Gut Barrier Unlocked: Dr. Maria Marco on the Power of Fermented Foods

In episode #151 we discuss the science behind fermented foods with researcher Dr. Maria Marco:

  • The role of microbes in gut health and their potential benefits for humanity and the planet.
  • Insights into the fermentation process of sauerkraut and its impact on gut barrier function.
  • The difference between probiotics and friendly microbes found in fermented foods like sauerkraut.
  • The potential for fermented foods to offer health benefits beyond just probiotics, focusing on the metabolites produced during fermentation.

Dr. Maria Marco is a Professor in the Department of Food Science and Technology at the University of California, Davis. She earned her bachelor’s degree at The Pennsylvania State University and PhD in microbiology at the University of California, Berkeley. She performed her postdoctoral research at the Wageningen University and NIZO food research, The Netherlands. Dr. Marco started her lactic acid bacteria and gut health laboratory at the University of California, Davis in 2008 and has built an internationally recognized research program on fermented foods, probiotics, and dietary modulation of the gut microbiome. Dr. Marco is currently President of the International Society of Probiotics and Prebiotics (ISAPP) Board of Directors and is a fellow in the American Academy of Microbiology.

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TRANSCRIPT:

Kyla Channell (00:03.027)
Hello everybody and welcome back to the Nutritional Revolution podcast. Today we have for you guys, Dr. Maria Marco. Thank you so much for joining us.

Maria (00:12.59)
Great to be here.

Kyla Channell (00:14.183)
We are very excited. We’re going to dive into a bit of gut conversation and gut barrier functioning with Dr. But before we do that, Maria knows the protocol. are going to do her two truths and a lie. So why don’t you break those down for me,

Maria (00:31.54)
All right, here we go. No particular order.

Kyla Channell (00:36.317)
Okay, good,

Maria (00:40.079)
I have them written down, so I don’t mess this up. right. There are more microbes on Earth than stars in the universe.

Kyla Channell (00:41.393)
Okay. Perfect.

Kyla Channell (00:49.681)
Okay.

Maria (00:53.998)
Second, there are probiotics and sauerkraut.

Kyla Channell (00:58.879)
Okay.

Maria (01:00.75)
and

And third, there are more beneficial microbes on the planet Earth than harmful ones.

Kyla Channell (01:11.871)
Ooh. Okay.

Kyla Channell (01:17.715)
I feel like the probiotics in sauerkraut is true, but then I feel like there could be exceptions to that. But that’s maybe what you’re going to teach us today. I feel like there are more microbes on the earth than stars. There’s got to be.

Kyla Channell (01:33.319)
Maybe it would be interesting if there’s more harmful ones than beneficial. That would be fun to learn or maybe not fun. I think that one’s the lie, but I will reveal the answer to the listeners at the end of the episode. So today we’re going to learn a bit more about Maria, but we will be diving into her study, the fermented cabbage metabolome and its protection against cytokine induced intestinal barrier disruption of

Kako to mono layers. Did I say that right? C-A-C-O to, how do you say it? Kako, Kako. Okay. Learning experience for myself, as I mentioned, and our listeners. But before we dive into the study, I’d love for you to share what drew you to gut barrier integrity and just gut research.

Maria (02:29.752)
That is a great question. I think the background on this is that rarely do our careers follow a single line. I certainly did not grow up thinking about this, but I became really interested in microbes as microbes and what they can do and really what they can do to help humanity and to help the planet. And so I really followed that.

Kyla Channell (02:38.686)
Mm-hmm.

Maria (02:58.348)
trajectory throughout my career and worked on different microbes. I worked on microbes in soil, on plants, in the mouth. And then it was my postdoc experience after my PhD, where I worked in the Netherlands and Europe and discovered this world of fermented foods and probiotics and intestinal microbiology. And this was like the

Kyla Channell (03:07.103)
Eww.

Maria (03:26.924)
early 2000s and the whole microbiome field was really starting to grow. so I think it wasn’t so much that, you know, I have to study intestinal barrier function. That’s my passion. It’s more about a story about my interest in microbes and being around people who were really inspiring working in that area that led me to really

I’m like, this is super cool. So when I started my lab in 2008 here in Davis, that was decidedly the focus. And I’ve just been working on it ever since.

Kyla Channell (04:06.143)
Amazing. And for our kind of review today with the gut barrier functioning, I think there’s going to be some terms in the paper that we will need breakdowns of for myself and our listeners. But maybe that’ll come with the description of the study. So we can go through a bit of that too.

What was the initial intention of the study? What did you think you were gonna hope or hoping to find from the study? how? Yeah, break it, break it down for us. How did you guys perform the study? All the all the good stuff.

Maria (04:45.198)
Yeah, there’s also a pretty big backstory in all this as well. I didn’t eat sauerkraut growing up. My ancestry is half Italian, half Slovakian, and many memories of my grandmother making pierogies with sauerkraut. know, New Year’s we’d have sauerkraut. And she would, the grandmother would make fermented.

Kyla Channell (04:50.042)
Yeah, please share.

Maria (05:14.2)
cucumber pickles and beets. you know, of course at that time I only thought they tasted good. I didn’t think more about it. The story of this paper and this interest in how fermented cabbage can affect our intestinal tract came about through a California Department of Food and Agriculture, rather research grant.

Kyla Channell (05:15.571)
Mm-hmm.

Maria (05:42.732)
you know, just as a little plug. It’s really, really important for every dimension of our life that research is funded in the US and around the world. We really can’t do this research without these extra funds because the university doesn’t have them and they’re never provided. So it’s been a really cool project. We called it Eat Lack.

