Does your gut need a reset?

Yes, I'm Ready

Do you want to start feeling better?

Yes, Where Do I Start?

Do you want to start feeling better?

Yes, Where Do I Start?

Do You Really Want a Hunter-Gatherer Microbiota? Pearls and Pitfalls for Your Gut Health

I recently presented at the Ancestral Health Symposium in Boulder, Colorado. My presentation was entitled “Do You Really Want a Hunter-Gatherer Microbiota? Pearls and Pitfalls for Your Gut Health.” I covered some very important information regarding how hunter-gatherer research pertains to improving your gut health. Today’s post includes both the lecture video and full transcript. Enjoy!

If you want to learn more about the hunter-gatherer microbiota, click here.

Subscribe to Dr. Ruscio’s YouTube account

Do You Really Want a Hunter-Gatherer Microbiota? Perils and Pitfalls for Your Gut Health

Dr. Michael Ruscio: I’m excited to talk today about “Do You Really Want a Hunter-Gatherer Microbiota,” because this is an area that I have a lot of clinical specialty in. I’m also writing a book on the topic. So I’ve been knee-deep in the research for the past several years.

And there are some things we may want to replicate from an ancestral perspective. And there are other things that can be detrimental to our health. And I think it’s important that we delineate which ones we should do and which ones we shouldn’t do so as not to harm ourselves or, if you’re a healthcare provider, harm the people that you’re working with.

The Problem

So to outline the problem, essentially deficiencies and exposure to dirt, bugs, “old friends,” animals, whatever you want to term it, and overuse of antibiotics plus we could say maybe C-section births and things like this are creating imbalanced microbiotas and immune systems, leading to a host of autoimmune and inflammatory conditions. I’m sure we’re all aware of this.

And the microbiota, in case you’re not familiar, is essentially the world of bacteria but also fungus and protozoa, even things like archaea, even viruses that coat our skin, that line our gastrointestinal tract, which is what we’ll be focusing on, our urinary tract, our pulmonary tract. And they provide a number of health benefits for us.

What’s the Ancestral Perspective?

The ancestral perspective is that not living like our hunter-gatherer ancestors has created an imbalance in our microbiota and thus our immune systems. And one of the items you often hear cited is that hunter-gatherers don’t have autoimmune or inflammatory conditions.

The Proposed Solution

The proposed solution, to try to summate it very shortly, is boost our diversity by eating lots of fiber and prebiotics, maybe test and track your microbiota, be less hygienic, get more time in nature and exposure to dirt, soil, animals, etc.

Pitfalls of the Proposed Solution

There are some pitfalls associated with the proposed solution. Too much fiber and prebiotics will make some people feel worse. And this is really important to understand. And we’ll outline this in more detail in a moment.

Children who experience periodic exposures to animals may experience increased allergy. Episodic trips might not be enough to replicate the ancestral environment. And we’ll talk about this in a little more detail in a moment.

But essentially, what some research studies show is that children who only go to a farm occasionally actually see inflammatory and allergic conditions worsen because of that. And what that may come down to is we have a limited window through which our microbiota and thus our immune systems can form.

And so if you’re not brought up in this constant saturation of bacteria and fungi and what have you but when you’re six, all of a sudden you get a—boom—a strong exposure from going to a farm, your immune system may look at that as an attack.

This isn’t the constant background noise we’ve grown up with. This is sudden. This is more than we’re used to. And so now, we’re going to go on the offensive, or the defensive, however you want to term it.

So this is important to understand because if you didn’t evolve or if you didn’t form in a certain society, if we jam you into that type of society later, you may not respond well. So it’s important for us to keep this in mind.

The sad truth, as I just said, is we have a limited developmental window for the immune system, after which the immune system is much less amenable to change. And what this means is that someone with a Western immune system might not do well with a hunter-gatherer diet or lifestyle if they decide to switch at 30 years of age. And this could even go as early to maybe six, seven, eight years of age because most of the formation seems to occur by about three-ish years of age.

Pitfalls of the Proposed Solution: Examples

Those with nonideal gastrointestinal immune regulation may attack the resident microbiota or have difficulty regulating their microbiota and thus do better with a minimally fermentive dietary approach. So what this means is they may not do great with copious amounts of fiber and prebiotics because you’re feeding a system that has a hard time regulating itself.

