What follows is a transcript for the podcast The Science Of Gut-brain & Probiotics - Dr. Michael Ruscio - Gut-Brain
Sub-section topics within the interview include the following:
- Gut-Brain Connection
- What is the best diet for the brain?
- How limbic retraining can help alleviate gut and brain symptoms.
- Types of Probiotics
- How regenerative agriculture can help
Heather Sandison: Welcome back to Collective Insights. I'm your host today, Dr. Heather Sandison, and I'm so pleased to be joined by Dr. Michael Ruscio. Welcome to the show.
Michael Ruscio: Hi, thanks for having me.
Heather Sandison: So I'm really excited to dive into the gut-brain connection. How did you get started on seeing that this was an important connection to be making?
Michael Ruscio: Yeah, unfortunately I lived through it as a patient to... Unbeknownst to me, I had a parasitic infection and these are actually quite rare, true parasites are actually quite rare to find especially in the US population, but I was one of the rare cases. And what was so ironic, but probably helpful for my future career as a clinician was having a parasite, but having no digestive symptoms. The only symptoms I was exhibiting were brain fog, fatigue, and insomnia.
And that was a really big lesson for me to learn early in my career is that you can have an amoeba, in this case, amoeba histolytica and not have diarrhea, like most people will, but only have insomnia fatigue and brain fog. And it was really pretty debilitating brain food... Sorry, brain fog. So yeah, that's how I initially found my way into the gut-brain connection, was just the horrid experience of brain fog, eating something, and it was a coin toss, "Well, I may feel like I'm an idiot and in a fog for the next three hours, or I might not. Let's just hope for the best on this one." And suffering through that for a while, until I finally discovered that it was really a by-product of just having a gut, that was a mess.
Heather Sandison: So parasites are really fascinating. You'll hear some clinicians say they're actually quite common and that the testing just isn't great. I'm curious how you discovered that you had this. Did you do conventional testing? More of the functional medicine testing? How did you know?
Michael Ruscio: Yeah, good question too. I did a stool test and the methodology that they were using, because this was 15 to 17 years ago now. So this was before the DNA based or PCR tests were available or at least widely available. And so I used a... It was a functional medicine lab, but they were using the stool antigen recognition, meaning a microbiologist is looking for these things underneath the microscope. But it was also cross confirmed via antibodies via another lab, because with amoeba histolytica it can get into other cavities of the body, and so it may not always shed in the stool. So there was cross confirmation. And you're right, maybe that's something we can talk about later, if you want to, the parasites being a contentious issue.
And certainly I'm someone who is empathetic to that situation as someone who had a parasite. But as a clinician who was doing and still is two tandem stool test on patients for about five years until I started to pull back and do a little bit less testing. You can count on one hand usually, the amount of parasites that you find in an individual, or I'm sorry, in a year when doing testing on all of your patients. But yeah, that was how mine was found.
Heather Sandison: Interesting. So going back to this gut-brain connection, not just parasites, but a lot of other imbalances in the gut can show up in the brain. Can you talk through what symptoms might be telling us that there's a gut imbalance that may not show up as constipation or diarrhea?
Michael Ruscio: Yeah, it's such a great question, and I really think that's if there's one take home I want people to bring away from the conversation today is that you can have a digestive problem that manifests only outside of the gut. This is probably the most well-documented in celiac disease. I want to be careful to say that there are plenty of people who can eat gluten without any problem. But celiac does provide a good model for which some people will only have a manifestation neurologically, or some might only have a manifestation dermatologically or perhaps even rheumatologically. So there are people who will just have brain fog and depression from eating gluten who have celiac, and they'll have no abdominal pain or diarrhea.
You see some of this in literature with SIBO or small intestinal bacterial overgrowth. Leonard Weinstock has published at least one, well actually two studies showing non-gut symptoms that were alleviated after treating SIBO, small intestinal bacteria overgrowth. One was a neurological condition, restless leg syndrome, and the other was a dermatological condition, rosacea. So there is additional and progressively emerging evidence that finds that problems in the gut may manifest solely in areas outside of the gut.
What is the best diet for the brain?
Heather Sandison: What's the best diet? Can we use diet to address these things? And if so what's the best diet for supporting this?