Kyla Channell (06:01.343)
Ray.

Maria (06:11.564)
I’m forgetting what it means. Yeah, I’ll pull it out later. But it’s really about lacto fermentation using lactic acid bacteria.

Kyla Channell (06:13.191)
Is it lactobacillus for lactobacillus?

Kyla Channell (06:21.311)
Mmm.

Maria (06:27.84)
eating and analyzing lactate ferments across the country to that effect. We’re trying to get it going again with a new grant, but we have an active Instagram site and so I can provide that later. The bigger picture of this whole grant was really about translating the science to everyday people who want to make these foods at home by providing recipes, by providing workshops.

Kyla Channell (06:36.819)
Mm-hmm.

Kyla Channell (06:41.075)
Yeah.

Kyla Channell (06:51.625)
Mm-hmm.

Maria (06:57.602)
We had webinars and provided videos. Of course, this was during a pandemic, so we really didn’t have in-person workshops. We tried to do as much as we could in kind of communicating with everybody who’s interested in making fermented fruits and vegetables.

Kyla Channell (07:13.673)
Cool.

Maria (07:15.638)
And we even had a community science project where we invited everybody to submit to us a little sample of their homemade ferment and we looked at the microbes in there. So yeah, that whole project was really fun. And one of the goals of the project was to take one of the foods, one of the fermented fruits and vegetable foods, and to go a bit further, right? And to see

Kyla Channell (07:26.623)
Amazing.

Kyla Channell (07:42.271)
Mm.

Maria (07:45.39)
not just how they’re made, but how they could affect.

We decided on sauerkraut because it’s a really simple fermented food. If you ever made it at home, very easy. You just get cabbage, slice it up, shred it and mix in a little bit of salt and pack it in a jar and then wait. Right? I mean, it’s like, don’t need anything fancy to make it. Leave the jar on the counter.

Kyla Channell (08:15.144)
Yeah.

Maria (08:20.354)
as the fermentation happens. It’s kind of like magic. Yeah, you can eat it after a few days, but most people wait a week, two weeks, or even longer. And you’ll see if you taste it after a few days and then week later, it’s going to taste different because the microbes continue to do their work and they change kind of flavor compounds in the ferments over time.

Kyla Channell (08:25.007)
Yeah. How long does it take to get the end product?

Kyla Channell (08:41.513)
See ya.

Mm. Mm.

Maria (08:50.03)
So we chose for sauerkraut in part because it’s really simple and allows us just to look at the microbes in the ingredients, mainly the cabbage. And then what we found is a lot of people are making sauerkraut at home in our community science project. We had a lot of sauerkraut submissions. So we had another reason there to focus on that food. Yeah. And so the bigger picture of the project, we were really interested to know

Kyla Channell (08:58.143)
Mm-hmm.

Kyla Channell (09:12.659)
So cool.

Maria (09:19.534)
Does sauerkraut, fermented cabbage do anything to our gut barrier function? And on top of that, we wanted to test store-bought sauerkraut, homemade sauerkraut, and in this case, a lab-made sauerkraut. made it in the lab. And when we made it in the lab, we also added to some of the sauerkraut a probiotic strain. So we wanted to add that layer on as well.

Kyla Channell (09:45.471)
Mm.

Maria (09:49.928)
And really what I’m describing here is the work of Wade Lay, who was a PhD student at the time. And I’m talking about it, but she was the one doing all the hard work in the lab. I just kind of sit behind the desk and make decisions and discuss the data. So I want to make sure I talk about Lay there, because she is very precise and made sure that everything was done properly throughout the study.

Kyla Channell (09:58.939)
Amazing.

Kyla Channell (10:04.051)
Yeah.

Kyla Channell (10:16.265)
Well.

Maria (10:17.484)
Yeah, so that’s kind of the backstory. We selected the looking at gut barrier function and the particular cell culture approach because it is pretty broadly used for looking at effects of dietary components and pathogens and…

Kyla Channell (10:30.238)
Mm-hmm.

Maria (10:44.056)
drugs, you know, it’s a commonly used approach for assessing what a compound or microbial do to the gut lining. I already say it’s not perfect, right? There is no perfect assay. It allowed us to test a lot of samples at once and we can’t do that with people. So as much as it’d be great to do with people, that would not be possible in the kind of study that.

Kyla Channell (10:54.239)
Mm-hmm.

Kyla Channell (11:06.793)
break.

Maria (11:13.634)
that we could do.

Kyla Channell (11:15.025)
Right. And with the probiotic that you’re adding to the lab version of the sauerkraut, are you guys also taste testing out of curiosity? Did that change the flavor profile?

Maria (11:26.646)
It definitely changed the acidity and therefore changed the flavor profile. Yeah, it was the most acidic of our ferments. And I think that tells us that the microbe grew really well. We were able to measure the numbers of that specific probiotic strain and it grew really well. So that all tracks with regard to

Kyla Channell (11:28.404)
Mmm.

Kyla Channell (11:31.944)
Okay.

the

Kyla Channell (11:43.271)
Mmm, okay.

Kyla Channell (11:50.099)
Mm-hmm.

Maria (11:55.874)
because they make acid when they grow, they make lactic acid, then the fact that those ferments were more acidic makes sense.

Kyla Channell (11:58.164)
Mm-hmm.

