UC Davis

Transcribed by A.I. May contain errors.

Amy Quinton 

Hey. Guess what! Unfold was a winner in the 3rd Annual Signal Awards! We won Silver in the Science and Education category for an episode about UC Davis researchers communicating with a humpback whale named Twain to figure out how to communicate with aliens. You can listen to "Close Encounters of the Whale Kind" on your device or on our web page at ucdavis.edu/unfold. Listen and then subscribe to Unfold so you never miss an episode. Thanks for listening.

Kat Kerlin 

Amy, as you know, I'm a mom.

Amy Quinton 

Yep. 

Kat Kerlin 

Okay, so sometimes the kids come to the grocery store with me, and lately they have been bugging me to buy them these new probiotic or prebiotic sodas. Have you seen these?

Amy Quinton 

Yeah, like, Poppi or Culture Pop?

Kat Kerlin 

Yeah, like the ones that say they're good for gut health? 

Amy Quinton 

Yeah, they seem to be everywhere in grocery stores.

Kat Kerlin 

The sugar in these drinks is much lower than in regular sodas, and I don't really want my kids drinking sugary drinks, but I had to wonder, are these drinks actually good for them? Also, what does it really mean to be probiotic?

Amy Quinton 

Well, you know, I've always associated probiotics with maintaining a healthy gut or digestive system, or that they are something one should consume while on antibiotics. And all these products made me wonder if everyone is sick, or if there's something I could be missing from my diet.

Kat Kerlin 

And it's not just sodas, I see probiotic or prebiotic written on all kinds of food products and beverages, from kimchi to kombucha. It's something I was just really curious about. Yeah, me too. So we turned to some of our nutrition experts at UC Davis to answer some of these questions.

Amy Quinton 

And they told us we really should be talking to a microbiologist.

Kat Kerlin 

We found Maria Marco, a microbiologist and a professor in our Food Science and Technology Department.

Amy Quinton 

And she told us exactly what a probiotic is.

Maria Marco 

A probiotic is a live microorganism that when administered in a sufficient amount, confers a health benefit on its host.

Kat Kerlin 

She says that could mean it could treat or prevent disease or make symptoms less severe, and that it's been studied in humans. 

Amy Quinton 

So naturally, you may now think that these products labeled probiotic are healthy. But as is the case with most food topics we've covered in this podcast, the answer to that question is complicated.

Maria Marco 

Foods can have the probiotic label, but actually don't contain probiotics.

Kat Kerlin 

Yeah, you heard right. So it's a term that has been misused by a lot of food and beverage companies.

Maria Marco 

It's a word that means for many like a good microbe, and it doesn't mean that specific microbe that has been studied in human trials. So just having a microbe in a food doesn't make it probiotic.

Kat Kerlin 

But it turns out, we may not be getting enough good microbes in our diet either. 

Amy Quinton 

You might be now a bit confused, but we're going to sort it all out for you. In fact, Kat, there will be a lot to digest.

Kat Kerlin 

We're going to take a peek at the proliferation of probiotics in this episode of Unfold

Amy Quinton 

Coming to you from UC Davis, this is Unfold. I'm Amy Quinton 

Kat Kerlin 

And I'm Kat Kerlin.

Kat Kerlin 

To understand the topics of probiotics and friendly microbes, we have to think back to our pre industrial diets, before refrigerators.

Amy Quinton 

We had to preserve food.

Kat Kerlin 

Yes, and a lot of that was done by fermenting food, making cabbage into kimchi or sauerkraut, or turning milk into yogurt.

Amy Quinton 

And that exposes foods to all kinds of good microbes. Literally billions. Fermented foods are made through microbial growth.

Kat Kerlin 

But in today's industrialized society, Maria says we're no longer eating a lot of microbes.

Maria Marco 

We live in clean environments, more or less, right and and our food supplies are also very clean. And what that means is it's potentially true that we are depriving ourselves of friendly microbes.

Amy Quinton 

And before you think exposing yourself to a lot of microbes sounds gross or unsafe, fermented foods include things like wine, cheese and beer, which are a significant part of my diet.

