Thyroid Myth Busting (Part 2): What Actually Helps and What Doesn't

Getting diagnosed with Hashimoto's can feel overwhelming, especially after spending five minutes online. Suddenly you're told to eliminate gluten, avoid broccoli, stop eating soy, buy expensive supplements, and ask your doctor for desiccated thyroid. But how much of that advice is actually supported by evidence?

In Part 2 of the Thyroid Myth Busting series, endocrinologist Dr. Komal Patil-Sisodia separates fact from fiction using current medical research.

You'll learn:

•  Why cruciferous vegetables are not harming your thyroid 
•  When soy actually matters (hint: it's about medication timing) 
•  Who should—and shouldn't—consider a gluten-free diet 
•  Why iodine supplements can actually worsen thyroid disease 
•  Which thyroid supplements have evidence (and which don't) 
•  The truth about desiccated thyroid versus levothyroxine 

If you've ever felt overwhelmed by thyroid advice on social media, this episode is your evidence-based guide.

Timestamps

00:00 Welcome to Clearly Hormonal

01:03 Why thyroid wellness advice can become overwhelming

02:04 Cruciferous vegetables, iodine, and what actually affects thyroid function

05:03 Soy consumption and levothyroxine timing

06:16 Hashimoto's, gluten, and when celiac testing matters

09:35 The dangers of iodine supplements and seaweed products

13:08 Fact-checking popular thyroid supplements:

•  Ashwagandha 
•  Vitamin B12 
•  Low-dose naltrexone (LDN) 
•  Selenium 

17:05 Desiccated thyroid vs levothyroxine: What the evidence says

23:05 Key takeaways and what's next

Resources & Links:

• Catch up on Part 1 (testing myths, TSH, subclinical hypothyroidism)
• Follow @drpatilsisodia on Instagram and TikTok

Disclaimer: This podcast is for education, not personalized medical advice. Talk to your own healthcare team about what's right for you.

Thanks for listening. Find more info about Clearly Hormonal on the website or Instagram.

