FAACT's Roundtable

Ep. 255: Gut Diversity & Prevention of Food Allergy

• Season 5 • Episode 255

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We are joined by Carina Venter, PhD — gut diversity expert, researcher, and registered dietitian—to unpack how gut health influences people living with food allergies. She’ll also share insights on using everyday foods as a powerful tool to help prevent food allergies in infants.

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Caroline: Welcome to FAACT's Roundtable, a podcast dedicated to navigating life with food allergies across the lifespan. Presented in a welcoming format with interviews and open discussions,

each episode will explore a specific topic, leaving you with the FAACTS to know or use.

Information presented via this podcast is educational and not intended to provide individual medical advice.

Please consult with your personal board certified allergist or healthcare providers for advice specific to your situation.

Hi everyone, I'm Caroline Moassessi and I am your host for the FAACT Roundtable podcast.

I am a food allergy parent and advocate and the founder of the Grateful Foodie Blog. And I am FAACT's Vice President of Community relations.

Before we start today's podcast, we would like to take a moment to thank Genentech for being a kind sponsor of FAACT's roundtable podcast.

Also, please note that today's guest was not paid by or sponsored by Genentech. To participate in this specific podcast today we're joined by Carina Venter, gut diversity expert, researcher and registered dietitian to unpack how gut health influences people living with food allergies.

She'll also share insights on using everyday foods as a powerful tool to help prevent food allergies in infants.

Carina, welcome back to FAACT's Roundtable Podcast. We are just delighted you are back because you bring us really important information and things that are very actionable and things that listeners can hear about and then go do.

But also you help us understand certain areas that are confusing. So thank you so much for being here.

Carina: Thank you so much for having me back, Caroline. I always look forward to talking to you. Thank you.

Caroline: Let's help our listeners to get to know you better before we start our exploration into gut diversity and the prevention of food allergy. Can you share your background and your path into the world world of food allergy?

Carina: Yes. I'm South African, grew up in South Africa and I studied to be a dietitian in South Africa because that's what I am, an allergy specialist dietitian. We then moved to the United Kingdom where for many reasons I got involved in a food allergy clinic, then did my master's and PhD in allergy and immunology.

I lived and worked on the Isle of Wight for 20 years. It's an island just off the coast of England.

You have to take a boat and then a train to get to London. It takes about an hour and a half. I was then recruited to Cincinnati Children's Hospital where I worked for two and a half years working in eosinophilic esophagitis and after that I was recruited to Children's Colorado,

where I've been for the last six, seven years.

And here I am professor of pediatric allergy and immunology, where I do clinical work seeing children or families with food allergies. And my research focuses on the maternal diet in pregnancy and also the infant diet and how that interacts with the microbiome, the immune system,

and eventually prevent food allergies and other allergic diseases.

Caroline: Well, listeners, I hope you understand what a treat it is to have Karina here because she is really quite the expert on gut diversity and food allergy prevention and everything she just mentioned.

And as you can see, she traveled the world just to get to us.

Carina: That is true.

Caroline: So now let's just turn our attention to gut diversity. Just what is that exactly?

Carina: You know, gut diversity really refers to the variety of different microbes, mainly bacteria that live in the digestive tract or in the gut. And a healthy gut contains hundreds of different species of bacteria that work together to help digest food, train the immune system and protect against harmful organisms.

But I also work very closely with a colleague from, from Cork, Liam o', Mahoney,

who's really an international expert in the field of the microbiome. And one day I said, Liam, just explain to me why do we need a diverse microbiome? Why can't we just have a handful of good bacteria?

And he said to me, well, Karina, imagine a school playground.

He said, you need the really goody two shoes kids. He said, you're always going to have a few rebels on the playground and then you're going to have peacemakers on the playground.

He said, and you know, you may have some sporty kids and you may have some academic kids, but at the end of the day when you look at the playground,

there's a variety of children and everybody's happy.

He said, if we take one of the groups out or if we overpopulate one of the groups, there's likely going to be either a fight breaking up or it's going to be a really boring playground.

And he said, really?

Just as we want to have a diverse playground with many different children from different racial groups, ethnicity, different personality types, different interests, you know, to make everybody happy. This is what we want from a gut microbiome.

We need all these different species so that at the end of the day we have harmony, diverse harmony in the gut.

Caroline: That is probably one of the best descriptions I've ever heard, because I can completely visualize this. Thank you. That is. That is amazing.

So now going Just a little deeper then, why is the gut diversity so important to people living with food allergies? And also if you can mention how listeners can change their diets to embrace the concept of gut diversity.

Carina: Yeah. So my research have shown that the more diverse your diet is, the more diverse your gut microbiome is.