And we see this in IBS. And we see this in IBD. And we’ll outline some of the data there in a moment also.

Regarding antibiotics—Abx is just an abbreviation for antibiotics—antibiotics increase the incidence of allergy and autoimmune diseases when administered earlier in life. However, they can also induce remission of inflammatory bowel disease and help greatly in IBS in adults.

So we see that time is really important here. Antibiotics—the earlier they’re administered—they’ve done studies looking at antibiotic administration at three months, six months, nine months, 12 months. And for every few months earlier you administer, it heightens the risk for allergic and autoimmune diseases later.

Now, the same thing works inversely with probiotics and prebiotics. The earlier the administration, the greater the protective effect. In fact, there was one study done in type I diabetes. I believe they found administration of probiotics before 27 days was protective but after 27 days had no protective effect. So the timing of these things makes a big difference.

Exposure to “Dirt” Is Helpful for Infants/Children but May Be Deleterious for Those Who Are Older or for Children if Exposure Is Punctuated: References

And here are several references to support that timing issue.

Pitfalls of the Proposed Solution

So some of the pitfalls to the proposed solution, continued. There is currently confusion regarding what a healthy hunter-gatherer diet is. And why is this? It’s because there’s a bias in the research right now. So when we’re studying modern-day hunter-gatherers and trying to sample their diet and their microbiotas, we have a very equatorially skewed, or latitudinally biased, sample.

Insights from Characterizing Extinct Human Gut Microbiomes

Here’s one study that illustrates that. This study was looking at coprolites. So it was fossilized stool remains. But you can see a somewhat equatorial region. And I’ll overlay this on top of the entire globe so you can see what that looks like in a second.

What Do We See When We Take a Good Dietary Sample of Hunter-Gatherer Populations?

So what do we see when we take a better sample?

Lattitude, Local Ecology, and Hunter-Gatherer Dietary Acid Load: Implications from Evolutionary Ecology

So here are another few references showing that the farther away from the equator you go, the lower the carbohydrate intake and the higher the protein and the fat intake. So these lines from before show us that when we’re sampling in this narrow region, for many of us being of potentially European descent, you are not going to be getting a representative sample.

So this is very important because I see a lot of confusion regarding, “The Africans are eating so much fiber. Maybe we should too.” But we’re not looking at other hunter-gatherer tribes. So we’re getting a biased sample. We’re trying to force everyone into an African way of eating because they’re the only data point that we have.

But what we see the clinical science say is some people will do much worse with this type of high-fiber, high-prebiotic, high-fermentable approach. It’s not to say that none of us should be on it. But I’m trying to be the voice of reason in this microbiota runaway dogma that’s forming to keep us grounded.

Plant-Animal Subsistence Ratios and Macronutrient Energy Estimations in Worldwide Hunter-Gatherer Diets

So what we do see is that, at most, 73% of worldwide hunter-gatherer societies derived more than 50% of their substrates from animal foods. And so what we see there is, yes, the high-level literature does show us that most hunter-gatherers do not eat a high-carb, high-fiber diet.

Why Is This Biased Sample a Problem?

So why is this biased sample a problem? Like we just discussed a moment ago, it’s a problem because if we try to force an African type of diet into a Westerner with IBS or IBD, they will get clinically worse.

And what’s very helpful to sort this out is when you look at the clinical data. I’ll show you some studies later that show we give people with IBD a high-prebiotic diet, and we actually increase this inflammatory bacteria. But their disease activity gets worse. And they feel terrible.

So it’s important that we don’t think in a very micro way. This bacteria good. If we feed this bacteria, that’s going to help us. What we should be doing is looking at macro. We take this group of people. We do this to them. And here is what happens. Do you guys understand the difference between those two approaches? Okay. That’s very important.

A Better Solution

So a better solution. And we’ll outline some of the details regarding this in a moment. But eat to reduce symptoms, reduce inflammation, and control blood sugar as your chief objective, not with a chief objective of feeding your microbiota.

In a sense, what we’re trying to do is to create a healthy environment. And a healthy environment will allow a healthy microbiota to flourish. This is why we sometimes see people become healthier, feel better, and have diseases go into remission ironically when they eat a diet that may partially starve the microbiota. And what we see in some of these studies is that when we eat in such a way that creates a healthy environment, we actually see a healthier expression of the microbiota.

