Gut Feelings: How Concussions Affect Your Digestion | E35

Have you ever wondered why your digestion seems to have gone haywire after a concussion? You're not alone, and there's a neurological explanation behind those new food sensitivities and stomach troubles.

The brain-gut connection is far more profound than most of us realize. Through the vagus nerve—a critical communication pathway—your brain and digestive system maintain constant dialogue. When a concussion disrupts this delicate system, the consequences ripple throughout your entire digestive process. Your vagal nerve signaling weakens, stomach acid production falters, and gut motility becomes irregular. What's particularly fascinating is how brain inflammation can directly alter your gut microbiome, creating a cascade of digestive symptoms that seem disconnected from your head injury.

The mechanisms behind this connection are multifaceted. First, concussions often trigger autonomic nervous system imbalances that shift your body into fight-or-flight mode, diverting blood away from digestion. Second, inflammatory messengers produced in your injured brain enter circulation and increase gut permeability. Third, the protective barriers in both your brain and gut begin to leak in tandem, allowing harmful substances to cross where they shouldn't. Finally, the stress hormones and sleep disruption that follow concussions further compromise your digestive health by thinning the gut lining and disrupting your microbiome.

If you've developed mysterious food sensitivities, especially to gluten, dairy, or histamine-rich foods, understanding these connections is crucial. Standard elimination diets might not work as expected because many foods cross-react with gluten, including oats, corn, and rice. Additionally, the glyphosate residue in non-organic grains may be exacerbating your symptoms, which explains why some people can tolerate bread in Europe but not at home. Healing requires patience—sometimes 3-6 months rather than just weeks—and a comprehensive approach that addresses both brain and gut simultaneously. By supporting your digestive health, you're also creating the optimal environment for your brain to recover, turning a vicious cycle of inflammation into a virtuous cycle of healing.

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Chapters

• 0:00 Podcast Introduction
• 1:55 Concussions and Digestive Dysfunction
• 5:37 Brain-Gut Communication Pathways
• 9:23 Food Elimination Diets Explained
• 14:59 Glyphosate's Hidden Impact
• 24:08 Key Takeaways and Conclusion

Transcript

Speaker 1: 0:01

Welcome to Life After Impact the concussion recovery podcast. I'm Dr Ayla Wolf and I will be hosting today's episode where we help you navigate the often confusing, frustrating and overwhelming journey of concussion and brain injury recovery. This podcast is your go to resource for actionable information, whether you're dealing with a recent concussion, struggling with post concussion syndrome or just feeling stuck in your healing process. In each episode we dive deep into the symptoms, testing treatments and neurological insights that can help you move forward with clarity and confidence. We bring you leading experts in the world of brain health, functional neurology and rehabilitation to share their wisdom and strategies. So if you're feeling lost, hopeless or like no one understands what you're going through, know that you are not alone. This podcast can be your guide and partner in recovery, helping you build a better life after impact. Hello and welcome back to Life After Impact the concussion recovery podcast. I'm your host, Dr Ayla Wolf, and I am recording this episode from Toronto where I am teaching a private invite-only workshop this week. Today I am going to do my second ever solo cast from this very cute Airbnb that I'm at. Before we get started, I wanted to remind listeners far and wide, but for sure all of you local to Minneapolis, st Paul, minnesota, that you are so welcome to join me for my book release party October 24th at the Schmidt Artist Lofts in St Paul, from 630 to 830. From 630 to 830. Please RSVP to lifeafterimpact at gmailcom so we can plan accordingly regarding our gut and brain friendly catering here.

Speaker 1: 1:53

Okay, let's get to our topic at hand. When you think of concussion symptoms, the first things that come to mind are often headaches, nausea, dizziness, maybe brain fog, confusion. But the truth is, concussions can impact the body in ways you might never expect, and this is what we're going to talk about today. I want to walk you through one particular issue that can happen as a result of a concussion that often flies under the radar, in the sense that a person may not even realize that this thing they're dealing with is a downstream effect of an injured brain, and my goal is to help you connect the dots between seemingly random struggles and what may actually be a deeper neurological root cause. So if you've been dealing with digestive symptoms, this episode is for you, and in the future we might also tackle some other issues kind of in this same vein things that people often deal with that they might not even realize is from their concussion.

Speaker 1: 3:00

But today we're focusing on digestion. So one of the most common but least recognized effects of concussion is digestive dysfunction. Many people after a concussion can develop new food sensitivities, irritable bowel type symptoms, bloating after meals and other types of digestive symptoms, and it's not just a coincidence. Here's why we're going to break this down. Your brain and your gut are in constant communication through the vagus nerve, which is a parasympathetic nerve, and 80% of the information from that vagus nerve goes from your gut to the brain, and then 20% of the information is going from your brain to your gut. So, even though it's biased more towards sensory information going to the brain, that 20% of output from the brain is extremely important and we'll get to that in a little bit more detail here in a minute. So when the vagus nerve isn't firing properly after a concussion, digestion can slow down.

