Thyroid Health with Dr. Fiona McCulloch: Rational Wellness Podcast 137

Dr. Fiona McCulloch discusses How to Improve Your Thyroid Health with Dr. Ben Weitz.

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Podcast Highlights

3:45  The thyroid is a butterfly shaped gland in the neck that is responsible for the metabolism of every cell in our body.  The thyroid is running the show for how our brain works, how our immune system works, and how all the rest of our hormones work.

4:25  The thyroid produces mainly T4, the inactive form of thyroid, that then gets converted into T3, the active form, in the cells in different parts of the body.  These tissues then convert T4 to T3 as needed.  While it occurs throughout the body, it does occur more frequently in certain organs, including the liver and the gut.  But it even happens in our fat cells and if you expose a fat cell to cold, that fat cell will then start producing T3 in order to generate heat and energy. It becomes hyperthyroid inside that fat cell.  This is also why when people are hypothyroid they feel cold all the time and their basal body temperature gets low.

7:58  Testing for thyroid function should include not just TSH, but also free T4, free T3, reverse T3, and the anti-thyroid peroxidase (TPO) and anti thyroglobulin (TgB) antibodies.  Dr. McCulloch will also sometimes measure the thyroid stimulating antibody (TRAb), aka TSI, to screen for Grave’s.  It is common in medicine to only measure TSH, which is the hormone that the pituitary gland makes that tells our thyroid to make mostly T4.  But we know from research that if a patient is hypothyroid and you correct their TSH to 1.5 to 2.5, there may still not be a difference in their energy expenditure compared to people who have never had a thyroid problem. In such cases, their thyroid is producing T4 but the body is not converting the T4 to T3 very effectively.  There are a number of possible reasons for this, including stress, nutritional deficiencies like iron deficiency, and there are also some genetic mutations/polymorphisms in the gene encoding one or more of the D1, D2, or D3 iodotyrosine deiodinase enzymes that help to convert T4 to T3 and these can be a factor in hypothyroidism.  Dr. McCulloch said that if you have a patient who is not converting T4 to T3 (their T4 is at the higher end of the range, such as 19, and the T3 is at the lower end, such as at 3), and you have fixed their iron, improved their sleep, worked on their adrenals, their stress levels, and their diet, and they’re still not converting T4 to T3, then you might suspect one of these genetic polymorphisms.   

16:22  With respect to elevated TPO antibodies, this is an indication of autoimmune hypothyroid, and if they are also symptomatic, such as having brain fog, fatigue, weight gain, etc., then we should be concerned about this, esp. if the TPO antibodies are above 50.  You should look at their cortisol levels, their stress, and their sleep.  You should also check their levels of iron, vitamin D, zinc, selenium, inflammation levels (HsCRP), blood sugar, and look at CBC for signs of infection.  It is also a good idea to minimize iodine intake, such as avoiding kelp. If the person has lost a lot of weight recently, this can cause the body to lower thyroid output.  You should also look at the gut and remove any dysbiosis or yeast overgrowth.  Then you might want to use a natural desiccated thyroid supplement, such as Armour thyroid or Nature-throid in the US or in Canada the product available is ERFA.  The natural desiccated thyroid contains both T3 and T4, as well as some T2, which plays a role in cholesterol metabolism.

25:48  Iodine is an important component of thyroid hormone and the typical thyroid nutritional support product and the typical multivitamin will contain 100 to 200 mcg of iodine, but some Functional Medicine doctors are recommending iodine in the 12-25 milligram range (thousands of micrograms).  Both Dr. McCulloch agree that super high dosages of iodine usually cause a flare of the antibodies and of symptoms in patients with Hashimoto’s and does not help.  Most of the scientific literature also supports this view, including the data on various countries that have supplemented the diet with iodine, such as iodized salt, that while rates of hypothyroid goiter conditions have gone down, rates of autoimmune hypothyroid have gone up. Here is one paper: Effects of increased iodine intake on thyroid disorders.  In fact, Hashimoto’s is named for an area in Japan where there is more of this iodine intake.  On the other hand, there are cases where the ingestion of halides, which are elements in the same column of the periodic table that compete with iodine for absorption, including flouride, bromine, and chlorine, and these can also cause some thyroid aggravation.

31:15  Reverse T3 is an inactive form of T3 that the body can make from T4, so it is important to measure this.  Some practitioners will look at an elevated reverse T3 or look at the T3 to reverse T3 ratio and will recommend taking higher dosages of T3, but Dr. McCulloch feels that this is ignoring the wisdom of the body and can cause heart palpitations and arrhythmias and the patient not feeling well. First, we need to understand that reverse T3 does not compete with T3 and we should try to figure out why the reverse T3 is being formed.  New research indicates that reverse T3 may have some beneficial functions in the body, such as stimulating the immune system during periods of starvation or illness.

33:35  Patients who lose a lot of weight in a short period of time will often see a decrease in their thyroid function. This is because feels like it’s in a famine situation and it wants to conserve its fat reserves for survival. The body will tend to deactivate thyroid hormone and convert T4 into reverse T3. Exercise can increase the metabolic rate, so make sure that such weight loss patients are doing regular exercise, including resistance exercise.  In some cases, such patient may benefit from taking a low dosage of natural desiccated thyroid for a limited period of time to help them get their system reset and get past that plateau of weight loss resistance.

37:17  Patients who benefit from thyroid support will usually also benefit from some adrenal support as well. Dr. McCulloch finds the herb Ashwaganda a really good adaptogenic herb that can help both patients who need some calming and also those who need simulation of their adrenals. She also finds that stabilizing their blood sugar is very important, since if their blood sugar dips, their body will increase the cortisol levels.  To avoid an afternoon blood sugar and cortisol spike, Dr. McCulloch recommends a healthy lunch with a serving of protein the size of their palm, 2-3 cups of veggies, some healthy fat, like 1/2 of an avocado or a handful of nuts or seeds. She likes to see the carbs low and slow, like a 1/2 cup of beans or of sweet potato.