Now, really what a diverse diet means, it's really just a diet with a lot of variety.

You can count the number of foods eaten during a week, you can count the number of fruit and vegetables eaten during a week, you can count the number of burgers you eat during a week,

because you could have healthy diversity, which are fruit and vegetables, and you could have some unhealthy diversity, which means that you actually go to 10 different burger places over the course of the week.

But what our research have shown that it really is the healthy diversity that matters that gets us to having a healthy, diverse gut microbiome and particularly plant based food. Food.

And so the American gut study have shown that if we have about 30 different, so three, zero different plant based foods a week in our diet,

that is the best chance we have to have a really nice diverse gut microbiome.

And my data from the Isle of Wight in England showed that if we have a more diverse diet, we have less allergies in later life. So we counted bio-diversity in the first year of life and we look at food allergies up to 10 years of age.

And very interestingly, each additional food eaten by the children by 6 months of age reduced the risk of food allergy by 10 years with 11%.

But every additional food allergen eaten reduced the risk by and it was actually food allergen eaten in the first 12 months of life reduced the risk of food allergies by 10, by 30%.

And so I already knew that having a diverse diet in infancy is associated with a more diverse gut microbiome. But then Tom Marsh, one of my colleagues from King's College London, he was also part of the EAT study,

published data to show from the EID study data, and if you haven't heard of the EAT Study data before,

that's the study from England where they fed children six different food allergens during the first year of life and to see if they can prevent food allergy. And they were successful in preventing peanut and egg allergy, but nevertheless getting back to the gut microbiome.

So then Tom Marsh published this paper where he showed that as we were increasing allergen intake over the first year of life, so really increasing allergen Diversity.

We also saw a diversity in the infant gut microbiome.

So not just food diversity, but also having a diversity of food allergens can increase gut microbiome diversity. And one of the bacteria that we particularly like, the firmicutes, they make this chemical component or a short chain fatty acid called butyrate.

And so as the children were eating more allergens, they were also making more fumicates, which is normally associated with more butyrate in the gut.

And so if you can just take a little bit of a breather there. So I've explained that.

So now let's focus on this word butyrate.

Butyrate is, like I said, a chemical or a short chain fatty acid in the gut.

And this is really the key on how a diverse gut microbiome can affect immune outcomes or allergic diseases.

Because a more diverse gut microbiome make more butyrate, and then it's butyrate that actually tells to the immune system to calm down and stop making allergy cells.

Because sometimes it's like a disconnect. For me, I think, well, okay, you eat a diverse diet and now you've got a nice diverse gut microbiome. But what does that have to do with having allergies or not?

And the key is really the fact that you want to make this chemical component, butyrate, which really directly downregulate all the allergic immune cells and actually say, let's all be happy and calm down and not cause allergies.

Caroline: So now I know I've seen in the grocery store bottles of this butyrite.

So should people consider that? I mean, of course, after speaking to their doctor. Or is it just get that through the diet?

Carina: You know,

as far as I'm aware,

the only studies where they've used butyrate was actually to see if it reduces colitis, you know, or like  stools in children.

What I do know from my patients who actually go and buy it because they hear me talk about butyrate, I never suggest that they go, they go and buy it, but they come back and they say a few things.

It tastes absolutely awful.

And the other thing is that they have a lot of gastrointestinal distress. So the children start getting diarrhea, they get very bloated,

they may even get stomach cramps. And I think the reason for that is that we really don't know what dose or what amount of butyrate we need to take orally to get the optimal amount in the gut.

And these are the studies that's currently being conducted. So my personal advice would be,

we know that people are healthy when they have a diverse diet. The American Academy of Allergy, the American College of Allergy, and the Canadian Society say, let's eat a diverse diet for allergy prevention.

But the American Nutrition Guidelines or the Dietary Guidelines of America actually say, eat a diverse diet to be healthy.

So we know if we eat a diverse diet, we're happy and healthy. We don't have all these gut upsets and side effects. And so I think it's early days to suggest butyrate supplementation.

Will it cause any harm?

I don't know,

but I know my patients say they lasted about two days and that was the end of it.

Caroline: Well, I have to confess, I did have a friend that had a bottle of it in their house and on the bottle it did give a warning that it was going to smell really bad.

So, of course, what's the first thing you do is, can I open that and smell it? And it smelled awful.

Oh, my goodness,

it does.

Carina: And you know, particularly in the little ones because the capsules are quite big. And so I also couldn't help myself. I bought it and I thought, I wonder if we can break over the capsules because of course it's a choking risk anyway in young infants,

other than the fact that they couldn't swallow it. But if you, if they were to give it to them, it will be a huge choking risk. So, so I thought, I wonder if we break it open and we just use like a tip of a teaspoon mixed in with a bit of yogurt or fruit puree?