Speaker 1: 4:11

Stomach acid can drop. Many people when they have heartburn, they're actually experiencing heartburn because they don't have enough stomach acid to break down and digest their food in the appropriate amount of time and therefore it sits in their stomach for too long and it ferments in the stomach and it creates irritation of the stomach lining so that then the next time they go to eat, their irritated stomach lining actually takes the digestive acid they do have and sends it upwards because it wants to get it away from the stomach lining, and so that actually is causing the heartburn that many people experience. Another just kind of a little bit of a side tangent there, but in many cases heartburn is actually not enough stomach acid. It's not a matter of too much stomach acid. So okay, so that's one of the things. And then motility becomes irregular as well. When people have motility issues, they can either develop constipation or they can have alternating diarrhea and constipation in kind of one of those ear to bowel type scenarios.

Speaker 1: 5:20

On top of that, inflammation in the brain can ripple outward and disrupt the gut microbiome. You heard me right. Inflammation in the brain has downstream consequences that affect the gut health. So let's get into that a little bit in more detail here. One of the ways that this can happen is through vagal nerve dysfunction. The vagus nerve is the main superhighway between the brain and the gut and the gut microbiome, so that's really important. We often talk about the gut brain axis, but what we really need to be including in that equation is the gut microbiome, so more appropriately we should say the gut microbiome, gut-brain axis.

Speaker 1: 6:06

And after a concussion, brain inflammation can impair vagal signaling Remember that 20% of motor output leaving the brain going down to the body through that vagus nerve so that particular pathway can be impacted. This reduced vagal tone means slower gut motility, leading to things like constipation, bloating and weaker regulation of stomach acid and the release of digestive enzymes and a sluggish gut environment that then allows certain bacteria to overgrow while beneficial microbes decline. So that's one way. The next way, which is still very much intertwined with the first way, is through, we would just say, some autonomic nervous system imbalance. So concussions often trigger dysautonomia to some degree, whether that is mild, moderate or severe. And so when sympathetic activity dominates what we often refer to as fight or flight and parasympathetic activity is reduced, the outcome of that is that blood flow to the gut decreases, motility slows down and digestive secretions decline, and this can starve the microbiome of nutrients and oxygen and promote dysbiosis, which is just a fancy way of saying an imbalanced microbial community in the gut.

Speaker 1: 7:33

The third way that brain inflammation can impact the gut is because of systemic inflammatory signaling, so neuroinflammation doesn't necessarily stay locked inside the skull Cytokines, which we can just maybe describe them as inflammatory messengers. When they are produced in the brain, they can still enter your circulation and influence immune cells in the gut, and these circulating cytokines increase gut permeability, or what we like to call a leaky gut, and this further alters the microbiome and it creates a feedback loop for more inflammation. Number four we have blood-brain barrier and gut barrier crosstalk, so the endothelial cells that line the gut and the cells that line the blood-brain barrier. They behave in very similar ways and concussions can temporarily cause increased permeability of the blood-brain barrier, and this is normal if it lasts for like a week or two after a concussion. But sometimes this doesn't resolve quickly and it becomes more of a long-term systemic problem, causing systemic inflammation that weakens the gut barrier as well. So when both barriers are leaky, immune cells and microbial products lipopolysaccharide is one of them they can cross into circulation and go to places where they don't belong and cause more inflammation. And so this creates a compounded problem where brain inflammation worsens gut dysbiosis and gut dysbiosis then sends more inflammatory signals back to the brain in this very vicious loop that we don't want to have happen.

Speaker 1: 9:26

And then, lastly, this is compounded by stress hormones and sleep disruption. So concussion-related stress, physical pain, say from headaches and neck pain or other injuries that aren't healing, and poor sleep. All elevate cortisol and high cortisol levels actually thin the gut lining, suppress good bacteria and encourage the overgrowth of opportunistic species that we don't want to have overgrowing in the gut. We don't want to have overgrowing in the gut. So over time this shifts the microbiome away from a diverse resilient state towards one that actually perpetuates inflammation. So these are all the reasons why you may suddenly start reacting to foods that you never had an issue with before the concussion. And this can also kind of come on gradually, in the sense that you might not necessarily be aware of this within the first couple of weeks after a concussion, but possibly within six months to a year. This problem with food sensitivities and digestive issues might actually become more problematic over time. So that's one of the reasons why this is kind of a sneaky issue that people often don't trace back to a concussion is because it might actually take a little while to really fully develop into a full-blown issue. So if you're suddenly reacting to foods like dairy gluten or histamine-rich foods, it may not just be your stomach, it could actually be your brain struggling to regulate digestion. And the longer this goes unchecked, then the more gut dysbiosis it can create over time.

