ZOE Science & Nutrition - Our ancestors’ diet: surprising discoveries from a 5000 year old iceman

Episode Date: June 23, 2022

A mummified man found in the mountains of Italy on a nutrition science podcast? Have we gone completely off track?  We haven’t - we promise.  This unfortunate soul could be the key that unlocks an entirely new understanding of human health.  This mummy, discovered in an alpine snow drift by two hikers, gives us a remarkable glimpse into the surprising dietary choices of our ancestors. In today’s episode, Jonathan discovers some secrets held by our ancestors by speaking to two outstanding guests: Frank Maixner works at the Institute for Mummy Studies in Italy and travels the world uncovering the secrets of our ancestors. Tim Spector is a co-founder at ZOE and one of the top 100 most cited scientists in the world. Download our FREE guide — Top 10 Tips to Live Healthier: https://zoe.com/freeguide Timecodes: 00:00 - Intro 00:10 - Topic Introduction 01:45 - What happened thirty years ago high in the mounts on the border between Italy and Austria 03:02 - Who was the Iceman? 03:39 - What happened to him and what did we discover about him? 05:10 - How old was he and what do we know about his lifestyle? 06:01 - What was he eating? 09:02 - What’s surprising about his health? 11:56 - The Iceman & mushrooms 13:08 - Iceman’s microbiome 14:13 - The most surprising information about the Iceman’s microbiome 15:27 - What’s microbiome diversity? 17:30 - Iceman’s origins 17:56 - The start of a new academic discipline 19:41 - Finding out about salt miners 21:02 - What did these salt miners eat? 23:05 - How plant-based was their diet? 23:39 - Did they eat dairy? 25:05 - Their diet diversity 26:40 - What do their microbiomes tell us? 32:31 - What does this mean for us? What is the actionable advice? 36:24 - Summary 38:16 - Goodbyes 38:40 - Outro Episode transcripts are available here. Follow Frank: https://twitter.com/frankmaixner Follow Tim: www.instagram.com/tim.spector/ Follow ZOE on Instagram: https://www.instagram.com/zoe/ This podcast was produced by Fascinate Productions.

Welcome to ZOE Science and Nutrition, where world-leading scientists explain how their research can improve your health. Why would a podcast on nutrition and health run an episode on a mummified man found in the mountains of Italy? Have we gotten completely off track? We haven't, I promise. It turns out that this unfortunate soul could be the key that unlocks an entirely new understanding of human health. This mummy, discovered in an alpine snowdrift by two hikers, gives us a remarkable understanding of how we lived 5,000 years ago. New technologies have allowed scientists to examine every inch of him, from the contents of his stomach to the health of his arteries and even his gut bacteria.

Together, this provides a remarkable glimpse into the surprising dietary choices of our ancestors. The story of this discovery is a lot of fun, and we're joined by an incredible guest to help tell it. Frank Maxner has one of the most exciting jobs in the world. He works at the Institute for Mummy Studies in Italy and travels the world uncovering the secrets of our ancestors. We're also joined by Tim Spector, my co-founder at ZOE, and one of the world's top 100 most cited scientists to help us understand

the implications of these discoveries for our health today. Frank and Tim, thank you for joining me today. I have to say I'm very excited to have a mummy scientist on the podcast. I'm sure that like many of my listeners, as a young child, I was obsessed by Egyptian mummies and the idea of doing something, and now we get a real mummy scientist to talk to. And so why don't we start at the beginning of this story in modern times. And Frank, can you tell us about what happened, I think about 30 years ago, high in the mountains, you know, between Italy and Austria? Yeah, it was in 1991, actually. So there was this couple from Nuremberg, Erika and Helmut Simon. They made holidays and

they were on a hike in the mountains, in the Alpine Ridge between Austria and Italy. And it was quite late already at the day. And then they need to take a shortcut back to the hut there. And when doing this, they stumbled over a body which was still sticking half in the ice. And they immediately thought that this maybe is a hiker or skier who died up there. And they informed the hut owner. And he informed the Italian police, which then not felt responsible for this. And they then said the Austrians should take over this case. And yeah, this body was recovered and

it was for a long time not considered precious. It took some days actually until an archaeologist had a look at this finding and it turned out that it's a 5,300 year old mummy who died up there. And this was the start of this research on the Iceman actually. So they've discovered this 5,000 year old body sort of sticking out of the ice on the Iceman, actually. So they've discovered this 5,000-year-old body sort of sticking out of the ice at the top of the Alps. Who was he and what happened to him? It's a good question, actually. So some things we not yet know who he was, actually.

