!! Selma
Hi Selma,
I checked around and she doesn’t find anyone saying broccoli sprouts DON’T have goitrogens. It seems most assume they do. She doesn’t know if this is correct or not, but she would lean toward assuming they do, and follow the same guidelines for whether or not to consume them.
Millie
Traditional Cooking School Support
We live in Ireland right near the sea and make kimchi using dillisk. We have three in our family with thyroid issues, but choose to eat in moderation fermented foods. It was good to hear about the addition of seaweed.
Thank you! I love making home made sauerkraut but now I will add some seaweed to it, to create more of a balance.
This is helpful!
Heidi
In my research of hypothyroidism I have found that gluten is much more damaging to the thyroid than cruciferous vegetables. Across the board, functional medicine doctors agree that gluten should be eliminated in a thyroid healthy diet (which is why I’m interested in sourdough. The amount of gluten is tiny in true sourdough.) I am including this quote about cruciferous vegetables from the book “Hashimoto’s Protocol.”
“Crucifers contain nutrients that help support the liver’s detoxification…There’s a myth that these vegetables aren’t good for people with Hashimoto’s, but this is not true. While cruciferous vegetables do contain glucosinolates, which may block iodine absorption into the thyroid, most patients with Hashimoto’s do not have an iodine deficiency, and the goitrogenic mechanism in these healthy vegetables should not be an issue. Plus, you’d have to eat a lot of them for the goitrogenic effect. Cruciferous vegetables are only truly goitrogenic in a raw state, so if you are concerned, you can lightly steam or ferment them.” (Wentz 120)
Works Cited
Wentz, Izabella. Hashimoto’s Protocol. 1st ed., 195 Broadway, New York, NY10007, HarperCollins, 28 Mar. 2017, p. 120.
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