Artificial sweeteners — worse than sugar?

Artificial sweeteners are everywhere — not only in diet soft drinks but in many foods that you wouldn’t expect.

You’ve probably eaten some today without even realizing it. Sweeteners have been around for over a hundred years, yet they remain one of the most debated subjects in nutrition.  

It's hard to know how they stack up next to the alternatives.

In today’s short episode of ZOE Science & Nutrition, Jonathan and Sarah ask: Are artificial sweeteners worse than sugar?

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Studies referenced in today's episode:

Stevia leaf to stevia sweetener: Exploring its science, benefits, and future potential. The Journal of Nutrition.

Chronic intake of commercial sweeteners induces changes in feeding behavior and signaling pathways related to the control of appetite in BALB/c mice. BioMed Research International.

Personalized microbiome-driven effects of non-nutritive sweeteners on human glucose tolerance. Cell.

This podcast was produced by Fascinate Productions.


[00:00:00] Jonathan Wolf: Hello, and welcome to ZOE Shorts the bite-size podcast, where we discuss one topic around science and nutrition. I'm Jonathan Wolf. And as always, I'm joined by Dr. Sarah Berry today's subject is artificial sweetness. 

[00:00:22] Sarah Berry: So Jonathan artificial sweeteners are everywhere, not just in diet soft drinks, as many of us think, but they're throughout all kinds of processed foods. And maybe in some places that you wouldn't even expect. As they become more widespread, people will naturally have lots of questions about how they compare to natural sugars. 

[00:00:40] Jonathan Wolf: And there have been years of conflicting studies. So I think there's a lot to clear up about these sugar alternatives.  

[00:00:45] Sarah Berry: Yeah. And I think we can shed some light on the most important benefits and also the potential risks of these sweeteners.  

[00:00:52] Jonathan Wolf: Brilliant. Well, let's go. 

And to start with, we did some research and it turns out the first synthetic sweetener to make an impact globally was saccharin. It was discovered by accident in 1879 when a Russian chemist was studying coal and tar. Now the story goes that he was working with his chemicals, got a little on his hand and decided to give it a taste and Eureka! 

We have our first sugar alternative, which sounds like a very risky way for a chemist to behave. I'm a little skeptical that this is the story, but there you go. And within a few years, it had hit the market and was widely used during world war I, because sugar was in short supply.  

[00:01:35] Sarah Berry: Great. I didn't know that Jonathan, that's really interesting. 

So you know, it didn't stop after world war I, the development of sweeteners, there were more that were invented or discovered, and they've become a regular part of our diet. As manufacturers have started to include them for some time now in more of the food and drink, we regularly consume. Mainly in an effort to reduce the energy and also the sugar content of food. 

So when we speak about alternatives, a lot of people instantly think of diet soft drinks, which are where these sweeteners are most commonly seen by consumers. But it's really important to note that a whole wide range of foods use sweeteners that most of us probably aren't even aware of.  

[00:02:12] Jonathan Wolf: That's right. And I'm now increasingly amazed by how many foods when I look at the detail of the food wrapper, turn out to have sweeteners in them. 

But if you'd wanna understand how sweeteners work, basically they fool our sweet taste receptors into thinking that we're eating sugar. And some of them can provide the same intense sweetness that we get with sugar and they can deliver all of that taste in far lower portion sizes than you would do with sugar. 

[00:02:33] Sarah Berry: Yeah. And something to be aware of, Jonathan is that the term artificial sweetener is probably a little misleading when we talk about sweeteners because not all of them are artificial. Some sweetness occurs naturally such as Stevia. Some contain some calories, so are nutritive and some are non-nutritive and have no calories. Importantly, sweeteners differ from one to another, depending on how they're processed by the body. 

So how they're metabolized. So it's really important not to group all sweetness into one category and this is unfortunately often done when considering their health effects in research.  

[00:03:06] Jonathan Wolf: So basically you're saying as always it's complicated Sarah?  

[00:03:09] Sarah Berry: As always Jonathan. Yes.  

[00:03:11] Jonathan Wolf: And am I right that some of these naturally occurring sweeteners have been used for a long time? 

[00:03:16] Sarah Berry: Yeah. So sweeteners like Stevia which is, as you say, naturally occurring and native to Brazil and Paraguay. And it's believed that they've been used for around 200 years and Stevia especially has seen a massive increase in the last decade since it was made legal in the EU in 2011 and the US in 2008. 

And Jonathan, I think something really important to say is that there is a whole host of different sweeteners, but the four most commonly consumed sweeteners in terms of artificial sweeteners are called as Aspartame, ACE-K, Saccharine and Sucralose and the type of sweeteners used vary from country to country and also vary depending on the products and what I think really surprised me when I was researching this is that diet Coke. For example, you drink in the USA has a different kind of sweetener than the one that you buy in England. 