Kyla Channell (12:05.157)
Yeah. Okay. Amazing. And so then when you’re looking at a cell culture, how are you measuring gut barrier function? How are you taking these probiotic or sauerkraut and how are you putting it into your cell culture and interacting with it? Yeah.

Maria (12:27.09)
at epithelial cells. We know that we can, we didn’t want to apply just full on sauerkraut onto these four intestinal cells. That wouldn’t be fair to them. And that’s not what our gut would see, you know, of course there’s going to be dilution as we eat the food. So we were very specific to do a couple things. One of those was to

Kyla Channell (12:37.649)
Right. Yeah.

Yeah. Ray.

Maria (12:56.438)
remove the cabbage itself. So we didn’t want to apply the solids, the fibers from the cabbage, et cetera, onto the epithelium. Instead, we wanted to know more about the metabolites that are in the brine or released from the cabbage that could then diffuse to our intestine and our lining and then be absorbed.

Kyla Channell (12:58.975)
Mm.

Kyla Channell (13:02.622)
Right.

Kyla Channell (13:15.238)
Mm.

Maria (13:26.414)
So we did that intentionally. And the other thing we did is we did some preliminary work to test different concentrations of those metabolites. before we even applied them, we filtered the cabbage homogenate. So we broke it up and made sure we just had small molecules. And then we took different concentrations of those filtrates, those metabolites.

Kyla Channell (13:35.231)
Mmm.

Kyla Channell (13:51.977)
Mm-hmm.

Maria (13:54.614)
them onto the cell coat because we didn’t want to kill the cells either. we wanted to have enough that if there was going to be an effect that we’d see it, but not too much would cause the cells to die because it’s not a normal situation.

Kyla Channell (13:57.364)
rate.

Kyla Channell (14:05.917)
Right. Yes. Yeah. It does really show and explain like the delicacy of like how these, yeah, like you’re saying these cell cultures are just, they are so delicate. So with that exposure and the starting cell cultures, are these healthy cell cultures? these, how could we imagine these like from a human’s perspective? Are these quote unquote like healthy gut cells or these

cells with gut barrier dysfunction already.

Maria (14:40.558)
Well, it is a cancer cell line. So let’s just start there. are immune, I mean, immortal rather. And that’s not ideal, but it does allow us to perpetuate them and to use them in large quantities repeatedly. So to give that kind of metric of consistency.

Kyla Channell (14:48.126)
Okay.

Kyla Channell (14:57.311)
Mmm.

Kyla Channell (15:01.823)
Wow.

Mm-hmm. Mm-hmm.

Maria (15:05.714)
There are other cell lines that we could use and we know that that’s a weakness that we weren’t able to test other cell cell types and cell lines in this study. But what I can say about the benefits of this is that they do form these monolayers that are like our skin.

Kyla Channell (15:17.727)
Mm.

Kyla Channell (15:31.027)
Mm-hmm.

Maria (15:33.774)
go into our digestive tract, we take a camera and we may be a little gross, but there’s the epithelium that’s there. That’s really still the outside of our body.

Kyla Channell (15:43.176)
Yeah.

Kyla Channell (15:47.625)
Mm-hmm.

Maria (15:49.934)
doesn’t seem like it. And so it’s important that just as our skin doesn’t have any breaks, right, we would call that an injury or wound, we don’t want to have breaks in our intestinal lining. And so we can grow these cells and it takes weeks, honestly, but we can grow them so they form these monolayers, which is really just the skin. And with that, they form these bridges between cells.

Kyla Channell (15:59.039)
Mm.

Kyla Channell (16:14.802)
Mm-hmm.

Maria (16:19.79)
using proteins called tight junction proteins so that they’re really attached to one another. And once we know they form this lining, then we can apply tests to look at how well that lining resist molecules moving from one side to the other. And so we use these kind of metrics to tell us

Kyla Channell (16:26.163)
Mm-hmm.

Kyla Channell (16:44.447)
Mm.

Maria (16:49.326)
You know, it has that barrier of informed. And if so, okay, that’s good. That’s where we’ll start. And we can start to put challenges to it. Challenges could be like cytokines that cause inflammation that cause the epithelial cells to go, what is going on? And those tight junctions start to get leaky as the cells become unhappy.

Kyla Channell (16:56.862)
Yeah.

Kyla Channell (17:02.323)
Mm.

Kyla Channell (17:09.684)
Mm-hmm.

Kyla Channell (17:15.336)
Mm.

Maria (17:18.83)
then molecules can pass from the, food into the body, right? There’s that leakiness. So another example is like a pathogen like E. coli or something, E. coli, they have compounds called endotoxins that we can perturb or disrupt the barrier with. So.

Kyla Channell (17:23.401)
Mm-hmm.

Kyla Channell (17:41.564)
Mm-hmm.

Maria (17:44.408)
We have a model and then we can challenge that model and what we can see is what like sauerkraut, can it prevent that leakiness from happening when we apply cytokines, like inflammatory cytokines.

Kyla Channell (17:57.695)
Very cool. This is so fascinating. Like I’m nerding out through you. So with that process, so you have these solid gut junction lining cells. Are you then taking them and exposing them to the pro-inflammatory markers and having some damage occur and then bringing in the sauerkraut or walk us through that process?

Maria (18:22.67)
That’s a great question. That’s a really good and important question. I’m so glad you brought that up. We put the sauerkraut filtrate on before we applied the interfering gamma TNF alpha pro-inflammatory cytokines. And we don’t know what would happen if, say, the gut was already compromised by those cytokines if we applied the sauerkraut after.