Speaker 1: 12:23

So what can people do? Well, food elimination diets are a legitimate way to determine whether or not your body is reacting to a specific food, but there's some nuances to that that we're going to get into. But let's use a really simple example. So let's say you cut out corn 100% of your diet. You cut out all corn for three full weeks. So no corn, no corn chips, no corn syrup, no corn at all. Then on day 22, you eat a ton of corn. You have corn pops for breakfast, mexican street corn with lunch, corn tortilla chips and guacamole for dinner.

Speaker 1: 13:04

Whatever, if your body has an issue with corn, you're probably going to have some sign when you eat all that corn in one day, when you haven't had it for three weeks, and that might be stomach pain, it might be intestinal cramping, it could be bloating, gas, diarrhea, loose stools or, if you're like me, my nose starts running like crazy when I eat yellow corn, not blue corn though Me and blue corn are super cool with each other, but yellow corn chips and my nose will just start running like crazy. So because I'm pretty in tune with my body. I've kind of figured out these weird little signals that my body gives me to tell me what foods it is responding to in a negative way. Tell me what foods it is responding to in a negative way. But so that's the concept of a food elimination diet is you cut the food out for three weeks and then you actually eat a lot of it in one day and you see if you react to it. Now, obviously, if you know that you have a food allergy, you don't need to do this. But what?

Speaker 1: 14:05

Food allergies and food sensitivities are different. So we're not necessarily talking about true food allergies. We're talking about sensitivities to foods that can develop in the picture of inflammation. So here's where things can get tricky, and that's when we start talking about gluten, because I have heard from a lot of people that they have gone off of gluten for three weeks and then, when they added it back in well A, they didn't notice any improvement. Like they went off the gluten for three weeks, they didn't notice any improvement in their symptoms, and so therefore, they were like, well, that didn't do anything. So I guess I'm just going to keep going back to eating gluten.

Speaker 1: 14:46

Here's why gluten is a bit of a problem. Gluten cross reacts with many other foods like oats, corn, rice, barley, sorghum, even coffee and chocolate for some people. So when somebody does cut out all bread and flour products but instead they're still eating, say, gluten-free oatmeal, oat, cereal, rice, corn and all of the gluten-free processed foods that contain, like tapioca flour or cassava flour, they're likely still consuming foods that are keeping them inflamed and this is why they don't actually feel any better and don't notice a difference going off of gluten. So my advice to people with a lot of digestive issues and brain fog and fatigue is to just cut out all grains for a while, do a strict food elimination diet and then slowly add back in, one thing at a time to see how you tolerate it, one thing at a time to see how you tolerate it.

Speaker 1: 15:51

For me, after cutting out gluten, it became really obvious that I also really strongly reacted to oats, and I love granola, but for many, many years I couldn't eat it. I literally just couldn't buy it, couldn't have it in the house, didn't eat it. If I did have it, it would make me very tired and it would give me stomach pains pretty immediately. And rice is also a big problem for me. It gives me the worst brain fog that will literally last into the next day. So what's interesting is that within the last four years, as my gut and brain have gotten healthier, I've been able to add back in about one to two servings of granola per week into my diet with no ill effects. But the opposite is actually true for rice. I feel like I've become more reactive to it, or it's more obvious to me that when I eat rice, it gives me such bad brain fog and fatigue that I'm actually avoiding it a lot more now than I was even 10 years ago. Okay, but wild rice is actually an exception, because wild rice is actually a seed, it's not a grain, and therefore people tolerate it pretty well because it doesn't cross-react with gluten like white rice or brown rice can. So many people can actually do wild rice and they're okay with that.

Speaker 1: 17:10

If you want to actually do a test to try to figure out what foods you might be cross-reacting to in terms of how gluten has impacted your system, cyrex Labs has a specific blood panel. They run that tests for foods that cross-react to gluten. So if you're highly curious about diving deeper into that, you could find a functional medicine provider who works with Cyrex Labs and you can actually order these tests and get to the bottom of your personal reaction to different foods that may be cross-reacting to gluten when you eat them. So you can actually do some further testing to get into this. But for some people, you know, I do think that when you take gluten out of the equation and you take most grains out of the equation, it's kind of like getting rid of all of the white noise, so that when you do start bringing things back into your bubble, your body will tell you whether it can handle it or not. Some people are really in tune with their bodies, other people are not, and for those people maybe just running the Cyrex panel is the way to go. But just to let you know, like that does exist, we can actually test for these things. So the cross reactivity must be taken into account here.

