Podcast: The Best Diet for Optimal Thyroid Function (Q&A)

Intro to Thyroid Q&A 0:00

Doesn't it seem like when it comes to nutrition, there are more opinions than facts to go around? Every day we hear new [music] theories about diets and supplements and best foods to eat. Well, my role is to take the mystery out of good nutrition and look at the science. Welcome to the NutritionFacts podcast. I'm your host, Dr. [music] Michael Greger. Today we finish the webinar on thyroid health with answers to questions from our webinar audience. All right, it's time for me to take questions. First question in the queue, which is, >> [music] >> "Please comment on the effect of cruciferous vegetables, both raw and cooked, have on the thyroid gland. I've heard a variety of opinions regarding cruciferous vegetables, one being they need to be cooked for a minimum of 30 minutes and not to be eaten raw when dealing with thyroid disorder. What are your thoughts?" Um a fantastic question. So, there are these uh so-called

Cruciferous Vegetables and Thyroid Health 0:53

goitrogenic compounds found in some really healthy foods. Soy we talked about. There's also cruciferous vegetables, also flaxseeds. Now, these goitrogenic compounds interfere with the uptake of iodine into the thyroid gland. And so, really only cause a problem at normal uh doses of these foods when you have inadequate iodine intake. So, if you have marginal iodine status and then on top of that um you're eating uh lots of soy, cruciferous, or flaxseeds, you can run into problems. Okay, so the answer is to not avoid these super healthy foods. The answer is to just um make sure you have enough iodine. Um uh now, that's No, I made a little caveat saying normal amounts of food. If you go way back, and in fact, I looked it up um during the break here, this was uh the video on uh November 3rd, 2010, over 10 years ago on NutritionFacts. The video was called overdosing on greens, raw cruciferous vegetables, how much is too much? And yes, you can indeed overdo it. Um uh so, you don't have to worry about uh cooked cruciferous vegetables because the the goitrogenic compounds are are totally destroyed and it doesn't take 30 minutes. Um uh but uh you can overdose on raw cruciferous vegetables whether or not you have thyroid issues cuz everybody needs a functional thyroid gland. Um yes, New England Journal of Medicine, coma induced by raw bok choy. She was eating um about 3 lb a day, the the woman in this uh uh case study, 3 lb a day, every day, of raw bok choy, 15 cups a day. Um uh of raw cruciferous is too much. In the 2 months before she was admitted to the intensive care unit in respiratory failure, um she'd consumed about a thousand cups of raw bok choy.

Too much. Um now, each cruciferous vegetable is different in terms of the amount of these compounds. And so, if you actually go to the video I show, um you can uh probably get away with 50, 5 0, cups of raw cauliflower a day um because cauliflower has less of these compounds. Um the the uh the cruciferous vegetable with the most is mustard greens. And so, just three cups of mustard greens, of raw mustard greens, may be too much. I don't know who eats raw mustard greens. I mean, cooked mustard greens is delicious, but I don't know. But yeah, three cups of raw mustard greens, even if you have normal thyroid function, can raise your levels so much, interfere with even normal iodine uh levels.

And so, yes, indeed. Okay. Next question is, "Could my thyroid be the cause of periodic night sweats, inability to stay asleep, and general lack of energy?" Um well, what you describe is a kind of a combination of hyperthyroidism symptoms and hypothyroidism uh symptoms. So, probably not, right? You can't simultaneously have an overactive and an underactive thyroid gland. So, night sweats would more like a hyperactive hyperthyroidism, um whereas lack of energy may be more