So an ecosystem is not as simple as, hey, let’s throw some food in the mix, and the ecosystem will fix itself. So what I’m saying is we need to give the ecosystem a healthy environment. That will allow healthy expression of a microbiota. Not just, let’s just arbitrarily throw a bunch of food in the mix—prebiotics and fiber—and expect the whole ecosystem to recalibrate itself. It’s not that simple.

A Better Solution: One Example

Okay, so here is the example I was referencing before. The study took a group of people with Crohn’s disease. And this was in a randomized control trial, so the highest scientific level evidence that we have. And they put half on a high-FODMAP diet and half on a low-FODMAP diet.

Now, if you’re not familiar with FODMAPs, FODMAPs are essentially high prebiotic foods, mostly vegetables, some fruits. And as you see here, those in the high-FODMAP group had a near doubling of symptoms. But there was an anti-inflammatory bacteria, Akkermansia muciniphila, that increased.

So this illustrates something I think is really important for everyone to take away from here and carry forward into their day-to-day life. If someone is trying to convince you of a healthcare intervention based upon a mechanism, you should be very wary of that. You should be looking at what clinical data shows.

So what not do is to say, “We think this bacterium is inflammatory. And this prebiotic has been shown to increase this bacterium. So if you have an inflammatory condition and you eat this food to increase that bacterium, therefore, your inflammatory condition should go away.” That’s flawed logic.

What you should look for is, here is a group of people with this inflammatory condition. What intervention produced the most clinical benefit to them? Really, really important because this is where I see so much confusion really anywhere in healthcare—when you’re looking at these different levels of evidence. If you’re speculating from a mechanism compared to looking at clinical data, it’s very easy to get misled.

A Better Solution: Eat to Reduce Symptoms, Reduce Inflammation, and Control Blood Sugar—Not to Feed Gut Bugs

Now, additionally, just because we have low diversity and are sick doesn’t mean fiber and prebiotics will fix this. Low diversity may more so be driven by our shrinking, what’s been termed, microbiota pools and overzealous immune systems. I think Jeffrey Leach was the first person to term the microbiota pool. It’s the exposure to everything you have in your environment.

If you’re a Hadza, you go out, and you kill an animal, drag its carcass back to camp, eat some of that flesh that probably has a decent amount of dirt on it. You’re living in the dirt all day. Of course, they’re going to have way more diversity than we are.

It doesn’t mean, hey, we need to eat a bunch of fiber to boost our diversity. It’s like, come on, guys. It’s like you have a multifaceted problem. And you’re trying to solve it with one solution. It’s not a good strategy. And so the clinical support for this is overwhelming. And we’ll detail this in just a second.

How Do We Assess if We Have a Problem in the Gut? Testing

Okay. So something that comes up a lot of times is testing the microbiota. And microbiota is a broad term. When I say microbiota, I’m not referring to clinical tests like SIBO, candida, screening for ulcers or inflammatory bowel disease. I’m talking about getting a phylogenetic map of what your microbiota looks like.

I want to be very clear in saying these tests are not clinical. And if you’re looking to clinical answers for them, you’ve been misled. There are a few reasons. Okay, so again, microbiota assays are academic, not clinical.

Part of the reason for this is because the microbiota has been shown to oscillate from month to month and even diurnally within the day. So it’s very hard to make a treatment recommendation based upon a moving target.

Secondly, we don’t really know what a healthy microbiota is. Methanobrevibacter smithii has a very high colonization density in Africans. It helps them probably thrive on the food supply they have access to. However, any clinician who tests and treats SIBO will tell you that this archaea—not a bacteria. It’s an archaea. It’s similar to bacteria—causes constipation, bloating and may cause weight gain, high blood sugar, and high cholesterol in Westerners.

So do we really want a hunter-gatherer microbiota? In some regards, no. And Prevotella—there have been studies done with Prevotella copri 18205, a certain species of Prevotella. Depending on the context, it can worsen rheumatoid arthritis or improve blood sugar.