40:14  The thyroid has a huge effect on the liver including regulating cholesterol production.  The liver normally gets rid of cholesterol through the bile, but with hypothyroid, the bile flow slows and cholesterol gets reabsorbed through the liver again.  So a low thyroid may be the cause of high LDL, since in hypothyroidism the LDL receptor is reduced by around 50%, which suppresses the uptake of LDL.  The thyroid can also affect liver enzymes and increase the risk of fatty liver through the way that it regulates the liver’s glucose metabolism and sensitivity to insulin.  And fatty liver can reduce thyroid hormone conversion, so there can be a negative compounding effect.  If a patient has fatty liver, Dr. McCulloch recommends intermittent fasting, alpha lipoic acid, N-acetylcysteine, phosphatidylcholine, and vitamin C to reverse it, along with the proper, low carbohydrate diet.


Dr. Fiona McCulloch is a Naturopathic Doctor and founder of White Lotus Integrative Medicine in Toronto, Canada, serving thousands of women with hormonal conditions. Dr. Fiona’s best selling book, 8 Steps To Reverse Your PCOS, offers her well-researched methods for the natural treatment of Polycystic Ovarian Syndrome (PCOS). Dr. McCulloch is available to see patients and can be contacted through her website, DrFionaND.

Dr. Ben Weitz is available for nutrition consultations specializing in Functional Gastrointestinal Disorders like IBS/SIBO and Reflux and also specializing in Cardiometabolic Risk Factors like elevated lipids, high blood sugar, and high blood pressure and also weight loss, as well as sports chiropractic work by calling his Santa Monica office 310-395-3111.


Podcast Transcript

Dr. Weitz:                            Hey, this is Dr Ben Weitz, host of the Rational Wellness Podcast. I talked to the leading health and nutrition experts and researchers in the field to bring you the latest in cutting edge health information. Subscribe to the Rational Wellness Podcast for weekly updates. And to learn more check out my website, drweitz.com. Thanks for joining me, and let’s jump into the podcast.   Hello Rational Wellness Podcasters. I would really appreciate it if you could go to your podcast app, Apple podcasts, or wherever you listen to the podcast and give us a ratings and review. That way more people will find out about our podcast. Also, if you go to my YouTube page you can find a video version, and if you go to my website you can find detailed show notes and a complete transcript.

Today our topic is the effect of thyroid health on metabolism. The thyroid is the master regulatory gland, and it’s found in the front of the neck below the Adam’s Apple.   The thyroid produces three main hormones, T4, T3 and calcitonin. Calcitonin plays a role in regulating blood calcium levels. T4 known as thyroxin, and especially T3, triiodothyronine, which is a more active form affect metabolism, appetite, gut motility, heartbeat, breathing rate, the mitochondria and many other functions in the body too. Too little thyroid production, what we call hypothyroidism, including Hashimoto’s autoimmune hypothyroid, which counts for 90% of cases of hyperthyroid in advanced countries like the US and Canada can result in weight gain, a lack of energy, brain fog, feeling cold, constipation, hair loss, infertility, et cetera. Too much thyroid production, hyperthyroidism, including Graves’ autoimmune hyperthyroidism will speed up the metabolism and cause weight loss, et cetera. Today we plan to dig deeper into how thyroid works, how it affects our metabolism and the interaction between thyroid and liver health, with our special guest, Dr Fiona McCulloch.

This will be my second time getting to chat with the beautiful Dr Fiona after she made an appearance on Rational Wellness last year in episode 65, in which we focused on Polycystic Ovarian Syndrome. Dr Fiona McCulloch is a Naturopathic Doctor and founder of White Lotus Integrative Medicine in Toronto, Canada, serving thousands of women with hormonal conditions. Dr Fiona has written a best selling book, 8 Steps To Reverse Your PCOS, which offers well-researched methods for the natural treatment of polycystic ovarian syndrome. Thank you Dr Fiona for joining us here today.

Dr. McCulloch:                   Thank you so much for having me on your show again Dr Weitz, it’s great to be here.

Dr. Weitz:                          Good. So why don’t we start off talking about what thyroid is, what it does and what its importance is?

Dr. McCulloch:                   Absolutely. So, a lot of my practice is dedicated to treating thyroid issues even though.

Dr. Weitz:                          Oh my.

Dr. McCulloch:                   Yeah. So even though most of my practice is women’s health, I would say about 50% of that is treating thyroid health.

Dr. Weitz:                          Okay.

Dr. McCulloch:                   So it’s a huge thing and it affects so much about our health. So, the thyroid is a gland, it’s shaped like a butterfly in the neck, as you were mentioning. And it’s actually responsible for running the metabolism in every single cell in the body. So this tiny little gland is basically running the show for a lot of different things, including how our brain works, how we expend our energy, how our immune system works, and how all the rest of our hormones work. So this is a really powerful little gland that can easily have problems. So it’s definitely one of the most common hormonal conditions that we see in the clinic.

Dr. Weitz:                          Great. So, I’ve always wondered why does the thyroid primarily produce an inactive form of thyroid hormone T4, and then it has to get converted into T3.

Dr. McCulloch:                   That is a such a great question. And as we’ve been doing more and more research into this area, what we’re learning is that the way that the thyroid hormones are converted from the inactive hormone, which is mostly what the thyroid gland makes to the active hormone, it actually happens differently in different parts of the body. So in different cells there might be different things happening with the conversion of T4 to T3, so it’s a very intelligent mechanism that our tissues know what they need and they convert as they need so that the storage hormone that’s coming out, it’s our tissues that have to know what to do with it. And sometimes that goes really well in healthy people, and then at other times not so much.

Dr. Weitz:                          So, in other words each system of the body, each organ converts T4 to T3 as needed for its particular needs?

Dr. McCulloch:                   That’s right. Yeah. So most of the conversion happens inside the cell and these conversions are independent in many ways of other things that are happening in the body, so it’s very complicated what causes that. And there are certain people that have a lot of trouble converting and I can talk later about what those reasons are, but we’re learning more and more about why this is. We know there’s been a lot of people who’ve had thyroid disease, who are on medication, who’ve just never ever felt the same since they developed the thyroid disease, despite the fact that they’ve been treated and everything’s normal.

