EP 34: FIBERMAXXING for Kids: How and Why it Matters

What if one of the simplest ways to support your child’s gut, digestion, and long-term health is something most families are not getting enough of? In this episode, pediatrician Dr. Liz Daniels breaks down why fiber deserves more attention, not just when constipation becomes a problem, but as part of everyday prevention. She explains soluble and insoluble fiber, how fiber feeds healthy gut bacteria, and why whole foods often offer more benefits than gummies and powders. You’ll also learn easy ways to add more fiber through oats, beans, seeds, fruits, vegetables, and resistant starches without completely changing your family’s meals. Plus, Dr. Liz shares practical tips for slowly increasing fiber while helping kids stay comfortable and avoiding unnecessary pressure around food.

What You’ll Learn

• Why fiber plays an important role in digestion, gut health, and long-term wellness
• The difference between soluble and insoluble fiber and what each does in the body
• How much fiber kids need and which foods can help them reach their daily goal
• Why whole-food fiber sources may offer more benefits than fiber gummies and powders
• Simple ways to increase fiber gradually while reducing gas, bloating, and discomfort

Episode highlights:
(2:34) Why fiber matters beyond constipation
(3:40) Soluble vs. insoluble fiber explained
(8:31) How fiber supports gut bacteria and immune health
(12:47) How much fiber kids need
(14:25) High-fiber foods and simple serving ideas
(15:09) Fiber gummies, powders, and supplements
(17:47) Probiotics and the gut ecosystem
(19:40) Why beans and seeds are powerful fiber sources
(21:58) Resistant starch and kid-friendly food ideas
(23:27) How to reduce gas from beans
(24:24) How to safely increase fiber intake
(26:01) Small, realistic changes families can start today

NEW COURSE! "Read the Pattern: Feeding Your Baby 0–4 Months" — because a healthy relationship with food starts earlier than most people think. Course Link!

Disclaimer: This podcast is for educational purposes only, not medical advice.

Transcript

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Want to know what I think is one of the most important components in pediatric nutrition, nutrition overall, that we hardly ever talk about at well visits and in the pediatrician's office. Fiber. It's one of the most important things for our body's health overall, long term. And yet we don't get enough time to really dive deep into it unless we're addressing a problem. So today I'm shifting that narrative and we are talking all about prevention from the angle of fiber. Okay. Now, this is a topic that is relevant for both grown-ups and kids, but know that I am a pediatrician and I'm talking about this for the preventative perspective. Okay. So I hope that you are ready to get into a deep dive on fiber, the ins, the outs, um, mostly the outs, and all the different ways that we can support our kids getting more fiber and why it matters. Welcome back to Nutrition for the Earliers Podcast. I'm your host, Dr. Liz Daniels, your nutrition-focused pediatrician, here to give you guilt-free guidance for feeding your family well. And today we are going to talk about something that I don't get nearly enough time to do in the office, partly because I probably run my mouth way too long. And the other part is that I don't really know how much parents know about this or want to know about this. So I decided to reserve it for a podcast. And I have been waiting to do this for a while. It is a juicy topic and one that is really, really interesting biologically, partly because, you know, I would say that in the nutrition world, there's still so much to learn. And, you know, when I think about overall health, like I think about back in the beginning when I was thinking about medical schools, one of the reasons I chose to go to a DO school, I know this is tangential, but hear me out, was because the philosophy of care as an osteopathic physician is, you know, mind, body, all connected. And from a nutrition perspective, I've always seen that our what we eat and our body's function is so important, right? Like they go together. And whether we're talking about prevention or even treatment of disease, food serves as medicine. It has always been my love. And this is one of the central aspects. Fiber comes to life when we think about this. Like it truly does. And so hear me when I say that today's really, really interesting. It's going to be super nerdy, but stick with me because at the end, we'll have some practical takeaways too of how you can sort of support your kids' diet and your own health with really important ways. And we're going to even get into whether or not we should be doing supplements for fiber. Okay. So without further ado, let's get into it. Okay. Now, when I think about fiber, you know, like in our office visits, usually when we talk about this, it's at the angle of constipation and we're like obviously trying to increase it. But what