This would be a nice question to ask him. But it became more and more clear that he belonged to the so-called early European farmers, which already lived a settled lifestyle. They had access to domesticated animals and plants also. Yeah, he lived and grew up also in this Italian Alps, so in this Eastern Italian Alps. And tell us a bit about why he ended up stuck in this glacier, and then a bit about what we've been able to discover about him. Because I think this is one of the most amazing things. And this is a podcast only, so you can't see the pictures.

But, you know, it's amazingly well preserved. And I think the story of what we've been able to figure out is extraordinary. Help us to understand that a bit, Frank. Yeah, a mummy and this finding was particular for archaeology also. Normally, you not find any organic material anymore and this is really special. So all this equipment which we found with the Iceman was very particular. But also the mummy with the preserved tissues provided a lot of interesting insights. So for example, radiographic imaging revealed that actually the Iceman was murdered up there.

So they found arrowheads still sticking in his left shoulder. We saw also that he had a lot of calcification in his arterias, for example. So he suffered from atherosclerosis. And the most important part, which we are dealing now currently, is also that biomolecules are preserved in such mummies. So this means we can still analyze the original endogenous DNA or the proteins, and we can confront this data to modern day data also. And this is a very particular information source, I would say. So this is amazing. This is the oldest unsolved murder case in the world. Is that right, Frank, that you're working on? Very CSI. A true cold case.

Thank you, Tim. And how old was he? What do we know about his lifestyle? Obviously, on this podcast, we're fascinated in what this could tell us about diet and nutrition. Have we been able to figure out anything about this? Yeah, anthropologists think he's around 40 to 50 years old. He was a very slim guy, very trained. He hiked a lot. You see this, that he was hiking a lot in the Alps. And we know also that he was most likely hunting up there, hunting wild animals, which are present in this region, like the ibex or the red deer, for example. And yeah, he definitely was part of this community,

which was in this kind of transition from hunter-gatherers to settled lifestyle. And this is a very fascinating period because there's a lot of changes in diet also happening. And so what have we been able to discover about what he was eating? We were lucky because normally mummification, if it's not starting immediately, the degradation of body starts in the intestinal region. And here this mummification stops this and we have still access to the intestinal contents, to the stomach content and also the lower intestines. And by analyzing this, we not only microscopically, but also molecularly could see that he has eaten ibex meat, actually, of this mountain goat, red deer meat.

And in parallel, this was supplemented by cereals, ancient form, the einkorn wheat, actually, was part of his meal. And interesting was also the discovery of a toxic bracken fern, which definitely was also part of his meat, which we not yet can really identify why he has eaten this. So maybe in a young form where it's not so toxic. So it was composed of these parts. And a second thing which we see is 50% nearly was then also fat. So it was very lipid rich, very fatty rich diet to get the energy he needs up there. So this was another observation we had. Wasn't there something about the type of meat that was fatty meat rather than the lean bits? I remember reading something about that. Can you remind us how that deduction was made,

that they had the fatty bits of the meat, not the lean bits? That's true. So it was definitely intentionally sampled at the regions where the fat is more enriched. And these ibex, for example, normally the meat is quite fatless or not rich in fat. But certain regions like in the neck or other regions, you have quite accumulations of fats. And the Iceman took these parts and used it as his diet also. So it was most likely then air dried also. And we can imagine that it's in a form of a speck or in a form of air dried fat meat consumed. For weeks, they hunted together and they needed to, of course, also to conserve and preserve this meat. And the best way to do this is really to air dry it. So this was sort of the ultimate high density, high calorie food to allow you to exist in

pretty tough environment. And I guess part of the reason why this amazing information existed is that when he died, it was already so cold. Is this why the whole mummification gave you this sort of data, you know, right down to the food that was still in his gut? That's also our assumption that he was then subjected to a so-called most likely freeze-drying process, similar to lyophilization a little bit. So it's not that he was just covered by snow or ice, but in parallel also the drying process then conserved the biomolecules and all his tissues actually

okay isn't this what californians pay for to live forever i hope for a different outcome too yeah exactly but maybe this they look similar afterwards we don't recommend this at home just to be clear and i guess what's surprising so i think already tim's picked up on this idea of the meat. And I think you talked a bit about the fact that we were actually able to look at the health of his arteries. Could you just explain a bit, because we often talk about everybody being completely healthy in these sort of ancient times.