So the same bacteria can either help you or harm you, depending on the context, which comes back to my earlier posit, which is we shouldn’t look at this like one bacteria good, and we want to increase that

or decrease that. We want to manage the entire ecosystem.

We don’t know if patterns or diversity is a cause or effect. And again, when you look at the clinical data, you see this concluded in almost every study, that we’re still not sure if these things are cause or effect. So if you don’t know if it’s cause or effect, you can’t really treat it.

We are also missing a large part of the GI with microbiota assays, which look at the—and this applies for any commercial microbiota assay. It looks at the colonic luminal microbiota.

We’re missing the small intestine, which represents over 50% of your GI, 90% of caloric absorption, and the main area that programs your immune system. The largest density of immune cells is in the small intestine. And the small intestine is most amenable to leaky gut.

So we’re missing a whole heck of a lot with the current microbiota assays. They are great. And we need to participate in collecting data for research. I’m not saying that they’re flawed. But if you’re someone who is limited and you are sick and you’re not feeling well, you have a limited amount of money to contribute to testing, a microbiota assay is a waste of money.

And we don’t know how to treat the findings. At best—the best data that we have shows that microbiota assays that are not even commercially available yet may be a prognostic or diagnostic indicator for inflammatory bowel disease.

And the researchers that have discovered this are working to try to develop a training algorithm for doctors and make this commercially available. So the best data that we have shows that you cannot even—you can’t even do anything with it yet. You can’t do anything with it yet. So it baffles me that people are using these things or attempting to use these things clinically.

I had on my podcast one of the co-owners and directors of one of the large, commercial microbiota testing companies. And I gained a lot of respect for this gentleman when he said something along the lines of, “If someone presents to your office—” a doctor’s office “—with a microbiota test in hand looking for clinical answers, you should refer them to your colleague in psychiatry.” Literally said.

But I actually gained a lot of respect because there could be a potential financial conflict of interest for him. But I really gained a lot of respect for the fact that, yes, you own a lab. Yes, it does commercial testing for people.

But you’re not hoodwinking people, trying to tell them that this is going to help you solve your IBD, your IBS, your autoimmune condition. But rather, these are important tests that we should be engaging in to help gather data so that we can become clinical with this information.

Here are a few references supporting some of those past few points there.

So here’s an example, in case it’s not clear yet, of why testing the microbiota is not a sound clinical choice. In this study, women with obesity were treated with prebiotics. And yes, there was an improvement in blood sugar. But there was no change in weight.

Now, what was interesting was they tracked these women’s microbiota at the same time. And the blood sugar improvements did not at all correlate with changes in the microbiota.

So I think it really depends at how you look at this. If I am wanting to find a reference that shows a microbiota whatever is going to cure a disease, I can find something. I’ll probably have to find a lower level scientific support like a cell culture, an animal study. But I could find them. And I could craft a convincing argument to convince you of that.

However, if I’m a disciplined researcher and I look only at the high-level clinical science, I will see things like this that even the best data with prebiotics show a minimal effect on weight loss. They do actually show benefit for blood sugar. And we’ll go over how to use some of these things a little bit later.

Blood sugar is the one area where prebiotics probably have the most utility. But again, it didn’t come back to correlating with the change in the microbiota. So if you get this readout where I’m high in Fimicutes or low in Bacteroidetes, and so therefore, I should use this prebiotics, guys, there’s nothing to support that. It’s pure conjecture.

Testing that’s clinically relevant—things like dysbiosis, looking for SIBO or small intestinal bacterial overgrowth, yeast, candida, H. pylori; looking for pathogens like yersinia, certain amoebas, Blastocystis hominis; considering certain conditions like ulcers or inflammatory bowel disease; and screenings for colorectal cancer.

These tests can guide you toward a microbiota reset if you might need it, which we’ll cover what that means in a moment, or toward the appropriate treatment for a given condition. And these aren’t all of the things that are clinically relevant. I’m just giving you a few examples.

But what this means is we have a test that correlates to a certain treatment. And we’ve put humans through that treatment and shown clinical benefit that was somewhat relevant or dependent upon the results of said test. Does that make sense?

A test only has utility if it’s going to tell you how to do some differently. And it’s a major problem that happens in functional medicine. And I actively speak out against this because it wastes a lot of money on behalf of the healthcare consumer.

