Is a Vegan Diet Harmful to Thyroid Function?

By Published On: 23 January 2015Last Updated: 23 January 2017

January is Thyroid Awareness Month. Here's a quick primer on why the thyroid is important and how a vegan diet affects the function of the thyroid.

What's in this post

By Daria Zeoli, Guest Contributor

I was unaware that January is Thyroid Awareness Month. I find this surprising because I am an eight-year diagnosed sufferer of Hashimoto’s Thyroiditis. Did you know that an improperly functioning thyroid can really mess you up?

What’s the Thyroid, Anyway? puts it best:

The thyroid gland is a small, butterfly-shaped gland located in the base of the neck just below the Adam’s apple. Although relatively small, this gland influences the function of many of the body’s most important organs, including the heart, brain, liver, kidneys and skin.

And, what’s Hashimoto’s Thyroiditis?

Hashimoto’s thyroiditis is an autoimmune disease. I (only half-)jokingly like to describe it as my body being at war with itself. Specifically, the immune system mistakes normal thyroid cells as foreign tissue and produced antibodies to destroy them. When your thyroid isn’t working properly, you can develop hypothyroidism (which could increase risk of heart disease) or hyperthyroidism (which creates strain on the heart and increases risk of osteoporosis).

How do you treat thyroid diseases?

In my case, I’ve been on Levothyroxine tablets since I was diagnosed, and I get my thyroid hormone levels checked with a simple blood test every six months to make sure the dosage is still appropriate. I was on the same dosage for several years until last year, when, after some weight loss, my dosage was lowered.

Is a vegan diet helpful?

I think the more appropriate question is whether a vegan diet is harmful to thyroid function. I was sure to ask my doctor about cruciferous vegetables, as I had heard talk that they could interfere with things. My doctor agrees with Dr. Joel Furhman:

The fear (circulating the internet by some authors) of eating cruciferous vegetables or that those with hypothyroidism should reduce or avoid the consumption of kale or other cruciferous vegetables is unfounded and does a disservice to the community.

Can soyfoods affect thyroid function?

I asked my doctor about this as well, and was told I did not have to change my soy intake. It is important, however, to make sure you are getting adequate iodine. As Ginny Messina, RD says in her article Soyfoods, Iodine and Thyroid Function in Vegans:

Soy doesn’t adversely affect thyroid function in healthy adults either. As long as people meet the recommendations for iodine intake, consuming large amounts of soy has not been shown to have adverse effects. Whether soy is harmful to those who have deficient iodine intakes hasn’t been determined. But if this turns out to be the case, the answer will be to consume adequate iodine, not give up soy.

Ethical veganism is about the animals, but remember: one of the things we can do to best advocate for animals is make sure we’re taking care of ourselves.

Disclaimer: The information presented on this website is not intended to diagnose, treat, cure, or prevent any disease.  All information is intended for informational purposes only and is not a substitute for medical advice or treatment for specific medical conditions. Please read the full disclaimer here.


  1. Katie Rees September 4, 2021 at 4:59 pm - Reply

    Very important!!!! Please do some research on iodines function in thyroid health. This is extremely important. Also look at Bromine which is part of the halogen group along with iodine. Look at bromines effects on iodine absorption. BROMINE inhibits the thyroid ability to absorb iodine. BROMINE is in car apholstery, furniture, clothing ,soft drinks(bromynated vegetable oil). Also check out the benefits of artichokes mainly Canaria. Iodine and BROMINE I believe are the key factors in thyroid disease. I have done alot of research into this issue.

    • Katie Rees September 4, 2021 at 5:00 pm - Reply

      I meant cynarin in artichokes. Autocorrect

  2. AK August 14, 2019 at 4:34 pm - Reply

    Few months ago, I started 2 meal per day (lunch & dinner) vegan meal (mostly raw). In 2 weeks I felt a lump in my throat. It hurt every time I swallowed..felt like a small marble was stuck in my throat. So stopped vegan diet and lump disappeared. Re-started Vegan diet and lump re-appeared.

    So I switched to Vegan OMAD diet (one meal a day). Basically rice with cooked veggies. No lumps so far.

    I wonder if veggies are too potent for 2+ meals??!!! That’s why people stop vegan diets??!!! Vegan diet are best on OMAD??!!!

  3. Patricia December 8, 2016 at 7:41 am - Reply

    With the exception of the lacto-ovo vegetarian diet findings in the prevalence study, vegetarian diets were not associated with increased risk of hypothyroidism. Vegan diets which may be expected to lack iodine due to complete exclusion of animal products tended to be protective.

  4. profwatson February 3, 2016 at 3:38 pm - Reply

    I did not get enough tyrosine on my vegan diet, so I had the benefit of hypothyroidism. Hypothyroidism is called the longevity situation because things slow down so you can live longer. Be thankful for hypothyroidism.

    • Ashley Young February 16, 2016 at 7:12 pm - Reply

      It’s not so great if you are a female of child-bearing age. With hypothyroidism, it is much harder to become pregnant and maintain pregnancy. There are also high risks of delaying or inhibiting neural development so babies born to hypothyroid mothers are often developmentally delayed or, even worse, handicapped. The critical time for mothers to contribute their own thyroid hormones is up to about 8 to 10 weeks into the pregnancy so if women aren’t closely monitoring their pregnancy or don’t know they are pregnant or don’t know they are hypothyroid, the damage is already done by they time they find out.

      Subclinical hypothyroidism can be ok for the long term, but people with autoimmune thyroid disease become progressively more ill as their thyroid is destroyed. They don’t live as long and they don’t live well.

      • profwatson February 16, 2016 at 9:10 pm - Reply

        I found out, that it was not the tyrosine, but the lysine amino acid that I was short on. My TSH was 4.39 . Now it is 2.8. Now I am eating an 1 .oz of cheese. I am Norse, so I handle cheese well.

        • Apryl March 25, 2019 at 7:11 pm - Reply

          There are other sources of that rather than cheese. Non animal sources. Have you tried those?

        • Katie Rees September 4, 2021 at 5:06 pm - Reply

          Eat kelp seaweed for iodine

    • Apryl March 25, 2019 at 7:07 pm - Reply

      Did you give up the vegan diet or did you supplement tyrosine? I heard legumes are good for that.

  5. kittymama August 2, 2015 at 9:44 am - Reply

    Thanks for this post, I’m a long time vegan and just found out that I have Hashimoto’s. I was a little freaked out about taking yet more foods out of my diet, but so far gluten free hasn’t been bad. Planning on seeing a clinical nutritionist, meanwhile I’m collecting some recipe ideas. Glad I found your site!

    • Daria Zeoli August 8, 2015 at 5:51 am - Reply

      I’ve heard that many diagnosed with Hashi’s do well on a gluten free diet. I love my pasta and grains too much and haven’t had much of a reason to try it yet – knock on wood! I hope you find a wonderful nutritionist who is a proponent of a plant-based diet!

    • Apryl March 25, 2019 at 7:13 pm - Reply

      Don’t give up on being vegan! Most vegans don’t get issues like that. But you can find ways to fix it. Talk to your doctor about ways to fix it without adding any animal products. Also it might have nothing to do with you being vegan. Most people aren’t vegans and they get these diseases.

    • Katie Rees September 4, 2021 at 5:05 pm - Reply

      Research iodine and bromine effects on thyroid. All your answers can be found there

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HELLO! I'm KD Angle-Traegner.

Writer, activist, and founder of Four Urban Paws Sanctuary. I’m on a mission to help people live a vegan life. Read more about KD…