if, what if we took a step back and asked ourselves, do we even really know what it's doing in the first place? Because if we did, I would argue that maybe we would think about it as our preventative tool. It's an incredibly powerful component of our nutrition. And yet we hardly ever give it the credit it needs. So if I asked you right now, what are the top three ways to get fiber in your diet? I wonder what you would say. Because most parents would tell me veggies, fruits, and then beans may be on the list, but they're often forgotten. And honestly, that's not really where I'm gonna tell you to get fiber today. I want you to think about fiber in a very different way. I want to break it down in terms of what kinds of fiber there are, why we need it, how it's functioning in our body, and go into that. So let's do that. Okay, like let's think about this from the standpoint of a plant. Because yes, plants are where we get our fiber. There's kind of two categories nutritionally of fiber: there's insoluble fiber and soluble fiber. Insoluble means that our body doesn't really have the enzymes to break it down. And soluble means that some of the fiber can get broken down. But really, in total, if you think about fiber nutritionally, it's basically anything that passes through your small intestine. Because anything that makes it all the way down to the colon that's not fully digested and absorbed is essentially like the leftovers. And our body's really smart. As we digest food, you will absorb energy from anything you can efficiently, right? And that happens really in the small intestine. That's where we are getting energy from the food itself and getting all of those carbohydrates, those fats, those proteins, they're getting absorbed in the small intestine. And then whatever is left over, whatever we don't have digestive enzymes to break down is wasted. But is it really waste? Today we're gonna figure that out. Okay. Like, let's think about this. Nutritionally, the insoluble fiber are things that don't get well broken down. But I want to be a little bit more like biologic for you because I think it's really helpful. If you think about in the terms that like the names, I'm gonna give you the names of these types of fibers because I think it'll help you kind of understand, especially when you're in the aisle where there's fiber supplements and you're looking at things to be able to categorize where do these live and what are they gonna do, because there are different purposes for these types of fibers. So, fiber nutritionally is relatively broken up into two categories of that soluble and soluble. Insoluble fibers are going to be things called cellulose or hemicellulose as well, lignins, and resistant starch. We will talk about where those are located in the plant structure and what they do for us later, but just know those names. And then soluble has a lot more names. So soluble means that we may not have the digestive enzymes for it, but if it's in the small intestine, it can sort of turn into a gel-like structure because bacteria that live in our colon, hopefully they live there, can partially break down the outer portions of these carbohydrate structures. And when they do so, they create certain byproducts. And this in turn creates a sort of gel-like structure, which serves us in a lot of ways. But the names of these soluble fibers are fructooligosaccharide, galacto oligosaccharide. You'll see those in things like formulas, actually, and also in some fiber supplements for kids. More soluble fibers come by the terms of beta-glucan, gums, pectin, mucilage. You can also see that inulin and psyllium. And inulin and cilium are kind of some of the primary products that are on the market, along with some pectins for fiber supplements. These are important to understand the names of because they they serve in different ways and they do different things. Now, I think one of the things that's confusing is when you think about fruits and veggies, especially grains and beans, they actually have both kinds of these fibers and for good reason. And I'm going to explain why. But, you know, we don't categorize them super well in our heads as what has fiber because it's essentially the plant structure. And when I ask you what sources of soluble fiber are out there and what sources of insoluble fiber are out there, you might end up saying the same name. So it gets really confusing to people to say, which one do I need? Well, you need both, okay? And they serve in sort of two different ways. If you think about insoluble fiber sort of being the broom, because it works more mechanically. Since we don't have any digestive capability to break this down, nor do the bacteria that live in our gut, it naturally just creates this bulk, essentially sort of structure, right? So think of it like scaffolding and it sort of pushes things along in the colon to create movement and motility. And that that stimulates bowel transit. Now, it is important and we do need this. So things that are gonna have a