And I think actually you got some quite surprising results, didn't you? Yeah, that's actually really an interesting discovery talking about this maybe modern day diseases like arteriosclerosis. It's purring of the arteries isn't it that can lead to heart attacks and things like this. Yes and he has really severe calcification already of his arteries also in the heart region already and this is a little bit stands in contrast also to his lifestyle because he was slim. He was really hiking a lot.

The diet, you can, of course, argue now we have a snapshot only in the stomach content to have seen a lot of fat actually, but this maybe is just an exception. But the interesting thing when we now look also at other mummies from different regions like South America, also Egyptian mummies, we see always 30 to 40 percent of these mummies also suffer the same level of cardiovascular diseases or calcifications actually. So our assumption is that we see this also in the Iceman that there's a major also component coming from our genes or their genes. The Iceman has actually a high genetic predisposition to develop this kind of disease.

And we see this also in other mummies, which show already the signs. And this seems to be independent from the diet, from the origin, from the population you belong to. And I think this brings us away a little bit from this, this is only a modern day disease linked to our lifestyles. I think we should also not forget this. And just remind us how old we think he is. The Iceman is 40 to 50 years.

All right. So he was an early middle-aged man. So normally it would be quite unusual, even in modern times, to have heavy calcification of the arteries without it being genetic. So the genetic theory might be the one rather than diet or lifestyle related, given unless he had some other disease we don't know about, but that seems most likely. And so I would be too quick, would I tend to say, because I think one of the things that has sort of come through a lot of our work, right, is that animal fat in particular is one of the low quality fats. So I think I might have gone with this assumption that he's eating a rather unusual diet, probably

for this time, very high in this and that this is linked. But I think what you're both saying is that that's not enough really to explain this. I think so. And I think it's, we don't really know what his habitual diet was, because he might have been having a high altitude hunting type diet. And wherever he came from from they might have just been eating einkorn all the time you know his uh a sort of standard wheat if he was because he's not quite a hunter gatherer and we don't know which he favored i guess is before we move on i do remember hearing something about iceman having magic mushrooms on him Can you confirm that rumor? Yeah, he has a, we call it first aid kit with him. So he carried also mushrooms. One is to facilitate making a fire. So this is a particular

mushroom, which is then facilitating this fire making process. But the other mushroom is actually quite interesting. So this is one which we think he could have used also for medications or like a medicine which he carried with him. And we see also some signs that he bit into it. So this is also very interesting. What actually then the reason was for this, we don't know. It's known that this mushroom also stops bleeding. If you put it on a wound, it can help to cure this. And it has some bactericidic also action, but the real reason we don't know it actually.

Okay. But it wasn't a hallucinogenic mushroom as far as we know? No, it's not hallucinogenic. No, it's not. Seems like a dangerous thing to be taken at 3000 meters, I feel. So probably a good thing. Yeah. And then falling into a crevasse, that's right. Yes. So we've talked a bit about the diet, and I think that's already amazing that we can understand this, but you and your colleagues have managed to go further, right, and actually understand the bacteria, the microbiome that he had 5,000 years ago.

Tell us about it. This was actually also in cooperation with Nikola Sigarta's group and others, which are focusing on modern gut microbiomes, actually. And what we saw there is that the Iceman still carries these traces of the gut microbiome community, actually, and that we can confront this also to communities we know from modern persons. And this was quite surprising to see that he resembles not the gut microbiome we most likely carry in us but more the one which indigenous populations also still carry nowadays so populations which have more

traditional diet which have a different lifestyle to ours so we called it also non-westernized populations and the iceman was the first time also the proof that also non-Westernized populations. And the ice meme was the first time also the proof that these non-Westernized populations maybe are a good proxy of how the gut microbiome of our ancestors was. So this is really amazing. We're basically having this ability to look back 5,000 years and understand the microbes at that point. And 5,000 years is a lot of time for us, I guess for microbes that are potentially having another generation every 30 minutes, it's like some unimaginable number of generations. What was the most surprising thing that we found out when we look at the microbiome?