Michael Ruscio: Another great question. Very good interview. I like how your questions are framing these issues in a somewhat neutral way. And I think with diet, it's really important to keep in mind that there may not be a best diet for anything, but there's a few different diets on offer that we can experiment with and see which one feels best to the individual. I feel a good starting point to be your somewhat standard elimination diet, this could be something like a paleo template doesn't necessarily have to be. I think that's a good starting point because it encapsulates avoidance of a lot of the common food allergens. And maybe even a step before that would be just general food quality. That's really probably the most important first step is general food quality, fresh, whole, unprocessed, shopping the perimeter of the store rather than the aisles, so to speak.
Most people I'm assuming listening to this would probably tick that box. And so from there, paleo is one starting point. As it pertains to gut health, a low FODMAP diet can be a really helpful trial, especially for people who are in the lower carb and/or paleo community, because they're probably inadvertently eating fairly high FODMAP, high in foods that are rich in prebiotics, things that feed bacteria. And that's not necessarily a good or a bad thing, but in those that have imbalances in their gut, a high FODMAP content may actually make things worse. And what we see is this is reflected in some of the clinical literature where in IBS cohorts, irritable bowel syndrome, when they restrict their FODMAP intake, you see improvements, yes, in their digestive symptoms, but also improvements in energy levels, so that energy and fatigue often correlate with IBS symptoms.
And so the low FODMAP has the gut-brain connection appeal to it, for some individuals. Going lower carb certainly may be helpful for mental clarity in some, but you can also go too low carb and then people can start having fatigue and insomnia, because they're in this perpetual metabolic insufficiency. They just don't have enough carbohydrate in their diet. So those are a few different nuances that someone can think through food quality, elimination diets, a low FODMAP diet, and then trying to dial in where their carbs maybe should be.
Heather Sandison: When you're talking about food quality, how important is organic to you?
Michael Ruscio: Good question. I would say if you can wave a wand and it's not going to be a big deal to you, maybe from a financial perspective or logistics, then opt for all organic, all grass fed, what have you. If not, I'd rather someone focus on non-processed food over organic food, if they had to make a choice. I just give that a little bit of an out, just because sometimes I see patients in the clinic who put so much pressure on themselves to do everything perfect, and they create this unnecessary stress. So food quality is important and there are studies that have shown that people have less organic [inaudible 00:11:38] or whatever they're looking for in the research studies from pesticides in their urine or in their blood when they eat organic as compared to conventional. So there, there is an impact here, but if you can't do everything, do the best that you can and come back to the things that you couldn't do now in the future, when you may have the ability to do so.
Heather Sandison: I'm curious if you see patients where they are taking more and more and more out of their diet, right. They come to you and we say, "Okay, let's cut out gluten and dairy." And then all of a sudden they're like, "Well, I'm not even tolerating corn now, and I'm not tolerating eggs now, and I'm not tolerating the next thing." And so their diets get more and more and more limited. And if someone's experiencing these sorts of food sensitivities, what does that mean for you? How do you interpret that?
Michael Ruscio: Yeah, another great question. And I think it's important that as clinicians, we handle these individuals the right way, because it's easy to get pulled into the gravity of progressive dietary restriction. And there, there is this law of diminishing returns or this tipping point where further dietary restriction doesn't really seem to make much of a benefit, but it does risk someone under eating or developing an unhealthy relationship with food.
And in Healthy Gut, Healthy You, I lay out this concept of let's not force a dietary solution to what might be a non dietary problem. So you should be seeing some benefit from diet. You make a few different changes. You zig zag, you try the paleo, you try the low FODMAP and maybe dial back the carb. You make a couple of those trials. Usually three weeks on each one is sufficient, three to four weeks perhaps, but then if you're not seeing much benefit, then I start thinking, you're like me in that you were eating pretty much perfect, but you were still having a horrid food, reactive brain fog and insomnia and fatigue. Because there's probably something going on in your gut, throwing off normal gut function.
And that's really the solution. And you can't really diet your way out of some of these problems. And it's important not to force people into harder and harder and more restrictive diets if they're not seeing some signal of improvement from the earlier phase diets, and that's actually a good thing, right? If we can come in with a strong probiotic protocol or antimicrobial therapy or whatever it is, then that person should start seeing improvements in how they're feeling and also be able to shortly thereafter, broaden their diet and that has implications for their lifestyle. One of the things I think the community doesn't acknowledge is all of these recommendations, especially if someone's piecemealing them all together, "Well, I'm going to go low carb, and paleo, and low histamine, and low FODMAP, and low oxalate and low sulfur." They can really work themselves into a very overly restrictive diet. So yeah, that's the way I interpret that and I try to really proceed cautiously, so that we don't lead people into having an overly stressful life and overly reclusive social life due to these really heavy handed dietary restrictions.