Dr. Weitz:                          So where is most of this being converted? So you’re saying it’s in every cell in the body? I thought it was primarily in certain organs like the liver and the gut.

Dr. McCulloch:                   So it definitely happens more in certain organs. Like the liver is definitely a big one, but we see this happening in the brain immune system, so all the different cells have different needs for metabolic energy. And for example, even our fat cells. So I was reading a study the other day that was showing us if you take a fat cell and you expose it to cold, that fat cell will then start producing T3 in order to generate heat and energy. So it becomes hyperthyroid inside that fat cell.

Dr. Weitz:                          Really interesting.

Dr. McCulloch:                   Yeah, it’s pretty interesting.

Dr. Weitz:                          So that can be another mechanism for why getting exposed to cold has a beneficial effect. Normally we hear about being exposed to cold increasing brown fat production, which is metabolically active and helps us burn calories. But it sounds like it has a direct effect on thyroid?

Dr. McCulloch:                   Yeah, exactly. And that’s actually part of how that whole thing works is by using the thyroid hormone to generate what we would call a sympathetic drive, so that kind of fat burning energy producing mechanism. So it’s really the thyroid hormone that’s involved in that. And that’s why a lot of people when they are hypothermia they feel very cold all the time, and their basal body temperature gets really low. And when you correct that you’ll see that their temperature gets much better.

Dr. Weitz:                            Right, yes. And you see more commonly in women who get cold easily and tend towards a little hypothyroid. So how do we measure thyroid? What are your favorite tests, and what do you think is the most important measurements of thyroid?

Dr. McCulloch:                   Yeah. So I’m so happy you asked this because it’s definitely one of the number one problems that we have today in understanding the thyroid. So the common-

Dr. Weitz:                            I’ve heard some doctors, even a prominent functional medicine doctor say, “Just TSH, that’s it, end of story. You don’t really need to worry about anything else.”

Dr. McCulloch:                   Yes, exactly. And so this has been sort of the standard for years that we only need TSH, which is really the hormone that the pituitary gland makes. And TSH basically tells our thyroid to make mostly T4, which can then trickle down into T3. But the TSH is supposed to be the regulator and it is true. And that it often is a leader in showing you problems with the thyroid first before you’ll see that sometimes with the other hormones. But it’s not going to give you all the information.  So we know from research, for example, if a patient is hypothyroid and then you correct their TSH age within, when you correct it to one point or to 2.5, what they find is that there’s actually not a lot of difference with the person’s energy expenditure at those different levels of correcting the TSH and getting their T4 levels optimized. But what they find is that there is still a deficiency in energy expenditure compared to people that never had a thyroid problem. So there is something where the tissues can still be hyperthyroid even if the TSH is normal in someone who has a thyroid condition.

Dr. Weitz:                          Wow, interesting. So what exactly is happening there?

Dr. McCulloch:                   So, probably the vast majority of what is happening is that the T4 is really not being converted in the cells very effectively into T3. And there’s so many different reasons for that.  So some of the reasons we’ve known for some time involve things like illness.  So they’ve known for a really long time that when patients get sick in the hospital their T3 levels go down, and their levels of reverse T3 which is like an inactive kind of hormone that our body turns T4 into, those levels go up.  So when someone is sick, so they could have inflammation or an infection or be sick from surgery or something like this, so their T3 will go down. And this is just the body’s way of preserving the energy and protecting against energy loss when you’re sick. Other things can do that as well, like stress for example, or nutrient deficiencies, like iron deficiency. And there’s also interestingly some genetic polymorphisms in some of the deiodinase enzymes. So those are the enzymes that convert T4 to T3. There’s three different enzymes, D1, D2, D3. So D1 and D2, those two are the ones that convert T4 into T3. And especially D2 it does most of that. So when we’re converting, this enzyme is responsible for most of that. And then D3 turns T4 into the inactive reverse T3. So what they’ve found is that about, I believe it’s something like five to 15% of people have a genetic polymorphism in D2, meaning that they can’t convert T4 to T3 as well.  So when you’re giving T4 hormone or Synthroid for example, which is the most commonly prescribed medication, there are many people no matter what they take they’re just not going to convert it the same way. And the way that, that’s given is not exactly the same as all the complex regulations the body would to if it was healthy, because we’re actually giving a hormone. So for that reason, yeah, some people they just don’t convert that well and they still have symptoms.

Dr. Weitz:                          Interesting. Since a lot of conversion is happening in the cells, I wonder if even serum levels of T3 are necessarily even going to reflect this?

Dr. McCulloch:                   Yeah. So it is thought that the serum free T3, because it’s a free hormone, does to some degree mostly correlate to the intracellular levels.  Because we do see that people’s energy expenditure rates when they’re looking at people in a metabolic chamber where they’re controlling everything, when their T3 goes up, their free T3, their energy expenditure goes up.  So there is some kind of correlation there, but there is all kinds of other things that we are not seeing.  You are so right, and so many things that we do not even understand at this point.

Dr. Weitz:                          So are these genes, these genetic polymorphisms for D1, D2 and D3, are these part of 23andMe or an Ancestry panel?

Dr. McCulloch:                   I have not seen them on there. I would have to revisit that and look again because I haven’t looked at what they have recently, but the last time I looked at it I did not see them on there.

Dr. Weitz:                          So do you test those?

Dr. McCulloch:                   Well, in Ontario where I practice we are not allowed to do genetic testing here.

Dr. Weitz:                          Really?

Dr. McCulloch:                   Yeah. I used to do that back a while ago when that was allowed. But my background is in molecular biology, but yeah, we are not allowed to do that. But patients can do that on their own, with 23andMe for example.

Dr. Weitz:                          Oh, okay. So it’s part of the 23andMe, okay.

Dr. McCulloch:                   Yes. I’m just not sure if those are in there or not, the deiodinase polymorphisms because I just haven’t looked recently. But it would be interesting to know.