Things the doctor is excited about—“Ooh, this is really interesting.” But how is it really going to change the way I treat the patient? Or do you need this test in order to treat me in such a way? And if the answer is not yes, then the test is academic.

And then it’s your prerogative as a patient or a healthcare consumer if you want to spend $300, $400, $500, $600 on a test just for, “Hey, let’s just see if this thing goes up or down.”

How to Create a Healthy Environment for a Healthy Microbiota

So how to create a healthy environment for a healthy microbiota.

Pop Quiz

Pop quiz. What do we have to do to create a healthy environment for a healthy microbiota? There are two things we talked about. Come on. Someone give me something here so I know you’re listening.

Female: Diversity.

Dr. Ruscio: No, not diversity.

Male: Early exposure.

Female 2: Eat [inaudible audience comment 20:36]

Dr. Ruscio: Eat to reduce inflammation. Eat to control blood sugar. Eat to reduce symptoms. Remember? So the meme is very powerfully ingrained in you guys. So it’s important that we unwind some of this.

A Better Solution

Eat to reduce symptoms, reduce inflammation, and control blood sugar.

How to Create a Healthy Environment for a Healthy Microbiota

So how do you do that? One note—manipulation versus optimization. Manipulation means, “Here’s your microbiota test. Here’s how we want to specifically manipulate those test results to produce a health result.” I think we’ve already covered how that’s a fallacy.

But we can optimize. We can try to optimize your microbiota. We know that pathogenic bacteria thrive in an inflammatory environment. So if you have an inflammatory condition like inflammatory bowel disease or something where we know inflammation is typically present, like IBS, if you eat in such a way that manages that condition and thus reduces inflammation, we know that we will decrease the amount of these opportunistic bacteria because we’ve changed the environment. You follow me on that?

So you can’t go in there and say, “I’m going to force this down and that up.” You can’t micromanage an ecosystem, guys. But you can create an environment that will allow what you want to grow and discourage what you do not want to be there from growing. So that’s manipulation versus optimization.

So ways that you can optimize. Diet and lifestyle. We’ll go through some specifics. But of course, our foundation should be diet and lifestyle, obviously. Microbiota supports—things like HCL, enzymes, vitamin D, and maybe fiber.

And by the way, I’m not anti-fiber. I don’t want to paint that picture. It’s just I see the pendulum swinging way too far to an extreme position. So I’m trying to bring this back to a more reasonable center.

A microbiota reset—this is where things like herbal antimicrobials, antibiotics, or even liquid elemental or semi-elemental diets can be helpful, because what this can do is not custom manipulate your microbiota but turn the favor back to the good guys. So it kind of gives the microbiota a little bit of a nudge. And it kind of poisons partially the bad guys, allows the good guys to start to grow. And the good guys then kind of push out the bad guys. So it’s a nudge or a reset.

And then you can gradually increase your dietary boundaries. So if you were a little bit lower fiber or lower fermentable, like FODMAP, now you’re going to bring those back in and try to find the broadest diet you can eat. And wean off the supports that you were taking earlier. So like I said, this includes more carbs and fermentable foods.

And then the final step would be considering to add in some supplemental fiber, prebiotics, or even resistant starch. We save this for the end because feeding the microbiota is best done when the microbiota is somewhat calibrated and also because these have a probability of causing side effects. So we want to leave them to the end and try to get you as healthy as we can first and then evaluate if these may or may not be a good fit for you.

How to Create a Healthy Environment for a Healthy Microbiota—Diet

So with diets, there are two general camps. There is higher carb, fiber, and fermentability. So these are things like moderate-to-higher-carb Paleo, Mediterranean, or traditional dietary advice that’s more vegetarian or high carb/low fat.

So it’s important that we identify that many of the high-carbohydrate and high-fiber diets have already been tried for a while, fairly unsuccessfully I should say in a lot of cases.

They do work better than unhealthy diets. When we look at a traditional diabetes diet that’s high in carbohydrate, it works better than the Standard American Diet, yes. But when we look at that next to the Paleo diet, a Paleo-type diet does better.

So we have our traditional dietary advice. And then we have more contemporary diets like lower or moderate carb, lower fiber, and lower fermentability. And these are things like low carb, moderate-to-low-carb Paleo, and low FODMAP. So these are the diets.

