Carbs, IBS, Metabolism, and Thyroid

I was supposed to discuss carbs, IBS, metabolism, and thyroid on Ben Greenfield’s podcast, but Ben and I had to reschedule our recording, so I thought we could cover this today. Let’s discuss some important aspects of how carbs affect IBS, metabolism, and thyroid and provide guidelines to make sure you are using carbs to your advantage and not your detriment.

Dr. R’s Fast Facts

Today we will cover

  • For digestive conditions like IBS (gas, bloating, abdominal pain, constipation, lose stools) – is there a consensus regarding the role of carbs? Good carbs, bad carbs, high carb, low carb?
  • How does the microbiota influence this? Do people with digestive conditions need to feed their healthy bacteria in order to feel better?
  • Why is there so much conflicting data regarding carbs and digestive conditions?
  • What about the relationship between carbs and metabolism? Some swear by low carb, but then others swear by high carb/low fat. Who is right?
  • Carbs and thyroid: does a low carb diet cause damage to one’s thyroid?

If you need help using this information to become healthier, click here.

Carbs, IBS, Metabolism, and Thyroid - RUSCIORadioWeb
Episode Intro 00:00:42
Carbs & IBS (Diet Choices) … 00:04:00
The Microbiota Influence … 00:08:32
Histamine & Immune Activation … 00:11:20
Prebiotic Diet … 00:13:38
Conflicting Data … 00:15:45
Dr. Ruscio Resources … 00:18:32
Homo Habilis vs Paranthropus Boisei
… 00:19:28
Carbs & Metabolism … 00:22:34
Carbs & Thyroid … 00:27:57
Episode Wrap Up … 00:36:03

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  28. Future of Functional Medicine Review

Carbs, IBS, Metabolism, and Thyroid

Episode Intro

Dr. Michael Ruscio: Hey, everyone. Welcome to Dr. Ruscio Radio. This is Dr. Ruscio, and let’s talk about carbs, thyroid, metabolism, and IBS. I was supposed to go on Ben Greenfield’s podcast to talk about some of this stuff, and we ended up getting our scheduling confused and had to reschedule.

So I had a bunch of notes in preparation for that show, and I thought I could just run through those on our show today because I think there is some important stuff we can check in on.

Now, before we do that, there are a few other things I wanted to talk to. First, thank you, guys, so much for your continued support of the podcast. The past couple months, the growth of the podcast has been so ridiculous that I’ve literally had to go back and check that the numbers weren’t typos or errors because it has been growing so fast.

So thank you, guys, so much for your support. And I’m so happy that this message is catching on because I think this whole message of cost effective and practical functional medicine and what have you that we’ve been discussing really needs to get out there and catch on in order for the field to grow and in order for the field to help more people.

And for the patients listening to this or consuming that type of healthcare, it’s going to make it a lot better for them also. So it’s really a win-win for everybody involved.

The other thing I wanted to speak to briefly was—if you remember back to the podcast where I introduced the Future of Functional Medicine Review, I just wanted to make sure I didn’t come off offensive to anyone who works for a supplement company.

And it’s a delicate balance trying to call out some of the things that need to be amended without offending people who might be a party to the companies or the field or the part of the field that needs to make some of those amendments.

Certainly, there are a lot of good and virtuous supplement companies out there and doctors or nurses or healthcare practitioners who lecture for or work for supplement companies, so I don’t want to paint the picture that I’m some kind of supplement company or lab company conspiracy theorist.

But I’ve also seen some pretty disturbing things, and it definitely is disheartening to me when I’m sitting in a room of people listening to a doctor at the podium, and when everyone is looking at this doctor and everything they’re saying like gospel, and I’m the only person in the room who, fortunately, has figured out that this person has a very cozy financial relationship with the lab and the supplement companies that he is recommending.

And I’ve seen some things like this, and it has really been disheartening.

Of course, I can’t name any specific names. But what we can do is we can just be a little bit honest in this conversation and bring a higher level of being critical, both from a patient perspective and from a healthcare practitioner perspective, to evaluating some of these things and just being cognizant of the fact that we have to be a little bit careful in some of the advice that we’re taking.

But that’s going to be more so a few bad apples rather than the whole bucket of apples, I guess. So I just want to make sure to say that. Okay.