Transcript

Dr. Komal Patil-Sisodia 0:01

Welcome to Clearly Hormonal, the podcast where we stop googling our symptoms at midnight and actually start understanding what's going on in our bodies. I'm Dr. Komal Patil-Sisodia, an endocrinologist, internist, obesity medicine specialist, and a Menopause Society Certified Practitioner, which is really just a whole lot of words to say hormones are kind of my jam. I've spent 17 years watching women try to navigate their hormonal health without ever having been taught the language for what's happening in their own bodies, and then meeting clinicians who want nothing more than to help them figure it out, but are up against 10-minute appointments and a system that just wasn't built for it. This podcast is my answer to that gap. We'll cover menopause, metabolism, hormones, and everything in between with real evidence, not trends, and without the overwhelm. A quick disclaimer. I'm a physician, but this is education, not personalized medical advice. Take what resonates and discuss it with your own healthcare team. Now, let's get into it and talk about what's clearly hormonal and what's not. Somewhere out there tonight, there is a woman who just got a diagnosis of Hashimoto's thyroiditis, and she is doing what all resourceful women do, which is going online and trying to find information about ways that she can improve her health. And within 48 hours of joining an online support group, she's been told to eliminate gluten, cruciferous vegetables, soy, and dairy, start iodine drops, take ashwagandha for her adrenals, and demand desiccated thyroid from her endocrinologist. And her grocery cart now looks like a different person's. Her anxiety is through the roof, and she still feels terrible. Today, I want to be your fact checker because the thyroid wellness space is huge, and it is largely unregulated, and most of what it's selling is not just unhelpful, some of it can be actively harmful. So on today's episode, which is the second part of the Thyroid Myth Busting series, we're going to go through all of that. The first myth that I want to bust is around cruciferous vegetables and soy consumption. Cruciferous vegetables are things like broccoli, kale, arugula, which is my favorite, cauliflower, Brussels sprouts, collard greens. Cruciferous vegetables contain glucosinolates, which are substances that can potentially interfere with iodine uptake in your thyroid gland. And like we talked about in the last episode, iodine is necessary to make thyroid hormone. But the important thing to note is that anti-thyroid effects, meaning how they interfere with that iodine uptake in our thyroid gland, are only clinically relevant when you are consuming huge amounts... When you are consuming extremely large amounts of these cruciferous vegetables, like say you're juicing a 10-pound bag of kale or something like that. I don't juice, so maybe that's unreasonable. But you're juicing large amounts of cruciferous vegetables, and then you also have iodine deficiency. Those two things together will mess up how your thyroid gland takes up iodine and can impair thyroid hormone production, meaning it can prevent how efficiently you make thyroid hormone in your body. Broccoli, kale, Brussels sprouts, they all contain minimal levels of this at normal dietary amounts, and there is nearly a zero clinical risk in people who have enough iodine in their diet. The United States started iodizing their salt in 1924. So that actually helped with iodine deficiency. But interestingly, iodine deficiency is re-reemerging in the United States, and the highest risk populations are pregnant and lactating women because pregnancy will increase iodine needs by roughly 50%, and up to 46% of women don't actually get the right amount of iodine. The interesting thing is that iodine deficiency is reemerging in the United States, and a lot of that comes down to the fact that people are starting to avoid iodized salt. And if you eat out or you eat any packaged foods, you're probably getting some iodized salt. But for people who are swapping out the Morton's iodized salt that we all grew up with the little girl holding the umbrella on the container. A lot of people have stopped using that and they're swapping it out for specialty salts like sea salt or Himalayan pink salt or kosher salt, which generally are not iodized. But the overwhelming majority of people, if they are eating out of their house, are getting enough iodine in their diet. Additionally, people who are vegan and vegetarian are at higher risk, as are women who are pregnant and lactating. And then racial and ethnic minorities like Black women or Hispanic women will be at higher risk for iodine deficiency compared to the general population Next on the list is soy. Here's the evidence around why soy is still pretty safe for people to eat. There have been several studies, a systematic review, and a meta-analysis of 18 randomized control trials that found that soy supplementation had no significant effect on free T4 or free T3. The TSH only showed a modest increase, but there was no clear clinical significance around why that happened. And when we look at the long-term study, avoiding soy hasn't really shown any benefit in thyroid patients. So here's one practical note, though, where soy can impact. If you have hypothyroidism and you're on levothyroxine, soy can impair how your body absorbs the levothyroxine. So if you're eating soy within three to four hours of taking your thyroid medication, it may not get absorbed properly. So timing matters, but you don't have to eliminate soy altogether from your diet. So the important takeaway I want you to have is that you don't have to be afraid of these vegetables. You don't need to be afraid of your salads. You do need to possibly fear your supplement aisle and what they