Kat Kerlin 

The kinds of microbes that result from fermenting also kill the bad bacteria. So Maria says they're not the kind that can harm you, and she says depriving ourselves of friendly microbes could even impact our health. 

Maria Marco 

A lot of our immune system is sampling from our digestive tract, and so when we don't have those exposures in our foods, we could be affecting our immune system and metabolism and other aspects of our health.

Amy Quinton 

So adding friendly microbes to our diets may have benefits, even for healthy people, in ways researchers just haven't uncovered yet.

Kat Kerlin 

Marie looked into this a bit more. She conducted a study that looked at the foods people were eating.

Amy Quinton 

Yeah, and it was from a database that's updated every couple of years, in which large groups of people have a medical exam and are asked what they've eaten. 

Maria Marco 

What we found in looking at what people were eating across the US was that, first of all, most of the foods we eat, like 96% of the foods we eat, have no microbes or very, very, very low numbers.

Kat Kerlin 

And then she looked at health records, considering cardiometabolic data, things like metabolism, cardiovascular health, body weight, etc.

Maria Marco 

What we found is that eating foods with live microbes helped all of these metrics. Yeah, looking at waist circumference, BMI, cholesterol, systolic blood pressure and insulin, they all went in the right direction when we're eating more foods with live microbes.

Amy Quinton 

Of course, Maria points out that more study is needed before we can tease apart correlation with causation. But still, that's super interesting. 

Kat Kerlin 

It is, Okay,o now we know that we perhaps should be getting more friendly microbes, and that probiotics, by definition, should show a health benefit. So how can consumers know what a probiotic is versus a friendly microbe?

Maria Marco 

I'd say, as a consumer, to look at the label and to look for not just the species, but also a series of numbers or letters that come after the species name. A common one you could see would be Lacticaseibacillus rhamnosus or Lactobacillus rhamnosus GG. So GG is the strain.

Amy Quinton 

So it's a certain strain of a microbe that can be a probiotic and has been studied in human trials to have a health benefit, not just having the microbe itself. Like, for example, Kat, when most people think of E coli, they envision getting sick, right? Not something you want on your plate. 

Kat Kerlin 

Yeah, no. 

Amy Quinton 

But E coli bacteria normally live in our intestines, and some are beneficial. However, E coli, O157H7 can cause sickness or even death.

Kat Kerlin 

So consumers should look for numbers and letters to find the strain of microbe to know whether it's probiotic, but

Maria Marco 

But it's frequently, unfortunately, not on the label. You may see in your yogurt container, you may see microbes like L casei or B lactus, and those are frequently added in to be beneficial, but they don't go that far to make a claim on that yogurt container.

Amy Quinton 

Specific strains of microbes that are probiotic have been shown to help your immune system function properly, reduce digestive symptoms and side effects of antibiotics, improve lactose intolerance and decrease the risk of some common infections.

Kat Kerlin 

But no probiotic can deliver all those benefits at once, so look for the strain on the label and find out its corresponding health benefit.

Amy Quinton 

It is a lot of research for consumers.

Kat Kerlin 

Yeah. 

Amy Quinton 

But moving on, let's talk about what it means to be a prebiotic.

Maria Marco 

For a compound to be called a prebiotic, it needs to also show a health benefit through human studies.

Kat Kerlin 

Prebiotics are not digested by our stomach, but instead travel to our large intestine.

Maria Marco 

And then those compounds are selectively eaten by the microbes we want to have in our digestive tract.

Amy Quinton 

So basically, prebiotics are food for friendly microbes in our gut. An example is inulin, a dietary fiber. Maria says it's also found in fructooligosaccharides, a type of carbohydrate found in plants.

Kat Kerlin 

You can also get prebiotics in lower levels, in foods like whole grains, beans, onions, garlic, chickory root and artichokes.

Amy Quinton 

So now that we know some definitions, we did some grocery shopping and asked Maria to help us figure out how to shop for probiotics, prebiotics and friendly microbes.

Kat Kerlin 

Let's go to the, let's go to the grocery bags.

Amy Quinton 

So this is a, this is strawberry lemon Poppi. It is a soda and it says "for a healthy gut" on it. Do you know anything about this? Or can you, like, how would a consumer look at this and make any sort of judgement?