Heather Sandison: Not only that, but reducing the variety means you reduce the nutrients, right? I had a patient once who, he had limited himself to beef and broccoli only, and he ended up with a thallium overload. So a toxic metal that was high because it's naturally found in broccoli, and that was almost all he was eating. And so you can create new problems, just basically enhancing imbalances by limiting the variety so extremely. So in preparing for this conversation, I was grateful to see that you have a similar message to my own, which is increase the variety. Don't limit to fruits too much, don't focus on restriction, but really a sign of health is when you can start adding more variety back.
Michael Ruscio: Yeah, well said. Fully agreed.
How limbic retraining can help alleviate gut and brain symptoms.
Heather Sandison: So we've been talking about how the gut might affect brain function. I'm curious how the brain function affects gut, and you shared a case recently about limbic retraining, helping to alleviate some gut symptoms. I just want you to go into your mental model, your clinical model for how... When is it what, right? Is it the chicken or the egg? Is the brain affecting the gut or is the gut affecting the brain?
Michael Ruscio: Yeah. Great question. And there is a bi-directional relationship here, as there is in many systems of the body. It's not just a unilateral direction of communication or influence, there's this back and forth, but to your question, when are you on one side of the chicken egg, and when are you on the other? And in my experience for the majority of people, it's normally a gut to brain, but there are exceptions. And one of these exceptions is the limbic. I should also mention really quick, if someone's had a concussion or head trauma and some symptoms started to pop up after that, that's another example of when it could be from brain to gut. To your other point, probably more common than this, especially in a population of people who really care about their health and are making an effort, in keeping with our last question who may read and listen to a bunch of stuff online and start to develop fear and angst.
Then they can start to develop these limbic imbalances where they're becoming overly, emotionally charged about food. And sometimes it's even happens on the subconscious level where there's been so long with this really diligent attention to what they're reading and how they're feeling, they overly facilitate and develop imbalances about vigilance, about how they feel and what they eat. And how what they eat affects how they feel. And this can run away with you, almost like if someone has, as an example, maybe they have really, really strong quads and really weak hamstrings. And now the quad just progressively start carrying the hamstrings. And it can be really hard to rectify that balance unless they do some specific work to rebalance the quad hamstring balance of the knee. And in limbic retraining there's things that you'll see in someone's paperwork that made them note that they would be a candidate for limbic retraining.
If someone... If you ask a simple question and someone has a page of information to answer that question, or you ask them, "How is your bloating?" And it's a five minute diatribe, or if they've tried 18 diets, or if you see they're on 20 supplements. And these all tell that this person is really gripped to their health tightly, and they're thinking about it a lot, and there's a lot of emotionality and venting. These are indicators to the clinician that the issue here, or one of the issues that needs to be resolved is this emotionality around food. So just looking for those really verbose, almost overly thought out answers or responses to clinical questions, "How are you feeling? How did this diet go? How do you eat? What supplements are you taking?" Those are all pretty good indicators that this person may benefit from this somewhat intensive form of mindfulness meditation that can start to rebalance some of that hyper-vigilance that can ironically actually make them more reactive to foods.
And when they go through this training or retraining, it can be pretty drastic how much their reactivity can improve, and they start having better energy, and in clear cognition and less bloat or whatever it may be. So yeah, those are a few things to look for that may cue you in that the limbic system may be on overdrive.
Heather Sandison: That's exciting to hear you share, because I've seen profound results with patients just in a few days. Symptoms they've had for years, resolved using limbic retraining. I'm curious if you're using Annie Hopper's work with DNRS or Ashok Gupta's, or if you have another favorite that you turn your patients on to.
Michael Ruscio: Well, Gupta recently published a trial on his method. So that's appealing to me seeing that Gupta is subjecting to scientific scrutiny and documenting pretty impressive benefit in that trial. We use both. What patients who have done both have told me is that the DNRS or Annie Hopper's program, it's a bit more comprehensive and thorough, but it's also there's a little bit more of fluff and in bells and whistles. So for the people who are really Type A and want to do things to the point, then I typically will recommend Gupta. For the people who seem to want, or like a little bit more handholding or verboseness, then we'll use the DNRS. They both seem to be quite effective. The one thing that's been really helpful for me in clinical practice is something that actually [inaudible 00:21:38] when she was on my podcast mentioned and it was such an aha, because I feel this way with almost everything that I do.
