Green is the new black – when it comes to food.
Green smoothies have been trending for several years now in the kitchens of clean eaters and in hipster and health cafes. With ingredients like kale, celery, mint, cucumber, spinach leaves and avocado, they offer a super-nutrient hit.
But are cruciferous vegetables like kale and collard greens a good choice for women who are seeking hormone balancing diets? And most importantly, are they the right choice for your body?
Or, could that morning smoothie or plate of bok choy with broccoli be upsetting your thyroid function and causing symptoms of hormone imbalance? And could it be upsetting your thyroid gland?
Your thyroid is a butterfly-shaped gland located in your neck below your Adam’s apple. It works like the gas pedal for your metabolism and also regulates your weight, energy, gastrointestinal health, nervous system, and hormone balance. It produces two important hormones:
- T4 (Thyroxine): This is produced by your thyroid gland when it binds with iodine. It is largely an inactive hormone but gets converted to the more active T3.
- T3 (Triiodothyronine): This is the Queen of thyroid hormones. It’s the more active thyroid hormone and is produced from T4 by a metabolic conversion that happens in your gut and liver.
Goitrogenic Foods and Cruciferous Vegetables
Women who are balancing hormones through diet often eat these. They include:
- Arugula (rocket)
- Bok choy
- Broccoli and broccoli sprouts
- Brussels sprouts
- Collard greens
- Mustard greens
Does Kale Lower Thyroid Hormones?
There are very few human studies like this one that measures how the thyroid is affected by crucifers.
Of the available evidence, there is very little to suggest that foods like broccoli upset natural hormone balance and thyroid health.
In this study involving the University of California, researchers concluded that though collard greens, Brussels sprouts, and some Russian kale (Brassica napus) contain enough goitrogenic compounds to potentially decrease iodine uptake, that’s not true for all cruciferous vegetables. The researchers found that turnip tops, broccoli, broccoli rabe, and kale contain less than 10 μmol of goitrogenic chemicals per serving of 100g, concluding that those foods can be considered minimal risk.
In another small study, participants were given 150g of Brussel’s sprouts daily for 4 weeks. Even though these sprouts contained a super high 220 mg per 100 g. of sulfurous chemicals called glucosinolates, they did not affect thyroid function. Measurement of thyrotrophic hormone, thyroxine and tri-iodothyronine in the study subjects was unchanged. The researchers believe this was because the Brussels sprouts were cooked and produced myrosinase, an enzyme that helps to deactivate the glucosinolate levels.
There is no evidence that cruciferous vegetables slow down or “kill the thyroid.” Unfortunately, there are many health bloggers who don’t fact-check and have cut and re-pasted incorrect statements claiming that “all leafy greens are bad for your thyroid,” when that’s not the case.
In fact, cruciferous vegetables are super nutritionally dense foods so they are good for women with thyroid issues who are often depleted in micronutrients.
Why Leafy Greens Are Great for Your Thyroid
While it’s possible that large amounts of raw cruciferous foods can somewhat inhibit the thyroid gland’s ability to take up iodine to produce the T4 hormone, there’s a bigger picture. If you have a condition such as Hashimoto’s, the primary focus should be restoring your digestive tract and detoxifying the body – as they are usually the original triggers for thyroid conditions. Avoiding cruciferous vegetables completely does not help improve those health issues.
Leafy greens are richer in vitamins and minerals than any other of their distant veggie cousins. As most Americans are undernourished, cutting out these foods then makes us rely further on supplements – which is not the way we should be living and healing.
Since 90% of thyroid problems occur for autoimmune reasons, I believe it’s more important to restore the health of your immune system through your gut, than obsess about cutting out all crucifers.
I have found that for most women who experience hormone imbalance symptoms, the benefits of cruciferous vegetables outweigh the very small risks. The color and sharp, often bitter flavor of cruciferous veggies confer an impressive range of health benefits that largely come from their levels of glucosinolates, which are powerful plant chemical compounds which come in around 120 different varieties.
Facts About Cruciferous Vegetables
1. Are Potent Anti-Inflammatory Agents
When you chew and digest your leafy greens, glucosinolates break down into biologically active nutrients called isothiocyanates, which have anti-inflammatory actions. The two most powerful varieties are called sulforaphane and indole-3-carbinol. These protect you against disease. They help switch on antioxidant genes and enzymes in specific immune cells and may neutralize cancerous cells so that they don’t grow and multiply.
