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Originally published on 28th March 2016 Last updated on 17th December 2018
The more I learn about hypothyroidism, the more I understand how big a part diet can play in the disease and helping our symptoms and recovery. Especially since gaining my qualifications in Diet and Nutrition.
It is reported by many that if consumed in excess, goitrogenic foods can be problematic for thyroid function and even lead or contribute to the formation of a goitre (an enlarged thyroid) in some cases.
They are reported to inhibit the body’s ability to use iodine and affect the process of iodine converting to T4 and T3, which obviously isn’t good for our hypothyroid symptoms and overall thyroid function.
What are they?
Goitrogenic foods include:
- Brassicas, e.g. brussel sprouts and cabbage
- Bok Choy
- Bamboo shoots
- Canola Oil
- Choy sum
- Radishes (Horseradish)
- Soy and soy milk (soy ‘anything’ really)
- Pine Nuts
- Peaches (mildly)
- Pears (mildly)
- Spinach (mildly)
- Strawberries (mildly)
- Sweet potatoes (mildly)
But you don’t necessarily need to completely abstain from eating goitrogenic food.
The general consensus is to have goitrogenic foods in moderation and that it seems they’re only goitrogenic in their raw state. Therefore, many suggest that cooking them adequately removes the goitrogens, or at least a large majority of them. For example cooking goitrogenic vegetables like broccoli and sprouts until the ‘crunch’ has gone, can indicate that the goitrogens have also gone.
Whilst consuming fermented and cooked cruciferous vegetables is preferred, occasionally eating small amounts of them raw, should not aggravate autoimmune thyroid conditions.
The key is moderation really. I don’t actively avoid any goitrogenic foods but also do not eat large quantities of them daily.
Soy is a goitrogen that blocks the activity of the TPO enzyme, which has therefore been linked to the development of autoimmune thyroiditis and hypothyroidism. A lot of thyroid patients therefore choose to avoid it.
You could have had the tests done by your doctor to check for Coeliac Disease, and it come back negative, yet you suffer from symptoms such as:
- Mood swings/Depression/Anxiety (Research and studies confirm that gluten intolerance can be linked to depression, anxiety and mood disorders)
- Brain fog
- Aches and pains
- Acid reflux
- Joint pain
- Skin issues
- Swinging lab results and feeling hypo then hyper and vice versa
- Poor gut health/Leaky Gut, also meaning low absorption rate of minerals and vitamins
- Rubbish immune system
- Dental Issues
Gluten is said to trigger the same autoimmune reactions that cause you to have Hashimoto’s in the first place, since supposedly, the cells of your thyroid are similar to the make up of gluten, and it confuses your body, increasing inflammation and antibodies as an attack on your thyroid is launched, destroying more thyroid tissue, and so worse/extra hypothyroid symptoms occur. As a result, many autoimmune hypothyroidism patients eliminate gluten from their diet, and see good results.
Worsening thyroid hormone levels over time as well as swinging test results, are thought to typically be due to the ongoing destruction of your thyroid gland, which obviously causes it to not work properly (hypothyroidism). Lowering thyroid antibodies is believed to stop or slow this down.
When Italian researchers also put subclinical or ‘borderline’ hypothyroid people with coeliac disease on a gluten-free diet for one year, thyroid function normalised in 71% of them, with another 19% normalising their thyroid antibodies. The researchers concluded that in some cases, a gluten-free diet may single-handedly reverse the abnormality. 
The Effect of Gluten-Free Diet on Thyroid Autoimmunity in Drug-Naive Women With Hashimoto’s Thyroiditis: A Pilot Study concluded that their results suggested a gluten-free diet may bring clinical benefits to women with Hashimoto’s. 
Consuming gluten can also lead to leaky gut, where holes form in the gut lining and when food is ingested, gluten in this instance, it allows small particles to leak into the bloodstream, leading to symptoms of gluten sensitivity like those listed above. The immune system sees these particles as foreign entities and creates antibodies and mounts an attack not only on the foreign protein, gluten, but also on thyroid tissue because of its close resemblance to gluten. Eek!
If you often have low levels in vitamins (B12, D, Iron etc.), it could well indicate Hashimoto’s and/or damage to the gut (leaky gut) caused by consuming gluten.
Thyroid Pharmacist Izabella Wentz conducted a survey amongst thyroid patients in May 2015, that showed that 86% of people who went gluten-free reported an improvement in digestive symptoms.  Notably, only 3.5% of the respondents were actually diagnosed with celiac disease, thus it confirms what a lot of thyroid advocates and specialist doctors have been saying all along: That you do not have to have coeliac disease to benefit from a gluten-free diet.
Sugar and Processed Foods
For obvious reasons, sugar and processed foods should be avoided or limited in everybody, not just thyroid patients. They drive inflammation and disease, something we should be wary of when we have thyroid disease, and can make symptoms worse. They can also contribute to poor gut health which is incredibly pivotal to our overall health. Addressing my gut health was one of the biggest interventions to managing my hypothyroidism and Hashimoto’s.
Of course, this is only a guide with suggestions which may help you. Not all thyroid patients do well on the exact same dietary adjustments and what some find to be helpful in managing their symptoms, others do not. We’re all individuals after all! You must find what works for you.
Do you avoid any of these?
You can click on the hyperlinks in the above post to learn more and see references to information given.
There is also the online thyroid course ‘Freedom From Thyroid Fatigue’, which walks you through how to overcome thyroid fatigue by personalising what you eat.
Rachel Hill is the highly ranked and award-winning thyroid patient advocate, writer, blogger, speaker and author behind The Invisible Hypothyroidism. She has two books: ‘Be Your Own Thyroid Advocate‘ and ‘You, Me and Hypothyroidism‘. Her thyroid advocacy work includes authoring books, writing articles, blogging and speaking on podcasts. Rachel has worked with The National Academy of Hypothyroidism, BBC, The Mighty, Yahoo, MSN, ThyroidChange and more. She is well-recognised as a useful contributor to the thyroid community and has received eight 2020 WEGO Health Award Nominations.