You don't have to hit the full recommendation in order for it to be helpful, meaning you could do 15 minutes per day, rather than the often recommended one hour per day and still see benefit. And again, that was such an aha for me, because I'll tell people, "Yeah if you can only sneak in one dose of the probiotics per day, not the end of the world, if you can't be fully compliant with the diet, that's okay. Take some leeway, have some liberty." And so it was nice to see that, that also followed for the limbic retraining, which makes the barrier to entry for people a lot lower. An hour versus 15 minutes, the 15 minutes is obviously much easier to wrap your head around.
Heather Sandison: Do you also notice that the people who maybe benefit the most from it are initially the most resistant to getting started?
Michael Ruscio: Good question. I haven't seen that. It might be because a fair facet of my audience has listened to the two interviews with Gupta and the one with Annie Hopper. So they may be a little bit front loaded on it, but it wouldn't be surprising to me to see that people were resistant to that. Because yeah, sometimes the thing that they need the most is the thing that they're most resistant to.
Heather Sandison: That's great. I need to adopt that. Prime people, because it is one of those things that's so profoundly effective, but you have to do it even if it's just partially, you still have to do it to get the benefit.
Michael Ruscio: And I echo that, it is one of the therapies that... There are certain categories of therapy and there are some that all clinicians say to themselves, "This is an effective therapy, really effective." And limbic retraining is one of those that people will come back and, "How are you feeling today?" And it's, "Wow, I'm feeling a lot better." And there's not many therapies that can boast that, but I agree with you, limbic retraining is one of them.
Types of Probiotics
Heather Sandison: You mentioned probiotics, I want to switch gears and talk about the different, I guess not just different types of probiotics, but the different strategies of addressing microbiome. So there's the spore based probiotic that is very popular, there's also this soil based. And there, I think there's a book called Eat Dirt, right? This soil-based probiotic idea. There's also the idea that let's just throw as much variety and as many organisms as possible at it and see what happens.
And then there's also... You don't see this come up as often, but this idea that we are first exposed going through the birth canal. So what we want to get is are things that are more present in the vaginal microbiome, and then that is going to be the most healing. And then taking it even one step further, there's this idea of fecal transplants. So this is... What I'm trying to do is describe the entire scope of this probiotic field. And I want to get your insights about what works best when, if there's a place for all of them, if there's one that's your favorite, where do you go first? Let's dive into probiotics because you are one of the experts around this.
Michael Ruscio: Yeah. Well thank you. And it is something that I've paid a lot of attention to, and I've really stayed abreast of the clinical literature and tried different approaches in clinical practice. And because probiotics are not very expensive, they are certainly safe, and they have benefits outside of just treating the gut so to speak. They have these secondary benefits, like a modest ability to reduce cholesterol and blood pressure is one example. They're really an attractive therapy, and one that I think is deserving of a high level of attention. One of the things that's unfortunate about the probiotic landscape is much of the educational information that's brought to doctors is sponsored by the companies that make the probiotics. And that's not a bad thing in and of itself because certain interests from industry can help to spur healthcare and medicine and innovation.
And so some of that is good, but unfortunately what I don't think has happened on the behalf of many doctors is fully figuring that out or just seeing that for what it is. And giving the other lab companies or supplement companies too much credit, and taking their word too much for it, rather than information that should be taken with a grain of salt, so to speak. And why this is so problematic is because if a company makes a formula, and then they publish a trial with that formula, they want to herald that study in, and that formula as the best formula for XYZ, the best formula for constipation, the best formula for depression. And it's not really in their interest to say, there's also two probiotic formulas that have been shown to be helpful for depression or for constipation, or what have you.
So what this does is it creates a flood of competing claims in the marketplace, and it makes it really hard for the doctors, clinicians, and for patients to figure out, "What do we do with probiotics?" And as someone who's really looked at this question so much, so to the fact where we've even taken, let's say in the model of IBS, irritable bowel syndrome, probably one of the best models we have for showing what impact probiotics has on gut health at large. And taking all of the major formulas on the market that have been shown successful, put them in an Excel sheet side by side to compare not only the species, but also the strain. And what you see is that there are different formulas that have all shown benefit for IBS. And that goes to the species level and also to the strain level.