2. Support Liver Function and Thyroid Hormone Conversion
Studies also show that these glucosinolates support your liver function by activating phase 2 detoxification. A well functioning liver is critical in helping the conversion of T4 to T3 and that is particularly important for thyroid patients. That conversion in part happens in the liver via a process called deiodination.
3. Help Combat Estrogen Dominance (The leading cause of thyroid nodules and thyroid cancer!)
Most pre-menopausal women I work with have some level of estrogen dominance, which is barely surprising, given the estrogenic cocktail of skincare products, cleaners, packaging and food we are exposed to in our modern world. Leafy greens can reduce the load. Goitrogenic vegetables are rich in a substance called DIM (diindolylmethane) which is key in liver detoxification as well as the elimination of mutated estrogen metabolites. This, in turn, helps women maintain a healthy balance of estrogen, progesterone and thyroid hormone, which is critical if you want to naturally balance hormones.
As a result, you can better filter estrogen metabolites from your body, suggests this research from The Institute for Hormone Research.
In this study, after indole-3-carbinols from crucifers were given to people in supplement form, urine samples were taken. The results showed that increased concentrations of estrogen metabolites were filtered from the body, including greater removal of estradiol, estrone, estriol and 16-alpha-hydroxytestrone. As these estrogen byproducts can be harmful if they keep circulating at high levels, women who eat their leafy greens may reduce estrogen dominance. Stabilizing estrogen can also help stabilize many other hormones. I offer other tips on how to do this here in this article.
If you’re experiencing symptoms estrogen dominance, you can find out more by taking my Free Estrogen Quiz. The truth is estrogen dominance symptoms occur to 75% of women, but a whopping 90% of them don’t even realize they have it. I recommend taking this quiz to find out for yourself here.
4. Have Protective Benefits Against Cancer
Leafy greens not only help prevent cancer and block the new blood vessels that cancerous tumors set up to feed on, they can also help to improve odds of survival for women with breast cancer.
For other natural ways to combat breast cancer, check out this recent post.
5. Benefit Good Bacteria
The rich soluble dietary fibers in crucifers include hemicellulose and pectin. These have been shown in studies to help stabilize blood glucose levels and lower cholesterol. Most importantly, they provide food for different kinds of healthy bacteria.
These bacteria can help to increase your levels of serotonin (which helps boosts your mood) and melatonin (helps aid in sleep) and lower your levels of insulin (protects against weight gain and Diabetes Type 2). Resistant starch can also boost your levels of good bacteria. Learn more about resistant starch foods and how they benefit thyroid health here.
There are two effective ways to reduce the goitrogenic content of foods like broccoli, kale, silverbeet, and cauliflower:
1. Cook Your Crucifers
As I have explained, cruciferous foods are goitrogenic when raw. But once cooked, the glucosinolates they contain are deactivated, losing up to 80% of their goitrogenic chemicals, so that they no longer block the uptake of iodine. Research from the University of Illinois shows that when lightly cooked but still al dente (after being steamed for three to four minutes), the short exposure to heat warms up broccoli enough to destroy a protein it contains that holds on to sulfur. At the same time, lightly cooking broccoli activates (but does not destroy) the myrosinase enzyme that helps release the broccoli sulfurs. This ensures the sulfurs are more bio-available to be absorbed when eaten, while the goitrogenic effects are lessened.
Boiling can also be very effective because it allows the glucosinolates to leach into the water.
Do you find yourself bored by your usual recipes containing crucifers? Add this delicious Cauliflower and Coconut Red Lentil Dal dish to your cooking repertoire.
2. Ferment Your Crucifers
Fermented vegetables are powerful hormone balancing foods because they contain good bacteria to boost your gut health. And, though fermented crucifers like sauerkraut are raw, you don’t need to cut them out. It’s okay to have one or two small tablespoon servings of fermented foods like broccoli, cabbage, kale or cauliflower a day.
Mix up your ferments so they are not all filled with cruciferous vegetables and don’t forget about fermented foods like miso, dill pickles, coconut water kefir and coconut yoghurt. For a tasty fermented drink, try my recipe Kvass, a Probiotic Beetroot Tonic.
You can also consider cooking crucifers then mixing them in with raw vegetables like carrot and beetroot, for fermentation.
What About Green Smoothies?
Some experts who specialize in female hormone imbalance believe that women with thyroid problems can eat goitrogenic foods with no problem.