Yeah, there's difference to nowadays. And this is what you said already, 5,000 years seems to be not long, but within this 5,000 years, there seem to be changes going on. We not yet understand well when this happened, but there was clearly a higher diversity of microbes in the Iceman. So strains we nowadays not carry anymore in our guts were present in the Iceman. Shifts of this gut community, which we see, and this is actually very surprising, that within this very short timeframe, we see diversity decay similar to the decays in diversity in plant or animal kingdoms. And this potentially can be linked also

to some other developments, diseases, we nowadays know linked to diet maybe. And when this decay or when this diversity change happened, this we are now currently investigating actually. And Tim, can you explain a bit for us what this diversity means? Yes, diversity is a way of microbiologists generalizing a very complicated picture of our gut microbes into something that most people can understand. It's the way of saying how many different species there are in all the trillions of gut microbes in the average gut, what that community looks like.

And so a highly diverse gut microbiome is one a bit like a garden where there are lots of flowers of all types flowering and the soil is incredibly rich and there's hardly any room for weeds to grow. It's a very healthy community with one species helping another and it just looks beautiful all year round and a non-diverse gut microbiome. It looks more like an Arizona backyard with dust bowls and toxic waste and other things going down it. I'm not sure everyone in Arizona is going to like this particular positioning Tim. Not all gardens in

Arizona are like that but I'm just trying to visit a more desert-like thing where there's a few sparse plants you know that have adapted to that rather rugged environment and there might be cactuses and things like this. So it's that large contrast you've got to bear in mind visually in how you might see your gut microbes. And we know that people with nearly all the common diseases we're seeing today of westernized societies, which don't happen in non-westernized societies, such as diabetes, such as obesity, such as autoimmune diseases, cancers, heart disease, etc., anything with chronic inflammation, plus even mental disorders as depression, autism spectrum disorders, they all have a reduced diversity compared to the healthier

types of Western society. So we sort of generally link this number of species with health in a very broad sense of it. And I understand, Frank, that he is an Italian, which we obviously know means that clearly had a very good diet, right? That's the general view and not an Austrian. Is that right, Frank? Is that the conclusion? Yeah, he was found 90 meters on the Italian side. So the Austrian border was 90 meters away. So he's definitely Italian. And the diet, of course, tells us also that he liked to eat Italian diet. That's true. So I think this discovery sort of started a whole new academic discipline, right? Looking at our ancient ancestors in a lot more detail

and with all of these new techniques that were possible. And in particular, my understanding is that the science has really expanded in the last few years to not just look at mummies in general, but actually to look at mummified poop, or I think paleo feces is I think the technical word if you want to sound smart at a dinner party and you're really at the forefront of this. Can you tell us a bit more why and I think particularly really interesting to talk about your big investigations in the house that salt mines in Austria and in these caves in Mexico. Yeah it's exactly now the search of having more science for this kind of diversity and to also investigate more the diet of our ancestors. And for this, we need different kinds of samples, material where also this biomolecule preservation

as well as in the Iceman. And there, this paleophysis is actually very well suited. So we were also surprised how well preserved plant material, but also then DNA or proteins are in these materials. So they have a similar kind of preservation. So they got desiccated very rapidly. All water just wasn't removed. And then they are in a similar state like lyophilicized.

And this is either due to the positioning of this cave in Mexico, where we analyzed paleophysis material, which is in high altitudes, very dry conditions. And the same holds true for this other site in Austria, where salt mining is done. And in these salt mines, also a rapid desiccation takes place of all organic material. And this is then leading to this extremely well preservation. And so how long have people been at the salt mines? And so how far back have you gone? And then tell us, what did you find? Yeah, it's a very unique site, I would say. So I

was there two weeks ago also. You have to drive there hours and hours because it's in the middle of nowhere. It's around 1,500, 400 meters altitudes. You have snow there until May, snow again from September on. So a site where you normally would not expect that a high culture developed, a European culture, the so-called Hallstatt culture, which is part of the Iron Age. We are talking about 2,500 years ago. And they all were there because they had access to this salt. So this salt for their own purposes, but they also traded this salt.

And since then, there was a continuous salt mining going on until nowadays in an industrial scale actually. And there's an interesting culture also. They were working hard in the mines, but they had, in addition, due to the salt, very rich grave goods. They had access to different dietary components like wine from the south. They had ember, they had gold, they had ivory from Africa. So we see really long trade networks here, including also trade networks of exotic foods, for example, like the walnut, which was not present at that time in Europe. So tell us, what did you find about what they were eating through this?