might be selling you, but we'll get to that a little bit later. The next myth that I want to bust is that everybody who has Hashimoto's should go gluten-free, and this one is complicated. And again, it really matters what clinical situation you find yourself in. So here's what the evidence shows for the general population who has Hashimoto's thyroiditis. There is not enough evidence right now to routinely recommend going gluten-free for all patients with Hashimoto's who do not have celiac disease. And now you might think, "What is celiac disease?" Celiac disease is an autoimmune disorder that happens when you eat gluten, and that's a protein that's found in things like wheat, barley, and rye, and that causes the immune system to attack and damage the small intestine. That can lead to abdominal pain, bloating, malabsorption of nutrients. It can cause quite a bit of damage internally, and it can be associated with other autoimmune illnesses. So in people who have Hashimoto's thyroiditis, but they don't have celiac disease, the studies do not show a huge improvement in thyroid outcomes. And usually, when we're looking at Hashimoto's, I think a lot of these studies have looked at whether the antibodies or the inflammatory markers for the Hashimoto's are going to improve by going gluten-free. So there was a meta-analysis of four studies that total contained about eighty-seven patients, and that showed borderline non-significant reductions in thyroid antibodies on a gluten-free diet. So only eighty-seven patients. Then there was a twelve-month randomized control trial that was done that showed no significant differences in the anti-TPO, or thyroid peroxidase antibodies, or the anti-TG antibodies, which are the anti-thyroglobulin antibodies when they looked at people who were put on a gluten-free diet versus people who were allowed to eat anything. But here's what I think is really important. In people who have Hashimoto's thyroiditis and celiac disease, this is a well-documented association. So if you have Hashimoto's and you're having GI symptoms like abdominal discomfort and bloating and diarrhea and malabsorption, it's really reasonable to test for celiac disease. The gold standard will always be an upper endoscopy with a small intestine biopsy to prove it on biopsy. But there are blood panels that you can do if somebody is eating wheat and they don't necessarily want to go through the endoscopy. Sometimes these panels can show positive antibodies that we see in celiac disease, and you can make a diagnosis that way based on symptoms and the lab test. But truly, the gold standard is the endoscopy with the biopsy And in patients who have confirmed celiac disease or confirmed gluten sensitivity, a gluten-free diet can improve levothyroxine absorption and reduce the high levels of thyroid antibodies. And the benefit in that population is very real. But recommending it to everybody with Hashimoto's, even if they don't have celiac disease, that doesn't really make sense. So a gluten-free diet isn't harmful, but it's also not a thyroid treatment unless you have celiac disease, and you should definitely talk to your doctor about getting tested for that. Now, the next myth I want to talk about is iodine supplements. Everywhere I look online, and maybe this is just my feed because I'm an endocrinologist and all endocrine things happen to pop up on my feed, whether they're good or not, is that iodine supplements boost thyroid function, and that is not the case. Taking too much iodine can actually be incredibly harmful. And the reason that people will take it is because iodine is needed for thyroid hormone synthesis. We just talked about what happens to people who are iodine deficient. If you don't have enough iodine, which is a building block for thyroid hormone, you won't make enough thyroid hormone. Some people think, "Okay, well, that just must be a very easy conclusion to draw." The logic is the more iodine, the more thyroid hormone, and that's not always what happens. It can backfire pretty significantly in people who have enough iodine in their diet, which is really most of the people in the United States with access to iodized salt and a variable diet. Supplementation does not improve thyroid function in people with normal thyroid glands. And here's where it gets interesting. Taking too much iodine can cause either hypothyroidism, hyperthyroidism, or inflammation of the thyroid, especially in people who have underlying Hashimoto's or thyroid nodules. And things like kelp supplements are a big risk because they have a lot of iodine. It's not really regulated how much iodine is actually in that supplement, and I've seen multiple patients who have had thyroid dysfunction triggered from that. Too much iodine confuses your thyroid, it will either look at all that iodine and get analysis paralysis and then shut down and be like, "I don't even want to make the thyroid hormone because there's too much, and I'm too overwhelmed, and I don't want to do it." Or it can go the flip side, and you can have an eager little thyroid gland that sees all this iodine around and goes, "Ooh, let me make more thyroid hormone." And in that case, people become hyperthyroid. So in the analysis paralysis situation, there's no thyroid hormone production or decreased thyroid hormone production because the thyroid gland is overwhelmed, and then you get hypothyroidism. Or in the overeager thyroid gland, and it's just sucking up all the iodine, you can become hyperthyroid. And it's not predictable which way it will go. In fact, I had a patient, gosh, I want to say this was a few years ago, who was eating those seaweed snacks from Costco and was eating, like, six or seven of them a day and came into my office hyperthyroid on the labs. We couldn't find any antibodies for Hashimoto's or Graves' disease. There