[00:04:05] Jonathan Wolf: I remember when we were looking at things between the US and the UK and just all this added complexity of like, even when they say the food's the same, you know, it can have different sweeteners. 

And people said 'these sweeteners are completely inert' it doesn't matter. But if you start to realize, as we're discussing, that maybe they have some impact, then these two products might not be the same. So we have these food and drinks where the sweeteners in them are obvious because the food is marketed as low-calorie or no sugar products. 

And then we have these sweeteners that are hidden in everyday things that we eat that are processed. Why do we consider using artificial sweeteners at all, instead of just using sugar?  

[00:04:41] Sarah Berry: So sugar is something we know has unfavorable long-term effects when we consume it in excess, which unfortunately the majority of people in the Western population do. 

And these include everything from obesity, diabetes, and many other chronic, ill effects.  

[00:04:58] Jonathan Wolf: So, I guess the idea is if you could find an alternative to sugar that would reduce your overall sugar intake, then that should be beneficial.  

[00:05:04] Sarah Berry: Yeah and there are two key arguments for using artificial sweeteners. 

The first is that sugar substitutes have significantly fewer or no calories compared with real sugar. So it stands to reason that for people wishing to reduce their calorie intake. So their energy intake, swapping full sugar drinks for artificially sweetened drinks would be a good move. For those individuals to reduce energy intake. 

The other argument is that replacing sugars with artificial sweeteners will prevent the large peaks and dips in blood glucose. That's typically seen after we eat sugar or any refined carbohydrates. And we know Jonathan from our own ZOE PREDICT research that these large peaks and dips in glucose are associated with really unfavorable health effects such as increased inflammation, elevated hunger after we've eaten and increased energy intake in the subsequent few hours.  

So anything that can improve blood sugar control and these peaks and dips in general is gonna have a positive impact on our health.  

[00:06:00] Jonathan Wolf: And I imagine on top of all of this, they're better for your teeth too? 

[00:06:03] Sarah Berry: Yeah. So as a mum to two young kids who are partial to too much sugar, I'm happy to say that there's good research showing that specific artificial sweeteners, particularly xylitol, can have a positive effect in relation to oral health.  

[00:06:18] Jonathan Wolf: So what about the other side? There was a time when you couldn't open up a newspaper without seeing headlines about the cancer risk linked to artificial sweeteners. Was there ever any science to back up these claims?  

[00:06:28] Sarah Berry: I think let's take a step back and think of the four main arguments that I typically think are used against the use of sweeteners. And we can dive into each of these very briefly. So one is that, as you've said, they may increase the risk of cancer. Two is that they impair the effect of glucose control. Three is that they may modify our microbiome composition. So this is the ecosystem of trillions of bugs in our gut that we know are important for our health and four is that they increase the desire in people for sweetness, which ultimately over time might encourage the intake of other sweet foods containing sugar. 

[00:07:04] Jonathan Wolf: So maybe let's take that step by step. So starting with the risk of cancer that I remember reading about when I was younger. So again, we took a look at this Cancer Research UK and the US National Cancer Institute are on record saying that there is no increased cancer risk regarding artificial sweeteners. 

Overall the evidence that links cancer and sweeteners turned out to be thinner than initially feared. I think a lot of those concerns are still attached to the product. People still have some of these fears, despite evidence that today there's really not the data to link about that. 

What about the effect on blood glucose control and the microbiome? 

On paper, you would think a sugar alternative. That means you don't have these blood sugar peaks and dips, you know, should be really good, particularly with people, for example, with diabetes, or prediabetes.  

[00:07:50] Sarah Berry: Yeah. There's been a lot of research in mice showing that sweeteners impair glucose control.  

[00:07:55] Jonathan Wolf: Which is shocking. Right. So the reverse of what you would expect.  

[00:07:58] Sarah Berry: Yeah, the problem is there hasn't been as much research in humans, but interestingly, a paper that just came out this week from the Wiseman Institute showed that two particular sweeteners, sucralose and saccharin impaired blood glucose control while aspartame and a control had no effect. 

[00:08:18] Jonathan Wolf: That's fascinating. So they've been able to measure some real effects on human beings. And as you said, it's complicated because not all the sweetness was the same. So one thing we haven't mentioned yet is the effect of sweeteners on weight. And I think we do have to touch on that because the whole idea of a diet soft drink is that you aren't drinking all of those calories. 

If you believe in calorie counting, then people should have lost weight, right? As they swapped out their full sugar, Coca-Cola. For diet Cokes. So, you know, Sarah did it, did it work?  