Dr. Weitz:                          Yeah, I’m going to have to check. I know in the last year or a year and a half, 23andMe is not testing as many genes as they were before.

Dr. McCulloch:                   I know. I know they took some off their panel, some of the bigger ones too.

Dr. Weitz:                          Yeah. They use the less advanced method of testing unfortunately. So apparently Ancestry might be a little better for some of our purposes.

Dr. McCulloch:                   Yeah. It’d be pretty interesting to see that. And I think also the other way that I really noticed it is that the patients are taking T4 medication. And you check everything, you get everything fixed for them, you fix their iron levels, do everything you can for their sleep, their adrenals, their stress levels, their diet, and they’re still not converting T4 to T3, so you’ve got high T4 and low T3. My guess is it’s probably one of these polymorphisms that’s involved there.

Dr. Weitz:                          And so what do you consider a high T4 and a low T3?  Is it outside the typical range or is it more nuanced than that?

Dr. McCulloch:                   The way I look at it is where are they in the range comparatively to each other. So is the T4 up at 19 and the T3 is down at the bottom of the range at 3? Then we know for sure they’re not converting. If they’re around that same level, it looks like they’re most likely converting. But there’s a large percentage of people I would say, especially the people that are on a lot of Synthroid. So they’re on a very high dose of Synthroid, many of them are not doing well on that medication because they’re raising their dose to try to improve symptoms, and they just end up accumulating a lot of T4, it’s just all trickling down into reverse T3. So those levels on the panel can really tell you a lot, just the TSH, free T3, free T4 and reverse T3. And then looking at that compared to if they’re on medication or not, you can get a lot of answers from that.

Dr. Weitz:                          Interesting. So what’s your complete thyroid panel consist of besides TSH?

Dr. McCulloch:                   So yeah. So I definitely include TSH, free T3, free T4, reverse T3. And the two thyroid antibodies that I do most commonly are anti thyroglobulin and anti-thyroid peroxidase. I also do sometimes do the TRAb, which is a thyroid stimulating antibody that you’ll see more in patients who have hyperthyroidism or Graves’. So if I see anything like that, I’ll definitely run that as well.

Dr. Weitz:                          Is that the same thing as a TSI? I think they call it in some of the labs here. Okay.

Dr. McCulloch:                   Yes, exactly.

Dr. Weitz:                          So, now when it comes to TPO enzymes, what level are you concerned about? So this is an indication of autoimmune hypothyroid. So, I’ve heard one prominent functional medicine practitioners say, “Well, basically if it’s under 500 you don’t really need to worry about it.”

Dr. McCulloch:                   So, I kind of look at it, at first I look at the patient and I’m like, “Is this person well, or are they sick? Are they experiencing fibroids symptoms, are they experiencing brain fog, fatigue, weight gain? Do they have like a low body temperature, they’re feeling depressed and they weren’t like that before?” And then I look at the panel and I see how does their function look, and then I look at the antibodies. Now, you can see some people with really high antibodies that are totally fine, which is always interesting to me.

Dr. Weitz:                          What do you mean? What level antibodies are you talking about?

Dr. McCulloch:                   I even have some patients who are doing really well, but they have maybe in the hundreds. And they have no symptoms, it’s founded incidentally, their levels look great. So, for me it really matters if they’re sick or not. And then the more sick they are and the higher the antibodies are, the more concerned I am about that. And especially if I see the antibodies jumping, especially in the order of like a hundred or a couple hundred, or going from something like 50 to 300 then I know something’s going on there. So I think I am like, if they’re in the tens, like up to like 50 or so, many people like this can have a more mild type of Hashimoto’s. But if their thyroid’s really hypothyroid, maybe there’s more going on than we’re seeing those antibodies, then they have more damage to their glands. So I find the antibodies they guide, but they don’t tell me as much as looking at those hormone levels and correlating that with the patient’s overall history and how they’re doing their health. So I kind of take it all in consideration.

Dr. Weitz:                          Yeah. I think some of the labs say under 30 they consider that normal.

Dr. McCulloch:                   Yeah, they’re. Anything under like around 30, I don’t know if you guys use the same units, but yeah, around 30 for the TPO is considered normal. And everybody has some of these antibodies, you don’t see anybody with none. So I don’t tend to see people at that level, below the reference range or really having, I don’t see that as an issue really. If it’s a mild elevation, like sometimes I’ll see that for women who’ve just had a baby and then that can go back down, and that can go away. But when you see the people in the hundreds, that’s probably not going to just disappear overnight. So usually those people have to manage it for the most part. There are the rare cases that don’t, but most of them do have to manage their Hashimoto’s ongoing.

Dr. Weitz:                            So let’s say a patient comes into and they do have some hypothyroid symptoms and they do have elevated antibodies, let’s say not super high, let’s say they’re 150 or 200 or something like that. And what is your rationale? How do you think about this? How do you try to drill down and try to find some of the underlying causes of what’s going on here besides simply putting them on thyroid?

Dr. McCulloch:                   Yeah. So the very first thing I’ll do is if they’re having those symptoms, I’ll try to see do they have low T3 or are they not converting well? And then I’ll start looking at all the reasons they might not be converting well. So I’ll take a look at their cortisol and their sleep and their stress because that’s just huge. I’ll also look at, another good example is if people lose a lot of weight, their T3 will tank at that time because of the weight loss and the body is just really trying to conserve energy. And this all happens because the leptin actually has a huge impact on pushing back on the brain and causing us to actually not burn fat basically. So that mechanism there is a huge part of why people once lose weight, they hit the plateau.

So I always look at that. Did you lose a lot of weight recently or did you do a major change to your diet? I’ll check their iron, their vitamin D, I’ll check their blood sugar to make sure they don’t have diabetes or prediabetes. I’ll check their hsCRP to see if they have inflammation. I’ll look at their CBC to see if they have any signs of an infection. So I look for all the things that might be like the brain is trying to lower the thyroid about, and try to fix those things because that’s the underlying cause of the problem. But if they have these antibodies that are high and you’re working on everything else and you’re still seeing that problem, I’m always going to look at providing the nutrients the thyroid needs because with the antibodies you’re going to need a lot more selenium.