Carbs & IBS (Diet Choices)

So let’s talk about carbs and IBS. So one of the questions that Ben and I were going to discuss was, “Is there a consensus for the amount of carbs that are best for digestive conditions like IBS, which can oftentimes include gas, bloating, abdominal pain, constipation, and loose stools?” So is there a consensus?

Well, that’s tough to say. I think that there’s a consensus in the data. Oftentimes, you get a non-objective reporting from a given expert as to what the consensus of the data shows. So the true data, I think, shows at least a suggestion of a consensus. The expert opinions may not, unfortunately, reinforce this sometimes because there is sometimes dogma that limits or hinders objectivity.

But essentially, I do think there is a consensus. And there are maybe two or three components to consider with this. I guess, first, the practical take home is to experiment with a couple diets to see which one works best for you. And the carb component of this is oftentimes addressed as part of the diet’s rules or guidelines.

So the Paleo diet is a great place to start. This will restrict many types of food allergens. Many of the food allergens are carbs. For some people, it’s gluten. For some people, it’s dairy. For some people, it’s more so the processed food or the sugars. But the Paleo diet is a good place to start.

Now, other people may need to limit carbs that are highly fermentable, and this is the low FODMAP diet. So those people may go off gluten and notice they don’t feel any better.

“Oh my gosh! Is that possible? I thought everyone and their mother needed to go off gluten because it’s this evil thing.” No, not everyone notices improvement from going off gluten.

For some people, restricting fermentable substrates in their diet, which is outlined by the low FODMAP diet and its cousin diet, I guess you could say, the SCD diet. And there’s also the Fast Track Diet by Norm Robillard.

They’re all very similar in the sense that they restrict carbohydrates that feed bacteria. And if you are someone that has excessive bacteria or your immune system is not very well calibrated to handle those bacteria, you will do better with a dietary approach that does not encourage bacterial growth but rather keeps the shrubs trimmed, so to speak.

So this doesn’t necessarily mean low carb, but it definitely can push people in a lower carb direction. So for some people, they will clearly do better on a lower carb-type diet.

And I do think it’s a good place to start because when you go onto Paleo and if you do a Paleo/low FODMAP-type diet or the like, then you tend to relatively start restricting your carbs.

So I think moving in the lower carb direction initially makes sense, seeing how someone does, and then considering bringing the carbs back up, depending on how they do, because there is also a subset of people that do better on a Paleo diet or a low FODMAP diet that’s a little bit higher in carbs.

So it’s not to give these absolute rules, but from a carb perspective, a little bit of a lower carb diet and a diet that restricts certain types of carbs that tend to be allergenic, as the Paleo diet outlines, or highly fermentable, as the low FODMAP diet outlines.

So the general consensus is caution regarding carbs—not necessarily low carb, but caution regarding carbs and doing some experimentation with limiting carbohydrates, both in the types of carbs that can be allergenic like gluten, for example, or other grains that can highly encourage bacterial growth, like the low FODMAP diet. So that’s something I think we can say that’s a consensus.

And if someone doesn’t respond to those things, then finding a good clinician who can look for things like SIBO or candida or other pathogens or potentially imbalances in acid—high acid leading to ulcerations and gastritis or low acid leading to things like bacterial overgrowths and also motility impairments—can be very helpful.

The Microbiota Influence

So another component of this question is, “How does the microbiota influence this?” And oftentimes a question is, “Do people with digestive conditions need to feed their healthy bacteria in order to feel better?”

And you would think so. But what I’m increasingly coming to believe is the answer to that question is no. Feeding bacteria for many people is not the ideal approach.

And it’s kind of a generalization. But let me explain, and maybe even let me preface by saying this: the healthier someone is, the better they tend to do with approaches that feed bacteria—things like fiber and things like prebiotics.

This helps bulk the stool. It makes stool movements easier, sometimes more consistent. And the compounds in fiber and prebiotics tend to slow down the absorption of carbohydrates, which can be good for metabolism.

But the challenge is, for those with digestive conditions, the bacterial feeding approach tends to be highly problematic—again, not for everyone, but many people, I find, need to generally design their diet, their lifestyle, their supplement program around somewhat limiting bacterial growth, keeping the shrubs trimmed, if you will.

And I’ll outline a couple studies that speak to this. There was one study (1) that took 20 patients and put them on a low FODMAP diet for three weeks. 85% of the subjects experienced a notable improvement in their digestion. This was with IBS patients—not sure if I said that. So 20 IBS patients went on a low FODMAP diet. 85% saw improvement.

