Chris Kresser explains it thoroughly here. Excerpt:
"In the first article in this series, I showed that hypothyroidism is an autoimmune disease in 90% of cases. In this article we’re going to discuss the connection between autoimmune thyroid disease (AITD) and gluten intolerance.
Several studies show a strong link between AITD (both Hashimoto’s and Graves’) and gluten intolerance. [1, 2, 3, 4, 5] The link is so well-established that researchers suggest all people with AITD be screened for gluten intolerance, and vice versa.
What explains the connection? It’s a case of mistaken identity. The molecular structure of gliadin, the protein portion of gluten, closely resembles that of the thyroid gland. When gliadin breaches the protective barrier of the gut, and enters the bloodstream, the immune system tags it for destruction. These antibodies to gliadin also cause the body to attack thyroid tissue. This means if you have AITD and you eat foods containing gluten, your immune system will attack your thyroid.
Even worse, the immune response to gluten can last up to 6 months each time you eat it. This explains why it is critical to eliminate gluten completely from your diet if you have AITD. There’s no “80/20″ rule when it comes to gluten. Being “mostly” gluten-free isn’t going to cut it. If you’re gluten intolerant, you have to be 100% gluten-free to prevent immune destruction of your thyroid."
During the year and a half that I've been eating a modified paleo diet, which is wheat- and grain-free, I've had several blood tests to monitor my thyroid levels. My thyroid gland seemed to be coming back to life; my medication was reduced by 2/3 in the diet's first year. Blood tests showed that my thyroid antibodies have been steadily decreasing.
On July 11, 2012, my doctor wrote "No thyroid antibodies. Hashimoto's - resolved" on my blood test. I asked him if that meant I no longer had an autoimmune disease. He replied, "You no longer have an autoimmune disease." When I asked what he considered the reason for the antibodies' disappearance, he said, "Probably the wheat."
I have never had ANY other symptoms of gluten intolerance; if I had, it probably would have been picked up much earlier in my life. In the last year I have learned enough about wheat to realize that it is something I never want to eat again.
Perhaps this post will help you understand why people you know are serious about avoiding wheat. Perhaps this post will help someone with thyroid issues, or other autoimmune diseases; wheat is a culprit in many of them, as well.
Remembering that we are all to some extent metabolically unique, we can begin to understand that food can be a major player in many health issues. Cure Hashimoto's with food choices? Apparently so.
I won't lie and say it's easy, but there's something supremely motivating about reclaiming health territory once lost. My deepest thanks to my stepson for his patient, non-preachy sharing of information, books and links about diet and the gluten-thyroid connection. Be well.