were no thyroid nodules, and we were just trying to figure out where it came from because usually there's a pretty clear cause for why people become hyperthyroid. And so finally I started asking about diet and iodine consumption and what they were eating, and it did not even register to this person that these seaweed snacks have a lot of iodine. But seaweed is basically kelp, which, you know, if we shouldn't take kelp supplements, we really shouldn't be eating a ton of seaweed snacks from Costco. I had this person stop for a period of a few months, and we checked the thyroid function test after stopping eating the seaweed snacks, and everything went back to normal. So this can happen very commonly. You have to be really careful about what you are eating, and I would say stay away from high amounts of iodine, especially iodine supplements, because it's really unpredictable about which way it's going to go. Now, the next myth I want to talk about are all the supplements that are out there that are showing up on your TikTok feed or your Instagram feed about treating your thyroid disease or curing your thyroid. And I want to explain whether there is any evidence behind each of these. First on the list is ashwagandha. I have seen this everywhere for adrenal support, for improving mood and depression and calming people down, and there are also some claims out there saying that it might help improve the TSH in what we call subclinical hypothyroidism. So that's where the TSH is elevated and the T4 and T3 are normal. But this evidence is very preliminary. They have done studies in very small numbers of people, not enough for us to look at the statistics and draw a conclusion that it can be helpful. And the other thing with ashwagandha is it actually contains active compounds that will interact with thyroid medications and potentially other medications. So you want to be really careful about that, and if you are going to take it, I don't think thyroid should be the reason why. And if you are on thyroid medication, talk to your doctor. I usually tell people any supplements need to be four hours apart from thyroid hormone so that there's not any interference. Next on the list is vitamin B12. B12 deficiency is pretty common in hypothyroid patients, and you do need to correct it. But the B12 supplementation doesn't actually treat thyroid disease. So you will feel better, and you might feel more energy if you treat the B12 deficiency because that can impact your energy level, but it's not actually doing anything for your thyroid. And a side note that I think is really important, for people who are vegetarian or vegan, you will tend to be more B12 deficient compared to the rest of the population Because B12 is largely found in animal byproducts like milk or meat or, eggs, things like that. So if you're not eating any of those things or you're a strict vegan, you might be B12 deficient. And taking that is important for your health, but not going to fix your thyroid. Next on the list is low-dose naltrexone. Now, this is one that I hear quite a bit, and it seems to be gaining a lot of traction in autoimmune circles. And when you look at the mechanism of action of how it can potentially reduce autoimmunity and reduce inflammation, it's possible that it could help with reducing the antibodies in Hashimoto's, but there's still not enough data for that. There's been a few case series, a few one-off stories about it, but there's no randomized control trials looking at this. So I think, under guidance of your provider who's prescribing these to you, it would be reasonable to try. But if you're not seeing an improvement in your symptoms or the levels, continuing it doesn't really make sense. So again, proceed with caution. Definitely talk to your healthcare team about whether that's right for you. Now, the one supplement that actually does have the most data is selenium. Selenium supplementation has shown some small but real reductions in the TPO antibodies in Hashimoto's patients in a lot of randomized control trials. But it's not really ready for universal recommendation because I don't think we have quite enough data yet, but it is the most evidence-supported supplement that we have. And when patients ask me about it, I always give them a trial of it. We'll check TPO antibodies before and after, after they've been taking the supplement for a few months, and if it's not really making a huge difference, I'll tell them, can continue it if you want, but I don't know that it's going to help your antibodies." So again, making sure we're looking at what is actually happening to these levels and then adjusting things I think is reasonable. And again, for any supplement, you want it spaced out four hours from when you take your thyroid medication because you don't want to interfere with the absorption. Now, the last myth on my list for this episode is that desiccated thyroid is superior to levothyroxine, and desiccated thyroid is the preparation that is made from a pig or a porcine thyroid gland that is dried up and then encapsulated, and it contains both T4 and T3. Some people claim that it's more effective than, quote, "synthetic levothyroxine," which is T4 only. Here's the funny thing. Synthetic levothyroxine is technically bioidentical, it's just made in a lab, so hence it got the name synthetic. But that levothyroxine is-- people glom onto that word synthetic or thinking that it's not natural from the body. But here's the deal. What's natural for pigs is not necessarily natural for humans. The T4 and T3 ratios in humans versus pigs are very different. In humans, the T4 to T3 ratio is about ten to fourteen micrograms of T4 per one microgram of T3. In pigs, it's about four micrograms of T4 to one microgram of T3. So in pig thyroid glands, there is a lot more T3 compared to