Speaker 1: 18:33

And then I have two other things that I want to say about gluten in particular. One when people are really inflamed in their gut, it really truly can take longer than three weeks to bring that inflammation down. So going off of gluten for three weeks simply may not be long enough to see benefits. For three weeks simply may not be long enough to see benefits, especially if both the brain and the gut are inflamed. It really may need to be more, like three to six months. And then, lastly, we have to talk about glyphosate. Many people will say to me when I talk about going grain-free, or at least gluten-free, they will jump in and they'll say well, I've been tested and I don't have a gluten problem. Even if that's true, eating gluten every day also means you are consuming its evil twin, glyphosate. So gluten is a protein found in foods themselves.

Speaker 1: 19:27

Glyphosate is a chemical that gets sprayed onto crops that ends up as a residue in foods, and the foods that have the highest glyphosate residue content are typically wheat, especially non-organic wheat oats. So think oat-based cereals. I'm pretty sure Cheerios is made of oat flour, for example. Granola and many snack bars have oat flour in them. So even a bar that you might think is a healthy, like a protein bar or something like that, if it has oat flour as one of the main ingredients, it actually is testing pretty high for glyphosate residue. Barley, rye and corn are also kind of at that top of that list of foods that tend to have a larger glyphosate residue.

Speaker 1: 20:17

When they test for these foods, the United States uses the largest amount of Roundup in the world, continue to increase in our food supply because of our use of Roundup. The US government has continued to raise the allowable amount of glyphosate in our food supply. So rather than saying, ooh, you know, the glyphosate residue in our food supply is increasing, we need to put some restrictions in place on the amount of Roundup that can be sprayed onto the food. Instead of doing that, they're basically just saying well, let's just say that this is now okay, that the amount of glyphosate residue in our cereal is much higher than it used to be. So that's really the truth of what is happening, and our allowable amounts of glyphosate in our food is much higher than what is allowed in Canada and Europe and other parts of the world.

Speaker 1: 21:20

So many people who are gluten-free in the US I hear this all the time they go to Europe and they say I can eat the bread here, I'm totally fine. And it's likely that it's not just because of, say, the type of flower. Maybe they're using some heirloom flower, maybe they're not. It's likely that glyphosate is playing just as big of a role as whatever type of flower it is that they're using that is somehow different from what we're using here. So I really think that the glyphosate is a bigger problem than people realize and as soon as people come back home from their European trip, they go right back to having, you know, their gut issues or digestive issues unless they're completely gluten free. And again, I think a big part of that is the fact that we are exposed to so much glyphosate residue in our food supply here, unless you're eating 100% organic and really limiting the amount of grains that you consume.

Speaker 1: 22:23

I know we've covered a lot of information, so let me just recap here. We've talked about how concussions don't just affect the brain. They ripple all the way down into the gut, from vagus, nerve dysfunction and autonomic imbalance to systemic inflammation, barrier permeability of both the gut lining and the brain lining, the blood brain barrier, and then even the impact of stress hormones and environmental chemicals like glyphosate stress hormones and environmental chemicals like glyphosate. So it's clear that digestive issues after concussions. They're not random. They're part of this bigger gut microbiome, gut-brain axis that has become dysregulated as a result of the concussion to the point where, if somebody could handle glyphosate and gluten and eat whatever they wanted, sometimes a concussion can throw them over the edge and cause enough dysfunction that, all of a sudden, they can no longer tolerate these foods. That are creating more inflammation.

Speaker 1: 23:29

Due to the leaky gut and the leaky blood-brain barrier and the crosstalk between the two, if you feel like you have developed food sensitivities, irritable bowel syndrome-like symptoms or unexplained fatigue after eating certain foods, it may not just be your stomach. Your brain injury may have actually set the stage for these changes to occur, and food elimination diets can be helpful. Paying attention to gluten cross-reactivity is helpful, and reducing exposure to glyphosate-heavy foods is, I think, much more important than we're giving it credit for. So the key takeaway is this your digestive struggles aren't in your head, but they do start with your brain, and the gut and the brain are truly inseparable partners in healing, and the encouraging part is that by supporting your gut, you are also supporting your brain's recovery.

Speaker 1: 24:31

Thank you so much for listening. If this episode resonated with you, please share it with somebody else who might be dealing with some unexplained digestive issues after a concussion, and remember there are always missing pieces we can uncover and pathways forward to better health. Thank you so much for listening. If there are specific topics you want us to cover, please email us at lifeafterimpact at gmailcom or you can click the send us a text link in the show notes. Medical disclaimer. This video or podcast is for general informational purposes only and does not constitute the practice of medicine or other professional health care services, including the giving of medical advice. No doctor patient relationship is formed. The use of this information and materials included not intended to be a substitute for medical advice, diagnosis or treatment, and consumers of this information should seek the advice of a medical professional for any and all health-related issues. A link to our full medical disclaimer is available in the notes.