And these diets have been shown to work better than the more traditional higher-carb, higher-fiber diets for metabolic conditions like diabetes, heart disease. And they tend to work better for gastrointestinal conditions like IBS, IBD, GERD, and reflux. You guys with me on that?

So these higher-carb, higher-fiber diets have been used. And they are better than the Standard American Diet. But when we pit them against more contemporary healthy diets like Paleo, like low carb, like low FODMAP, these diets actually work better.

And so what’s ironic—and I hope you’re appreciating this—is these diets aren’t great at feeding the microbiota. Yet clinically, when we give them to human beings, they actually work quite a bit better. Are you with me on that? Okay.

So then, it begs the question, should we all be low carb? No, you should first eat to reduce your symptoms, like we’ve been talking about.

Diet Pyramid

And so let me segue over to what this might look like. You may start with Paleo. That may help a little bit. But you may not fully get the results you’re looking for. So you may want to try a few different dietary derivations from there. Autoimmune Paleo or low FODMAP or low FODMAP combined with the Specific Carbohydrate Diet restrictions.

And really what we’re doing here is we’re progressing to more restrictive diets that tend to be more restrictive in carbohydrates, fiber, and prebiotics. And as we go farther and farther up this pyramid, we see that, especially for gastrointestinal conditions, these types of diets work really well. For inflammatory bowel disease and for irritable bowel syndrome, these diets clearly are the best. Lower-carbohydrate diets tend to work better for metabolic conditions.

So again, if you’re confronted with the philosophy that the reason we have diabetes is because of a shrinking microbiota, then a really high-prebiotic-and-fiber diet should work the best. But the low-carb diets actually work the best in clinical trials. So it’s important that we just keep that practical outlook in mind.

How to Create a Healthy Environment for a Healthy Microbiota—Lifestyle

So here are some lifestyle things that you can do. Living near diverse plant life has been shown to increase the diversity of the microbiota on the skin and correlates with reduced skin conditions in children. So if you can live near a forest, great.

Using a sponge compared to dishwashing increases microbiota diversity and decreases allergy in children. Walking in a forest increases vigor and well-being and decreases anxiety, depression, and fatigue. A 15-minute walk in a forest compared to a 15-minute walk in a city has been shown to have a massive impact on your health.

Those living near what’s termed “blue zones” or “green zones” have lower mortality rates. A blue zone is an ocean. A green zone is a forest.

The younger an infant or child, the more judicious we should be with antibiotics. The older one gets, the less this matters, of course within reason. But it’s important that we don’t make this a black or white issue. Antibiotics bad. Antibiotics always bad. We want to evolve from a Neolithic brain to be able to think through nuance.

The earlier antibiotics were administered, clearly the more detrimental they are. But they have less of a negative impact in adults. And so if you need one, you shouldn’t withhold it just because you have this philosophical opposition to it.

Stress causes reduction in healthy strains of bacteria. So of course, manage your stress as best you can. It’s been shown, ironically, that college students undergoing exam stress have a decrease of many different Lactobacillus strains in the gut.

Circadian rhythm disruptions lead to microbiota changes that may be causal in weight gain. So sleep. So here are some really basic things we can do to have a favorable impact on our microbiota, that have been shown to have a clinical effect.

The appropriate amount of exercise may increase microbiota diversity. And if you exercise too much, you may actually increase your risk for infection. Why this may be is some exercise may down regulate the zealousness of your immune system, which may allow bacteria to grow—good. But too much exercise causes immunosuppression. And now, we have overgrowth, infections, and things like that. So the appropriate amount of exercise.

And farm and animal exposure—the data are mixed, like I said. If you have constant exposure from while the baby is in utero up through the first few years of age, then you have a high probability of a very nice effect.

However, if you have just punctuated exposures, keep an eye on your child. If they have sneezing and redness and runny nose that happens every time or you as an adult notice you feel worse every time, then you may not want to keep subjecting yourself to that, thinking that you’re doing yourself a favor.

How to Create a Healthy Environment for a Healthy Microbiota—Support and Reset

So a support and reset for the microbiota. So what I’m going to do here is essentially show you how these different interventions compare better or worse to another. So for IBS, probiotics or herbal antimicrobials or antibiotics or elemental diets, all that partially are antibacterial—even probiotics are antibacterial—work better than prebiotics or fiber for IBS. The clinical data here is irrefutable.

