Does Your Thyroid Want a Green Smoothie?

In April 2013, I had a wisdom tooth removed. It is not pleasant to do this in middle age.

My dentist thought it would be no big deal. I knew she was lying. I didn’t realize how badly she was lying.

Post-surgery, I stumbled around in a Percocet haze. I don’t understand how people become addicted to Percocet. Let’s just say, if you ever want to go to the bathroom again, this is not the painkiller for you.

When I was awake, I spent a lot of time peering into my mouth with a flashlight while using a 10x magnifying mirror to check the progress of the healing. (J enjoyed mocking me for this. He felt it was excessive to check every 15 minutes. I can’t imagine why.)

The doctor told me to eat soft foods. Since I’m allergic to dairy products, ice cream was out. Applesauce got old really, really quickly. I decided this was the perfect excuse to treat myself; I would buy one of those fancy Vitamixes and make green smoothies. I envisioned myself emerging from my dental nightmare 20 pounds slimmer, glowing from all the green smoothie goodness.

What could be healthier than a green smoothie? People claim they’ve cured various diseases with green smoothies. Medical forums have green-smoothie threads. Fancy spas serve green smoothies, and celebrities are photographed daintily sipping them. Since I belong to a food co-op where I get cheap organic vegetables and I now owned a Vitamix, I figured that I, too, could hop on the smoothie bandwagon.

But I forgot about goitrogenic vegetables. It can be problematic to eat very large quantities of these vegetables in raw form if you have hypothyroidism. They can block the body’s ability to transform iodine into the thyroid hormones T4 and T3, and they can interfere with the conversion of T4 to T3 (T3 is the active form of thyroid hormone). The enzymes that make the vegetables goitrogenic are partially destroyed by heating, so it’s safest to eat goitrogenic vegetables cooked.

One of the vegetables popular with the green smoothie crowd is kale. It does give smoothies a lovely color. Since I was in a Percocet haze, I kind of forgot that kale was a goitrogenic vegetable. I made a LOT of raw kale smoothies. I used hemp powder for the protein source. (I’m allergic to whey.) The hemp powder had 12 grams of fiber. I had never used protein powder with that much fiber before, but I had heard fiber was really important for weight loss.

Oops. Between the fiber in the hemp powder and the kale (possibly more the fiber), my TSH went up to 7.85. At the time I was was taking Synthroid and compounded T3. So much for the smoothie weight loss miracle.

Fiber is healthy, right? Of course it is. It just sucks up your thyroid medication. Unless you take it 2–3 hours away from the meds. You don’t think of things like this when you’re zonked on Percocet.

Post dental nightmare, I still make smoothies, but I stopped using the hemp protein powder with fiber. Regarding goitrogenic vegetables, I picked up this tip from a food blog: If you want to make smoothies with a lot goitrogenic vegetables, you can always lightly steam the vegetables, puree them, and freeze the liquid in ice cube trays.

Update, November 2014: When I wrote this post back in February of 2014, I had no idea how controversial the whole goitrogen topic was. For example, Sarah Ballantyne, The Paleo Mom, says that goitrogenic foods are not an issue unless there is an iodine or selenium deficiency, and small amounts of thiocyanates (chemicals found in goitrogenic foods) can actually support the creation of T4, the storage form of thyroid hormone. According to thyroid practitioners such as Dr. Datis Kharrazian (whose books I haven’t read yet), gluten is a far more significant problem for patients with Hashimoto’s thyroiditis, because gluten can stimulate the immune attack on the thyroid. (I have been gluten-free for a while now; gluten is also bad for Lyme disease.) On the other hand, thyroid patient advocate Mary Shomon advises cooking goitrogenic vegetables. An article in Thyroid Nation also advises not consuming large amounts of raw goitrogenic veggies (for example, juices made from raw goitrogenic veggies like cabbage can contain very concentrated amounts of goitrogenic chemicals). What I got from all this reading was to have iodine and mineral levels checked, don’t eat a ridiculous amount of cruciferous vegetables in raw form, and don’t worry about avoiding all goitrogenic foods because many of them are very healthy (processed soy, not so much). Anyway, I still think it’s good to know which foods are goitrogenic, so here’s a partial list (the cruciferous vegetables are the most strongly goitrogenic).

