Hi Anna,
I've spent the past year researching hashimoto's and thyroid diseases. Surprisingly, even though doctors and many popular blogs talk about hashimoto's as if they have it figured out, it's very far from understood. The prevailing theory of the moment is that the immune cells of the body attack the thyroid and over time, destroy is, causing the patient to became hypothyroid. Periods of being hyperthyroid are said to be from large doses of thyroid hormone releasing into the blood stream when the immune cells attack. Periods of hypothyroid are seen as being cause by loss of function from the immune cells destroying the thyroid.
As of now, all of this is only theory. Science has not yet given us any definitive answers about what the antibodies mean for the thyroid. We do NOT know if the antibodies destroy the thyroid. We have only observed that a percentage of people who have antibodies eventually lose thyroid mass and function. A percentage of people with antibodies go on to have no loss in mass or function. We may eventually discover the antibodies to be a protective reaction to something environmental that threatens the thyroid. We just don't know enough yet.
Until recently, it was believed that another gland, the thymus, which was observed to shrink and for some, disappear after adolescence, was no longer needed in adulthood. Now we know that the thymus gland can shrink away and grow back again, depending on the needs of the immune system.
Many doctors do not even test for antibodies, because we do not know enough about their implications, AND because the treatment is exactly the same whether the patient has antibodies or not.
What we do know quite a lot about is that thyroid patients have a problem absorbing and metabolizing nutrients. Thyroid patients do not convert beta-carotene into vitamin A. We know that without T4, riboflavin cannot be used. Riboflavin deficiencies cause dryness of the lips, mouth, throat and eyes. High doses of riboflavin help thyroid patients, but also thyroid medication (T4) improve riboflavin metabolism.
Look for the study on hashmoto patients and thiamine. One of thiamine's many many roles is in making stomach acid. Thyroid patients have low stomach acid. Without stomach acid, food can't be properly digested and nutrients will not be absorbed.
There is also a study on vitamin A and subclinical hypothyroidism from 2012 that's really interesting.
My personal experience is that I have high TPO antibodies, and at one point had a very high TSH, with every symptom possible: loss of voice, cardiac arythmias, high blood pressure, swelling of the legs and face, high cholesterol, high liver enzymes, muscle pain, joint pain, headache, depression, fatigue, insomnia, heavy periods, frequent periods, and I'm sure more that I'm forgetting.... oh yeah, memory problems. lol Despite this long list, it took a while to get a diagnosis and it came only after I found improvement on my own, with supplements and foods like beef liver. I should have said yes to the thyroid medication they wanted to give me, because my recovery would have been faster with both meds and supplements together. But I was able to fully recover with just supplements and am now feeling better than I have in decades. It's been one year since my diagnosis. I had three breast lumps that have disappeared, and I've been able to go off all the allergy meds and decongestants I'd been using for my sinus symptoms for years.