Night Sweats, Sleep, and Energy Symptoms 4:10

hypothyroidism. Um I I I don't know who the questioner is, but it sounds like kind of symptoms of perimenopause. Um when you start going through menopause, you have night sweats, um insomnia, a bunch of other issues. But so, you go to your doctor, figure out what it is. Uh okay. Um next question. >> [clears throat and cough] >> Is there a connection between healthy thyroid and gut health, uh specifically bowel health? Um I think from what I saw, it's mostly yes, but it's the other way around. It's the impact of your gut on your thyroid, rather than the impact of your thyroid. Now, like if you have hypothyroidism, you get constipated, I mean, it can have implications for your gut, but what's I what I find most fascinating is how the gut can impact your thyroid. Um and so, uh what we want to do is eat a lot of prebiotics, which is fiber, resistant starch, found throughout the plant kingdom and all whole plant foods, but concentrated in the drier whole plant foods, which is whole grains and legumes, beans, split peas, chickpeas, and lentils. Those are the most concentrated sources. And so, that's where my broil bowl comes, right?

Gut Health and the Thyroid 5:19

It's one of the myriad uses of a broil, which is this prebiotic mix to feed your good gut bacteria and to foster the growth of the fiber-feeding bacteria like Prevotella, which have an anti-inflammatory effect. We feed them, they feed us right back with all sorts of wonderful things. Um whereas if we eat um foods stripped of fiber, uh like junk foods or animal foods, we can actually foster the growth of bad bacteria that make toxic things, toxin metabolites like trimethylamine, etc., etc. Anyway, so yes, there is a connection between healthy thyroid and gut health. And so, and we're finding more and more diseases are linked to the gut, even psychiatric uh diseases, anything having to do with inflammation because uh the the gut microbiome can have such a uh impact on systemic inflammation.

So, keep your gut bugs happy. How do we do that? By feeding them prebiotics. Um and not taking antibiotics unless we really need them. Okay. Can I take black cumin alongside prescribed medications? Does it have to be ground before eating? You can take black cumin with prescribed medications as long as that prescribed medication isn't your thyroid replacement hormone, right? We want to take uh uh all thyroid hormones on an empty stomach. Um but you can otherwise take black cumin um with um with other meds. Does it have to be ground before eating? Well, we don't know, but the study was done with ground. So, I would do what the study says.

Uh so, so I would presume many of the benefits of a black cumin seeds are lost if you don't grind them up. So, what do you do? You can buy pre-ground, certainly. Um uh and it uh or you can put it in a pepper grinder, which is what I do. I put black cumin seeds in a pepper grinder and just grind it on your food cuz it actually tastes tastes like pepper and it's tasty. If you don't like the taste, uh some people don't like spicy food, some people like bland food, you can get ground black cumin seed supplements. One

Black Cumin and Medication Use 7:22

ingredient, uh it's not an extract or anything, it's not a black seed oil, there's a lot of supplements like that. Just pure ground black cumin seeds. But uh try them out. I mean, it's actually tasty. Um if you like it, then, you know, one less pill to take. Okay. This person had a complete bilateral thyroidectomy a dozen years ago. Any specific advice for those who no longer have a thyroid? Um how much iodine should those without a thyroid take? Okay. So, if you don't have a thyroid gland, then, you know, uh suppressing the inflammation of your thyroid or preventing the autoimmune antibodies, suppressing the autoimmune antibodies that are attacking your thyroid glands, doesn't make any sense cuz you don't have a thyroid to attack anymore. So, you need to be on thyroid replacement hormone your whole whole life, like Synthroid, to just bring your levels up.

Uh many people are hesitant to take uh drugs, but don't think of it as a drug. It's not really a drug. You're just bringing your levels up to normal. It's not like adding some, you know, foreign substance. You're adding just normal, regular substance that your body would normally make. It's the exact same stuff. And you're just bringing your levels up to up back up to normal. Um the question about iodine intake is fascinating. If the only function of iodine in the body is to make thyroid hormones, then um you don't need any iodine if you don't have a thyroid. Um but I actually don't know if that's the case. That's the only thing that I know iodine does

Living Without a Thyroid 8:50

in the body is is as part of thyroid hormones. But does your body need iodine for other things? I have no idea. Wow. Uh this so this fascinates me when I don't know something I want to look it up. So, I don't know the answer to that, if you need any iodine whatsoever, you don't have a thyroid gland. Now, of course, if you got pregnant, then you do have a thyroid gland in your uterus or developing one. So, then of course, you need to get iodine. Okay. Um is intermittent fasting or time-restricted eating safe for someone with Hashimoto's? Well, I don't see why not. Um I mean, so if you have Hashimoto's and you have and you're being treated with thyroid replacement hormone, you're just like everybody else. Basically, you're just on this medication. I It's not really a medication, right? You're just bringing your levels back to normal. So, you should be able to intermittent fast or time-restricted eat like anybody else.