No. Oh, the taste comes through. It is absolutely an awful taste.

Caroline: Oh, I can't even imagine. And so now you also mentioned that 30 plant based foods, so is that like per week?

And when you say plant based, would that include like, you know, parsley or cilantro? Is that the herbs included?

Carina: That's a very good question. And actually, when I have these very bright young kids I see in clinic, that's the first thing they say to me. Would cilantro count? Or what about parsley?

Or what about garlic?

Now, you know, strictly speaking, for a food to count towards biodiversity,

you have to eat 15 grams or half an ounce of it.

So I guess if you can chop up 15 grams of parsley or cilantro and put it into something, it will count as one.

The other question I normally get, people say, well, what if I eat five different colors of peppers or three different colors of tomato?

You know, it all counts. I think it's Color, color, that counts.

And don't forget that most of the food allergens we have, other than milk and egg and shellfish are actually plant based foods. So, you know, if you get your nuts in, if you're not not allergic, peanut,

soy, wheat, sesame,

it really all counts towards your allergen and your food diversity.

And it doesn't have to be huge portions,

you know, for the most of it, I'd say about an ounce is perhaps 1 to 2 tablespoons of most food.

So small portions. I always say to mothers, rather than just doing,

let's say butternut squash for dinner, why not do a stir fry? Because if you have three tablespoons of stir fry, you already have three things opposed to three tablespoons of butternut squash.

And you know, the other thing that I really talk a lot about in my consultations and I'll come back one day and talk about sustainability is people think when they have a plant based diet, they have a sustainable diet, but not if they throw half of the foods away,

you know, because the number one thing that drives sustainability down, I would say, is throwing half of the stuff away.

And so I talk a lot to mothers about, you know, chopping up that little bit of the apple that's left or you know, freezing the handful of blueberries that may not look too great, but you can still put it in a smoothie.

So there's many different ways of actually getting those 30 plant based foods in without necessarily having to cook a dinner every night with five or six different vegetables.

Caroline: Well, I think you've definitely brought up the idea of a future podcasts on sustainability. I'm taking notes, I'm taking notes on that.

Thank you. That was a very, very good explanation of how the gut diversity really benefits people with allergies and then what we can do. And of course, you know, I'm going to start counting my plant based foods this week just because of this.

So thank you so much for that.

You mentioned about working with infants and preventing food allergies. So now let's talk about how to prevent food allergies in infants to just using food items, things that are in our pantry.

Carina: Yeah. So, you know, I spend a lot of my time talking to families about introducing food allergens. I think it's such a wonderful time working in the field of food allergy, isn't it?

Because when I started to work in allergy 30 years ago,

you know, food allergens were really the baddies. You know, we told people to avoid it for as long as they can. And then if they got a food allergy, we gave them a life sentence of this is never going to go away.

And now we have this wonderful opportunity of early introduction to prevent allergies. But then for those people who did go on to develop food allergies, we have so many different options now, you know, to give them hope.

We can do slit, we can do oral immunotherapy, we can give them Xolair, we can do milk and egg ladders. You know, there's just so much hope for families,

which is why I really love this, this time,

that in this area of food allergy. But getting back to early introduction of allergens, you know, we really want to give babies every allergen. But I would say the top five in America most likely are milk,

egg,

peanut, cashew, and walnut. I then think if you're a family that eats a lot of almond or almond butter, yes, included.

If you're a family that loves fish and shellfish, yes, include it.

I don't think the data on fish and shellfish is that great that I'm going to force families to eat these foods if it's not really part of their normal diet.

But, you know, for health reasons as well, it's good to include food. And then sesame is actually one I left out. That's probably the number six on my list.

And so when I talk about early introduction of allergens, milk is always easy. All kids love yogurt, so, you know, that's a way. And I, I almost don't even have to talk about frequency and consistency because once a baby eats yogurt, it's very easy to keep it into their diet.

Then we talk about egg. Now, interestingly, I'm also obsessed with milk and egg ladders. And so I've spent a lot of time in the last year or so analyzing all foods containing milk and egg.

But getting back to egg. A boiled egg does not contain one of the main allergens we need. And so as much as many families start with a boiled egg for first introduction of egg, really mash down mixed with breast milk, water or formula milk.

As soon as the baby is okay on that boiled egg, you really want to go on to scrambled egg so that the baby gets all the allergens that matter.

Then we talk about peanuts, almond and walnut butter. All three butters needs to be diluted with hot water, cooled down, or breast milk or formula milk. And really very, almost, almost like a thick liquid first fed to babies until they can manage more, more solid textures.