Others believe that cruciferous vegetables like kale, compromise or worsen thyroid function. They recommend that women with Hashimoto’s, Graves’ disease or suspected thyroid problems, avoid eating crucifers altogether. Let me share with you that in my experience, having worked over the years with so many Hashimoto’s patients, I have not seen anyone heal by just avoiding cruciferous vegetables.
Therefore, my recommendation is:
- Eat cooked cruciferous vegetables in abundance as they pose little risk to women with thyroid conditions and help your liver and gut, which are the key organs you need to support.
- Reduce intake of raw crucifers if you have a low thyroid function (don’t toss raw kale in your green smoothie every day). If you enjoy raw crucifers and their health benefits, limit your intake to 2 or 3 servings per week. Try this Creamy Asparagus Broccoli Salad for a quick and delicious way to toss together some greens.Or serve this super simple Massaged Kale Salad with some protein for dinner.
- Minimize oxalates: These are found in foods like kale and they can deposit themselves in the thyroid gland and cause damage. In turn, the thyroid does not produce enough of the T4 hormone. People suffering from poor gut health are particularly susceptible. Oxalates also bind to minerals like calcium, so they’re not easily absorbed.
- Eat Iodine Rich Foods: If you don’t have an overactive thyroid but you are worried leafy greens could reduce your intake of iodine, eating foods rich in iodine may help counter possible impacts of the goitrogens. Good choices include seaweed, yoghurt and eggs (if they are not reactive for you), fish and shellfish, prunes and of course, Celtic or Himalayan pink salt, which is rich in iodine and minerals.
- Minimize or avoid intake of soy: Soy (milk, tofu, tempeh, soybean oil) is not only goitrogenic, it also contains phytates, which can bind up your minerals like zinc and magnesium, so you don’t absorb them. For this reason I suggest that you shift from soy to coconut milk in your morning bowl of millet or daily turmeric latte. If you’d like to try making y our own coconut milk, I show you how in this step-by-step quick video cooking presentation. I think you’ll be surprised at just how easy it is to make it yourself.
A Word Of Caution
Having said that crucifers should not be banned from a hormone balancing diet, I want to add a few qualifying comments:
- If you have hypothyroidism due to a deficiency in iodine, goitrogenic foods could lower your iodine further. So eat them with caution.
- If you suspect you might have thyroid issues, you may still be making some of your own thyroid hormones in low amounts and goitrogenic foods could deplete that production further.
- I know many women with thyroid problems who have had great health results when they limit their intake of foods high in goitrogens.
- I have also met many newly converted vegans and vegetarians who developed thyroid symptoms months after replacing meat protein with lots of soy foods, and goitrogenic foods like kale.
The Bottom Line and My Final Thoughts
The key to treating thyroid conditions (since most of them are autoimmune conditions triggered by troubled digestive health), is to restore your digestive health. This article gives more information on how digestion impacts hormones and weight gain.
Estrogen dominance is the leading cause of thyroid nodules and thyroid cancer – the fastest growing cancer in the United States. Cruciferous vegetables help with estrogen detoxification and prevent the development of nodules and cancers.
If you’re struggling with estrogen dominance and would like to learn more about how to balance your hormones, I invite you to join my Estrogen Reset program.
This is a great resource if you are suffering from:
- Breast lumps and fibrocystic breasts Hot Flashes
- Amenorrhea (lack of periods)
- Irregular periods Dysmenorrhea & PMS
- Menorrhagia (heavy periods)
- Thyroid nodules
- Hip fat and cellulite
- Breast Cancer (ER+)
- High testosterone (PCOS)
You can enroll in the Estrogen Reset program here.
Thank you so much for this article. I never believed in the demonisation of cruciferous veggies. I’ve been working on healing my gut and Hashimoto’s and it has been a rocky journey. The part about oxalates is new to me. Would this mean it’s better to eat spinach for example cooked? Which other oxalates rich food are concerned?
Yes you should be eating your greens but cooked only. This changes the enzymes and removes the negative affect that is expected from the oxalates.
Thank you for your supportive comments.
So i am following Dr Christiansen’s Metabolic Reset Diet which is supposed to heal your liver in 28 days. He recommends a lot of cruciferous veggies cooked and uncooked. I have Hashimoto’s and usually cook them because of all i have read. I know that Magdalena and he are colleagues but he also promotes soy and cold pressed canola oil. It’s hard to know who to believe. I know estrogen dominance is a huge factor for me and i try to avoid phytoestrogens and xenoestrogens as much as possible. I also know my cortisol levels are high. I’m doing well physically except i have severe insomnia for the last 8 months or so and nothing seems to help, even prescription meds. Any ideas???
