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

**Michael Greger** (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 theories about diets and supplements and the best foods to eat. Well, my role is to take the mystery out of good nutrition and look at the science. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger.
Today we finish the webinar on thyroid health with answers to questions from our webinar audience.

**Michael Greger** (0:28)
It is time for me to take questions. The first question in the queue, which is, 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? A fantastic question. So, there are these so-called 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 doses of these foods when you have inadequate iodine intake. So, if you have marginal iodine status, and then on top of that, you're eating 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 make sure you have enough iodine.
Now, note that I made a little caveat saying normal amounts of food if you go way back. In fact, I looked it up during the break here. This was the video on November 3rd, 2010 Over 10 years ago on Nutrition Facts, the video was called Overdosing on Greens, Raw Cruciferous Vegetables, How Much is Too Much? And, yes, you can indeed overdo it.
So, you don't have to worry about cooked cruciverous vegetables because the good genetic compounds are totally destroyed. It does take 30 minutes. But you can overdose on raw cruciverous vegetables whether or not you have thyroid issues, because everybody needs a functional thyroid gland. Yes, New England Journal of Medicine, Coma induced by raw bok choy. She was eating. But three pounds a day, the woman in this case study, three pounds a day, every day, of raw bok choy. 15 cups a day.
Of Raw Cruciferous is too much. In the two months before she was admitted to the Intensive Care Unit in respiratory failure… She consumed about a thousand cups of robot joy.

**Michael Greger** (2:58)
too much.

**Michael Greger** (3:00)
Now, each cruciverous vegetable is different in terms of the amount of these compounds, and so if you actually go to the video I show, you can probably get away with 50, 50 cups of raw cauliflower a day, because cauliflower has less of these compounds.
The cruciverous vegetable with the most is mustard greens. And so just 3 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 are delicious, but I don't know. But yeah, 3 cups of raw mustard greens, even if you have normal thyroid function, can raise your levels so much, interfere with even normal iodine 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?
Well, what you describe as kind of a combination of hyperthyroidism symptoms and hypothyroidism 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, whereas lack of energy may be more hypothyroidism.
I don't know who the questioner is, but sounds like kind of symptoms of perimenopause. When we start going through menopause, you have night sweats, insomnia, a bunch of other issues. But, so go to your doctor and figure out what it is. Okay.
Next question. Is there a connection between healthy thyroid and gut health, specifically bowel health?
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. Right now, like you have hypothyroidism, you can get constipated, I mean, it can have implications for your gut, but what I find most fascinating is how the gut can impact your thyroid. And so 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 beans, chickpeas, and lentils. Those are the most concentrated sources. And so that's where my Brol Bowl comes, right? It's one of the myriad uses of Brol, which is this prebiotic mix, to feed your 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, whereas if we eat foods stripped of fiber, like junk foods or animal foods, we can actually foster the growth of bad bacteria and make toxic things, toxin-catabolized leg, trimethylamine, etc., etc. Anyway, so yes, there is a connection between healthy thyroid and gut health, and so we're finding more and more diseases are linked to the gut. Even psychiatric diseases, anything having to do with inflammation, because the gut microbiome can have such an impact on systemic inflammation. So keep your gut bugs happy. How do we do that? By feeding them prebiotics, and not taking antibiotics unless we really need them. Okay, can I take black human alongside prescribed medications? Does it have to be ground before eating? You can take black human with prescribed medications, as long as that prescribed medication isn't your thyroid replacement hormone. We want to take all thyroid hormones on an empty stomach, but you can otherwise take black human with other medicines that 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.