Kyla Channell (18:32.265)
Okay.

Kyla Channell (18:47.827)
Mm-hmm.

Kyla Channell (18:51.603)
Mm-hmm.

Maria (18:52.35)
We don’t know. From experience working with probiotics and they tend to work fast before there is an injury, right? So they’re building in that resilience or that prevention and that’s more effective than using them as treatment methods.

Kyla Channell (19:02.964)
Brave.

Kyla Channell (19:12.079)
Mm-hmm. It seems like that is a common theme, I feel like, across the board with a lot of things I’ve learned in nutrition, whether it’s, yeah, protein in your muscle before you get injured versus, is it omega-3s, like, in the brain and body before TBI? Yeah, it is an interesting area there. So how long are these tissue cells being exposed to the inflammatory markers?

before we’re seeing something happen. And you had mentioned there was was there three different types of sauerkraut being introduced the lab and yeah.

Maria (19:49.646)
There were a lot of controls. And then we looked at sauerkraut after seven days of fermentation, 14 days, and then with the probiotic and the commercials. So we had a number of different treatments. Again, that would have been really hard to test in a human study and then to measure barrier function on top of that.

Kyla Channell (19:58.537)
Boom.

Kyla Channell (20:07.987)
Yeah.

Maria (20:12.558)
But your question was how long after we applied the cytokines before we expect to see a change. It’s really 24, 48 hours afterwards when we’re measuring. So it’s not instantaneous. And also, we need to sleep and eat ourselves. So we’re not there measuring every 10 minutes.

Kyla Channell (20:24.797)
Wow. Mm-hmm.

Mm-hmm.

Kyla Channell (20:35.134)
Yes.

Mm-hmm.

Maria (20:40.206)
But what we’re looking for is a trend over time. for example, we measured 2448 and then I believe 72 hours after application of Gamma.

Maria (20:58.478)
TANF-ALFA rather, then, yeah, and then we could see this difference between our controls where we didn’t apply cytokines and controls where we did apply cytokines. Obviously we’d wanna see a difference there, otherwise our model is not working. And then when we tested just some brine,

Kyla Channell (21:17.897)
Mm-hmm.

Kyla Channell (21:25.279)
Mm-hmm.

Maria (21:25.496)
We wanted to make sure it just wasn’t the salt water that was having effect, that wasn’t having an effect. just raw cabbage itself with brine wasn’t protective. And yeah, so the way we measured that is using a couple techniques, looking again for those molecules to move across the barrier is kind of a primary indication that the barrier function is not working as well as it should.

Kyla Channell (21:30.354)
rate.

Kyla Channell (21:36.447)
Mmm.

Kyla Channell (21:52.329)
Gotcha, okay. And then for our listeners kind of walking around in bodies, what would be something that would trigger an increase in these pro-inflammatory cytokines in someone’s body?

Maria (21:59.63)
Thank

Maria (22:09.346)
Yeah, definitely kind of inflammatory conditions in the digestive tract. We have these kinds of episodes, I think, when we’re stressed. Being stressed, can cause it. There is some evidence of…

Kyla Channell (22:18.057)
Mm-hmm.

Kyla Channell (22:28.755)
Mm-hmm.

Maria (22:37.56)
compromised gut barrier function. You mentioned athletes and kind of high intensity situations. Certainly when we have foodborne illness, that’s an issue. I think the broader picture in this is maybe not just specific to the cytokines, but just generally what we want to avoid is having

Kyla Channell (22:39.465)
Mm-hmm.

Kyla Channell (22:44.776)
Yeah.

Kyla Channell (22:52.288)
Mm-hmm.

Maria (23:06.798)
our skin, intestinal lumen, epithelium being in a state that is taking up microbes, is taking up compounds from our diet that we don’t want, that we don’t need in our bodies. And that I think is what this model is trying to signal. It’s not the…

Kyla Channell (23:24.564)
Mm-hmm.

Kyla Channell (23:32.723)
Mm-hmm.

Maria (23:33.87)
It’s certainly not a perfect model, but it is one that I think is relatively validated to be useful for this kind of first step in looking at dietary components that protect and harm intestinal barrier function.

Kyla Channell (23:55.589)
Yeah, wow. So if we fast forward to the end of the study, did the findings end up being with the different, like I know you mentioned the brine versus, well, in the different days out, what did you end up finding? What ended up being effective from minimizing that gut barrier, tight junction degradation?

Maria (24:09.166)
Yeah.

Maria (24:20.088)
Sauerkraut.

Kyla Channell (24:21.489)
Amazing. No specific time, like fermentation duration or.

Maria (24:26.776)
That’s where I started to get really excited. That it wasn’t, for example, the probiotic sauerkraut or the commercial one, that it was pretty consistent across the ferments. And that then points to specific compounds that are enriched or made in the fermentation of cabbage that are barrier protective.

Kyla Channell (24:29.343)
Mmm.

Kyla Channell (24:42.015)
Wow.

Maria (24:56.942)
I think that’s really where the science of all this needs to go is what are the kinds of compounds like omega-3s, right? Or fiber, right? And what kind of fiber? But for me, what’s interesting is what kind of microbial compounds should we be eating? Like how many microbes should we be eating? But even more importantly, what parts of those microbes should we be eating to confer?

Kyla Channell (25:07.485)
Mm-hmm.

Kyla Channell (25:23.251)
Mm-hmm.