The analysis tells us that these miners actually, similar to the Iceman, had a quite fibrous diet. Again, carbohydrate-rich, different kind of cereals, a mix of cereals actually, which is interesting. So we have the wheat spelt and we have the emmer. We have einkorn again, also like Tim mentioned, but also the barley was present all the time. Then a form of cereal, the millet, which was more present at that time also. So we have quite a rich carbohydrate, rich diet, which was supplemented by proteins from the broad bean, from the garden bean also. And on top of this, there were also animal products consumed, such as meat from the swine or cattle meat or cattle, also blood products.

We found particular in one sample, a high presence of blood. This means also this very important protein-rich slaughter by-product was actually used for consumption and was actually a rich energy also source here just like current austrian sausages like bloodwurst crystal is that right yeah exactly this was one of the ideas also that they really already used this combination and you need also for certain of these clogging processes, high salt concentrations. So they would have had the possibilities to combine the salt and this blood and to enhance the blood processing here. And evidence of preserving meats at this time, like salamis or hams and things or not?

Yeah, they not only traded the salt, but as you said, Tim, it was really a network of different products and they also traded. And one of them were also ham. We found here a lot of bones from swines and then also archaeological manufacturer also holes where they actually then salted the meat. They also then processed the meat and conserved the meat. And this is not only for their own purpose, but also for trading these products. So they were eating a lot of different things, it sounds like, Frank. How plant-based was the diet? Because you started talking about a lot of different, you know, quite complex grains. Then we started to talk about quite sophisticated meat techniques. How plant-based

were they in comparison to our Iceman you were talking about before? Yeah, it's hard to say how much finally this made up, but it was very carbohydrate rich, this for sure. A lot of cereals, as I said already. And sometimes we find also wild plants, like the apple is occurring also, some grains, some berries also, which they supplemented their meals. And what about dairy, which is a topic that people often talk about, about being this sort of modern introduction, and you're going back two and a half thousand years. Was there dairy at this point or not? There was already dairy products present. This we know also from other sites. So not only the domesticated animals were used for meat production, but dairy products were used. And we see this also in that side. So we have indirect evidence also here using the DNA that they already

produced cheeses and not only produced cheeses but also flavored these cheeses. This was very surprising finding in my opinion since we not expected that they had really interest to change the texture or the taste of something like this cheese. And we saw here that they produced a kind of blue cheese, actually, which we nowadays know like the Roquefort or the Danish Blue. So there are similar cheeses like the Gorgonzola. And this was one of the most surprising findings actually here. So they were making their own Roquefort two and a half thousand years ago up in the mountains in Austria. Have they managed to recreate this? I feel that Tim would be first on the list

if they were regrowing this. Ancient salt mine cheese. Yeah, I think that would be a big hit. Particularly if you took, yeah, if you went in there and got all the microbes off the rocks and things, I'm sure you could make a really fascinating cheese. I think we should definitely start a company there, Frank.

Annoy the French to say this is the original rock for them. So, I mean, I think one of the things that's interesting about this is, you know, do you ever think about my own sort of history with food? In the past, I've given a lot of things up with a sense that like particular foods are bad for me and I'm trying to sort of deal with intolerances or think about my health. And I guess what's interesting is you're showing this really big diversity of foods. Both these cases, these were obviously quite rich individuals. And is that also something that you see across all of these examples?

When you look in Mexico, for example, do you see this very different story? It's definitely depending on the society you're looking at. So this is something we see now. So this Hallstatt is, as you said, a very rich community, having access to sophisticated foodstuff, I would say. So it's very rich and also exotic, traded also plants, for example. In this Palo Fis, it's from Mexico, for example. We don't see this diversity also. So there's mice, there's also plants which were growing there.

There were no meat products so far we discovered. Sorry, just to clear up, they weren't eating mice they were maize you mean is that right and maybe my maize sorry i mean they might have been eating mice and rodents again don't try that at home that's that's important difference so you're saying actually basically this is an entirely plant-based diet that you were you were seeing yeah thanks a lot, Tim. This was important. Yeah, actually much less diverse diets. So all of them had access to plant diets, no indications for animal components in this diet.