Of course, I would encourage people to check out my videos or read the chapter in How Not to Diet on intermittent fasting. I talk about the pros and cons of all the different types. There's actually downsides to many of them. So, there benefits to the um fast fasting mimicking diet and early time restricted feeding. Okay, that's the that's the kind of spoiler alert there. All right. Um do I think it's possible to reverse hypothyroidism or Hashimoto's with dietary change? Okay, well, it depends what's causing the hypothyroidism. Now, all hypothyroidism means is underactive thyroid gland. If it's caused by iodine deficiency, well, then absolutely can be reversed with diet. In fact, that's the only way to reverse I mean that's that's where you do you're not getting enough iodine getting enough iodine poof it reverses because that was a it was a it was a consequence of your iodine deficiency. Probably the most common cause um hypothyroidism on the planet uh presumably that's iodine deficiency not in the not in the industrialized world, but in the total world.

Um and so yeah, diet is the preferred treatment. Um but in terms of

Intermittent Fasting with Hashimoto's 10:49

Hashimoto's, can you reverse Hashimoto's with um dietary change alone? And we have no data. I mean well, the paleo diet was put to the test and found to be useless. Um there's never been a study where they put people on plant-based diet to see if you can actually change. Um and then there's this black human study which showed an improvement. So, I guess you could say that's a reversal of the progression, right? It's actually improvement in thyroid function actually start pumping out more thyroid hormone in your body which is responding and it decreased these anti-thyroid antibodies that were attacking your thyroid. So, in that way I guess it's reversing, but like when you talk about reversal like so that you don't have the disease at all anymore and your thyroid function is fine, um that we don't know. But, it's

Can Diet Reverse Hypothyroidism or Hashimoto's? 11:41

certainly um particularly because those because Hashimoto's patients are at higher risk for heart disease, well, then you have to be on a plant-based diet. I mean, we should be on a plant-based diet anyway uh hopeful plant-based diet um uh to protect yourself from heart disease. So, and try adding the black human and and report back to me and tell me how well it works. Okay. Uh next is uh question can a gluten-free diet help with Hashimoto's? Should gluten be um avoided uh for people with high thyroid antibodies? Before I say no, let me look up. Uh I'm doing quick PubMed search just to make sure.

But, the connection one here between gluten-free diets and Hashimoto's is just a connection between different autoimmune diseases. If you have one autoimmune disease, you are at increased likelihood of having another autoimmune disease. So, if you have type 1 diabetes or if you have Hashimoto's or if you have rheumatoid arthritis or lupus or um then you're you may be at higher likelihood of having other ones including an autoimmune disease called celiac disease. For celiac disease patients, you absolutely have to avoid gluten. Um it's rare. It's only about 1 in 140 uh um uh people here in the states. Um but, if you're at the less than 1% that actually has celiac disease, then you have to avoid gluten. And so, if you have anti-thyroid antibodies, you're um you're at higher risk um uh of having celiac disease, but it doesn't mean um you have celiac disease. And in terms of could it help?

There was just an article published um in uh summer of uh 2019 and it found that serum titers gluten So, a gluten-free diet for 6 months uh small group of 34 women Oh, yeah, did not affect thyroid hormone levels. So, going on a gluten-free diet for those without celiac disease um did not affect their um thyroid function. So, I there's the answer to your question. And are there any other studies that looked at it? Just I don't want to You always got to look at all the studies done on the There's only 19 19 papers and no it's only been put to the test once and it failed in the one time it was put to the test. Of course, you have celiac disease, it's another question.