Maria (25:25.89)
protection of our health or particularly our gut barrier function. So to follow that idea, we looked at the metabolites in these ferments and the metabolites we could get out of the raw cabbage. And it’s a no brainer. They are different. The raw cabbage has different metabolites. It tastes different. It looks different, right? Compared to the sour

Kyla Channell (25:29.449)
Mm-hmm.

Kyla Channell (25:56.191)
Mm.

Maria (25:56.654)
And we did find differences between the different ferments. The sauerkraut from the commercial product had a different metabolite profile compared to the ones in the labs. all of, you know, all together, they were more similar to each other than the raw cabbage.

Kyla Channell (26:08.233)
Mm-hmm.

Kyla Channell (26:14.111)
Cool, okay. And did you say, did you do a shelf stable fermented sauerkraut as well?

Maria (26:23.33)
Yeah, well, we received sauerkraut from a collaborator who just, yeah, we could buy it in the, I could buy it in the supermarket today, right? It’s in the cold section. we didn’t, yeah, so we don’t know if past rice sauerkraut would have the same effect, but once we know what metabolites are important, then we can test it or know whether or not the ferment or the

Kyla Channell (26:28.319)
Mm-hmm.

Kyla Channell (26:34.865)
It is in the cold section. Okay.

Kyla Channell (26:41.362)
rate.

Maria (26:53.452)
rather the pasteurized product would still have those compounds. So that’s why I think we need to move from like, this is an interesting phenomenon to what are the specific metabolites responsible for gut barrier protection. Yeah.

Kyla Channell (26:56.476)
Mm-hmm. Yeah.

Kyla Channell (27:03.668)
great.

Kyla Channell (27:09.695)
Wow, so fascinating. so out of curiosity, like theorizing now, do you, and maybe there is literature out there on this. Do we think that things like kimchi or I guess like other fermented foods, yogurt, like do we think those also have gut barrier protection capabilities?

Maria (27:37.186)
Yeah, yeah. It’s gonna be different and probably different, some different compounds depending on the food. We’ve looked at kimchi. We’re still looking at kimchi. We’re about to start a human study on kimchi. We’re excited about that. But kimchi has, besides cabbage, it has other ingredients and it has a lot of spice. So.

Kyla Channell (27:44.712)
Yeah.

Kyla Channell (27:48.436)
Mm-hmm.

Kyla Channell (27:52.627)
Cool.

Kyla Channell (28:02.011)
Mm hmm.

Maria (28:04.888)
kimchi might have different effects on the gut barrier. Interesting though, there’s some really nice human studies on kimchi performed in Korea suggesting that it can be useful for weight management. And so we’re gonna hopefully get some insight on that for folks here in the US. Previous to working with

Kyla Channell (28:07.892)
Mm-hmm.

Kyla Channell (28:18.303)
Mm.

Kyla Channell (28:26.611)
Wow.

Maria (28:33.194)
sauerkraut. We did look at fermented milk and to see how whether milk or fermented milk with probiotic strain could be very protective. We use the same model and we definitely see a trend in that the fermented food is more protective than the ingredient. So compared to milk. Right. So I think we’re seeing this trend towards

Kyla Channell (28:50.643)
Mm.

Kyla Channell (28:56.509)
Mm hmm. Amazing. Yeah.

Maria (29:03.278)
Um, you know, our ancestral diets had a lot of microbes and microbial metabolites. We didn’t have refrigeration, for example. Um, and, and so I think what we’re going to be learning is that just as we know our gut microbiome to be important these days, I think our food microbiome is going to be important, um, in complementing, uh, the

Kyla Channell (29:08.456)
Mm-hmm.

Kyla Channell (29:13.597)
Yeah.

Maria (29:31.554)
those things that our gut microbes are doing for us.

Kyla Channell (29:34.311)
Yeah, amazing. And so for our listeners, if there is a sauerkraut that is not refrigerated in a store and it’s on the shelf, will that still contain probiotics?

Maria (29:48.526)
It will not contain live microbes because it is pasteurized, meaning it’s going to be heated and maybe pressurized so any microbes that were alive in there would be dead. There could be still the good metabolites. We found these sort of metabolites that are made by microbes that we know to be gut barrier protective or enriched in the sour.

Kyla Channell (29:53.439)
Okay.

Okay.

Kyla Channell (30:01.704)
Hmm.

Kyla Channell (30:07.635)
Mm-hmm.

Kyla Channell (30:16.435)
Mm-hmm.

Maria (30:18.574)
those could still be there, because they’re just small molecules. They’re not likely to be destroyed. So hopefully we get more funding. We’ll actually measure that, because yeah, think the quality of the sauerkraut used to make that pasteurized product, right, that will also be important, right? The pasteurization will have an effect. But if they’re not,

Kyla Channell (30:21.263)
Mm-hmm.

Kyla Channell (30:29.031)
Yeah, yes.

Kyla Channell (30:43.399)
Mm-hmm.

Maria (30:47.22)
starting with a sauerkraut that is actually very good, know, or has the right kind of microbes and metabolites, they won’t be there in the end.

Kyla Channell (30:55.869)
Right. OK. And for our listeners, can you explain a little bit of the difference between fermented, pickled, and brined?

Maria (31:07.406)
Yeah, pickled is a tough one, right? I mentioned cucumber pickles, right? so the center of the supermarket, we have a lot of pickles. And unfortunately, a lot of the pickle products are just vegetables to which they’ve added vinegar.

Kyla Channell (31:11.002)
Yeah.

Kyla Channell (31:16.791)
huh.