Maria Marco 

Yeah, so it is a soda. It's for a healthy gut. So I'm like, what is that? And it says it has, well, interesting. It has apple cider vinegar and it has Agave inulin. So inulin is a prebiotic, and that's not something you would normally see on a soda. Should I open it? 

Maria Marco 

I'm gonna try it. Yeah. Well, I also see there's Stevia in here. You know, it seems like they are trying to watch the sugar content, but let's talk about the prebiotic in here, two grams. So I think better than nothing, but the studies with inulin as a prebiotic, people were having more of this prebiotic in order to expect a health benefit. So what we're getting here is less than what was done in a can, at least, right? I think you're going to need several cans.

Amy Quinton 

Sure 

Amy Quinton 

Right? Then we moved on to our next product. All right, tell me what this is.

Maria Marco 

Oh, yummy. This is a kimchi. Kimchi is a fermented cabbage with radish and sometimes fish, different spices, and this is a more of a natural ferment. What ends up in the bottle here will be the microbes, the metabolites the what they've done during the fermentation. We can taste that. But there could also be other compounds that they've released that can be seen as bioactive and good for us.

Amy Quinton 

So that could have probiotics in it. Yes, we just don't know. 

Maria Marco 

Well...no, it doesn't.

Amy Quinton 

She says with confidence.

Maria Marco 

It says probiotic on the label. But that's because we live in a time when this word can be used very freely and have different meanings. And here, I think the meaning is that there could be live microbes in here that are related to probiotic strains.

Kat Kerlin 

This can be so confusing to consumers, but again, if you're looking for a probiotic, look for the strain of microbe on the label with a series of numbers or letters after it.

Amy Quinton 

And make sure that it's applied in the right amounts to have a health benefit or eaten in the right amounts or drunk in the right amounts?

Kat Kerlin 

However you ingest things

Amy Quinton 

However you ingest things, right.

Kat Kerlin 

That said, kimchi does have friendly microbes in it. Fermented foods are full of friendly microbes.

Amy Quinton 

But we learned that even figuring out what food is fermented can be difficult.

Kat Kerlin 

Maria did a survey on this and found that most people knew things like yogurt or wine or beer are fermented, but lots of people did not know that cheese or bread is a fermented food.

Amy Quinton 

Yeah, and I always thought that olives were fermented.

Kat Kerlin 

Well, Maria says some are and some aren't. 

Amy Quinton 

That's not confusing at all.

Kat Kerlin 

No. The black olives you see typically on pizzas or salads that are usually canned, not fermented, but Kalamata and Spanish style are.

Maria Marco 

In California, the fermented olives made here are called Sicilian style, and they're made using very large green olives called Saviano, and they're put into very large containers with salt water and just left there for like nine months. And the microbes grow, and they do their business, and that's how we end up with these large green olives. They're frequently stuffed with garlic or blue cheese.

Amy Quinton 

And then frequently put directly into my dirty martini. 

Kat Kerlin 

You can have them. 

Amy Quinton 

Kat does not like olives. So after our conversation with Maria, it struck me how little we know about our food, how it's made, and whether it's good for us. And so Kat, I'm just curious to know now if you'd have a problem giving yourkids a soda that says it's prebiotic or probiotic.

Kat Kerlin 

I don't really have a problem with it, as long as the sugar levels stay low. I just really wanted to know if what seemed like a health claim on a can really was one. Sounds like, can't really hurt them, but I shouldn't go tossing out their vitamins anytime soon.

Amy Quinton 

And by the way, we had Maria talk about a variety of foods that could be probiotic, prebiotic, or have friendly microbes in them. And you can find out what she said and learn more about the topic at our website, ucdavis.edu/unfold

Kat Kerlin 

And you can test your knowledge with a quiz we've cooked up.

Amy Quinton 

Find a link at our website or go on our In Focus page at ucdavis.edu/health.

Kat Kerlin 

 I'm Kat Kerlin

Amy Quinton 

And I'm Amy Quinton, thanks for listening.

Andy Fell 

Unfold is a production of UC Davis. Original Music for Unfold comes from Damien Verrett and Curtis Jerome Haynes. Additional music comes from Blue Dot Sessions.