Yes, they are colleagues that is true. However, we cannot really comment on other programs, only Magdalena’s. Since, she herself had hashimoto’s and learned how to give her body the proper nutrients to put it into remission, I decided to follow her guidelines (as I have it as well). She does say to please tune into your own body and see how it is responding when you try something new. Have you had hormone testing done or had an appointment with a functional medicine practitioner?
~Deanna HB Team
I am severely hypothyroid since 1955. The things I am doing to sleep through the night is: 1. Turn off all electronic devices 1 hour before going to bed. Turn one low light on for reading and read something which helps me focus on the positives in my life along with making a gratitude list. 2. I read several months ago that Tart Cherry juice contains Serotonin which is a precursor to melatonin (the main hormone involved in sleep). Right before going to bed I drink an 8 ounce glass of Tart Cherry Juice. This helps me sleep.
These are great ways to promote sleep, and it’s wonderful to hear they’ve been helpful to you, Sharron.
– HB Team
Cooking the cruciferous vegetables helps but you may need more testing to determine you sensitivity to oxalates. Here is a link to a video Magdalena did regarding oxalates that you might find helpful. https://hormonesbalance.com/qawithmagdalena/#vid28
Hi 😊. Can you update your condition? Was you able to cure your hashimoto? Thanks
Twice in the last 20 years, I have gone from Hashimotos to Graves disease. Right now I have Hyperthyroidism (Graves). I have stopped putting kale in my smoothies. Is Swiss and Rainbow Chard, and spinach ok? I have stopped eating raw cruciferous vegetables.
I have severe TMJ and Diverticulosis, and it is difficult to chew many foods. What fruits and nuts are ok?
Hi Wendy Olsen,
You have had to deal with some challenges. Magdalena suggests tuning into your body and seeing what it says when you eat different foods. So, you can see how you do with spinach and document your findings. Swiss chard is a cruciferous vegetable, that would be good if cooked and you can tolerate it well. If someone has diverticulitis, nuts can sometimes pose a problem. Here is a good workshop for you to look into and learn more about what you can do with food to help heal. http://www.cookingforbalance.com
Thank you for sharing Wendy that is a challenging situation. According to Magdalena’s article about cruciferous veg there is no evidence that cruciferous vegetables slow down or “kill the thyroid.” Unfortunately, there are many health bloggers who don’t fact-check and have cut and re-pasted incorrect statements claiming that “all leafy greens are bad for your thyroid,” when that’s not the case.
In fact, cruciferous vegetables are super nutritionally dense foods so they are good for women with thyroid issues who are often depleted in micronutrients. You could grind or blend nuts and those diverticulosis are encouraged to eat a high fiber diet.
Hi, a quick question for Dr Wentz about not prescribing iodine for your patients. I have endured Hashimoto’s for over five years and have finally found an informed naturapath who prescribes a strict ketogenic diet along with kefir and iodine and substituted with the correct adrenal and thyroid supplements. Within two months I’m totally off my prescriptive meds of thyroxine and liothyronine which were keeping me alive but keeping me ill. Really I just wanted to share that the iodine was an important ingredient on my healing journey. I found ‘The Iodine Crisis’ book very informative.
Hi Wendy, that is interesting and thank you for sharing. We will pass on the information.
Hello Ms. Wendy Hayhurst.
Thank you for sharing your post, it was really reassuring to other such as myself, who is going through the same journey.
If I may kindly ask, would it be possible for you to provide with me your naturapath information?
I would like to graciously thank you in advance for your valuable assistance..
Hi Wendy….could u please please tell us more…..thank u….
Suffering in NM
Please share the naturopath’s name. I been diagnosed with hashimoto after a 30 day green juice fas.
Hi Sonia. Here is a great tool to find a functional medicine practitioner in your area: https://www.ifm.org/find-a-practitioner/
You can also contact our customer support team at any time with questions. We’re here to help! Please send a message to [email protected].
– HB Team
I’m confused? So we can eat raw vegetables or cooked?? I have to wait for 2 MONTHs before seeing a doctor on thyroid. My thyroid blood test levels are high and my regular doctor said I just have thyroiditis. What to I eat to lower my levels?? Veg, salmon, Brazil nuts?? Please help while I wait.