Kyla Channell (31:25.747)
Mm-hmm.

Kyla Channell (31:35.453)
Mm-hmm.

Maria (31:37.186)
right, because of vinegars, acetic acid, it has a strong flavor. When we’re fermenting, it takes time. like I mentioned making sauerkraut, could take a week, two weeks. And so that’s one indication I have of saying, OK, this is a fermented food as opposed to only a pickled food.

Kyla Channell (31:43.775)
Mm-hmm.

Kyla Channell (31:56.712)
Yeah.

Kyla Channell (32:05.439)
Mm-hmm.

Maria (32:07.726)
The confusion can be is that the microbes that grow in the fermented foods, the pickles and the sauerkraut, they too make things taste like vinegar. They make acetic acid through their metabolism. And so it can be a little confusing and difficult as a consumer to know whether something is just pickled or something is fermented.

Kyla Channell (32:16.703)
Mm-hmm.

Kyla Channell (32:21.791)
Mm-hmm.

Kyla Channell (32:32.414)
Mm-hmm.

Maria (32:36.974)
Just talking about cucumbers, right? For example. Always look at the side of the container and then I myself will go to the cool section of the supermarket where it’s more likely that the fermented vegetables that are there are going to be fermented.

Kyla Channell (32:39.25)
Yeah.

Kyla Channell (32:57.009)
Mm-hmm. Awesome. I think that’s very helpful. So for our listeners, is there a suggested serving of sauerkraut that you would encourage people to start with?

Maria (33:12.11)
I think a typical serving size is about 100 grams. So it’s not a lot. And you could eat it with anything. I was thinking, you know,

I don’t eat hot dogs, so don’t even think of that. But on salad or just as, I think kimchi is maybe a little bit more commonly eaten as a little condiment on the side. One could think of that putting on a sandwich, I think would be good. Potatoes and sauerkraut, in my opinion, go well together. But what was exciting again about the study that we did is the kind of

Kyla Channell (33:31.086)
yeah.

Kyla Channell (33:41.779)
Mm-hmm.

Mm-hmm. Mm-hmm.

Kyla Channell (33:50.676)
See ya.

Maria (33:57.294)
quantities we were testing of the sauerkraut on the intestinal cell model were the same quantities we would be eating. So I’m not suggesting you go get a big container of sauerkraut and just eat that for lunch. I think my son would do that, but I have no interest, right? So just a typical serving size of about 100 grams would be sufficient to get those healthy.

Kyla Channell (34:15.903)
Yeah.

Maria (34:27.472)
those good metabolites.

Kyla Channell (34:29.695)
Awesome. My brain goes, of course, to the endurance athlete population, like we discussed a little bit with a lot of those long hours running or on the bike and in the heat and that hypoxic environment they create at the level of the gut or the jostling and the rubbing and all of yeah, all of that, can happen. And then a lot of them will have, I mean, little to no appetite, certainly post-race and then…

Maybe they’ll have GI issues during the race. yeah, then the appetite sometimes can take a couple of days to come back. So I do certainly see a use case for the endurance athlete population. Kind of moving on to, so you mentioned, let’s see, beyond kind of the probiotics, you said you showed that a milk filtrate with

I’m going to probably butcher this, but lacto casey bacillus parakeci offered. Did I say that right? my gosh.

Maria (35:32.14)
Yeah, it used to be just Lactobacillus KCI, but now all of these Lactobacilli have new genus names that are sometimes quite common.

Kyla Channell (35:38.463)
Oh, OK. BL23. Is that the short? Yeah. You had reported that it offered a similar protection as the sauerkraut metabolites. That’s very neat. is.

Maria (35:43.502)
There we go. That’s the screen.

Maria (35:55.97)
Yeah, yeah, we don’t, but I think those are different kinds of metabolites. Lactic acid would be in both, because they’re both lactic acid, bacteria ferments. When we tested lactic acid alone, it wasn’t very protective for us. So we think it’s something else that’s being enriched in these ferments. We think it’s more than one thing, essentially. When we tested individual compounds out of the sauerkraut,

Kyla Channell (36:12.575)
Eugh.

Kyla Channell (36:17.407)
Mm-hmm. Yeah.

Maria (36:27.938)
they were generally beneficial, but not as good as the complete ferment. So we think if that mixture, that’s important.

Kyla Channell (36:32.511)
Mm.

Kyla Channell (36:36.34)
Yeah.

Yeah, okay. And no difference between like, do we know red, like a red cabbage versus green cabbage?

Maria (36:46.656)
I don’t know. We didn’t try the red cabbage. Yeah, it be better.

Kyla Channell (36:47.653)
Yeah. Okay. The antioxidants seem like they’re maybe more potent in that. Yeah. So if we pair specific maybe prebiotic fibers with fermented food metabolites, is there a synergistic effect, do you think, that we’re able to unlock there?

Maria (37:08.088)
Mm-hmm.

Yeah, that’s why we need these studies on whole foods in people, right? There’s been one human study with a kind of health endpoint measured on sauerkraut. Yeah. Yeah. So we have a lot of work to do here. The good news is that looked like the, in that study, was a pilot study and there was a reduced

Kyla Channell (37:13.289)
Yeah.

Kyla Channell (37:21.469)
Really?

my gosh, wow.

Kyla Channell (37:28.337)
Yes.

Maria (37:38.188)
reporting of symptoms for IBS patients with sauerkraut intake. But to your bigger point, so putting the whole fiber, right, the cabbage, which has fiber together with the brine, where you have the metabolites more accessible, I think it puts it together in a probably even better way because those fibers will reach the gut microbes in our

Kyla Channell (37:41.407)
them.

