I am reposting this article written by Chris Kresser LAc as he did such a great job on it: The Gluten-Thyroid Connection
Basically, 90% of the cases of hypothyroidism are actually autoimmune thyroid disease (i.e. hashimoto's or graves disease) meaning that there are antibodies present that are attacking the thyroid gland. Recent analyses show that there is a very strong connection between gluten intolerance and thyroid antibodies–basically the body mistakes the gluten protein (gliadin) as thyroid tissue and it just attacks and attacks. This leaves the thyroid patient who is eating gluten with a severely inflamed body (achey joints, skin rashes, brain fog, poor memory, sinus and lung issues, and more!) and a weak immune system.
Bottom line: if you have a thyroid disease read this article and avoid gluten!
As well, if you have any autoimmune disease (i.e. fibromyalgia, endometriosis, lupus, rheumatoid arthritis, ms) you should strongly consider removing gluten from your diet. Your body and your health will thank you!
And to go one step further, if you are a women struggling with infertility–remove gluten. The inflammation and aggravation gluten wreaks on your body and your immune system could be the cause of your infertility.
I have seen such drastic differences in my patients who remove gluten from their diet.