Zinc is another important nutrient as well. So I look at making sure the person’s sufficient in those nutrients and they’re not deficient in anything really important. And also that they have what they need to protect the thyroid gland from oxidative stress and damage from these antibodies. So the selenium is really important. I also tend to minimize iodine intake if they have recently elevated antibodies or a big spike in antibodies because those can be a bit of a trigger too. So I just tend to make sure they’re not consuming kelp or anything else that might be kind of triggering up the antibodies. And then I look at their gut and make sure that there’s nothing triggering infection with their gut infection or inflammation. They’re having some kind of reactions to foods. Do they have a gut infection of some sort, dysbiosis, yeast or bacteria or something else really happening with their gut that’s aggravating their immune system. So I try to look at the autoimmune part that way, and then once I’ve taken care of all of that then I might consider looking at natural desiccated thyroid as an option for some patients.

Dr. Weitz:                            So you prefer using natural desiccated thyroid versus synthetic T4?

Dr. McCulloch:                   I think if certain people are doing very well on synthetic T4 that’s totally great. If your cells work well enough to convert it, fantastic. I think that’s a great sign of being really healthy. Unfortunately, most patients with Hashimoto’s are not in that boat and they’ve gone through a lot like just they’re not feeling well. That might have disrupted their sleep, it might’ve caused stress, they might have other hormone problems. So those patients tend to do better on the desiccated thyroid because it doesn’t require every cell to convert T3 exactly right on point. It would be great if we all could do that, but not most people who have Hashimoto’s are not feeling well. So not so much in that case.

Dr. Weitz:                          What’s your preferred desiccated thyroid product? And there seems to be some issue these days with Armor having maybe change their formulation and some of the products being difficult are on back order.

Dr. McCulloch:                   Oh yes. So we have that problem here too. So in Canada we have only one product which is pharmaceutical called… Yeah. So we don’t have Armor and we don’t have-

Dr. Weitz:                          WP and Nature-Throid no?

Dr. McCulloch:                   No. We don’t have WP or anything, but we do have Erfa. And Erfa is great. It’s actually a really good desiccated thyroid product. So I actually really liked that. And I know a lot of Americans do order that from here, but we are having the same issues with the shortages which appear to be raw material related, because it’s a problem with the manufacturer. So it’s really like a worldwide raw material shortage that seems like it will be improving soon, but it’s really come from that, that all these deficiencies. And that’s why all of the different companies have run out of stock around the same time.

Dr. Weitz:                          So the reason you liked the natural desiccated thyroid is because it’s essentially is a combination of T4 and T3? Is that the main reason why or are there other reasons as well?

Dr. McCulloch:                   That is the main reason. And I also feel that the other thing that it has the other thyroid hormones in there, like T2 for example, which we’re learning does have to play a role in cholesterol metabolism. And you’ll just see night and day changes with patients when they switch from a T4 medication to desiccated thyroid. And there’s very consistent ways that we don’t sit and tweak people’s medications. And my clinic we’re pretty experienced with doing that with the desiccated thyroid and we have really good results. So we tend to get more of the patients who aren’t feeling well on Synthroid. So I think that they’re coming to us for that reason. That tends to be my preference probably because I’m already getting the patients that are not doing well in the first place.

Dr. Weitz:                          Right. You mentioned nutrients and you mentioned iodine, and there are some docs out there recommending super high dosages of iodine. Typical amount of iodine recommended per day is typically you 100 to 200 micrograms per day in most multivitamins or somewheres in that range. And yet there are products on the market that have 12 or 25 milligrams, so that’s thousands of micrograms.  And some doctors claim they get really great results with that. I’ve tried it on some patients that weren’t doing that well and I haven’t seen good results with it.

Dr. McCulloch:                   Yeah, this is a super controversial topic and I totally agree that these higher dose iodines, they’ve been around for quite some time as well as the testing for it.  And I agree there’s probably people that do feel well on this. There’s lots of people who report that they do. I have not seen that either, I agree with you. I haven’t seen patients improve and I’ve actually had patients come in who’ve done this on their own, maybe like the really high dose milligrams of iodine, like Lugol’s for example. And ended up with really bad flare ups of their antibodies and even thyroiditis and hyperthyroidism. So, and we do know from some of the population studies that populations that increase their iodine intake, they have increased levels of antibodies.  Hashimoto’s is actually even named for an area in Japan where there is more of this iodine intake.  So it’s just something I have not seen personally to help that much. And to me it’s potentially risky. And I have seen patients who were intaking iodine in medium amounts, maybe not as high as these really high milligram amounts, but when they cut back on the iodine their antibodies have gotten better.  So I know we have a lot of information in the literature that high-dose iodine is definitely going to be aggravating too many people.  It’s difficult to predict who those people are, so I tend to go towards the treatments that I know are safe and effective and that I have more experience with prescribing.

Dr. Weitz:                          Have you looked at the other products–halides?  So these are elements in the same category as iodine, like fluoride and bromine and chlorine, and some have claimed that these can negatively affect thyroid by interfering with the iodine. Have you looked at that or do you have an opinion on that?

Dr. McCulloch:                   Yeah, I agree with that. I think that can be an element where you can see that these elements will interfere with the uptake of iodine and the utilization of iodine, so that could potentially be true.  There are some tests where you can check for urinary bromide for example, and fluoride and see if you’re being exposed to that.  You would want to make sure you’re not deficient in iodine if that’s the case.  But it’s very difficult to know that without doing this testing.  And then to give them iodine and assume that these negative reactions are a detox type of reaction.  We just don’t really have evidence that’s what’s happening because there are a lot of people that have reactions to iodine and they’re not feeling well, but people are saying this is a detox reaction.  We just don’t really know. It could be the iodine aggravating the patients because we know that this can happen too. So I do believe there is some definitely the fluoride is not great for our thyroid and bromide.