Kyla Channell (37:49.107)
Mm-hmm.

Kyla Channell (37:54.793)
Mm-hmm.

Maria (38:08.024)
in our digestive tracts, our gut microbiome. And we need to more fiber generally and partly because just for us, but the important part of this is that it feeds our gut microbes. Those microbes will eat it and make compounds like short chain fatty acids that are absorbed in our energy sources for our colon and reach the brain and other important for metabolism.

Yeah, I think we looked at one aspect of that being the diffusible metabolites, but it’s really the whole food that offers the full package of goods.

Kyla Channell (38:49.887)
That seems to be the recurring theme, I feel like, too, in nutrition. It’s like there’s components in there that all work together in a beneficial way. So are there any unanswered questions that keep you up at night regarding sauerkraut or fermented foods and gut barrier functioning that you’re wanting to look into in the future?

Maria (38:52.526)
Hmm.

Maria (39:02.926)
Ha!

Maria (39:15.468)
Yeah, I think we need kind of a big project to really unravel what are the microbial foods or microbial components in foods that we should be eating more of. If we have a salad, we’re eating microbes, right? Quite a few of them actually, but they’re very different than the microbes we would have in yogurt or a sauerkraut or used to make bread, right?

Kyla Channell (39:27.123)
Mm-hmm.

Kyla Channell (39:31.817)
Mm-hmm.

Yeah.

Kyla Channell (39:43.036)
Mm-hmm.

Maria (39:47.373)
And why I think this is really cool is because we’re learning so much more about our own gut microbes and what they’re doing for us in good times and in bad time. But just emphasizing the good, right? We can’t really necessarily change which microbes live in our digestive tract.

Kyla Channell (40:06.12)
Mm-hmm.

Maria (40:09.422)
take antibiotics, right? But that’s not really desired, right? So it’s really hard to change that, but we can in principle change our diet.

Kyla Channell (40:11.859)
Yeah. Yeah.

Kyla Channell (40:17.939)
Okay, amazing. I just more recently spoke to someone who does FMT, fecal microbial transplant, and my mind was just like blown. That’s like a whole other thing. okay, so I do want to be mindful of your time here since we’re getting close here. So I’m going to do some rapid fire questions for you, and then we’re going to jump back to your tutus and line, find out if there’s more microbes on this planet than stars.

So let’s see, what is your favorite way to eat kraut?

Maria (40:49.963)
You

Maria (40:54.452)
Yeah, that’s a great question. Pretty much anyway, I do like it with potatoes. So if I’m thinking of making anything with potatoes, I always have my sauerkraut right there.

Kyla Channell (41:07.615)
Nice. Do you make your own sauerkraut?

Maria (41:10.688)
I have, I haven’t done it recently.

Kyla Channell (41:12.529)
Yeah. If there’s a recipe too, can share that with the listeners. It sounds pretty simple. And then is there a fermentation experiment that you feel like flopped in the Marco Lab, Dr. Maria Marco Lab? Anything that was not a hit, didn’t go the way you planned?

Maria (41:18.635)
Okay.

Maria (41:36.379)
The didn’t go the way we planned.

Kyla Channell (41:38.909)
Yeah.

Maria (41:41.91)
No maggots or anything like that. So I think a testament to the quality of the microbiologist in my group.

Kyla Channell (41:43.881)
That’s good.

Yes. Good. Good, good, good. And then is there a microbiome myth you’d like to retire forever?

Maria (41:59.118)
retire forever. Well, maybe we’ll get to that.

Kyla Channell (42:05.055)
Okay, we will get to that. okay. So maybe that’s part of our tooth-frozen lie. Let’s find out. Let’s find out. Okay. So if we jump back there, you said that there’s more microbes on earth than stars, that there are probiotics in sauerkraut, which I think we just found out was true, hopefully. There are more beneficial, I forget if you said microbes or probiotics on earth than harmful. And I thought that one was the lie.

Maria (42:10.382)
you.

Maria (42:31.534)
Yeah, no, that’s true. There more beneficial microbes on planet, on our thin, than harmful ones. Here are the pathogens. We give them so much attention.

Kyla Channell (42:36.935)
Ooh.

Kyla Channell (42:42.589)
That’s good to know.

Kyla Channell (42:46.777)
Yeah. Yeah. That’s good to know. And then which one was the lie? There’s not probiotics. So are probiotics technically a manmade or how do you define probiotics? is it different than bacteria?

Maria (42:52.91)
probiotics.

Maria (43:03.628)
Yeah, this is where I stand on my pedestal, I guess. don’t know. So probiotics are very specific strains.

Kyla Channell (43:08.084)
Yeah.

Kyla Channell (43:13.779)
I see.

Maria (43:14.892)
that were shown in clinical studies to confer a health benefit. Okay. And what I mean by a strain is a very specific genotype, very specific genome. Okay. Now you and I are both people, right? But we’re both homo sapiens, but we have different properties.

Kyla Channell (43:19.263)
Hmm.

Kyla Channell (43:26.793)
Mm.

Kyla Channell (43:38.867)
Mm-hmm.

Maria (43:39.704)
Bang, bang for two strains of Lacti KCI, Bacillus KCI, right? Or Lacti Plantibacillus plantarum, So although they have the same genus and species names, two isolates have different genotypes. So we can’t say with certainty that I get a plantarum, L-plantarum out of my sauerkraut.