Um I mean and you just have to avoid gluten, but it's not because your

Gluten, Elimination Diets, and Hashimoto's 14:07

thyroid is because of your celiac. Okay. Um uh next question, what are the chances of introducing eliminated foods back to your diet intermittently at a later time after healing? So, this question is um implying that an elimination diet will help with Hashimoto's and that's not the case. Uh elimination diets are useful for if somebody has some strange allergy or food intolerance to figure out what is causing uh the an issue. I would not expect that to be the case with um uh thyroid function. Okay. Uh next question, is there a relationship between thyroid um issues and uh PCOS, polycystic ovarian syndrome? Hmm, I don't know. Let's find out.

It says Hashimoto's may increase um polycystic ovary syndrome in Asia. This is a 2020 study. It does look like there's an increased risk of PCOS in those with autoimmune thyroid disease. All right. Oh, even suggesting that PCOS may actually be an autoimmune disease or have some autoimmune component. I'm just trying to see um the hazard ratios here. Not huge amount, but increased risk like uh 40%. That's significant. Um so, whatever risk you have for polycystic ovaries, um if you have autoimmune thyroiditis, your risk is about 40% more based on the single study published April 2020. It's just the most recent study that's been done on it at least that's cataloged by the largest medical library uh database um which is PubMed. Um can a person following a plant-based diet ever completely come off thyroid medications like levothyroxine? Um and the answer is probably no because most people with Hashimoto's, they so fibrosed their thyroid so scarred it up cuz your body was attacking it um that it basically loses its function.

Just like, you know, if you have type 2 diabetes, uh plant-based diet can often reverse completely type 2 diabetes, but the good odds are only within like the

PCOS and Thyroid Autoimmunity 16:13

first 8 years you can get some really good success rates with reversing type 2 diabetes completely, but after 8 years it's still possible, but the reversal rates go down and that's because your ability of your pancreas to secrete insulin uh just gets so hammered after so many years that even if you go on a good diet, um it may be kind of too late. Your pancreas may have petered out. Well, another gland, your thyroid, can also get so adversely affected there's just kind of uh no going back even if you were able to decrease the inflammation, decrease the autoimmune antibodies, it may be too late. Um but again, it's not really thought I don't think about the thyroid medication cuz it's not medication. It's just the actual hormone that your body makes or

Coming Off Thyroid Medication on a Plant-Based Diet 16:58

used to make, but just doesn't make enough. So, you're just bringing your levels up. So, you're not introducing some kind of um you know, fancy pharma drug. You're literally just taking the same hormones, very simple hormone, simple molecule back to the levels where it should be for optimal health which [music] is important. Visit nutritionfacts.org/audio to see all the podcast episodes with descriptions that include links to the associated videos. Sources cited and other details are available on each video's page. Information about my books, How Not to Die, How Not to Diet, and How Not to Age is at nutritionfacts.org/books.

All proceeds of which I get are donated directly to charity. And I've got a new book in the publication pipeline, the manuscript for How Not to Hurt on diet and lifestyle approaches to pain management. It's been handed in and will be published December 15th. Going to be doing a series of webinars to feature some of the new research I discovered. Sign up for our free newsletter at nutritionfacts.org/subscribe to stay updated on when those will be. Nutritionfacts.org is a science-based nonprofit and everything on the website is free. There are no ads, no corporate sponsorships, no kickbacks. We're strictly noncommercial, not selling anything, just put up as a public service as a labor of love, as a tribute to my grandmother whose own life was saved with evidence-based nutrition. We just have like a a [music] Wikipedia type nonprofit model where everything's free and we just hope maybe, you [music] know, one in a thousand people will find it so valuable that they'll kick in a few bucks so we can continue to churn out new content >> [music] >> to help you and your family be healthier. Thanks for listening.