Then from there, they were divided into two groups. Half stayed low FODMAP. Half started on 16 grams per day of fructooligosaccharides, a prebiotic.

Now, of the half that stayed low FODMAP, 80% maintained their improvements. Of that half that went on the prebiotic, only 30% maintained their improvements.

So we definitely see, in this case, prebiotics don’t seem to be very helpful. What else is interesting here—and we talked about this in the Future of Functional Medicine Review podcast—the people on the low FODMAP diet saw improvements in their symptoms and in their inflammation.

But some of these other markers that we don’t really know exactly what they mean or exactly what optimal are—like microbiota levels and short chain fatty acids—they actually looked “less healthy” even though the subject looked more healthy.

Histamine & Immune Activation

There’s another component of this also that’s very interesting (2, 3). And this has to do with the immune system in the gut and a key mediator of the immune system in the gut, which is histamine.

Now, histamine and the immune system are caught in this self-feeding cycle. Now, if the immune system in the gut activates, that causes a release of histamine.

Now, also, if you have too much bacteria in the gut, those bacteria themselves release histamine, which can then cause further immune activation. So histamine and gut bacteria are intimately linked.

And the other part of this that’s important to mention is many people, because of the society and the environment that we live in, do not have healthy immune systems. They’re a bit prone to over-activation of the immune system.

So how this is relevant to the whole carbs and prebiotic piece is it has been shown by following a low FODMAP diet, one can yield an eight-fold decrease in histamine. So that’s a pretty big deal.

So this may be another component of why low FODMAP is helpful. But you have to think past the aspect of, “Oh my gosh! This bacteria colony decreased on a microbiota test. This must not be healthy for someone to be on low FODMAP.”

If we think about this from an immune perspective, what might be happening is that low FODMAP diet is helping to weed or decrease the level of bacteria the immune system is acting against. And by doing that, there’s less bacteria to A) produce histamine, which pisses off the immune system, and B) there’s less histamine present, which stops the immune system from further attacking the microbiota to begin with.

So there’s more to these things than just one narrow component of Bifidobacterium levels decreased on the low FODMAP diet. There’s far more to a biological system than one of these parameters.

And so the histamine and immune piece may be another aspect of this that’s important. And when I say “this,” I mean the merits of a lower fermentability, lower FODMAP, and potentially lower carb-type diet.

Prebiotic Diet

Now, another argument that comes up sometimes is, “Well, once someone has gotten their gut healthier, they can go on a higher prebiotic diet, and it’ll work well for them at that point”—which I am not opposed to.

I do think it’s a good exercise to start with a bit more of a strict diet, if you will. But then, once someone is healthier, try to expand to a broader diet totally. And we should be working to get people on the broadest possible diet in the long term possible.

But looking at another study in quiescent Crohn’s—we also talked about this briefly in the Future of Functional Medicine Review—but it just happens to be salient again now (4, 5). Quiescent Crohn’s means these people had been in remission for a while, so you could argue their gut was probably doing pretty well.

Half of the patients went on a high FODMAP diet, and these patients saw a near doubling of their symptoms. And diet would probably be the safest way to get some prebiotics in the system, rather than taking a fiber supplement, which would be concentrated, or a prebiotic supplement, which would also be concentrated.

This is a food-based intervention for feeding your gut bugs. And this did not go well for those with IBD.

Now, coming back to my earlier point, does this mean that a high FODMAP diet would not work for someone who is super healthy? No, they would probably be okay with it.

But many people have imbalances in the gut and may not have adequate immune system programming in the gut, which is something that doesn’t change a ton, and we just have to learn how to create the best environment for the immune system that has been programmed, the predominant part of which happens by about 3 years of age.

So it’s just trying to create an environment for the immune system that we now have. And it seems like, in many cases, when there are problems in the gut, this lower carb, lower fermentability-type approach seems to work the best.

Conflicting Data

So another question that comes up in this conversation is, “Why so much conflicting data regarding carbs and digestive conditions?” Because you’ve probably heard, unfortunately, lots of people, and even people who are highly credentialed and have written really popular books, talking about how important fiber is and prebiotics, which is true to an extent.

