Autoimmune diseases develop from a predictable route of breakdown in the body starting in the gut. You must heal the gut in order to stop the progression of autoimmune diseases. Through improper digestion and absorption of nutrients, for a variety of reasons including antibiotic use, parasites, candida, bacteria and viruses , the thin mucosal lining becomes porous or "Leaky" which allows undigested food proteins into the blood stream. Certain food proteins mimic our body's tissues and causes our immune system to not be able to distinguish "Self" from "Foreign invader", so it mistakingly attacks the healthy tissue. The best example of this is wheat & gluten, which is very similar to our thyroid gland tissue. So, Thyroid autoimmune disease frequently develops from a wheat/gluten sensitivity over time and can be completely reversed once wheat and gluten are completely removed from the diet and the gut is able to heal. It takes many years to develop autoimmune diseases and the progression is slow enough that people often don't realize that they have food sensitivities if they are always consuming that food. To find out if you have sensitivities to the most common intolerant foods of Wheat/Gluten, dairy and eggs, stop eating the given food(s) completely for 10-14 days and then reintroduce it back into your diet slowly and watch for symptoms. During the 10-14 days without the offending food, your gut gets a break from the constant inflammation and irritation and begins to heal enough that if the offending food is eaten again, it will react and you will know that you are sensitive to that certain food. Wheat/gluten produces stomach and intestinal pain, gas, bloating, diarrhea, headaches and nausea. Dairy manifests as nasal and sinus congestion and being generally "Snotty". Most people have no idea that they are sensitive/intolerant because their body compensates so well for so long until it can no longer, but each day you ingest a food that you are sensitive to, you're on a continuum heading towards autoimmune disease. One autoimmune disease always leads to other autoimmune diseases if it is not contained.
It's a free way to assess if you are creating constant inflammation and irritation in your gut which weakens your immune system and is leading you down the road to autoimmune disease. If after 10-14 days you reintroduce the food and show no symptoms, then you can continue to eat a small amount of those foods each day. I can provide many reputable research articles from PubMed if you need further information since I simplified this for ease of understanding. Try it, especially if you have been diagnosed with an autoimmune disease and watch the improvement when you go off the offending food! It takes time to truly heal the gut since it took years/decades to get to the point of autoimmune, but I have helped people reverse their Rheumatoid arthritis, Hashimoto's, and various GI disorders by providing the body what it needs nutritionally and eliminating what is taxing it! It can be done!