And what's interesting is from type to type, to type to type, there's some overlap, but there's also notable differences. Same thing holds for constipation. There have been different formulas that have all shown benefit for constipation. There are different formulas that have shown improvements for depression. So there's this claim that you need the certain species or the certain strain, and we've really looked at this in earnest, and while there's some evidence that supports that notion, the much larger majority of data show that probiotics don't work like drugs. They don't work to relieve a headache or relieve depression like an antidepressant. What they're working to do is predominantly to rectify these problems in the gut that then have offshoot systems as where other problems can pop up, joint pain, skin issues, depression, anxiety, brain fog. So what the probiotics are trying to do is successfully dampen inflammation and immune reactivity in the gut, rectify overgrowth, or dysbiosis or infection and reduce leaky gut.
And when that happens, you have better nutrient absorption, you have less inflammation, you have less immune activation. And this is the healthy core situation from which someone will no longer have the brain fog, the insomnia, the depression, what have you. So in the IBS literature, there's also a trend that multi-species probiotics work better than single-species probiotics. So there's this trend that, to your earlier point, that a more diverse array seems to work better.
So we've been taking that a little bit further at the center, and we've been using what's known as probiotic triple therapy, meaning instead of using one formula, we'll use three at the same time. And what this does is it provides three different legs of support in helping to rectify and balance the gut. The other part of this that explains the rationale behind the three different formulas of the triple therapy, so to speak, is when you do look at all of the studies on probiotics or the vast majority, you see that they tend to filter into one of three different general types. Your traditional lactobacillus and bifidobacterium species blends. This is your VSL #3, and there's many out there like this. Your Florastor, which is your Saccharomyces boulardii, or your soil based which contains various bacillus strains.
And there's over a hundred studies for the lactobacillus bifidobacterium, I think there's about 500, actually. There's about 100 or so of the Saccharomyces boulardii type. And there's about 20 to 40, depending on what pocket of literature you look at for the soil based type. And so all these probiotics show benefit and what we've been doing in-
Heather Sandison: For what, in particular?
Michael Ruscio: Well, they've been... So the lactobacillus and bifidobacterium are the most well-studied, they've been around the longest, they have the most research interests. So that's where you'll find evidence showing benefit, everything for infants in the neonatal intensive care unit, having better overall outcomes all the way through anxiety and depression. The Saccharomyces boulardii are a bit newer, less researched, but then shown helpful for IBS, for Traveler's diarrhea. Some studies have shown that the Saccharomyces boulardii is as effective as antifungal medications for eradicating fungus. They also tend to help with H pylori eradication.
And the soil based probiotics, the newest, they have the least amount of study. So they've been documented to benefit the least amount of things more likely because there's just been less inquiry into them, but they've been shown to be effective for IBS and also for inflammatory bowel disease. And there may be other data there, but that's the real thrust has been consolidated to matters in the GI. And so what we've been doing at the center is combining all three of these together, and we've documented case studies where someone may have been on, let's say, a low FODMAP diet and a probiotic before and seen some results. And when we get them on the triple therapy, they really see additional needle movement they weren't seeing before.
And that's likely for two reasons. One, we're taking the dose a little bit higher of the probiotics because you're using three formulas rather than one. And the other is you're supporting the gut in these different ways, the soil based probiotics, the bacillus species are different than the healthy fungus, the Saccharomyces boulardii, which are a little bit different than the lactic acid forming bacteria of the lactobacillus and bifidobacterium. Now we haven't published anything on this yet, but we're actually in process of studying the triple therapy with a quality of life measure, pre-post intervention, a SIBO breath test pre-post intervention, and an IBS visual analog scale pre-post intervention. Because we've been doing this long enough and we're confident enough in this observation that we want to document this scientifically so that we're not just conjecturing. But that's what we've been doing in the clinic and it really works quite well.
Heather Sandison: That's exciting. Is there a minimum number of billions of organisms in each of those three legs of the stool? And then also the age old question around probiotics with, or without food before bed, when do you take them to get the most benefit?
Michael Ruscio: Okay. So I haven't found... To your last question first. I haven't found that with, or without food makes a difference. Earlier on in my career, I was a bit more strict about with food, without food. And then as patients were busy and they say, "Doc, it's really hard to take these supplements without food and then those with food." And I said, "Okay, well, let's just try doing everything dosed twice per day." And we've been doing that now for a couple of years and we're still seeing great outcomes. So I don't think it really matters, now there's the mechanistic argument that, "Well, if you take them with food, the stomach acid..."