lot of cellulose or lignins are gonna be found in things like wheat bran. I think, you know, celery is another example of that. Some vegetable skins are gonna do this, which sometimes people eat, sometimes they don't. Seeds and whole grains. Those are really good sources of insoluble fiber. Soluble fiber, on the other hand, actually creates this sort of, like I said, gel-like substance. And it can serve the role nutritionally and medically as like sort of stabilizing the stool pattern. So that if you're on one extreme of being really loose and having really, really watery stool, or you're having really, really heavy and um sort of hard stool, soluble fiber can sort of serve both of those territories and make it a little bit softer in general, but still solid enough, like that gel kind of structure. Now, the big thing that soluble fiber does is that it actually feeds the gut bacteria. And this is really important because right now it's sort of the hot, I would say it's like the up-and-coming hot topic. It's gonna take over protein in terms of like social media stuff. Just watch and see. It's gonna be super cool. But soluble fiber serves a lot of roles by being able to feed the gut bacteria. And when that happens, it actually can promote a balance of gut bacteria that do a lot of really cool things for us. And if you don't have enough of it, then you lack that opportunity. If you could picture with me an oat, because oats are a good example of something that has both insoluble and soluble fiber, this will help you kind of picture moving forward why this is valuable. Okay, insoluble fiber, if you have an oat, the outside part, the husk of the oat contains some of the cellulose. And even the layer underneath the outer shell of the oat is going to have hemicellulose and those both together, and a little bit of lignin too, those will be sort of the casing that protects the oat from external damage. It serves a purpose for the oat. And structurally, it provides insoluble fiber for us. But on the inner part of the oat, it's called the endosperm, not to be confused with other things, but it's sort of like the storage form of energy for the oat. And that is full of beta-glucan. And it has even a little bit of um pectin in there too. But those are really awesome structures that provide structural integrity for the plant cell itself, or like for the oat itself. And the beta-glucan also stores some energy for the oat as it goes on to be a seed and then reproduce. But in our bodies, bacteria will break down parts of the beta-glucan. And when it feeds those bacteria, then the bacteria are able to then produce something called short chain fatty acids. And short chain fatty acids are really cool. There's like really about three of them: there's acetate, um, propionate, and butyrate. And that's not really as important, except for that they have sort of different sort of ways that they communicate in the body. But at the end of the day, what I want you to take away from this is that short chain fatty acids are so amazing. They actually feed your colon cells energy. So they're the energy form for your colon cells to be able to reproduce, and that's super helpful. But they also act as signaling molecules. So they basically will like text message the inside of the colon cell and communicate to it as well as immune cells down there and say, hey, I'm here. And it's a good environment. You should make more of these awesome T regulatory cells, which are an immune cell, and they serve as like a peacekeeper. You're like, hey, it's a super good environment out here. Like you can come out here and play. And by doing so, they actually promote more of important immune regulating cells that we need. And sort of by like doing both of those things, by not only nourishing the cologne and prevent dangerous things from sort of or like food substances and other like sneaking into in between channels between the cell walls, but it also helps promote signaling that things are a peaceful environment out here and we don't need to create a big inflammatory situation because there's we have strong defenses. So we don't need to go into fight mode. And that's a really important message for your body's growing colon. So there is actually some data here to suggest that there's a connection between our fiber intake, primarily from fruit and veggies, and um our risk for some of these inflammatory processes down the road. But this is not something to hang your hat on and feel like even more pressure that if your kid doesn't eat fruits and veggies, you're doomed. So please understand that when I say there's benefit here, yes, and it's super cool. Yes. But this is why I care about you. And this is why you as a parent want to keep modeling these fruits and veggies and why you as a parent want to keep offering them. Because in the long run, we know that there's a lot of value in here, but we also know that pressuring our kids is not the way to get there. So hear me when I say, yes, our fruits and veggies are the