Dr. Weitz:                          Do you have mandatory fluoride added to your water up there in Canada?

Dr. McCulloch:                   Yes we do, absolutely.

Dr. Weitz:                          Yeah, I know a lot of our water has chlorine. I know in Los Angeles where I am we have chlorine and ammonia both added as antiseptics in the water.

Dr. McCulloch:                   Ammonia, that’s not good.

Dr. Weitz:                          Chloramine, yeah.

Dr. McCulloch:                   I don’t know what we have. I have a reverse osmosis in my house.

Dr. Weitz:                          I use that too. Yeah.

Dr. McCulloch:                   Yeah, because I just don’t even want to know what is going into the water supply. One day I moved into my new house and there was a lot of rain and I had my tap on, and I smelled this chlorine smell so strongly coming out. And I was like, “This is crazy. How is this coming out of my tap?” And then I was talking to someone who works in the city and they were saying, in this area because we’re on the Lake and there’s a lot of rainfall, they’ll shock the water supply with chlorine to get rid of organisms. And so that’s what that was.

Dr. Weitz:                          Yeah. There goes the organisms in your gut, right? Bye.

Dr. McCulloch:                   Yeah. I figured it’s got to be bad if your tap water smells like bleach, it’s intense.

Dr. Weitz:                          Yeah, not good. You probably could have lit it on fire, right?

Dr. McCulloch:                   Yep. So, then I called up the water filtration company and here we are.

Dr. Weitz:                          There you go. So talk a little bit about reverse T3. I saw you had an article about reverse T3 and why that’s so important.

Dr. McCulloch:                   Yeah, so reverse T3 it’s one of the hormones that is inactive. So we have the T4 that can turn into either T3 or reverse T3. So T3 is the active hormone and reverse T3 is the inactive hormone. So when people learn about this, I think something happened on the internet where people started to almost villainize reverse T3 as this terrible hormone that we must eliminate and get it down.

Dr. Weitz:                          And everybody said you have to look at the free T3 to reverse T3 ratio. And that was the true marker for thyroid health.

Dr. McCulloch:                   Yes, exactly. And then another trend that happened was if your reverse T3 is high, well what you must do is give T3 medications to force it down, and often very high amounts of this has been done. And it’s really ignoring the wisdom of the body. So the reason that the reverse T3 is high is cause your body wants that to be the case. It’s choosing to do that because it’s saying there’s something that it wants to conserve energy around. And I think before we can say that we need to lower this reverse T3, we need to figure out why is it like that and help the patient overcome that.

And reverse T3 does not compete with the T3 for the T3 receptor, that’s been proven. So it’s not a competitor, it’s just a product that your body is using to kind of get rid of extra hormone it doesn’t want or need. And we’ve also found in new research reverse T3 seems to have, it actually seems to have functions that are on the immune system that are related to times like starvation or illness. So forcing that down is in my opinion pretty risky, especially if you don’t really know what’s happening. And I’ve seen a lot of patients taking all this T3, they end up with palpitations or arrhythmias or not feeling well. Just kind of stressing out, getting yourself into that flight or fight stimulated stage. Sure you have energy, but it’s not great, it’s not good for your health to be in that kind of amped up state all the time.

Dr. Weitz:                          Yeah. You mentioned that people who have a lot of sudden weight loss will see a decrease in their thyroid function, so can people with normal thyroid just because they lost a bunch of weight all of a sudden be suffering from hypothyroid?

Dr. McCulloch:                   Yes, absolutely. And the thing with that is that the thyroid gland is totally fine. It’s more the peripheral conversion. So the fat cells they start burning the fat, the fat mass decreases. And then our fat cells are like, “Oh, I think we’re in a famine maybe because these are very primitive parts of our brain.” So the fat cells are now buckling down and conserving all the energy. And that part of how they do that is actually by deactivating the thyroid hormone. So changing T4 into reverse T3. This happens in healthy people who have no thyroid problem, but it’s not really that their thyroid is involved, it’s more that the cells are doing this to conserve energy.

Dr. Weitz:                          So what do you do about that if you’re trying to lose weight and now you hit this sticking point where your thyroid is slowed down or the conversion of T4 to T3 and the periphery is slowed down?

Dr. McCulloch:                   Yeah, it’s a really good question. So, firstly we would want to do anything we can to optimize that conversion and take away other stressors. And I always say to people the worst time to lose weight is especially I think drastic is if you have stress or a lot going on or can’t get enough sleep.

Dr. Weitz:                          Is there anybody who doesn’t have stress?

Dr. McCulloch:                   Yes. So, no. But yeah, you want to do it at a time that your life is somewhat normal. You’re not doing something really super intense like releasing a book for example. It may not be the best time. Yeah. So basically we take care of everything else that could be contributing to that first. And then there’s different methods that you can use, for example with exercise to just increase your metabolic rate. Ways that you can increase your mitochondria so they’ll burn more energy, so those I always prefer to recommend first. And then there are some patients who do benefit from a little bit of natural desiccated thyroid when they get really stuck. And so in those patients, as long as everything else is taken care of and that’s not going to be a stressor to their system, it’s something that I’ve done for patients and it’s been really helpful for them.

Dr. Weitz:                          Is that something that they’re now going to have to take the rest of their life?

Dr. McCulloch:                   Not usually, so it depends. Yeah. So it’s more when they get to the weight they want to be at, especially if they’re able to increase their muscle mass or do other types of methods to make sure that they do kind of keep their metabolism healthy, then that small amount might just be there to help them get through that plateau and improve further with their metabolism. But yeah, these would be very tiny amounts, not clinical like the higher clinical doses we would see in hyperthyroid patients.

Dr. Weitz:                          So what dosage are you talking about?

Dr. McCulloch:                   Maybe 15 milligrams. The standard starting dose is between 30 and 60 for the patients that have that real weight loss resistance, just like a little bit because their T3 sometimes can be like really, really low and they start getting really cold. And so we do that along with everything else that we can. So getting their sleep and their exercise all dialed into.