But do remember,

eating peanut butter or any nut butter off a spoon till 5 years of age is really not recommended because of a choking risk. Then we say get all of these in twice a week.

Normally when I've done the three butters I would say to parents, you can just mix them now don't worry about recipes and ratios, mix them together, stick them in a blender with a bit of olive oil or sunflower oil and just feed, you know, a heaped teaspoon two to three times a week.

And then we do the sesame as hummus. By the time we get to the sesame, they really at the point where they can do baby led weaning type of foods or at least, you know, hold the food and perhaps dip it.

And. And so we use a lot of hummus for the introduction of sesame. There's also now some products out there that is sesame paste mixed with chocolate. And of course the young boys on sesame OIT,

they told me about it and they're very excited because that's how they're gonna take their OIT dose. So it's not a great idea for babies, but perhaps, you know, when they get older and once a week or once a month you want to give sesame in a nicer way.

You can use the ones mixed with chocolate, but that's definitely not my preference.

But I think, you know, and then I normally say to families that now you've got the allergens in consistency,

frequency, keep going is the main thing.

Babies get sick, they go off their food, they may refuse to eat for a week, that's okay too. We just keep going the week after.

It doesn't have to be like such a perfect exact dose. And now you think, oh, now she's only eaten, you know,

half of a teaspoon, what am I going to do about the rest? It's okay if one day they eat half a teaspoon, one day they may eat two bites of egg.

Next time they're going to eat two eggs, you know, that's fine. So just, just keep it in the immune system. And we know that particularly from the studies where they looked at early exposure to cow's milk protein.

The immune system does not like us chopping and changing our minds. Once we've shown it an allergen, we gotta keep that allergen in not to become allergic. It doesn't have to be obsessive, it doesn't have to be exact,

just make it part of your normal family routine.

Caroline: This is so mind blowing to me. Cause my son was diagnosed with food allergies 25 years ago.

And to go from this avoidance at all costs until they're three to actually encouraging feeding it right out the chute and being able to actually avoid food allergies is just mind blowing to me.

It is such a miracle. It's so amazing that researchers have been able to get to this point and then people like you are actually out there facilitating it. I mean, this is just so exciting.

I mean, I would assume that in the future the prevalence of food allergy would be a little smaller to people who really are just going to have food allergies, but that we're avoiding so many other patients being diagnosed.

Carina: Yeah, but you know, you make an important point by saying we hope that in future on a population level we will see less allergies.

It will only work if we keep going once we've introduced it. Because there's data from Australia showing that peanut allergy prevalence did not come down despite a huge uptake of early introduction of peanut.

One of the things the study didn't show us and we don't know is whether they continued.

So it's not just the early introduction, it's keep going.

And then there's some data coming out now as well that even if you've done early introduction in your first child or older child and prevented peanut allergy, if you don't do it in the second child,

we see much higher rates of peanut allergy than we've ever seen.

So it really has to be a family thing. You know, if you are committed to prevent food allergies in your family,

it really counts to the whole family and all the subsequent babies. Don't forget about baby number two and three. They need their allergens too.

Caroline: Truly a family affair. So our time has come to an end here. So before we say goodbye, is there anything else you want listeners to hear from you?

Carina: Well, I do have, I've helped with them to develop a range for early introduction of allergens and that where the allergens are also mixed with a diverse range of plant based foods.

So in total over the course of the week you get 16 plant based foods in.

So there's still scope for you to do 14 of your own preference. But at least we have you towards 16.

It's called let's grow Happy.

Even if you don't like the range, that's okay. But do sign up for the email list because we have the world's most amazing guide for early introduction of allergens that you will receive.

It was a Fact check by Dr. David Fleisher from Children's Colorado, Edwin Kim from UNC Chapel Hill, Sharon Chinthrajah

 from Stanford, and also George Du Toit, lead author from the LEAP Study.

So really a fantastic resource. Please sign up and get that guide and just feed the allergens and relax.

Caroline: Thank you for that advice and I'll get the link from you and we'll put it in the show notes so listeners you can find it. But Karina, thank you so much.

You are incredibly busy. I mean listeners, she is super busy. So you taking the time to spend with us and to educate really means a lot. And thank you so much.

We appreciate you.

Carina: No, thank you for having me. I always love being here on the podcast. Thank you.

Caroline: Before we say goodbye today, I just want to take one more moment to say thanks. Thank you to Genentech for their kind sponsorship of FAACT's roundtable podcast.

Also, I want to note that today's guest was not paid by or sponsored by Genentech to participate in this specific podcast.

Thank you for listening to Facts Roundtable Podcast.

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Have a great day and always be kind to one another.