Sure, I hear that argument, and that's a mechanistic conjecture, but it doesn't really seem to be clinically meaningful, meaning, okay, perhaps taking probiotics with food where you're going to release more stomach acid leads to a 2% decrease in the viability of the probiotic. That 2%, just as an arbitrary estimate, it doesn't seem to have any difference in the clinical outcome of the probiotic. So I've been simplifying the dosing there, and it seems to work really well, or the same, maybe better if people are more compliant, right? Because if they're skipping doses, then they're less compliant.
And then regarding the dosages, there are ranges that have been used for each categorical type. And I don't have the dosing ranges committed to memory, but in our probiotic recommendations and people can find them pretty easily on the internet, you'll see a dosage range that we list for each categorical type. And that's pretty much using the lower limit that's been used in the clinical trials and the upper limit. Now, there might be an outlier study here and there that used a whoppingly high dose or a very, very small dose. We cut those outliers out. And the ranges that we report are with the majority of the studies, the lower and upper end of the range. And the reason why we list the range is so that we can personalize the dose, for people who respond really well, they may only need one dose per day. For people who are a little bit less responsive, they may need two doses per day. And what this bottom lines out to is for a formula as a rough guide, you either take one or two capsules at a dose, and you take the dosage one or two times per day. Roughly speaking that gets you into the range.
And what's nice about that is it doesn't confine people to one specific dose, but they can listen to their body, start low if you're on a budget and if that's working great, we'll ride that wave. If you start lower and you're noticing some improvement, but you think there's more improvement that you've yet to realize, then let's go up to the higher end of the dose range and see how that goes. And so there's a bit of range there for people to navigate within.
How regenerative agriculture can help
Heather Sandison: You speak a bit about regenerative agriculture. How does that tie into our guts and our brains and our health generally?
Michael Ruscio: Yeah, it's a great question. This is something, one of my friends and colleagues, Anthony Gustin has been doing a lot with lately. And one of the things that we seem to be missing when compared to hunter-gatherer societies, if we're using that as a model of how free living humans would naturally associate, if there wasn't all the modern technology and such that we have. One of these things we're missing is contact with dirt and naturally occurring germs and animals. And this is where sustainable agriculture has a lot of merit to start fixing really the root cause of where some of these problems that clinicians like you and I ended up cleaning up the end result of. Meaning someone didn't have the healthiest formation of their microbiota up to four years of age, and now on an ongoing perspective, they're not getting enough inoculation from the environment. And so they're hyper reactive to food and they have an overgrowth of bacteria in their gut, ironically, right? Ironically, lack of bacteria exposure can lead to an overgrowth of bacteria probably because it throws off the immune system amongst other things.
So one of the ways that we can help to unwind that is not to have animals and/or farming partitioned into these big agro or industrial farms. So that it's a path forward in terms of not putting everything into these very isolated and unnatural settings, and trying to get us back a bit more to a farm-like model. I don't necessarily have a great answer there other than advocating for it. It's not an area of study for me. It's just one thing that I support, because those exposures do help give our immune systems, the training or the exercise that it needs to really function optimally.
Heather Sandison: Well, we started this conversation talking about your experience with parasites and the hygiene hypothesis does lay out a bit of this. And this also bears out in the literature that if you are not exposed to parasites as a child, then your likelihood of developing auto-immune diseases and also allergies is higher as an adult. And so there's a push pull here, right? There's good and bad bugs. There's imbalance that determines that, and really becoming completely sterile is not the goal and that creates new problems. And so it's about creating balance and, looking to those natural systems to see how we can, I guess get the best of both our modern technology, our modern world and maintain the benefits of the natural world.
Michael Ruscio: Yeah. I fully agree. It's well said, and I think it's just important to echo that I'm not advocating that we go fully back to hunter-gatherer because that would create other problems. I don't think we'd be able to feed everyone, if we were fully in the hunter-gatherer model. And there are benefits of technology, like reduced infant mortality, it is something that has been a huge achievement for us. But yeah, to your point, it's trying to find the optimum balance point between those two extremes.
Heather Sandison: Yeah. Dr. Ruscio, it's been an absolute pleasure having you today. I know you're a busy guy, so I'm going to let you go, even though this conversation could go on and on.
Michael Ruscio: I know.
Heather Sandison: [inaudible 00:40:21] from you, and I'm really grateful for your insights, and I'm sure that our listeners are as well. Thank you for joining us.
Michael Ruscio: Yeah. Thank you so much. It's been an absolute pleasure chatting with you.