So quite different society for sure. We talked about diets, but I think you've also been able to look at the microbiome of these different groups. Isn't that right, for example, we have a sample which comes from the modern times. So we are here in the 18th century when Mozart, for example, was in Salzburg performing and we are in the Baroque period, actually, it's called. And this sample shows the same like the Iceman, like this Mexican, like this Bronze Age or Iron Age samples, the same community structure. And of of course it's now one sample and we need to extend this also but this brought us to the conclusion that most likely we are having also other factors which came during industrialization for example which

were much more severe affecting also this gut community structure so that not only diet but also other factors are important to consider so that's quite cool you might have mozart's grandfather's stool sample is what you're saying is that right you know what his microbiome is and and you maybe we have an inkling now maybe on mozart's microbiome and what you're saying is it's a lot healthier than ours this is the key that you're saying frank is it that like just to make sure i'm understanding this right this microbiome actually looks more similar to something two and a half thousand years ago than actually to mine, which is not so great, or even Tim's who, you know, in the Western world is supposed to have a pretty good microbiome.

You really see that shift so recently? That's exactly what we see. So, of course, as I said, it's one sample now. So so we are now trying and this is a nice thing on this side it's really that we have access to a lot of these samples so that we can also use a lot of samples which are even more recent we are talking about the 19th century or beginning of 20th century so we can really now make this in a diachronic approach and we see maybe really more signs when such shifts happened. So we always have to keep in mind, of course, that those people were working in the salt mine. They had a particular also site where they worked on. Maybe we cannot generalize it too much to everybody now.

I mean, Tim, maybe talk a bit specifically about sort of the micro part of this. Frank's done this brilliant job of explaining like beyond just changes in diversity have we been able to understand more about like particular bugs and you know where is the science in terms of understanding what's changed between the you know what would have been in my gut you know 200 years ago and and where i am today yes well obviously it's very complicated so there are thousands of different species, some strains have disappeared, some haven't. And it's hard to know which ones to focus on, because there's so many. But I think a lot of scientists are focusing on a few that we do know what their functions are. There are a couple I'll mention. One is a bug called Prevotella copri, which is found in nearly all non-Westernized populations in large amounts and in only a

small proportion of Westernized populations or individuals, I should say. So it does vary within one population. You might have it and Frank might not. It's highly variable. Unfortunately, I don't have it, but yes, thank you, Tim. It's certainly with general good health and having less metabolic syndrome and less inflammation. And so trying to understand what's happened there is really important because these certain microbes could in the future be used as probiotics, as treatments, or given to you when you have medicines or anti-cancer therapies etc so understand the exact type it's not just the broad species but the exact subtypes could also be really important and that some of

the things that have changed so we might have kept the general species but we have a very different strain to our ancestors that's really important so provatella is a really important one because of its role particularly in inflammation and the immune system. And another interesting one that which only came to light again with the work of Nicola Segata's lab that we've been working on with the ZOE samples has highlighted just recently in the last few weeks that this parasite, which five years ago we used to have sent to a doctor to get eradicated with antibiotics, is present in all westernized populations. It's called blastocystis. So we all had it. The Iceman has it. It was like completely ubiquitous.

Blastocystis, this parasite. And it was thought this was bad for us and so eradicated when it was found, but it hasn't been hard to detect until the latest genetic sequencing, which we've found in the ZOE predict samples. But it turns out only 25% of the UK population have it. And it's commoner in men than women, so less women. But amazingly, when you go to the US samples, it's less than 5% habit. And so we're even seeing within the Western populations, really big changes in this. And what's really fascinating is this parasite is actually good for you. It's associated with having low body weight, better metabolic syndrome, less glucose responses, and less internal fat and lower blood pressure.

So it's quite amazing when we've now looked at over nearly 15,000 samples across the world. This is proving like a real barometer of westernization, if you like, and must be related to not only environment, but also diet. And so I'm really lucky because whatever reason I've still got it. I'm not quite sure why maybe it's my Australian mother gave it to me. If I sort of pull this all together, I think one of the things we always try and do this podcast is talk about what does this mean for us today? And what's the actionable advice? So I think it's this amazing story and insight is so much fun. But if I can't just go and get these microbes today and I can't buy them in the store, what's the actionable advice that comes out of this, do you think? I think learning that when non-Westernized

populations have better sets of microbes means that we should be generally thinking about reducing our antibiotic intakes, particularly for our children, who generally have 18 courses of antibiotics by the time they're 20, certainly in the US and in most Western countries. So we're overusing antibiotics, which is one reason that we've probably killed off a lot of our microbes, not being too sensitive about sterilizing everything, and making sure that our children, particularly when the microbiome is really most responsive, are given the chance to be outdoors and hug trees and eat dirt and play with animals like our ancestors did. And then finally, you know, improving our diet so that we don't pollute it with highly processed foods, chemicals,