what we make in our own glands. And here's what the evidence shows. There was a three-arm double-blinded crossover randomized controlled trial of 75 patients who compared levothyroxine, levothyroxine plus liothyronine, and desiccated thyroid extract, and there was no overall difference in quality of life, cognition, or mood. And neither the European Thyroid Association nor the American Thyroid Association actually endorses desiccated thyroid as a first-line treatment. But here is where I think it's important to listen to people. In the same trial, there were a few scenarios that I think deserve some attention. About one-third of the people who were the most symptomatic, about one-third of the people who were treated with levothyroxine who had the most symptoms actually preferred and showed subjective improvement on a combination therapy, so a combination of T4 and T3. And the meta-analysis confirmed that patients overall preferred the T4/T3 combination, which is really important patient-reported data, even if the objective measures of looking at the TSH and free T4 and free T3 numbers weren't significantly different. If they felt subjectively better and there was no harm done, I don't see any problem with giving people a combination of T4 and T3. When I say combination of T4 and T3, I'm talking about levothyroxine plus liothyronine, which are two separate pills. The desiccated thyroid extract, which is coming from the pig thyroid glands, one of the biggest issues that I have with it is there is a lot of dose variability, just even in one batch of pills. There was a study done probably over a decade ago now that looked at all of the different desiccated thyroid hormone preparations that were out there, and they found that there could be a huge amount of variability just in one batch of pills alone so you could be getting a whole lot of nothing or a whole lot of something. And there's a few clinical situations that I don't want people's thyroid levels to be going up, down, right, and left, and those are pregnancy or if somebody has thyroid cancer. So desiccated thyroid is not on my list for patients who are pregnant or who have thyroid cancer because you actually need stability of those thyroid hormones, number one, in pregnancy for good neurodevelopment of the baby and then in thyroid cancer to help with TSH suppression and prevent thyroid cancer from recurring. I want to tell you a funny story about when I first started practice. So we would have reps come by for different medications so that they could leave samples. Somebody came in to talk about the desiccated thyroid preparations. At that point, there were like three or four different companies who were making them. And they asked if I had any questions about the medication. So I asked, "Do you test the pig's thyroid gland before you harvest the thyroid gland and then dry it out and encapsulate it?" And they just kind of looked at me like I had five heads. And I said, "No, no, no, I'm asking this question seriously because if the pig is hypothyroid or the pig is hyperthyroid, and you don't know that before you extract their thyroid gland, and you're going to assume that all pig thyroid glands are created equal, you can't actually say that people are getting the same amount of medication in each pill." No company that made those hormone preparations were able to answer that question for me. So that's another reason I don't trust it. I don't know that the testing is robust. And if you look at all of the data, it was actually grandfathered in by the FDA because the treatment is so old, going back so many years, that they didn't actually have to do all the studies that the makers of, the brand levothyroxine or liothyronine preparations had to do. What I always tell my patients is, "If you're not feeling great on levothyroxine alone, let's try the branded preparations. Let's try adding liothyronine if you're still not getting there." And then as a last resort, I will try desiccated thyroid hormone. The majority of people actually feel better on either levothyroxine in a brand formulation or a combination of levothyroxine and liothyronine. So your preference for how you feel on the medications really does matter. And the important thing to know is the evidence does not prove in any which way that desiccated thyroid hormone is better. If anything, I have a harder time adjusting the doses and the levels for some of my patients because the absorption is so up and down, and I don't know what's actually going into these pills. So it's really important for you to talk through each of these different scenarios with your doctor so that it makes sense to you and you're picking the best treatment. This wraps up our second episode on thyroid myth-busting. If you missed part one, go back. It's just the episode before this one, and it covers testing myths, TSH, subclinical hypothyroidism, and what a normal thyroid result actually means. If anything you heard on this episode resonates, and if you know somebody who was recently diagnosed with Hashimoto's and is really struggling about what to do next, and is very overwhelmed by all of the information online, forward them this episode. I really think it can help dispel some of the myths that they might see out there, and may save them from buying some supplements that they don't actually need Thank you all for being here today, and I will see you on the next episode. That's it for today, but the conversation doesn't have to stop here. Come find me on Instagram or TikTok at drpatilsisodia. And if something from today's episode resonated, I'd genuinely love to hear about it. Leave a review, which makes the podcast searchable, share the episode, or just send me a message. The more women who have access to this information, the better. I'll see you next week on the next episode