That Neuroscience Guy - The Neuroscience of Bad Eating Habits

Episode Date: March 27, 2024

Previously on the podcast, we've discussed how a strong diet can improve brain health. But what happens to our brain when our diet is bad, or when we skip eating altogether? In today's episode of That Neuroscience Guy, we discuss foods that are bad for your brain and why they're bad. 

Hi, my name is Olof Kregolsen, and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. So, I've talked a lot about brain health and things that you can do to improve brain health. And one of those things I've talked about is diet, you know, what you should eat and how a good diet impacts your brain. But I thought I'd flip this around a little bit and talk about what are the worst things you can eat and what do they do to your brain and what is not eating do to your brain. So on today's podcast, the neuroscience of either bad eating or not eating at all. So basically, dietary patterns that are high in processed foods,

you know, what we'd call a Western diet, they're basically tied to a range of issues, increased risk for depression, increased cognitive impairment, and even ADHD. So having diets that are western in nature or rich in the things that are bad for us, if you will, lead to a whole bunch of things. Also mood disorders, anxiety disorders, and overall poor brain function. So what are these things that add up to bad brain health? Well, number one on the list is sugary drinks. And I'll point this out right away as a parent. Yes, we mean pop, but most juices that you get off the shelf in a store

are as rich in sugar as Coca-Cola. So any drink that is rich in sugar is not good for brain health. And the evidence is pretty clear. There's an increased risk for dementia, even in people that don't have diabetes, people that aren't overloaded with sugar. And basically what happens is you have this high intake of fructose, which is sort of the main ingredient in these things, high fructose corn syrup. And this leads to all sorts of brain problems. This leads to all sorts of brain problems. Now, a lot of the research is focused on the long-term studies that lead to dementia, but other studies that have been done in animals have shown that this high fructose intake can lead to an overall reduction in brain function.

It impacts memory, it impacts learning, and it impacts the formation of brain neurons. Now, how does it do this? It does this at the cellular level, all right? These things are impacting the way neurotransmitters are released. So if you start messing around with neurotransmitters, of course, overall brain function is impaired. So number one on the list of things to avoid for brain function or positive brain health would be sugary drinks. Number two, refined carbohydrates. So basically this is sugars and highly processed grains. We've all heard about white flour and the problems with white flour, But the research on this is incredible. If you give kids a single meal with a high load of refined carbohydrates, it's shown to impair their memory. And then this research was replicated in adults. So one meal, to heck with this being a part of your lifestyle, one meal can impact your memory.

Now, it doesn't wipe out your memory completely, but it results in reduced memory performance. So if you're going to study tonight, if you're a student, you've got to look at what you're eating. And if it's rich in refined carbohydrates, you're going to struggle to remember more than if you didn't eat that. And these effects on memory are really interesting. Some of the brain imaging work has actually shown inflammation in the hippocampus. And the hippocampus is responsible for memory formation. And of course, there's long-term risks. The research that's coming in that looks at, you know, a diet of refined carbohydrates over a long period of time shows increased risk for dementia. Again, it's, it's one that's commonly looked at, you know, one study,

for instance, showed that, that elderly people who had basically ate too many of these, uh, refined carbohydrates, they had double the risk of mild cognitive impairment. carbohydrates, they had double the risk of mild cognitive impairment. So refined carbohydrates avoid, they lead to memory problems. Foods that are high in trans fats. Now, trans fats occur naturally in animals. Okay, they're out there in meat and dairy. These are okay. But we're talking about hydrogenated vegetable oils, things that are artificial trans fats. And you find these things in like shortening, margarine, frosting, snack foods, you know, ready-made cakes and prepackaged cookies, all those good things. And in fact, just as an aside, if you ever want to see or read a good thing on margarine, just look up a book called In Defense of Food or watch the Netflix show. The bit on margarine is fascinating because I used to use margarine

all the time and now I wouldn't touch it. But if you have a diet that's high in these things, again, higher risk for Alzheimer's disease. Okay, some of you are a lot younger, but diets that are high in trans fats have also been shown to result in poor memory yet again. Actual reductions in brain volume, in cognitive decline. So these kind of trans fats, again, massive impact. Another study I found actually showed that diets high in trans fats impact something is what I thought would be pretty much automatic is visual recognition. So diets and high in trans fats, not so good for you. Now, some fats are good for you, right?

Omega-3 fatty acids have been shown to help protect against cognitive decline, and they lead to anti-inflammatory effects within the brain. So some types of fats are good, but it's these artificial trans fats that are bad for brain health. Highly processed foods. Well, you know, one, I'm not a dietician, so don't take this as dietary advice, but you know, one thing you probably hear is the perimeter diet. As soon as you start going down aisles, all those things in cans and packaging, those are highly processed foods. They tend to be high in sugar.

They have added fat and added salt because that's why they taste good. So we're talking about potato chips, sweets, instant noodles, microwave popcorn, anything in a can effectively for the most part, ready-made meals, and basically diets based largely on highly processed foods, decreases in brain tissues, like the amount of brain tissue, like actual MRI scans showing a reduction, again, increases in Alzheimer's. And some of these studies are massive. I found one that had 18,080 people, which is an amazing amount of people for a study. And these were diets that are high in fried foods and processed meats. And these people had, the people that, you know, on the higher end for fried food and processed meats had lower scores in learning and memory. Another study, 5,038 people, diet high in red meat, processed meat, baked beans and fried food,

