Aidan:

Hello and welcome to the Ideal Nutrition podcast. My name is Aidan Muir and I’m here with my co-host Torin Eerkins. And this is episode 233 where we are going to be talking about whether you should avoid artificial sweeteners for gut health. So, there are a few reasons why we want to talk about this. I see online quite a fair bit. And I even saw today a pretty well-respected dietitian talking about avoiding this for this reason.

And yeah, I think it’s just worth exploring, right? So, we’re going to start off with definitions of like what we would call gut health. I personally would define it in two separate ways. Firstly, one is the microbiome and all of the bacteria in our gut specifically. And then also the other side of it is gastrointestinal symptoms like diarrhoea, bloating and stuff like that. Because often if somebody says they have really good gut health. They would probably be referring to both of those things I believe.

And we’re going to talk about different kinds of artificial sweeteners. But, we want to keep it specific to the category of artificial sweeteners. So, that means we’re not going to be talking about sugar alcohols. And the reason I put them in a separate category is sugar alcohols often have some pretty well-documented. Not all of them.

But, pretty well-documented effects on things like bloating and other gastrointestinal symptoms. I only want to talk about artificial sweeteners. So, the main ones we’re going to be covering are going to be aspartame, sucralose, saccharin, and ACE-K.

Torwen:

Really good intro, I agree with you there. And I want to just add that when we look then at should you avoid them. We’re looking at does it impact the microbiome. Or does it cause you gut symptoms as both of those should you be avoiding those sweeteners. So I think we’re just going to run through them individually. If we start with aspartame then.

Aidan:

Incredible, so let’s start with aspartame. One of the good things about aspartame is there actually has been plenty of research done on aspartame. It’s been popular for quite some time. There has been human research that has had some mixed results and for all of these sweeteners. There is a lot more animal research than human research. One broad study that I’ve put in the show notes. They gave participants various forms of artificial sweeteners, including aspartame. And they found a link between aspartame and microbial changes.

But even that study was quite unclear on the changes and whether they actually mattered. Another study found no noticeable differences. They did link a reduced microbial diversity to people who were habitual artificial sweetener consumers in general. But this brings us back to the common question. Do the artificial sweeteners directly cause these changes or did other variables cause these? And the one that I really want to point to. And I have said something about this on the podcast before. Is that mechanistically, it doesn’t make sense for aspartame to cause notable, noticeable shifts in the microbiome.

The reason for this is we’re often talking about the large intestine here. By the time aspartame gets to the large intestine, it is already broken down into other components. Which are specifically phenylalanine, aspartic acid and methanol. There is this whole thing about aspartame being 200 times sweeter than sugar. So it’s broken down into. Because you don’t have to use much of it. It’s broken down to really small amounts of these. And we get these in food at much larger amounts in general. So if there happened to be any effects, it would likely be quite indirect.

Torwen:

I had the exact same as with you there. So I think if we draw a bottom line then. Or maybe a takeaway for aspartame specifically. It appears that it’s unlikely that it’s going to cause meaningful harm to your gut microbiome. Or trigger gut issues in most people. So, potentially this isn’t one to be super concerned about.

Aidan:

Yeah, I’d say it’s the least likely. And with the gut issues thing as well. Because it’s like the same concept applies where it’s like, it’s no longer aspartame by the time it gets there.

Torwen:

Sucralose, then. I think this is one that’s probably been studied more often. And, look, again, research is conflicting. It has been linked with microbiome changes. A study that I looked at, which was a 2022 10-week study in healthy young adults. It looked at changes specifically in gut microbiome. And then also glucose and insulin levels with sucralose consumption of about 48 milligrams a day. Which is about two-thirds of a can of diet soft drinks.

So they found noticeable differences in all three. But then again, it was a small study, 40 participants. There are other studies out there that go against this. So another study looked more at 11 cans of diet soft drink a day. Which is a massive difference. So, 780 milligrams of sucralose. And they found no changes in any of those three. So that is very conflicting information.

Aidan:

Yeah, I think sucralose is the one that I have seen. It seems the most commonly accepted in the evidence based community that this has the potential to impact the microbiome. And it’s just whether the application of that, like that seems a bit unsure. I do find it really interesting that that first study and the second study coexist. I was thinking the exact same thing where we can see pretty quick changes in the gut microbiome.