Some Goitrogenic Foods:

African cassava
babassu (a palm-tree coconut fruit found in Brazil and Africa)
bamboo shoots
bok choy
brussels sprouts
canola (rapeseed)
Chinese broccoli
choy sum
flax seed
kai-lan (Chinese broccoli)
mustard greens
pine nuts
red radish
soy and soy products (less goitrogenic if fermented)
sweet potatoes
(Sources: Mary Shomon, Thyroid and

And here are two smoothies without goitrogens:

Green Smoothie

Base: mixed lettuces or romaine lettuce with plain water and a little coconut water

Mix with any or all of the following:
cucumber, 1
piece of raw zucchini
dandelion greens
apple (I like the green ones)
baby carrots or pieces of regular carrot
small amount (1-2 tsp.) apple cider vinegar
liquid stevia
1-2 tsp. coconut oil

For a simpler smoothie, I like combining celery, cucumber, apple, and romaine lettuce.

The liquid stevia is important, because it gets rid of bitterness in vegetables and gives the smoothie a generic “green” flavor. The apple cider vinegar adds a light, citrus-like taste, and there’s evidence it helps with digestion. I like Braggs.

You can throw almost any vegetable in there if you use liquid stevia. I like SweetLeaf clear liquid stevia for smoothies. Powdered stevia didn’t work for me.

Disclaimer: I’m not a food blogger, so if this smoothie sounds absolutely repulsive to you, maybe:

Sugar-Free, Dairy-Free, Soy-Free (but not Rice-Free)  Breakfast Smoothie

2 cups unsweetened rice milk
1/2-3/4 cup blueberries
stevia glycerite to taste (stevia glycerite works better in this smoothie than clear liquid stevia

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Hi! I'm Vicki. My blog is called "Miss Diagnoses" because I have too many diagnoses and because my Lyme disease was misdiagnosed for many years. In addition to being a professional patient, I'm a compulsive reader and doodler. Sadly, my writing and drawing are limited by repetitive strain injury and neuropathy. I use assistive technology, but I can't post as often as I'd like. You can also find me on Facebook, Twitter, Pinterest, Instagram, and I have two short cartoon videos on YouTube. Twitter and Instagram: @miss_diagnoses Facebook, Pinterest, YouTube: @MissDiagnoses

10 thoughts on “Does Your Thyroid Want a Green Smoothie?

  1. Thank you for this post, aside from having hypothyroidism I’m also a vegetarian so frequently have smoothies, not necessarily green because I don’t like most vegetables from the Brassica family, but this list helps me with other foods that I do eat and didn’t know caused a problem. And great to see that Linseeds or Chia seeds aren’t on the list because I used them instead of cod liver oil for my joints…..thanks again.


    1. Hi! You’re very welcome. Unfortunately, flaxseed and linseed are the same thing … just different names. The chia seeds I haven’t seen listed as goitrogenic. It’s frustrating because I haven’t seen a comprehensive list of all goitrogenic foods anywhere … not on any of the main thyroid websites, not on smaller websites, nowhere. But I have also never seen a site that says to avoid them completely (except for soy and millet–millet gets even more goitrogenic when you cook it).


  2. Ugh! This just gets so confusing. Don’t both strawberries and watercress actually have a great deal of iodine in them too? It sometimes seem like the more you learn, the less you know.


    1. Interesting! I wonder if the iodine balances the goitrogenic effects? There seems to be so much info on this topic … the woman from Stop the Thyroid Madness says she eats raw strawberries a few times a week, but not a ton of them. I used the Mary Shomon page for this post. I can’t think of the name of her Facebook page at the moment, but her Twitter is @ThyroidMary. It would definitely be a good question for her.


  3. Great info here on this topic! Just one point: my research found that green apples have the same amount of net carbs as other apples. I have Type 1 diabetes, and tested my blood glucose after eating a green apple. Confirmed this to be true. Wish those green ones did have less sugars but they don’t. Berries and grapefruit are the fruits with lower carbs per serving. Of course lemons and limes are very low.

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  4. Oh, interesting! Yeah, I guess that’s another myth. I just read something else that said the green ones have more malic acid and that’s why they’re more tart. I’ll change it … I still like them better in smoothies though. 🙂


  5. If possible could you post the link to that green apple and malic acid info? Will see if I can find it myself though. Very helpful to know about this, thanks! 😊


  6. I have been on 50 mg of synthroid for 8 years (diagnosed at 37 with Hashimotos). In a desire to feel/eat better, although the initial taking of synthroid was life changing–I felt 10 yrs younger… I bought a Nutribullet. In 6 weeks I felt horrible, I gained weight even though my calories were reduced. Every shake I drank contained spinach or kale. The next time I visited the doctor, for the first time my med levels had to be raised to .75 mg. I started doing research and first learned about goitrogenic foods. For me, it was very detrimental to eat these foods. It also was not a “you are what you believe” situation (as I read in the above comments) as I had never thought eating better could hurt me. I can attest that goitrogenic (raw) foods, once a day, had a very negative effect on my hypothyroidism.


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