source for our soluble and insoluble fibers, but in terms of actual volume of fiber, actually our oats and our grains are gonna carry a lot more. And this is important to understand because when we think about, you know, typical like developed countries, I'm gonna speak specifically to the US, although I know not all of my listeners are in the US, but you know, there are 95% of kids actually don't get enough fiber in their diet. And my own kids included in that, right? Like I'm no anomaly to this. But but what I want you to understand is sort of like how much do we actually need to get and where do we get it from? Because I don't want this to be a takeaway for you to go run to the store and get all the fiber supplements you can. I want you to be strategic because the types of fiber you get matter. More on that. So stick with me, okay? The rule of thumb that I like to use is your kid's age plus the five. So if you have a two-year-old, that's seven grams of fiber. If you have a 10-year-old, that's 15 grams of fiber. Okay. Now, when we think about that, it's a goal, right? And that's what we would love to see. So don't be too hard on yourself if you're not there. But there are some simple ways we can we can try to increase that number. This isn't a number you need to hold your parental worth next to and see, am I doing it right? It's a deck that's stacked against busy families. It's hard to get there. Okay. And this is part of the reason that you might be seeing more foods over the next, you know, couple of years having fiber that's added to them. But be careful because you want to know what kind you're getting, right? So the fiber, though, that lives in our produce and in our legumes is really gonna have much more effort and much more value. And that's what I want to kind of land on. So this isn't about being feeling guilty. It's about knowing what that threshold looks like because it also means that your four-year-old doesn't need 20 grams of fiber. Okay. So here's what moves the needle. Okay, here's some real concrete examples. Half a cup of raspberries has four grams of fiber. A pear with the skin on it, like a full pear, is five and a half grams of fiber. A half of an avocado has almost five grams, like 4.6 grams of fiber, a quarter cup of black beans. So we're talking actually a very small amount of black beans, has 3.8 grams, one of the best sources. Lentils as well. And then when we talk about seeds, this is a really great way to think about fiber. One of my favorite ways to do this is actually in protein balls that I would make for my kids, where I have oats, peanut butter, as well as flaxseed and um hemp seed in them too. So there are some really simple ways that you can do this without having to change your whole diet. Okay. But the big thing that I want to talk about now is sort of fiber gummies and and where to get them. Because, you know, when we talk about constipation, especially, I usually have families who say, I just don't want to use Miralax. And I hear that. I do think that's sort of a separate conversation from the standpoint of like, is there value? Is it bad? Is it good? All the things, and there's hype, and there's what I'm gonna just tell you like this podcast and this conversation is really more about the preventative piece of this, right? So, what I want to talk about is not so much mirrorlax is a yes or no, but it's a how do we help our kids get more comfortable with fiber-rich foods? And how do we make sure as parents we're offering fiber rich foods both to ourselves and to the whole family because it's not about a quick fix. PSA though, if your kid is struggling with serious constipation, don't wait around because you really want to get the support you need. And it's a chronic condition, not just a one-time deal. Okay. So back to the lesson here though. Quick myth though. Um, fiber gummies and powders, there is a place, there is a role. And there are some that I will from time to time say, hey, this is like a nice way to think about it. But it's not actually gonna be our main thing because your fruit, your veggie, your grains, your beans are a plant. And a plant, in order to grow and be structurally supported, is not gonna use just one type of fiber. It's a whole complex. And your fiber supplements and gummies are typically one or maybe two kinds of fiber. And I think this is also part of the reason why when kids do use these products, a lot of times parents will tell me that their kid felt really gassy or bloated and maybe liked eating them, but they didn't always see an appreciable change in their stool content. And that's also not the best method to decide is this really the best product for me? Because again, it's happening on the inside of our body. It's not happening just in terms of the outcome or the finished product. The reason we care about these soluble fiber structures is because it impacts the gut bacteria and the whole microbiome of the colon. That needs multiple species. If you go into a subdivision, you're gonna see