Low FODMAP has also been shown to be very effective—very effective. Probably the most well-studied diet for IBS. And again, low FODMAP is a low-prebiotic diet. Now, the one exception here might be soluble fiber for those with IBS/constipation. Soluble fiber tends to be helpful for constipation. But there is one drawback to it. For some patients, it causes a worsening of gas and bloating. So we have to be a little bit careful. But most of the interventions here that are somewhat antibacterial actually work best for IBS.

For IBD, probiotics, herbal antimicrobials, antibiotics, or elemental diets work better than prebiotics, according to the clinical studies. And if you’re not familiar with an elemental diet, an elemental diet is essentially a very easy to absorb, low-fiber, low-prebiotic diet that’s like a meal replacement. Low FODMAP has also been shown to be very effective. The data on fiber is equivalent.

For weight loss, low carb clearly works better than prebiotic or fiber interventions, whether they be dietary or supplementation. I talked about this at AHS in 2014. The best weight loss we see from fiber supplementation or prebiotics is usually under three pounds. And this is usually in those that are obese. But low-carb diets can be very effective.

So I hope you’re starting to see that when you look at this through a treatment lens, the treatments that modulate, that increase bacteria don’t tend to really be that great. And this is why I’m up here giving this perspective, because I look at these things through a clinical lens.

And I’ve weighed the evidence for the past few years as I’ve been writing the book. And you see a very interesting thread appear, which is, these interventions that increase bacterial growth don’t really shake out to be awesome clinically.

For diabetes, low carb works better than a higher-fiber diet. Although I will say, the one area that shows a lot of promise, I think, is using prebiotics for diabetes but—and this is why I put but—if the patients could get through the potential for gastrointestinal side effects because some of these studies used up to 20 grams of a prebiotic, which is a really high dose. And for many people, they won’t be able to get through that because of the gastrointestinal side effects.

For autoimmunity, not as much data here. But there is one study showing that elemental diets work better than prednisone for rheumatoid arthritis. Elemental diets are better or equivalent to the frontline drugs for inflammatory bowel disease.

And it’s been shown that antibiotics decrease thyroid autoimmunity in those with thyroid autoimmunity and that also have H. pylori and/or a Blastocystis hominis infection. This is preliminary data. But I think it’s promising.

And probiotics and prebiotics early in life decrease autoimmune conditions. And the earlier these are administered, the better. And for infants, probiotics are safe. They have been shown they reduce infantile colic, respiratory infections, GI infections. And they are very safe.

And ironically, even one study showed that an elemental diet increased small intestinal diversity. Again, I don’t want to get too wrapped up in the diversity because this is pulling us back into this erroneous paradigm. But what probably happened is the elemental diet starved the pathogenic bacteria, allowing healthy bacteria to grow and, therefore, increasing diversity.

So somehow, these interventions that are somewhat antibacterial may actually increase our diversity through the giving the microbiota a chance to reset.

Pyramid of Research Types

If some of this seems a little bit dissonant to what you’ve seen, heard, or read elsewhere, it’s probably because the person, with the best intentions, is not citing the highest level science.

Notoriously, we are bad—and when I say “we,” I mean functional medicine, progressive medicine, integrative medicine—are bad at wanting to believe something and, therefore, citing cell studies, animal studies to support that. And we see this being done on the microbiota all the time.

I always look at information from here down. And when we go through these issues, we literally have a research team that combs through the data from the top level down. And we lay it out in such a way where we can see what the best-level evidence shows.

And when you do that, you very clearly cut through the confusion because you’re looking. You’re not spending your time wading through here. You’re saying what actually happens when we look at clinical trials or summaries of clinical trials.

And maybe a way to break this down to make it simple to understand—this is like saying a restaurant is good because they have this kind of meat in the refrigerator. This is like going to a restaurant and giving it a trial and saying, “That was pretty good.” Or reading someone’s Yelp review. And then up here, this is like reading 70 Yelp reviews of people who’ve eaten at the restaurant. You follow me?