Dr. Weitz:                          And when you have a patient who needs some thyroid support, how often do you find that they also benefit from some adrenal support?

Dr. McCulloch:                   Pretty much every single time. Yeah, I don’t think there’s any. Because the other thing too is that having a thyroid condition is really stressful. It just affects so much. So it affects your brain a lot. A lot of people don’t realize how much it affects our brain chemistry. We can have depression, anxiety. People who’ve never had these issues in the past, just develop them. So this causes a lot of disruptions to sleep which really affects the adrenals, or you can have anxiety, which really affects the adrenals. So, just having a thyroid condition is a stressor. And then treating the thyroid as well it can take some time. And so giving the person that extra stress relief and helping them their adrenals to be healthier, helping their brain to perceive stress more normally and have less cortisol reactions to stress is always very helpful for thyroid patients.

Dr. Weitz:                          So what’s your favorite way to support the adrenals?

Dr. McCulloch:                   Oh, I have quite a few. I guess one of my favorites would have to be ashwagandha if we’re looking at a supplement, because it’s so multipurpose. I find many people respond really well to ashwagandha, whether they’re hyper or hypo. It’s nice and calming, so it’s not overstimulating. And then my other favorite would really be keeping blood sugar under control.  A lot of people don’t think of that as something that relates to the adrenals, but every single time your blood sugar drops your cortisol goes up.  And so when you run people’s cortisol, a lot of the time their cortisol spike in the afternoon above the range and it’s because their blood sugar dropped at that time.  So it’s just one of those little things that I’ve learned that makes a huge difference for people’s adrenals.

Dr. Weitz:                          So how do you keep their blood sugar from dropping in the afternoon?

Dr. McCulloch:                   So, I just make sure that they have a really good lunch with a lot of… serving of protein about the size of the palm, two or three cups of vegetables, a nice serving of healthy fat. So something like a half of an avocado or a closed handful of nuts or seeds. And then just keeping the carbs on the lower side. So like a half of a cup of carbs for example. And then choosing carbs that are more slower burn. And so you could look at resistance starch. So something like for example, white beans have a good amount of carbs but they’re high in resistant starch, which really stabilizes blood sugar. Or you could look at sweet potatoes as a tuber that is a very low reactivity kind of carb. So, but really making sure that it’s the proteins, the fats and the vegetables are dialed in. And then just keeping the carbs from running the show, that really stabilizes blood sugar for many, many hours.

Dr. Weitz:                          How does the thyroid interact and affect the liver?

Dr. McCulloch:                   So, the thyroid actually has a huge impact on the liver. Some of the different things that it does, one of the big ones is regulate cholesterol production. So the liver produces cholesterol and a lot of this is actually under the regulation of the thyroid. So for example, if someone’s hypothyroid, what happens is their bile actually slows down. So the bile is the stuff your liver secretes, it goes through your gall bladder and out into your intestines and out your body it goes, and there is cholesterol in the bile. And what happens in hypothyroidism is that slows down and so the cholesterol is actually reabsorbed back up through the liver again. So you’re getting more cholesterol taken back up. The other thing that it does is it reduces-

Dr. Weitz:                          That’s interesting. So if you are working up a patient for cardiovascular disease and you’re trying to control their cholesterol, maybe they have elevated LDL particle number or a small dense LDL and your strategy’s not working, think about looking at the thyroid?

Dr. McCulloch:                   Oh yes, absolutely. I see so many patients who have high cholesterol, they actually have a thyroid problem.

Dr. Weitz:                          An alternative to simply increasing the statin level.

Dr. McCulloch:                   Yes, because it’s not the cause, it’s actually in many cases it’s… I think I saw a study where they were saying that-

Dr. Weitz:                          A Lovastatin deficiency is not the cause of high cholesterol?

Dr. McCulloch:                   Yeah, whatever. It’s just that’s not addressing that the fact that their thyroid is low. But yeah, it’s super common. One of the first things I think when I see high cholesterol, I’m always like, “Lets look at the thyroid.” Because a lot of the time it’s that.

Dr. Weitz:                          By the way, with men, they hardly ever screen for thyroid.

Dr. McCulloch:                   I know. Yes, absolutely, they never do. And if they do it’s just TSH, they’re not looking at anything else.

Dr. Weitz:                          Right, absolutely.

Dr. McCulloch:                   And a lot of men they’re just tired or they’re gaining weight, but they’re not as likely to mention this to the doctor and they’re just in there getting their blood. They’re like, “What’s on my blood?” Your cholesterol is high So they don’t necessarily think to mention that they’re feeling tired or they’ve gained some weight, it’s just not something brought up to men very often is hormones unfortunately. And it really should be.

Dr. Weitz:                            Absolutely, yeah. So go ahead with thyroid and the liver. So it affects cholesterol and?

Dr. McCulloch:                   Yeah. And then the other thing is that it’s responsible for the production of the LDL receptor. So, basically when someone’s hypothyroid their LDL receptor can reduce by around 50%, which is huge. So it suppresses the uptake of LDL, and then of course you’re going to have increased LDL. So that’s another way. So it has a pretty profound effect on cholesterol. And then it also regulates the way that the liver produces glucose, and the liver is sensitive to insulin through actually the nervous system that goes from the brain down to the liver. So it has really high level effects on the liver and metabolism too.

Dr. Weitz:                            Interesting. So, what would we see on a lab test if we saw somebody with the liver enzymes are slightly higher? We typically start thinking maybe they have fatty liver. And so you’re saying this can be related to thyroid?

Dr. McCulloch:                   Yes, very much so. And they exacerbate each other. So having fatty liver can reduce thyroid hormone conversion because of the inflammation that’s there. So they actually make each other worse. So, the hypothyroid affects the liver and causes all of the fatty liver, it slows the metabolism down too. So, the burning of fat is lower. So it just accumulates more, less is going out, more is getting taken back up, the receptor is down. So it’s just a vicious cycle.

Dr. Weitz:                            So, besides lowering the carbohydrate intake of the diet, what other strategies are there for… what are your favorite strategies for combating fatty liver?