Definitely if we’re eating a highly processed diet that’s devoid of fiber, then we want to get some more fiber in. But it can become misleading because it paints fiber and prebiotics like the cure to all ails.

And really, most of the benefit you get from “increasing your carbs” comes from when you go from a standard American junk diet to eating any one of the healthy diets, which could be Mediterranean, it could be paleo, it could even be a higher carb, vegetarian-type diet.

Most of that benefit comes from making that transition and not necessarily going above and beyond. So the modern day fiber enthusiasts could just say, “Eat a healthy diet. You’ll be eating some more fiber as part of that diet. And it’ll be healthier for you.”

But trying to paint it as the miracle of bacteria in your gut holding the key to all health ailments is not really accurate, because for the people that have the biggest problems with those bacteria in their guts, eating a high fiber and high prebiotic diet is probably going to be detrimental to them—not for everyone, but for many.

And as a clinician who sees these patients every day and doesn’t just write books about it based upon the research, I can tell you what we see in the research, when you look at the clinical research, reinforces absolutely what I’m saying.

So part of the reason for the confusion is the small intestine is left out of the equation. Remember, the small intestine represents over 56% of your gastrointestinal tract, whereas the large intestine, where much of the “you need a lot of bacteria, you need to feed your gut bugs,” research in Africa, hunter/gatherers who eat a high carb diet have lots of colonic bacteria, comes from.

So large intestine, 20%, where some of this skewed data is coming from, misses 56% of the GI which is the small intestine. Small intestine is also responsible for 90% of caloric absorption, much more prone to leaky gut because it has a thinner mucous membrane, and there’s much more absorption that occurs there.

The small intestine also has the highest density of immune cells out of any area of the body. So this is where this whole immune/autoimmune connection comes in and is very important.

Dr. Ruscio Resources

Hey, everyone, in case you’re someone who is in need of help or would like to learn more, I just wanted to take a moment to let you know what resources are available. For those who would like to become a patient, you can find all the information at

For those who are looking for more of a self-help approach and/or to learn more about the gut and the microbiota, you can request to be notified when my print book becomes available at You can also get a copy of my free 25-page gut health e-book there.

And finally, if you’re a healthcare practitioner looking to learn more about my functional medicine approach, you can visit All of these pages are at the URL, which is, then slash either “Get help,” “Gut book,” or “Review.” Okay. Back to the show.

Homo Habilis vs Paranthropus Boisei

And then another piece here, maybe not to get too anthropological, if that’s even a word, but I just want to throw this in there. So one of my hobbies is studying evolution. That’s probably not too surprising, someone being friendly of the paleo movement. But outside of me looking at this from a scientific perspective, I just find it very interesting.

And when you study a lot of the developmental literature or documentaries, you see that there was a key point in time—and we’ve discussed this on the podcast before with Aaron Blaisdell and a few others—where there were two competing hominids at the same time, Homo habilis and Paranthropus boisei.

Now, Homo habilis was a scavenger. And they were highly omnivorous. They ate whatever they could get their hands on. They would scavenge meat off a dead carcass that maybe a saber tooth tiger had killed earlier in the day. They would crack open bones and try to eat the marrow. They would climb a tree and eat honey. They would eat ripe fruits.

Whereas Paranthropus boisei was a specialist in the terms of they just ate these heavy vegetative plants and roots that were easily accessible.

So Paranthropus had more of a colon or large-intestine-centric digestive system—lots of bacteria that would ferment and break down these hard-to-digest grasses and roots. And life for him was pretty easy because this food stuff was in plenty.

Homo habilis had more of an omnivorous nature where they couldn’t break down those heavy and hard-to-digest food stuffs. And they relied a little bit more heavily, at least we think, on their small intestine because they didn’t have the robust colon to digest the easy-to-access plant matter.

So how this is relevant is when the climate started to shift in the region of Africa where these hominids were competing, much of the vegetation started to die out. And Paranthropus boisei, because he had a specialist digestive tract that was large intestine and bacteria fermentation dependent, died because he could only eat one food, whereas Homo habilis was able to eat different foods, and even though some of the plant life started to die, he could still scavenge from animals.

And we think this was a key evolutionary turning point that set our digestive tracts on the path of being less fermentive, less large intestine dependent, and more small intestine dependent. So there is definitely some important evolutionary pieces behind why the small intestine is so important.