Kyla Channell (43:44.742)
Mmm.

Kyla Channell (43:58.592)
Mm-hmm.

Maria (44:07.554)
that it’s going to do the same thing as a probiotic strain that has been tested in clinical trials and shown to have a value.

Kyla Channell (44:14.351)
Hmm. Interesting.

Maria (44:17.454)
So that, think probiotics is a useful term to convey beneficial microbes. But there’s actually a definition for probiotics. It was very specific. And that’s why I said that was the lie.

Kyla Channell (44:26.419)
Mm-hmm.

Kyla Channell (44:35.965)
Gotcha, gotcha, okay. So there are fermented, is that, how would you, like there’s fermented bacterial strains in sauerkraut?

Maria (44:47.094)
In sauerkraut, there’s friendly microbes. They can be beneficial for us, but to call them probiotics is sort of the myth that I guess I would think of because we don’t know what their genomes are. We don’t know what they can do. We know they are friendly and they’re not going to hurt us, but we don’t even know their numbers.

Kyla Channell (44:49.193)
friendly microbes.

Kyla Channell (45:05.851)
Mm-hmm.

Mm-hmm.

Maria (45:15.426)
Right? When we go to the store and we see probiotics, sauerkraut, I would challenge the company, well, how many are alive in there? How many are even in there? It’s unlikely to be even that many because it’s such an acidic food and over time, it’s gonna like basically kill themselves from all the acids that they’ve made. So anyway, that’s…

Kyla Channell (45:16.081)
Yeah.

Kyla Channell (45:22.383)
Yeah. Yes.

Kyla Channell (45:30.461)
Mm-hmm.

Kyla Channell (45:36.505)
Yeah, wow. That is fascinating though. So then when you hear the term like get more probiotics in your diet, it’s really more of like get more friendly micro producing foods in your diet. Yeah, okay.

Maria (45:53.742)
Yeah, there are some particularly dairy products that have added probiotic strains. I would look for the strain name on the label, like you mentioned, BL23. That is a specific strain of L. pericasi. Sometimes you might need to go to the company’s website to find that information.

Kyla Channell (46:00.376)
Great.

Kyla Channell (46:05.108)
Mm-hmm.

Mm-hmm.

Kyla Channell (46:11.827)
Mm-hmm.

Kyla Channell (46:18.751)
Mm.

Maria (46:20.696)
We’re not doing a great job in the food industry of saying what exact strains are in the foods. That will help us as consumers to make the best choices.

Kyla Channell (46:33.083)
Okay, so like when you go and pick up a yogurt and it says that they’ve added lactobacillus, you’re okay. But should there be a number associated with lactobacillus or are you saying there’s more like more specific versions of lactobacillus?

Maria (46:39.032)
That’s a friendly microbe.

Maria (46:48.526)
You’ll probably see lactobacillus acidophilus. That’s a common one you’d find in yogurt. And that’s species. That’s not a brain.

Kyla Channell (46:52.068)
Mm-hmm. Mm-hmm.

Okay. Gotcha. Okay. Okay.

Maria (47:00.366)
And that’s why I think we need this bigger approach that is saying, well, what about all the microbes and microbial parts and metabolites we’re getting exposure to in our diet? Because I think that’s what my work is pointing to is that it’s not just one strain or cocktail of some microbe that does all these miraculous things. It’s just this microbes and general parts of these microbes that are doing

Kyla Channell (47:08.435)
Mm-hmm.

Kyla Channell (47:14.366)
Yeah.

Maria (47:30.242)
this good stuff in our gut.

and probiotics, know, there might be particular, I call them superpowers, they may have that are different from the ones in sauerkraut, the microbes in sauerkraut. Sometimes that line is a little bit tricky to know the difference, you know, what is the exact difference. So more work than that.

Kyla Channell (47:40.116)
Mm-hmm.

Kyla Channell (47:44.797)
Gotcha. Yeah.

Kyla Channell (47:51.43)
Mm-hmm. Yeah, yeah. No, this is really helpful and fascinating. Okay, so where can our listeners find you, follow your research? Where would that be?

Maria (48:07.482)
Yeah, I would put them at the Eat Lack Project on Instagram. We do try to post different traditional ferments made around the world and try to provide

Kyla Channell (48:13.073)
Okay.

Kyla Channell (48:18.623)
Mm.

Maria (48:24.706)
you know, information that’s been studied in research, so from publications. And then you’re welcome to visit our the MarkoLab website. Try to keep up with that.

Kyla Channell (48:29.897)
Mm-hmm.

Maria (48:46.06)
I don’t have a podcast yet. I’d also mention to ISAP, which is the International Scientific Association for Probiotics and Prebiotics. It’s all run by academics like myself, and we’re trying to put out scientifically validated or assessed information. Could be critical of probiotics and prebiotics and so on, but…

Kyla Channell (48:49.195)
We’ll help you start one. We’ll help you start one.

Kyla Channell (49:04.223)
Mm.

Maria (49:13.806)
also just kind of set terms of what does this mean. so I would suggest taking a look at that. It’s really great infographics. There’s videos and lots of papers.

Kyla Channell (49:15.483)
Mm-hmm. Yeah.

Kyla Channell (49:25.865)
Perfect. We will definitely link all of that in the show notes for the listeners so they can check that out. I will be checking that out as well. This has been so amazing and informative. I really appreciate your time and knowledge, Maria. Thank you so much for joining us.

Maria (49:39.756)
Yeah, was great talking with you.

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