and that we try and eat up a rich diversity of plants and try and learn some of the lessons from our ancestors. I think that to me is the take-home message. We don't have all the answers, but I think there are some sensible things we could start to do now that would try and reverse some of this really bad trend in our biology. And Frank, one other takeaway it seems to me from your research, which is really interesting, is there isn't just one ancient diet. Is that a fair conclusion? I fully agree. In the Hallstatt, for example, samples, we had four specimens so far. One of these individuals really ate blue cheese and drank beer. The other's not. So this is already

a good example that there's quite a variation in between these different diets i like that guy so it's my diet yeah but it's also an interesting in a respect of does this reflect maybe different social statuses yeah so this is really something we want to now investigate more so is this a more frequent phenomenon or is this more seldom? Yeah. I think also see this big variation, it sounds like in meat eating, this idea that we didn't eat any meat doesn't seem true equally well. You're not really seeing anybody on an almost exclusively meat diet. Is that also a fair takeaway from this? Definitely. This is definitely linked to the availability also of food.

Finally, we had now in Mexico a very plant-based diet only, but most likely because it was more poor also society. And then we have the Iceman, which would have had already access maybe to domesticated animals, but at that time they went back again and hunted animals also. And still they stick to this omnivorous diet, having plant-based and animal-based diet. And this then continues in the salt mines also, where they not only had plant-based diet, but also animal-based diet. So this is something we see throughout. But it's always availability and access to this foodstuff, actually. So no evidence of a keto or carnivore diet.

There were no fanatics for that that you were able to detect so far. No, I cannot imagine that there was this kind of fashion already. Omnivores, yeah. Omnivores, yeah. They ate everything. Yeah. My one takeaway of this is this idea that you could just imagine this, we're all built for this one diet that we all had in the past isn't really true because depending upon where

you were living, you're talking about, you know, a variation from entirely plant-based to like surprisingly high in meat to other things. And this, I guess, ties into the story we often hear about, you know, how our microbes themselves are helping us to adapt to these different environments. To try and wrap that up, I think we covered a lot of things and I always try and do a little summary to try and pull it together. This is a challenging one this time, but let's see. I think that we started by talking about this amazing story of the Iceman and about how

modern science can now recreate the way that our ancestors lived 5,000 years ago. That for most of human existence, our diet was very different from what we've sort of had over the last 200 years, that this was very varied in the past. But what we see is critically that our gut microbes were very different in the past. Tim talks about them being much more diverse, many more species, and that actually that seems to have continued until very recently. And this is very new information that just in the last, even 200 years ago, it looked more like hunter-gatherers today. There are things that we can do to try and compensate for where we are today.

And Tim talked a lot about things we can do with our children, about less antibiotic usage and being able to sort of probably interact more with nature, that in general, trying to improve our diet is valuable, and that we can't just say there's this one diet in the past. Actually, you know, we saw this big variation. Some people eating lots of meat, some people eating none. They were certainly eating cheese 3,000 years ago. So we've been living with cheese for longer than I would have guessed, and lots of fiber. So you talked a lot about these fibrous grains and lots of variety. And then finally, I think we may have lost some of

the very best bugs, Tim. And if I can pronounce this right, you mentioned both Prevotella and Blastocystis as two bugs that we're just starting to discover could be really health promoting, that were present in the Iceman. And although Tim has one of them, I know I don't have either of them. And so maybe that's something we can get back in the future. But today, I guess we have to focus on diet. Is that right? Yeah, I think you've summed it up well. Very good. Well, Frank, we will definitely invite you back as you discover more. And I hope that we will be jetting you around the world to find these ancient paleo feces close to listeners on this podcast.

That would be very exciting. I think many people engaged with Zoe are passionate about trying to push forward the science. Thank you both so much. I've really enjoyed it and look forward to speaking again soon. Thanks to you, Jonathan. Thanks, Brian. And Tim also. Yes.

Thank you to Frank and Tim for joining me on Zoe's Science and Nutrition today. We hope you enjoyed today's episode. If you did, please be sure to subscribe and leave us a review as we love reading your feedback. If this episode left you with questions, please send them in on Instagram or Facebook and we will try to answer them in a future episode. And absolutely do let us know if you believe there is one of these paleo feces in your neighborhood frank is serious about being willing to follow up on that at zoe we want to improve the health of millions by understanding the right food for each

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