[00:08:49] Sarah Berry: Um, so Jonathan, yet again, I have to say that we just don't know. Unfortunately, there have been loads of clinical trials on this overall, the evidence, in my opinion, suggests that changing from full sugar drinks or foods to low-calorie alternatives with artificial sweeteners will have either no effect or only a small effect on energy intake and body weight. 

So whilst having an artificially sweetened drink between meals might reduce your energy intake within that few hours at that specific point in time, studies tend to show that over 24 hours, we tend to maintain the same amount of energy intake. Irrespective of whether we swap our full sugar drink with an artificially sweetened drink. 

[00:09:38] Jonathan Wolf: So Sarah, after all of this, in your opinion, Sugar or sweeteners.  

[00:09:44] Sarah Berry: I think this is a really tough one, Jonathan because I think without a doubt, we know that we are consuming too much sugar in the US adults consume an average of 77 grams of sugar a day in the UK. It's around 56 grams.  

[00:09:56] Jonathan Wolf: Which is a huge amount of sugar. Right. If you imagine it just sitting in a bowl in front of you, right?  

[00:10:01] Sarah Berry: Absolutely. It's way above what the recommended amount is. So we need to reduce our sugar intake full stop. It has to be reduced. What are we gonna replace it with? Well, ideally we would swap our full sugar Coke with water, or maybe even some kind of milk, but the reality, is people want to make swaps that have the same functionality, whether it's the same consistency or the same taste.  

So an alternative, therefore, is going to be that artificially sweetened drink. I think in that instance, it's better than the full sugar drink 

[00:10:33] Jonathan Wolf: And I think I would probably be slightly stronger, Sarah, which is never going to surprise you, which is that. 

I think about this a little bit as a big scientific experiment over the last 40 years, which basically has failed. If you think about the starting point of this, I think there was a great reason to believe that if you could swap out all of this sugar with this sweetener you were gonna collapse the number of calories that people would drink and therefore it would have this transformational effect on obesity, which is there was already a concern. And, the period, when you really saw the rise of these diet drinks, we actually saw obesity going up even faster than before. So I think that this failed, we don't really understand what impact this is having on, our microbiome. And it makes it hard to manage that. 

If you think these are foods that don't have that. Where I think in many cases it might have been much better to have a much simpler product that had some sugar in it than something that has been swapped out for sweeteners. So am I far too radical here?  

[00:11:25] Sarah Berry: No, I think that's a really important point to pick up on there that so many sweeteners are hidden. 

And the Wiseman study that I referred to earlier specifically recruited people that said that they do not consume artificial sweeteners. They then monitored their diet to see what foods they were consuming. And they had to exclude the majority of the people. So recruitment was hard for the study because people who thought they weren't consuming artificial sweeteners were in all of these products where they're hidden. 

[00:11:54] Jonathan Wolf: That is amazing isn't it? We're living in this environment where we're trained for these incredibly sweet tastes, we're pushed towards these foods that tend to not fill you up for very long, partly because we've moved to a lot of sort of high carb, low-fat foods. And so, yeah, I agree with you drinking these full-sugar drinks is shocking. 

If you see what happens to your blood sugar, we know that those peaks cause hunger later what's interesting? Therefore why aren't these sweetened drinks more successful? So if they aren't leading to much lower weight gain, there's gotta be some balancing things that aren't good. So my view would be to try and avoid it where possible. 

[00:12:32] Sarah Berry: Okay. So my view is, to watch this space for more evidence. If I was given the choice, I would say to opt for water or milk, my second best option would be an artificially sweetened drink and I would choose that above a full sugar drink.  

[00:12:49] Jonathan Wolf: I think you've convinced me, Sarah. And I think we should follow up on this topic soon because it feels like this is one of the areas where the science is swiftly changing and we're saying something quite different than we would've said even a couple of years ago and sounds like that's continuing. 

[00:13:04] Sarah Berry: Yeah and I think calling something healthy or unhealthy, we need to be a little bit careful. I think what we can say is whilst there is no evidence to show that artificial sweeteners are healthy for us on balance, I believe the evidence would show that they are a healthier alternative to a full sugar drink.  

[00:13:24] Jonathan Wolf: I think that's a brilliant conclusion to come to Sarah as always. Thank you for taking us through this complexity and this minefield. We will return to this topic again soon. If based on this conversation, you are interested to understand more about your own body. Do you think about trying ZOE's personalized nutrition program to improve your health and manage your weight? 

You can get 10% off by going to I'm Jonathan Wolf.  

[00:13:48] Sarah Berry: And I'm Sarah Berry. 

[00:13:49] Jonathan Wolf: Join us next week for another ZOE podcast.