Carbs & Metabolism

So moving on here and shifting gears a little bit, another one of the things that we were going to talk about—Ben and I—was the relationship between carbs and metabolism and speaking to this debate where some people swear by low carb. And then other swear by high carb and almost more of a vegetarian-type diet.

And so the question is, as a confused person trying to weigh through all these conflicting opinions, what do you do? Well, something that can be helpful is not to be dogmatic in your approach and just have an honest look at the literature.

And I review this in my coming book in a pretty detailed fashion. What the literature shows is that any diet plan can cause improvements in someone.

So this would be the Atkins on the low carb end, paleo or Mediterranean maybe more on the moderate-ish end of things, or even a vegetarian-type diet like Pritikin or Ornish. They can all improve people’s health. This has been documented, so we really shouldn’t question that.

Now, if we take this a step further, we can say, “Okay. Compared to no diet or eating garbage or what have you, any one of these diets can work. But maybe we could compare one healthy diet to another in a head-to-head trial.”

Now, what this does is it stops us from arguing over, “Here’s my study. Here’s my P-value. Here’s what happened in this group of paleo dieters.”

And then the vegetarian person comes back, “Well, here are all these vegetarian diets. And they also show these good things. But my P-value is better than yours. Or the amount of subject we had was better than yours. Or the impact on lowering blood sugar was better than yours.”

When you look at two different studies and try to compare them, it’s hard to assess what is better. However, if we can design a trial that compares in a head-to-head nature, one healthy diet against the other, now we can have a much more practical way of assessing what diet might be the best out of all these diets that can help.

So when we do this, we see clearly for certain conditions a paleo-type diet seems to be better. And a lower carb diet also seems to be better. So let’s look at a few of these specifics.

A clinical trial (6) comparing a low carb diet to a more traditional low fat diet found lower carb worked better for treating type 2 diabetes—not surprising.

Another clinical trial comparing low fat versus low carb for type 2 diabetes found that they both worked. But lower carb worked better (7).

A paleo diet has also been shown to work better than conventional, lower fat, higher carb/grain diets for type 2 diabetes (8). So paleo and low carb both are working nicely here.

Now, again, there are many studies showing that traditional low fat, high carb diets that increase fiber and fruit and vegetables and grains help with heart disease and obesity. And I’ll put a number of studies in there. So that’s totally fine, guys.

(9, 10, 11, 12, 13, 14)

But when we look at more of the comparative trials, we see more of the same. A recent trial found that a paleo diet improves cholesterol levels to a greater extent than traditional, heart healthy, low fat dietary recommendations (15). And you have to look at the entire cholesterol picture, not just LDL cholesterol because that can be misleading.

Another study found a paleo-type diet for only two weeks was able to improve several cardiovascular risk facts compared to a healthy reference diet, which is a traditional low fat diet, in subjects with metabolic syndrome (16).

Additionally, a paleo diet caused better improvements to blood sugar and several cardiovascular disease risk factors compared to a diabetes diet, which is again just another off tick of a traditional lower fat, higher carb diet, in a group of patients with type 2 diabetes (17).

Possibly most compelling, a systematic review with meta-analysis—now, remember, this means a group of researchers summarized the available clinical trials to give us a summary of what all the data says—and they showed that the paleo diet was more effective for metabolic syndrome than standard nutritional recommendations, which are typically lower in fat and higher in carb (18).

Also, for weight loss, a systematic review with meta-analysis of 53 studies found a lower carb diet works better than lower fat, higher carb diets (19).

So when we start looking at these things comparatively, we see pretty clearly that in many cases a paleo diet or a lower carb diet tends to have an edge.

Now, is this to say that the only diet that can help someone out there is going to be a paleo diet or a lower carb diet? No, because they’ve all been shown to work.

But if we’re going to look at which ones look better, at least based upon some of this literature that we have, which I think is pretty impressive when you look at some of these head-to-head trials, we do see a general trend that the paleo diet or lower carb diet tends to work better.

Carbs & Thyroid

So shifting gears and moving on here to carbs and thyroid—just so much to say here, because thyroid is just one of these things, to be honest, that is so popular because it’s used to market stuff, guys. People oftentimes think they have a thyroid problem because the symptoms are so broad and so nonspecific.

And so it’s just one of the key areas that’s gone to when a business is trying to reach a healthier consumer. It’s oftentimes wrapped in the cloak of thyroid.