So when you read about something and it’s saying, “Ooh, in this cell, this anti-inflammatory compound interleukin was increased. And it decreased this other issue. And we saw the binding junction shut off.” And you get all excited. And you see this cool cell culture. And you’re like, “Wow. This person must be really smart.”

Okay, yeah. I’m not taking anything away from their argument. But this from an evidence-based perspective is the lowest level of science. And you’re the most likely to be misled by the conclusions that person is giving you, which is why we want to look at clinical trials and summaries of clinical trials.

Sometimes, we don’t have this type of data. So we have to do our best and draw inferences from data down here. But, guys, most of the time, we have clinical data. And it’s ignored sometimes because someone’s in love with the concept. And they’re just looking for references that reinforce that concept.

So I don’t mean to be overly critical. But this is disheartening to me when I see patients coming in having spent $600 on a test. And I look at them. I say, “This test is useless.” And this poor person is like, “Geez, I did three consults with the doctor. And I got this test. I’m already $1,500 in. I don’t feel any better. I think I might feel a little bit worse.”

I see this all the time, guys. So again, I don’t mean to be critical just to be critical. But I want to help you out here.

The Irony of It

So the irony of it—those with the most digestive imbalances and symptoms are most likely to do the worst by following a fiber enthusiast’s advice to feed your gut bugs.

On the other side of the coin, the healthier you are—if you’re one of the guys here who’s a CrossFitter and you feel invincible, go for it, dude. You’ll probably be fine with resistant starch with prebiotics, with fiber. And you’ll be like, “Yes! This is awesome, feeding my microbiota. [grunts]”

If you’re someone with inflammatory bowel disease or irritable bowel syndrome and you do that, you have the higher probability that you’re going to feel a lot worse. So it’s important to keep that in mind.

But Fiber Is Good, Isn’t It?

So in close here, isn’t fiber good? I just want to cut to the chase. Colorectal cancer—probably the biggest concern about eating a low-fiber diet. This was the worst part about writing the book. I almost just quit.

The amount of data that came back to me from this search—174 pages of abstracts. And there were multiple abstracts on a page. I almost didn’t get through it. It was terrible.

But after sifting through all of it, I can tell you this very simply. (Thank you.) The overall impact of supplemental fiber, including resistant starch, on colorectal cancer risk appears to be minimal at best. Most of the data show no positive impact. And in my book, we’ll go through this in a very detailed fashion.

Now, what about dietary fiber? The similar seems true for dietary fiber. Some studies show benefit. But an equal number of studies show no effect. So I’ve broken out the references for you. And, guys, these are almost all systematic reviews or meta-analyses. So every one of these is looking at least a few thousand if not tens of thousands of people. But when you weigh them out, you see an equivalent number of studies showing fiber helped protect against colorectal cancer. And then fiber had no effect.

What to Do

So why this is relevant? You may be asking, “Well, then, should we all be low carb and low FODMAP?” No. Consider starting there and then working toward the broadest diet that you can. So start a little bit lower carb, a little bit lower fiber, a little bit lower FODMAP as some of those diets are, like we laid out in the pyramid. And then slowly increase your boundaries to see what you can tolerate.

Some clearly do better on a higher-carb diet. Some clearly do better on a lower-carb diet. The point of all of this is for you to be okay with where you end up.

If you feel best on a lower-carb, lower-FODMAP diet but you keep reading about all the benefits of fiber, it’s important that you don’t keep subjecting yourself to the perils for your gut that can be induced by fiber, because I want you to know that any of these diets will allow you to be very healthy. Does that make sense?

So I just don’t want you to be fearful that if you follow that kind of dietary approach you’re going to increase your risk of colorectal cancer or something similar. So this is our hierarchy again.


Here are some resources for you. We have a weekly podcast, a newsletter, articles. We have one research study we’re working on. We have two clinical trials coming up through our office. And my book should go out in early 2017.

So I’m over time, so I’ll take questions, I guess, out in the hallway. But thank you, guys, so much for your time and attention.


If you want to learn more about the hunter-gatherer microbiota, click here.

What do you think? I would like to hear your thoughts or experience with this.


I care about answering your questions and sharing my knowledge with you. Leave a comment or connect with me on social media asking any health question you may have and I just might incorporate it into our next listener questions podcast episode just for you!