reduced reasoning, all right? So the ability to make decisions was impaired in addition to inflammation within the brain. And when you go into the animal studies, because the advantage to animal studies in the sense is they can really get in and look at actual neural connections, neuroplasticity, if you will. Well, they basically showed that diets, if you put animals on diets that are rich in high fats and high sugar, so these pre-processed food ingredients, basically the brain plasticity itself was impacted. So the ability to release more neurotransmitter, the ability for receptor sites to grow, the ability

to form new neural connections. Another one, number five on the list of things to avoid, aspartame. Now aspartame is, it's basically an artificial sweetener, right? It's what gets put in sugar-free products so that they taste okay. I have to admit, I went through a phase where I just relied on diet Pepsi. I'm perfectly fine, right? As long as, you know, because I was trying to lose a bit of weight, and that's where people buy into these things. But what's interesting is high, you know, an increased incidence or a large amount of aspartame in your diet, research has shown that it leads to behavioral

and cognitive problems, problems with learning systems within the brain, problems with emotions and emotional control. And the results are interesting. In fact, in one study, they actually put people on a high aspartame diet, and they found that by the end of the study window, people were more irritable. They had increased incidence of depression, so the depression scores had gone up, and they performed worst on mental tests. Number six on the list is alcohol. We actually have a whole episode on alcohol in the brain if you hunt back through previous episodes.

But it's kind of pretty straightforward. If you drink too much alcohol, there is debate about the right amount. I actually don't know what the answer is from a neuroscience perspective. Is it zero? Is it one glass of red wine? The jury's still out, but if you're drinking too much alcohol, you basically lead to brain damage. You're damaging your brain. This can include memory loss, problems with eyesight, confusion, motor issues, so unsteadiness. And I'm not talking about when you're actually tipsy. I'm talking about after you've been tipsy. Anyway, we have a whole episode on this.

I will note, though, that even one-off episodes of drinking have been shown to have effects. People interpret emotions differently. They make poor decisions and it's a carryover to when they're not impaired. Last on the list of things to avoid, fish that's high in mercury. Now some of these types of fish typically include things like shark, swordfish, tuna, king mackerel, towelfish. You'd have to look up and do some research there in terms of your favorite fish and whether it's high in mercury. But basically, a high mercury diet leads to brain damage. It disrupts neurotransmitter release. It promotes the growth of neurotoxins, which are bad

things within the brain. Mercury is not something you want to have interacting with your brain in any way, shape, size, or form. So those are seven things that have a negative impact on the brain and how they do, and you should avoid them. Just some other stuff before I wrap up here. There are some ties to the gut-brain connection. If you have an unhealthy diet, basically we did an episode on that quite recently, but that whole gut brain connection is disrupted. And what happens is you basically got a release of all these hormones that you don't want to be releasing, and the release process is not constant. That leads to inflammation, and that can negatively affect cognitive abilities. So it makes it harder to plan, focus, or remember things.

Depression always comes up when you're on an unhealthy diet. Now, what about not eating at all? Whether you're in a starvation situation, because you have no choice, or possibly due to an eating disorder. Well, basically, not surprisingly, you have an increase in negative brain issues. You're going to have, uh, uh, detriments or lack of vitamins like B12, B9, zinc, and that can lead to depression, uh, increased incidence of dementia, mood issues, fatigue, cognitive and physical, cognitive decline, irritability. Um, it can also lead to more severe patterns of mental illness. And basically the brain starts to starve.

Okay, the brain requires glucose, which is a form of a carbohydrate to function. But if you're not giving it enough glucose, your brain literally can't function the way it's supposed to. And that basically means that you're not going to be functioning well. Okay, you can probably still sleep, although it's probably Okay, you can probably still sleep, although it's probably disrupted. You can probably still work and participate in school and other must-do things, but you're not going to be doing them optimally. Your performance will suffer, and people will see this. And like I said, this is going to lead to sleep disruption, problems with concentration, problems with attention span, lack of interest in things, because the prefrontal cortex is going to get

hit more than anywhere else, or at least it's going to get hit first, because your body's going to be, and your brain's going to be in survival mode. And the reason it is, is you're messing with your neurotransmitters. You know, I mentioned, you know, the fact that you're going to have some glucose issues, but you're also going to be disrupting serotonin, all right? You're going to be disrupting dopamine, and all of that is going to lead to negative mental health outcomes. So the bottom line is, don't do anything I've just said. Avoid those things that I mentioned earlier. Make sure you are eating and eat a healthy, well-balanced diet.

And if you're struggling, because I know it can be hard, reach out for help. Okay. If it's because you don't have access to the right kinds of food, try to see what you can do to find that. And I know that's a pretty broad statement that's easy to say from where I am. And if it's more of an eating disorder issue, please talk to someone. All right, your brain is important. Keep it healthy by eating a well balanced diet. All right, that's what I have on the negative aspects of brain nutrition. Hopefully you found that interesting. I would hopefully you didn't find it enjoyable. found that interesting. I would, hopefully you didn't find it enjoyable. Don't forget the website,

thatneuroscienceguy.com. Links to Patreon where you can support us. If you haven't yet, a dollar a week, a dollar a month, all of it goes to graduate students in my lab to help them do their studies in neuroscience. There's also links to Etsy. Occasionally we sell a t-shirt. There's a few of them out there. I actually saw one in public in San Diego and I was going to go over and say something, but I didn't. But if you, and if you have some ideas for merch or you have ideas for episodes, because we want to know what you want to know

about the neuroscience of daily life, make sure you reach out to us. You can get me on X or threads at that neuroscience guy, or you can email us that neuroscience guy at gmail.com and again thank you so much for listening to the podcast if you haven't already please subscribe and i'll see you soon my name is olaf kirkolson and i'm that neuroscience guy thank you so much for listening