And what’s unfortunate about that is, while that is not always done with ill intent, there are some that do it with ill intent. And it creates this excessive information out there that has a very low utility for actually helping someone with a thyroid problem or what in more cases looks like a thyroid problem but actually isn’t.

So we reviewed in the past that even those with full blown subclinical hypothyroidism show a very minimal improvement from using thyroid hormone replacement. And subclinical hypothyroid means, according to the conventional ranges, their TSH is high—5, 6, 7, 8, 9, whatever, 10—and their T4 is normal.

So if you have these symptoms but your thyroid is normal, it’s usually not a thyroid problem. It’s usually stress, diet, lifestyle, inflammation, a gut problem, and that underlying problem is causing symptoms that look like hypothyroidism but actually aren’t (20).

And this is a key thing to understand, because you can do all these advanced thyroid tests, but if they don’t tell you what’s causing the problem, all you’re doing is quantifying a symptom. And in this case, it would be quantifying the lab component of a symptom but not telling you where the symptom is coming from.

So, gosh, there’s so much I could say on that. But to put it simply, as long as you’re not frankly hypothyroid, then the answer to overcoming your thyroid-like symptoms is probably not your thyroid. It’s probably something else. And in many cases, it comes down to the gut.

Now, what about thyroid autoimmunity? Well, we’ve been talking about this maybe overzealous interpretation of thyroid antibodies. And I’ve been saying for a while that I’ve noticed in the clinic when someone achieves a thyroid antibody level, specifically their TPO antibodies, between 100 to 300, I’ve associated that with a clinical win.

What is a clinical win? The person looks healthy. Simple. They’re sleeping well. They have a good sex drive. Their hair is good. Their skin is good. Their digestion is good. They have good energy. They’re not depressed. They’re not bloated.

And we reviewed previously a study that showed that those that have TPO antibodies below 500 are associated with a minimal risk of progression of hypothyroidism (21, 22).

And I’d like to thank Dr. Sarah Lobisco (hopefully, I’m pronouncing that right). She made me aware of another great paper (23) that showed that when TPO antibodies were above 100, it correlated with poor psychological health.

So, we see one study showing above 100 shows poor psychological health. I haven’t had a chance to dig into the details of that study. I will soon, and we’ll probably review that study in detail in a future edition of the Future of Functional Medicine Review. But we see one study saying above 100 is problematic, one study saying above 500 is problematic.

That, I think, fits pretty squarely into my clinical observation of between 100 and 300.

So, why this is relevant is because we don’t have to treat someone indefinitely if their antibodies are in a low normal range. And I’m working toward the carb connection on this also. And that’s the next thing I wanted to go over.

We also, in an edition of the Future of Functional Medicine Review, went into quite a bit of detail on this study. But essentially, this study showed that a lower carb diet yielded a 44% reduction in thyroid antibodies, or reduced thyroid autoimmunity by 44%, which is great.

And essentially, this was not a crazy diet, which was the nice thing about this. I think it showcases one of the philosophies of this podcast, which is we don’t have to go to these crazy lengths to gain improvement. If we can master the fundamentals, we can get a lot of yardage out of that.

So this diet was not a crazy diet. It essentially reduced carbs to about 200 grams a day, which for most people who haven’t been on any kind of diet plan will be a relative reduction. And the subjects were instructed to eat leafy greens, vegetables, lean parts of red meat and avoid goitrogenic foods.

And they were also instructed to avoid eggs, legumes, dairy products, bread, pastas, fruit, and rice. So it’s a protein-rich diet that reduced some carbohydrates. It’s looking very much like the paleo diet. And after three weeks, we saw a 44% reduction in thyroid antibodies.

Now, here’s what’s really interesting about this study and comes back to this thread that I’ve been weaving throughout this entire conversation, which is the carbohydrate piece and the importance of the gut and especially the importance of the gut for thyroid.

83% of the patients with high levels of thyroid antibodies were breath tested. And they tested positive for lactase, which can suggest they have a carbohydrate malabsorption (24).

So part of the reason that this was helpful may have been because of reducing things like gluten in the diet if these people may have been non-celiac gluten sensitive. And that may have had a component.

But it may also have been because some of these people probably had malabsorption of carbs. And when you feed carbs to someone that doesn’t absorb them, guess what eats them? The bacteria in the gut. These bacteria then overgrow.