And if the equivalent of 11 cans of diet soft drink worth of sucralose isn’t causing a noticeable change. It does seem interesting to me. Going to the mechanism, sucralose is another one that’s also not metabolised by the gut microbiome. So that’s another relevant factor in how likely it is to make a difference. Although so just because something’s not metabolised doesn’t mean it can’t have any effect at all. But I do think it’s another thing to put in there as well.

Torwen:

What would your advice on this one then be? Because I think again, realistically, you’re not consuming 11 cans of diet soft drink. Two-thirds is much more likely. Risk again appears low, but individual responses may differ clearly and potentially. Yeah, this is one that you would be a little bit more wary of.

Aidan:

Yeah, I’m at the point that I’m not personally concerned. But it is something that I think if you are a very health-conscious person. And you are concerned about these types of things. And it’s quite easy for you to avoid these. I see reason to avoid it if you want, yeah. The next one is saccharin, and this is another mixed one. I’m going to start with what I call the scary study. I don’t know if this was the title of the study. But one of the findings was that artificial sweeteners induce glucose intolerance by altering the gut microbiota. So this is in the show notes.

So if I’ve got the title wrong, you’ll find it in the show notes. Directly quoting, it got seven healthy adults, each of whom consumed five milligrams per kilogram body weight per day of saccharin for six days. Which aligns with the FDA’s maximum acceptable daily intake. I don’t have the equivalent of that in diet soft drink. But saccharin actually does have a noticeably lower one. I don’t want to be, I don’t want to make a mistake here. I think it was something around the range of like 3.7 cans of diet soft drink is what comes to mind. Maybe a little bit higher.

But it’s one of the ones where we, I often say like artificial sweeteners are typically fine when consumed in all amounts. But the saccharin one’s a bit lower. And you’re like, oh, if this was like in a lot of products in the food supply. Maybe this is actually about being a bit more aware of. There’s a bit of a tangent. Don’t quote me directly on that. But going further with the direct quote. So, four participants developed impaired glucose tolerance. Keeping in mind we only had seven to start off with. Well, three did not, and they were considered non-responders.

So this indicates that people might kind of have a different response. In the responders, the study also found a pretty significant change in a bunch of bacteria. Whereas non-responders found minimal change. I made in my notes myself, I wrote a little thing saying, seems a bit drastic? Question mark, question mark. Because it does seem a bit drastic. And I’ve noticed I wrote for myself was like. Well, if this was relevant, wouldn’t we see this more in the real world? Like, a lot of people in the real world do have exposure to saccharin.

And I know that there’s a lot of people who are glucose intolerant in the real world. But I think this would pop up like if you got a bunch of like healthy, relatively lean people. And gave them moderate amounts of saccharin, or an equivalent of the maximum acceptable dosage. I think we would see this pretty quickly. And the alternative is the opposite type of study, the not-as-scary study.

They used a pretty similar hydro saccharin supplementation. And they found no change in the gut microbiota or glucose intolerance as well. They did the maximum acceptable daily intake for two weeks. And it just had no impact on glucose, insulin or microbial diversity. It brings me back to the question of like, seems kind of odd that both of these coexist.

It is another area that I would say caution. But it does also still seem interesting to me that like, they can be absolutely sending it on this and having the maximum intake. And like, there’s just no change as well. Whereas the other study four out of seven, like, I don’t know. It’s just, it’s a really big number.

Torwen:

It does raise a few questions as well of whether some individuals are potentially more susceptible. Is there other factors that come into play? As with most things, I think we just need a little bit more research in the area to make it a bit clearer what is going on. And the same goes for our last one, ACE-K. Which I found is probably the least studied of the four.

There was a human cross-sectional study that didn’t find any links between ACE-K and microbiome changes. But there was a little bit of a change in bacterial diversity. Again, is this something that was there before the study? We’d need to know. So, yeah, minimal evidence that I found here. But did you have anything to add on to that one?

Aidan:

I was in the same campaign. I was like, I wonder if you found any more studies. And I just didn’t find that much at all. Yeah, it’s another one that like if we go to mechanisms. It’s technically not metabolised by the bacteria in the gut as well. So any interaction would have to be indirect. Or like related to like chemical interactions rather than like the bacteria actually feeding on it. So that’s the summary of the state of play with the microbiome stuff.