trees lined all the way down the road, and there's typically a few kinds of trees, and it's really boring. But if you go to a jungle, it's a whole ecosystem where there's lots of different types of trees, lots of different types of animals, and it's much healthier and the soil is so rich and it is an entire ecosystem, right? We don't want to be in the subdivision of trees. We want to have the whole jungle, and that comes from the food itself. The gut bacteria need that to survive. So then the next argument means okay, well, if we do just a probiotic, probiotics actually are one strain. You need a whole bunch of them. And by the time they get to the colon, they also need food to survive. And if we don't have fruits and veggies, our probiotic may not be doing anything for us. And I think this may be one of the confounding factors when we look at studies and we see, okay, this study shows that this probiotic is really helpful, but in real life, we don't necessarily see that outcome. There's other issues there. There's a lot of steps to getting a probiotic in a pill form to being in our colon. There's also a lot of steps to being able to get the ecosystem in our colon a right environment for a probiotic. So it's not just one strain, it's not just one type of fiber that we need, it's that whole ecosystem. Okay. Now, when you think about your colon and you think about like all of the bacteria that live there, I'm sure that you have heard good bacteria, bad bacteria in the gut. And there's sort of this balance. And in the literature, I see a lot of the time there are kind of groups of bacteria that are really beneficial. And the way we kind of determine that is this sort of ratio of firmicutes to bacterioides. Those are the kind of camps that we think about, the types of sort of gut bacteria. And you really want to lean more towards the bacterioides ratio. Now, when we think about gut bacteria, this is a super hot topic and one that I'm not going to claim to be an expert on. However, I will tell you that in the shift of our gut bacteria, you do see clinical outcomes. You do see real health outcomes. And the same would be true in the reverse. When we see disease states, you see a shift in the gut bacteria. Now, the chicken of the egg, right? Like there's still a lot of learning that needs to be done because over and over and over again, there are lots of things that change in medicine. But the one thing that I would say has been so constant is the value of those fruits and veggies. But the value in fiber from our foods is just bar none. Now, lentils and beans, I haven't spent a whole lot of time talking about those yet. But what I want to shift to and tell you is that the complexity and the diversity of our beans and seeds is so valuable because these beans and seeds will provide not only a different array of micronutrients, but also amino acids and they complement each other beautifully. If we have a kid who really just does not want any fruits and veggies, but we need more fiber, before reaching for that fiber aisle, I'm really going to lean into beans and seeds because they're also incredibly diverse in how you can cook them and prepare them. And there are a lot of ways where we can get great value simply from maximizing those methods. And they're stables. Now that you kind of picture that, here's the other reason why I care a lot about the food. And that is the things that we don't have labels for are antioxidants, our bioactive components, the actual pigments and the color that make up your blueberries and raspberries. Those things, those amazing antioxidants, whatever kind of word you want to use for it, are amazing and they don't get absorbed. I hear this often when I get the example of like parents who are starting solids for their baby and they come in at nine months and they're like, oh my gosh, their poop is so wild. And I like to use it as an example because you get to visibly see, yep, we had sweet potato, yep, we had blueberries, and it comes right out. So they use it as an example that, you know, as your kids are growing and developing, you're gonna notice this especially. But these polyphenols and these colorful structures within the plant don't get absorbed. Again, we don't have digestive enzymes for them. And so as they travel, we used to not realize how important they were, but they actually serve a purpose. So the value in having these polyphenols here is really key. And it's also something that you're not gonna be able to get in your powders or your fiber supplements. Again, not saying you can't use them, but just generally saying that this is part of the reason why if there's a concern, I always like to go back to how can we get this in the food? Okay, so then the other question sometimes families will say is like, well, I can't get my kid to eat any fruits and veggies. What else am I gonna do? And this is where I want to go back to something I mentioned very briefly in the beginning, and it's resistance. So resistant starch is when you take us a