Dr. McCulloch:                   So yeah. I would say 100% diet is the number one strategy for that. But just to go even further into diet, intermittent fasting is fantastic because it really gets the insulin down and allows the liver to really release the extra energy that’s there.

Dr. Weitz:                            What do you call intermittent fasting?

Dr. McCulloch:                   So, it really could mean anything about going from one meal to another. But what I’m talking about more is at least 12 hours and maybe like a 16:8 would be the minimum that I would consider to recommend to patient. The 16:8 I find I recommend those several days a week for patients a lot. Not every single day, but a lot of patients can do that and it makes a huge difference with the liver and its function. So, that’s definitely one of the big ones that I suggest for people.

Dr. Weitz:                            Are there any nutraceuticals, nutritional supplements that can be beneficial for fatty liver?

Dr. McCulloch:                   Yes, absolutely. So, I find some of my favorites are alpha lipoic acid because it definitely helps with the insulin resistance as well as provides antioxidants to the liver. And acetylcysteine is another one of my favorites. It’s very much-

Dr. Weitz:                            Which is the precursor for glutathione, right?

Dr. McCulloch:                   Exactly, the precursor for glutathione. It’s used in liver detox pathways. It is antiinflammatory, it helps with insulin sensitivity. Making sure that there’s enough choline as well is really important, which can be taken in through something like phosphatidylcholine or you can get choline from eating liver or eggs as well. So those can be really key. And I’d find as well just making sure that there’s really good antioxidant status. So even something as basic as vitamin C, if you have low vitamin C, your liver will not be functioning at its most optimal. And when the liver is fatty, it’s already very congested and there’s so much inflammation and so much additional need for different nutrients, that vitamin C is very easily depleted.

Dr. Weitz:                            I don’t want to go down another rabbit hole because we’re just about out of time, but you mentioned choline and I’ve had several discussions on the podcast about the current controversy about TMAO being caused by consuming choline. Do you have a comment about that? TMAO is this marker that the Cleveland heart lab came up with for increased cardiovascular risk.

Dr. McCulloch:                   Interesting. I don’t know about that study, but is that a certain kind of choline or is it dietary choline or supplemental choline?

Dr. Weitz:                          Both. Absolutely. So, Stanley Hazen who developed this TMAO marker, it’s on a blood test, it’s being offered, I think Boston heart lab includes it now. And they’re saying this is an independent of cholesterol marker for heart disease risk. And intake from food or supplements of choline, L-carnitine or phosphatidylcholine are all the things that he says you need to reduce. And I have a lot of problems with this concept because those nutrients are super helpful and we found choline super beneficial for the liver, and L-carnitine another super beneficial nutrient, including for patients with congestive heart failure. So it’s really hard for me to buy into this TMAO hypothesis, but it’s a point of controversy right now in discussion.

Dr. McCulloch:                   Yeah. I’ve never heard of that.

Dr. Weitz:                          Look it up, TMAO.

Dr. McCulloch:                   Yeah, I definitely will. And I would find it, I would want to see like some kind of information that it shows because we know that the choline has been found in many other studies to be very beneficial for the liver.

Dr. Weitz:                          Absolutely. And we’ve seen eggs do not increase your risk of heart disease, which are high in choline. Yeah.

Dr. McCulloch:                   Yes. I want to see what are the elements that are related in how is this pathway, could it be related to something else and is it directly damaging? I’m just sort of interested to see more about that, but I’ll definitely look into that. That’s really interesting.

Dr. Weitz:                          Yeah. Listen to the podcast interview I did with Bob Rountree. That was one of the things we discussed, but it’s come up several times in discussions about cardiovascular risk.

Dr. McCulloch:                   So interesting because we don’t see in population studies that really consuming eggs increases cardiovascular risks.

Dr. Weitz:                          By the way, this is another tool right now for the… there’s kind of a dietary war going on right now and we have the different sides.

Dr. McCulloch:                   Yes.

Dr. Weitz:                          But the plant based side, i.e. the vegan side is, yeah, we got you with the TMAO now.

Dr. McCulloch:                   Yes. So may be there are certain things you can pluck in.

Dr. Weitz:                          Reason why you can’t eat meat, you can’t eat eggs.

Dr. McCulloch:                   Yes. I think we saw that with carnitine in the past as well.

Dr. Weitz:                          Exactly. Carnitine like this TMAO. Yeah, exactly.

Dr. McCulloch:                   Yes. So I will have a read and do some thinking on that too.

Dr. Weitz:                          Good. Okay. So how can viewers and listeners get ahold of you and contact you, and find out about your book and your program? And when is your thyroid book coming out?

Dr. McCulloch:                   I still haven’t recovered from my last book. But you can reach me at whitelotusclinic.ca. I have a practice in Toronto. We have a clinic where we serve lots and lots of patients with hormone problems. I have a book called 8 Steps To Reverse Your PCOS on polycystic ovary syndrome. I have an Instagram page @drfionand, and I have a blog also at drfionand.com with lots of information. So feel free to follow me there.

Dr. Weitz:                          Excellent. Thank you Fiona.

Dr. McCulloch:                   Thank you Dr Weitz, it’s so nice to talk to you today.

Dr. Weitz:                          Excellent, I loved it.


1 reply
  1. Jaclyn Downs
    Jaclyn Downs says:

    Awesome interview, great questions! And great answers by Fiona!

    23andme does report a couple DIO1 and DIO2 SNPs. However, I wouldn’t recommend someone go out and get a 23andme test since the chip changed to V5 in August 2017, as they took out so many (thousands) SNPs that many interpretation softwares reported. Plus, you’re basically selling your genetic info to the devil to do as he pleases with it. I recommend privately owned companies that designed a chip specifically for functional medicine doctors.

    Also, other thyroid genes that can cause issues are TSHR (TSH receptor gene) and TPO and CTLA4 (CTLA-4 A49G polymorphism seems to be an important genetic determinant of the risk of HT and GD in Polish patients. It is the second major immune-regulatory gene related to autoimmune thyroid disease)


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