It’s not as clear as I would like it to be. I can see caution in certain cases, like you’ve heard us talk about sucralose and saccharin. And then also the lack of research on ACE-K as well. You’ve heard us talking about mechanisms which make a lot of them seem a little bit less likely. Yeah, I’d say caution for sure. And like the bit I was going to talk about with the mechanisms for the aspartame. I’m not cautious with that one just because it’s unlikely. But what I want us to talk about now is the symptoms side of things. Do you have a bit of a summary of your thoughts on that?

Torwen:

I think this is so anecdotal and we always talk about anecdotal studies, people reporting certain things. I think when things come to light in social media. Are people being overly cautious or overly responsive to what symptoms they think they could be experiencing? Absolutely. Artificial sweeteners can be a trigger.

They can cause bloating, that sort of thing. But the thing is that most of these sweeteners. Like you mentioned, they don’t reach the colon in massive amounts. So they don’t ferment, they don’t produce gas. So it’s unlikely that the sweeteners are what causing like the bloating, diarrhoea, that sort of thing.

Aidan:

Yeah, I’m on the same page where at a population level. It’s incredibly unlikely there is individual cases. One mechanism could be changing microbiome stuff. But that’s not acute. That is over time, right? So somebody had a diet soft drink, then immediately got symptoms. Then that’s a different kind of thing. The amounts are tiny and pretty rare to be triggers. They’re not fermentable. That’s not going to cause gas buildup or anything like that.

We have the multiple moving parts thing where like. I don’t know. Say a can of soft drink is carbonated and then you’ve got the bubbles. And then that causes like bloating or gas or anything like that. There’s a lot of things in there. I think I’m pretty content to die on the hill of highly unlikely for most people.

Torwen:

I’ll join you on that one. And again, in regular intake, we need to keep in mind that a lot of these studies are high amounts. Like you’re trying to max the dose to see what it will cause. If you’re having two, three, four foods a day that contain artificial sweeteners. It’s unlikely that it’s going to cause a lot of gastrointestinal issues.

Aidan:

Yeah. And now let’s talk about those foods as well. There’s an interesting conundrum. I don’t have conundrum, interesting thing I’ve seen in the fitness space. Where there’s a lot of people who would never drink diet soft drink. But are indirectly consuming or directly consuming a lot of products that contain it.

For example, protein powder, almost every flavoured protein powder is going to have artificial sweeteners. Not every single one, but most of them. Pre-workout amino acids, like a lot of supplements will contain it. One of the newer trends in the food supply, say, is that some yoghurts have it. Like for example, the Paul’s Protein Plus is a great example. It once previously used Stevia. But like, there is quite a few yoghurts now that are flavoured that are using this to keep the sugar low.

There’s a lot of the higher milks. Not all of them, but some of them are using it as well. For example, Paul’s range is as well. And it does get to the point that you can end up having five plus different foods per day pretty quickly going down that route.

Torwen:

Yeah. And obviously sugar-free, zero calorie sorts of foods now in protein bars. Not just the powders, that sort of thing. I think it definitely can add up as well. So yeah, some practical takeaways or recommendations then.

Aidan:

Yeah, I was just going to say on that I think that I think they’re fine in normal dosages. And I’m pretty content with that. One of the things that I do want to point to on this is the human body has a lot of moving parts. And there are cases where we do a lot of the classic petri dish type study or even animal type studies. With like high dosages and stuff like that and we see certain changes. Let’s go back to the mechanisms of these small amounts getting to the microbiome and then potentially being fermented.

There are so many things we can do that have so much more impact. So many things like whether it’s to do with fibre or diversity of plant based intake. And nd all of these things that I believe are just going to have so much more impact if there is an impact of the artificial sweeteners.

Torwen:

I say that too. Gut health is so much about addition rather than what you can take out. Generally we recommend getting about 80% of your intake from whole foods anyway. Which obviously wouldn’t contain these things. So moderation is a big thing. I think context is another one. If including things like protein powders is going to help you reach your goal protein intake. Then, look, potentially it’s more beneficial to include those things and add them in.

That sounds really good. And I think that’s everything. So, yeah for me I agree with you. I think if we look at overall health, there’s bigger things to focus on if you include them in moderate amounts that makes sense. If you prefer to reduce them where possible look that’s a valid choice as well. So thank you for joining us on episode 223 of the Ideal Nutrition Podcast.

Aidan:

233.

Torwen:

233. Oh my goodness. Hopefully, we were able to break down a pretty hot topic for you guys. We will catch you next week.