That triggers the immune system, which releases histamine. The bacteria themselves also release histamine, which further revs up the immune system.

So I’m speculating here, but a component of this could certainly be that reducing the carbs helps correct dysbiosis or reduce overgrowth of bacteria in the gut, which had a favorable impact on their autoimmunity.

Now, to the point of goitrogens, I do not think a low goitrogen diet was probably a helpful component of this study. We’ve reviewed elsewhere where low iodine diets have been shown to be very helpful for thyroid autoimmunity. So by reducing goitrogens, you would think that that would not help thyroid autoimmunity.

Now, goitrogens are just compounds in foods like raw broccoli that block the absorption of iodine. So if you eat goitrogens, you have less iodine. If you eat fewer compounds, you theoretically have more iodine. But we’ve shown in previous episodes of the podcast that low iodine diets are actually very helpful.

So this study had people eat a low goitrogen diet, which would mean they would have improved or increased iodine absorption. Because of that, I don’t think there was an iodine piece of this study that was highly relevant.

It was probably most likely avoidance of allergens and avoidance of carbs that may be feeding overgrowth or dysbiosis.

Episode Wrap Up

One final study (25) I wanted to just speak to briefly here—this is actually a really interesting study. I’ll put the link in here. But it was called “Influence of a 10-Day Mimic of Our Ancient Lifestyle on Anthropometrics in Parameters of Metabolism and Inflammation: The ‘Study of Origin.’”

Essentially, this study had people go—not go on—they lived a hunter/gatherer lifestyle for ten days. So they walked every day. They cooked their own food.

They were given some raw foods stuffs that they would have been able to procure if they were trained in ancient survival skills. But of course, that’s a lot to ask. So they just gave these regular peple—what I’m assuming are regular people—the food. You caught the squirrel. Here is the squirrel now, skinned. And you can cook it over the fire. So they gave them food.

And they essentially walked a number of miles every day. I think it was 14 km every day. They had periods where they weren’t eating. And they weren’t drinking because they were trying to get to the next camp and what have you. And they were sleeping outside. I believe they had some tenting and stuff. But they lived very close to what a hunter/gatherer would live.

And virtually every metabolic marker that was tracked improved. No real surprise there. Except, the one thing you could say it did not improve, but it’s all, I guess, how you frame this stuff. Their levels of free T3 actually went down.

Did they damage their thyroid? Don’t they need to have really great T3 levels and everything else? Guys, probably not because in my experience, these highly elaborate thyroid assays aren’t super clinically relevant.

In fact, oftentimes when people decrease their carbs or engage in periods of fasting or intermittent fasting, which has been shown to be very helpful, we see some perturbations in thyroid metabolism that probably mean nothing.

In fact, if you look at some of the current functional medicine recommendations for interpreting some of these expanded thyroid assays, what you see is that when people do some of these things, like reducing their carbs or fasting, their thyroid profile actually looks worse while these people actually get better, which is one of the reasons I’m not a huge fan of these, because if the labs tell you someone is getting less healthy but they are actually getting healthier, then what utility do you get out of tacking on this additional $200 of markers to a lab test? In most cases, little to none.

I see a time and a place for them, but it doesn’t have to be that complicated. If we start with foundational factors like diet, stress, sleep, exercise—and the one that is probably the most important and most challenging is gut health—then the symptoms that are driving someone to want to do the expanded thyroid panel will go away. And then the need to do them will become almost nonexistent.

And I say this as someone who used to run these expanded panels, and I hardly ever run them now because what they tell me in terms of useful information is pretty low.

So I think that was everything that I wanted to go through. So yeah, some updates there on carbs, metabolism, IBS, and thyroid.

Once again, thank you, guys, so much for your support of the podcast. This has been humbling how well received it has been. And hopefully you guys are getting a lot out of these. Feel free to let me know what you think, or if you have any questions, in the comments section.

And until next time, I will keep nerding out on all this science and reporting back with whatever I learn. Alright. Thanks, guys. Bye-bye.

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Dr. Ruscio is your leading functional and integrative doctor specializing in gut related disorders such as SIBO, leaky gut, Celiac, IBS and in thyroid disorders such as hypothyroid and hyperthyroid. For more information on how to become a patient, please contact our office. Serving the San Francisco bay area and distance patients via phone and Skype.


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