I been suffering from Graves Disease for 23yrs. I’m tired of the meds I like a natural route to help me heal or balance my thyroid I already had radiation treatment but a couple of yrs later I became over active again. I need help.
Here is Magdalena’s book http://a.co/dq0DSD1. It shares on how to care for thyroid imbalance and addresses autoimmune boosting (which related to Graves and Hashimoto’s). If you have more questions, please contact the support team at [email protected]. ~Deanna HB Team
The last two paragraphs pretty well tell you what you need to know.
Thank you Randy 🙂 ~Deanna HB Team
Would the same apply for green powder supplements which consist more of grass-based greens, like wheat grass, barley grass, and various leaves (nettle, dandelion,etc)?
We cannot speak on all green powder supplements but Magdalena does encourage real food (fresh) first and foremost.
~Deanna HB Team
I don’t have any issues with the different foods raw or cooked except broccoli sprouts. Every time I eat them I become dehydrated and my upper lip chaps. But I know its so good for you and I have even muscled tested that my body wants it, so weird right????
That is an interesting reaction to note. However, it may good to take a break from those and found other sprouts to incorporate into your meals. ~Deanna HB Team
The article says there are two ways to deactivate goitrogen, yet then only supports one: cooking. Fermentation, which is suggested would be a second option, then goes on to explain that it produces good bacteria that is healthy for the gut yet gives no evidence that it actually deactivates goitrogen. In fact, the wording used, make it sound as if goitrogen remains completely unaffected by fermentation. I suggest reviewing these sections so that the article is factual and not misleading.
Hi Andreas, thank you for your feedback. The key is to restore digestive health and fermented foods are then beneficial for some. You might find this article helpful: https://hormonesbalance.com/articles/digestion-impacts-hormone-imbalance-weight-gain/ ~ Jeanne HB Team
Andrea’s comment reflects the topic of goitrogens, not the benefits of fermentation. Does fermentation destroy goitrogens, yes or no?
As stated in the article, there are two effective ways to reduce the goitrogenic content of foods like broccoli, kale, silverbeet, and cauliflower, and that is through cooking and fermentation.
If you are unsure of wether or not to include these in your diet, it may be best for you to speak with a functional medicine doctor who can assist you on a more individual basis.
I want to clarify that contrary to what is written here, Celtic or Himalayan pink salt, are rich in sodium (of course) and contain trace minerals, but NOT iodine. Iodine is found is fortified table salt, in the foods you mentioned and as a supplement.
Celtic sea salt does have trace iodine but not Himalyan.
Both sea salts naturally contain small amounts of iodine. -Taylor, HB Team
Is it safe to take sulfporaphane tablets if you have hypothyroidism? Thanks
Hi Paul, the primary focus should be restoring your digestive tract and detoxifying the body. If you have a reaction to sulfporaphane, it could mean phase 1 or phase 2 liver detoxification is not working properly. Taking sulforaphane along with some medications that are changed by the liver might increase the effects and side effects of some medications. We suggest you speak with your healthcare provider first, if you take any medications that are changed by the liver.
~ Jeanne HB Team
I am glad I found this article right after I posted on your Facebook page about a podcast from Dr. Paul Saladino in which he talks about studies proving that broccoli and others are not good. He does say that they are worst for people with a thyroid issue already but for everyone in general as well because of a compound we make in our gut that re-actives the goitrogens. Can you tell me about this? Thanks
Take a peak at the section of the article called “A Word of Caution”. If you have any further questions, please feel free to reach out to [email protected].
[…] Renowned thyroid experts such as Dr. Izabella Wentz and Dr. Kharrazian are on the same page: Cruciferous vegetables WILL NOT destroy your thyroid and they DO recommend eating them. I have written more about this topic in this article. […]
My doctor recommended I start taking Indole 3 Carbinol for my HPV and cervical Dysplasia to prevent cervical cancer. I was just diagnosed with hypothyroidism and read that cruciferous vegetables can make thyroid problems worse. Now I don’t know if I should still take the Indole 3 Carbinol. Is it still ok to take the I3C?
Hi Jamie. Our stance is that for most women with thyroid issues, cruciferous vegetables are super nutritionally dense foods that can support estrogen detoxification, restore digestive health, and provide essential micronutrients.
We cannot provide medical advice, so this is a great question to discuss with your doctor.
– HB Team
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