grain or starch, think like a potato or pasta, and it's been cooked with heat and potentially moisture, especially steaming is a good example of this, or boiling it, and then it cools. It actually, the heat itself partially breaks down part of the insoluble fiber that we couldn't digest and reshapes it into something called resistant starch. That by doing so, the bacteria in our large intestine can actually partially break down some of that resistant starch. So resistant starches, and I'm going to give you some examples, like a potato salad, really good one. Um, really good example of that. Or I like to make quinoa where I cook it and then I cool it and I use it in the morning, reheat it. Pasta that's been a little bit overcooked and then cooled down, and maybe turned into a pasta salad, or cooled and refrigerated to give your toddler. Or even toast that's been pulled out of the toaster and then cooled down before it's been eaten, are really good examples of how resistant starch can be added into our diet. So sometimes we take the foods that our kids are already doing really well and we see how we can make that just a little bit better for our gut microbiome, even if we can't get to that full quarter cup of black beans that we want our kid to eat, right? Like that's one little pro tip. Now, if you're in the camp where you're thinking, okay, I loved the idea of this, but beans really give my belly some trouble, then think about this. You can actually soak your beans overnight for full like 12 hours, or I would sometimes soak them in the crock pot and then um wash them off afterwards. So discard the water and then rinse them off really, really well before you actually heat them up. You can also add a little bit of vinegar or um lemon juice in that soaking water to help encourage some of the breakdown of a particular type of structure on the outside of the bean that is particularly gassy. And that can really help because then the more accustomed you get to it, guess what? Over time you can get used to some of this. So this takes a little bit of practice with your body. And if not used to eating beans, then jumping straight into it might be really uncomfortable. So here's a couple of practical takeaways for you to be able to get yourself more comfortable with some of these fiber-rich foods in a way that doesn't make you uncomfortably painful. So one of the ways that I like to think about doing this is just by going up in five grams over the course of a couple of weeks. So at a time, not right away. Meaning, if you started to increase your fiber intake by five grams, your body might notice, or it honestly might not notice at all. And then after a few weeks, you sort of shifted a little bit more of that digestive capability. And then a few weeks later, you can increase another five grams to get up to where you probably need to be. And it might not take that much because again, think about five grams. If you eat a whole apple and a half a slice of bread, that's five grams of fiber. If you had a half a cup of black beans, that's even more than five grams. So just a couple of takeaways for you to kind of think about. And definitely you want to add water to this. So, like if you had a little kid and they were struggling with this, you could even think about like as much as a banana or a half of an avocado is gonna definitely get you there. And that could be done in a smoothie. So it doesn't necessarily have to be a heavy lift in order for you to try to get that bump up in fiber. Same thing with seeds. Seeds pack a big punch, even with just a tablespoon or two. And this is part of the reason why my protein balls were kind of where I would go to for my kids, because it served both purposes. Now, I hope this has been encouraging. And the big takeaway from this is that fiber deserves a lot more time to be discussed. And fiber deserves a lot more research into understanding how it impacts our immune system, but it definitely does. And it is one of our most powerful keys for helping to support a healthy body long term. If all of that sounds like really heavy and you're like, that's even too much for me, then just consider shifting in really small ways. Say you have regular white bread and you want to switch to a little bit more whole grain bread. That's a lift. If you're eating maybe instant oatmeal, maybe try steel-cut oat. Or, you know, this doesn't necessarily have to be a big shift, but even the diversity in it. Say you are good at eating one type of bean, maybe you can try a different type of bean this week. Because again, the variety and the complexity of our plant foods are going to offer a broader diversity of the types of carbohydrate structures that support our gut health and really your immune health long term. So I hope this has been encouraging. If this kind of content is helpful for you, please hit subscribe and share with a friend so that more families like you can get the content that really encourages. Thanks so much for listening. We'll see you guys next week.