How do you tell exactly if hypothyroidism is autoimmune in nature? What would levels of TPO antibodies need to be? I’m asking because Chris talked about possibly using an AIP diet and how possibly people with Hashimoto’s don’t always respond well to iodine, but often it’s OK if you add selenium. How do you monitor their response to iodine, and how do you check their selenium levels via blood sample for both iodine and selenium? How long after trying to introduce iodine would you test their levels, and what dose would you try adding in the iodine, say, by kelp capsules or adding seaweed in the diet?

Dr. Amy Nett:   I’m glad we get to follow up on this because, Laura, I think you and I were talking in the Facebook group exactly about this—is it Hashimoto’s, is it not Hashimoto’s, and what do you do with the iodine? And I actually talked to Chris about it a little bit more, so I’m glad we get to sort of revisit this because it’s kind of a tricky topic and there’s a little more to say, so I’m glad we get to go into this, so thank you, Leslie, for submitting this question.

OK, so I’m going to break it down into these sort of component questions. “How do you tell exactly if hypothyroidism is autoimmune in nature?” I would say you want to test, as you mentioned, TPO antibodies and thyroglobulin antibodies. Both TPO and thyroglobulin antibodies should be tested. If they’re out of the provided lab range, I would consider that positive. I would consider that to be Hashimoto’s. Thyroglobulin antibodies, if they’re only mildly elevated, we do sometimes see a mild elevation of thyroglobulin antibodies in non-Hashimoto’s patients. So it has to be, like, hypothyroidism with mild-to-moderate Tg antibodies on multiple testing.

If you test once and they come back in normal range, you cannot exclude hypothyroidism completely. In our clinic, we normally test people maybe five or six times before saying, “OK, we feel pretty comfortable this is less likely to be a Hashimoto’s hypothyroidism.” Some people believe that essentially all cases of hypothyroidism are autoimmune in etiology. One paper did actually show that in some patients the TPO antibodies are only found in the thyroid gland, and of course, I would never recommend a thyroid biopsy just to figure this out, so this is sort of a debate. I don’t know if you can ever 100 percent say hypothyroidism is not autoimmune because maybe that person only has the antibodies in the thyroid.

The question is, how much does this matter? Well, as some people point out, if it’s Hashimoto’s, you’re going to be focusing a lot more on balancing the immune system and bringing down inflammation, but we’re all practicing functional medicine. The whole idea behind functional medicine is to continually look at where there’s inflammation in the body. So I don’t know, from our perspective and way we’re all addressing patients, that it really does change things. Maybe you would think about low-dose naltrexone or something like that if you were having trouble controlling the hypothyroidism, but most often, if you’re not seeing the thyroid antibodies, you can maybe think, Well, maybe this was initially due to an autoimmune insult that has since resolved. And maybe there are dietary factors that you would take into mind.

So I would say, depending on where you kind of want to put your beliefs on that, I think it would be fair to say if you test TPO and thyroglobulin antibodies, they come back in the lab range on about five occasions, you can say, “No. This is not autoimmune thyroiditis.” But there’s always a little bit of a question.

Then the next question is how to start with iodine and selenium and how to test for those. This is also a great question, and there’s some controversy. Iodine you can test with a blood level from LabCorp or Quest. Just do a random blood level and see what that is. If it comes back below the reference range, then they would be deficient. We don’t really do the iodine loading test anymore.

For selenium, great question. I asked Chris about this, and he said the best way to test for selenium is not yet commercially available, but it’s actually a toenail selenium test. I think we’ll have to keep looking at the research on that one, but it appears that toenail selenium is actually the most common way of assessing long-term status. If you go to PubMed and do a search for toenail selenium, you’ll get some more information on that. Fortunately—or unfortunately—we don’t need to start clipping our patients’ toenails just yet because it’s not a commercially available test, but that may be where we go in the future.

Then, Laura, this is where we were sort of talking on Facebook, and I said, “Well, I normally start patients at maybe 300 micrograms of iodine and see how they do and then go up to 1,000 micrograms.” Chris said that he has occasionally seen some people not respond well, particularly if they are a clear Hashimoto’s case. The way that you monitor how people tolerate iodine, because what you’re worried about is if you give iodine and the patient, they can convert that into thyroid hormone and get a thyroid flare, like a thyroiditis, so you’re going to be monitoring mostly for symptoms of hyperthyroidism, a thyroid storm type of thing. He said he will occasionally actually start people at more like 100 micrograms, so a very small dose, 100 micrograms. You can often get kelp capsules in either … I think it’s like 100 micrograms or 325 micrograms. You can do those two different doses. So he said, you know, it could be worth it, especially if somebody has kind of wonky antibody levels, to start at a much lower dose of iodine and see how they do. Our maintenance dose recommendation is still about 1,000 micrograms, so you can start at 100 micrograms and work up slowly.

If someone has a flare, that’s when you would want to give selenium. Then how do we know what dose? Well, 200 micrograms is a pretty standard dose for selenium. I think if you do a search in Emerson or Natural Partners, almost all of the selenium supplements come in a dose of 200 micrograms, so I would say use 200 micrograms. I don’t like using much higher doses of selenium. We do that sometimes in metal detox, and as part of the Quicksilver Scientific metals test … oh, so that would be, actually, two ways you could test for selenium, the best being toenail clippings, not yet available. You could do a micronutrient test, like Genova ION, or if you’re doing metals testing, you could go through Quicksilver Scientific. Their Blood Metals Panel has a section on nutrient elements, and that contains selenium, calcium, magnesium, zinc, copper, manganese, chromium, and lithium, so you would get an idea of where selenium is there.

When I use more than 200 micrograms of selenium daily in a patient, I’m seeing selenium go higher than I’m comfortable with, so I would say stick with about 200 micrograms of selenium. I would probably only use selenium for maybe a couple of months, two or three months, and then take them off, see how they do with the iodine. I think Chris has mentioned we’ve moved away from using long-term selenium supplementation because there was that study that looked at men taking 200 micrograms of selenium daily, and there was an increased risk of prostate cancer. The study was only done in male patients, so we don’t know what happens if women do long-term selenium supplementation, but there’s no reason for me to think that it would be uniquely toxic or troublesome in male patients.

Again, summary: It’s hard to know if it’s ever truly Hashimoto’s. If you want to be very conservative and almost all of your patients are going to start iodine in the form of kelp capsules because that’s a controlled dose, start around 100 or 150 micrograms once daily. You can increase that dose every three to five days by another 100 or 150 micrograms. If they show signs of hyperthyroidism, then you’re thinking about a thyroiditis flare. Back them off. Start them on selenium 200 micrograms daily. After they’ve been on the selenium for maybe a week or so, then reintroduce the iodine. Keep them on the selenium two to three months while you’re increasing the iodine. Then take them off the selenium and see how they do with the maintenance of 1,000 micrograms of iodine.