Recap: The truth about artificial sweeteners | Eran Elinav & Tim Spector

0:00Hello, and welcome to Zoe Recap, where each week we find the best bits from one of our podcast episodes to help you improve your health. Today we're exploring artificial sweetness. Back in July 1982, Coca-Cola launched a groundbreaking new product, Diet Coke, a healthier alternative for those Coke fans looking to cut back on sugar and manage their weight. Sounds great, right? Well, maybe not. You see, Dark Coke and many other low-sugar drinks rely on artificial sweeteners. And while they were once seen as a smart swap, emerging research is raising serious concerns about their long-term effect on our health.

0:39In this episode, I'm joined by Professor Iran Ilanaf and Professor Tim Spector to break down the latest science and explore how these sweeteners impact our gut microbiome. What is an artificial sweetener? Why do they exist? So artificial sweeteners, which are currently re-termed non-nutritive sweeteners, are a very diverse group of chemicals that feature a very intense sweet taste. In other words, they are much better than natural sugar in engaging and inducing taste receptors, which lead to our brain interpreting their tastes as intensely sweet. So there are hundreds of times sweeter than natural sugar.

1:27And these artificial compounds were developed and discovered over a century ago as means of satisfying people's sweet tooth without paying the caloric price. So I think the first of these compounds was saccharine, which was discovered over 100 years ago, and it was used as an inexpensive and intensely sweet substitute to sugar. These compounds have been extensively integrated into human diet with the hope and belief that we would generate this pleasurable, intense, sweet taste to many of our foods. So these compounds can be found both as independent additives to coffee and so on and so forth. But also, if you were to go to your local supermarket and look at the ingredient links of many foods, you would find these compounds integrated in many cases without explicitly telling the consumers that they're there.

2:29It's actually very hard and very difficult. It was one of our biggest challenges to find individuals who are not exposed to these compounds in their daily lives. And there's a huge range of them on there. As well as saccharin, which was the early ones, which came, I think, from the petroleum industry. A lot of these come from basic organic chemistry rather than as foods originally discovered by accident. Then you've got the aspartames, the sucraloses, the ACE-Ks, all the sugar alcohols, things like xylitol. Also some newer ones, monk fruit, neotame. there's an increasing list of these that are often used in combination now even with sugar so that's why it's very hard for you know people to work out what they're eating is because they're often mixed up now and very hard to separate them.

3:24Iran I'd love to switch to your research now you know very few people are actually doing studies on the microbiome in human beings where they're able to really understand specific impact of specific foods. That's obviously something that is really fascinating to me and I think lots of listeners. Could you tell us, you know, I think you're saying you started with this idea that these artificial sweeteners were inert. They didn't have any impact on us. What has your research shown? We started in exploring the possible impacts of these compounds, of these sweeteners in animal models, specifically in mice, which are very controlled settings that we can learn a lot from that are not as complex as human beings and as diverse.

4:08My graduate student, now an independent researcher in his own right at Hopkins in the U.S., designed an initial experiment in which he gave high doses of some of these compounds into mice that have never, of course, seen these compounds. And to our astonishment, his results were that these mice were developing a higher tendency to develop disturbances in their blood sugar control. They were kind of leaning towards the development of diabetes. He showed me these results. I did not believe them. Of course, being a skeptic scientist, he repeated them again and again and again. And this was very, very reproducible.

4:52And this was the first eureka moment, which taught us that something in the body of these mammals, of these mice, was actually reacting to these seemingly inert compounds in ways which could be detrimental to health. And this started a very long journey in which we, at the beginning, mainly focused on one of these compounds, which is called saccharine. It's the granddaddy of all artificial sweeteners. It's actually very popular as a sweetener in Israel where we performed studies. And we really dove deep into this one compound, tested it in different doses, including doses that are equivalent to the lower doses that humans consume, different mice, different genders, and so on and so forth.

5:42In all of these cases, we found that in mice housed in our facility that carry a specific microbiome, the consumption of saccharin was associated with a quite remarkable tendency to develop disturbances in sugar control, to develop diabetes. You're saying that you took these mice, you were just giving them this artificial sweetener. You weren't giving them any sugar or doing anything else that was changing their diet. You were just giving this artificial sweetener, which we've all been told doesn't do anything in our body. It tastes sweet, it goes through. And in these mice, you actually ended up giving them diabetes, which is a disease that I associate with having lots and lots of sugar and other sweet food.

6:22Is that right? Yeah, that's absolutely right. And this occurred when we gave these mice different diets. For example, a diet reminiscent of the Western diet, full of fat, or in healthier diets. And this seemed to be at least in our facility. And the question was, since this compound has been known and studied for a century, and we know that the mammalian cells, the mouse cells, and the human cells probably don't digest it, how do the consumption of this compound result in this diabetic effect? And this is where the microbiome came in. And we started looking into the microbiome because this is what we do in life.

7:05and we found to our surprise that the microbes were actually reacting to this compound and we could even induce diabetes by taking the microbes from the guts of mice that were consuming saccharine and transferring just the microbes into mice that have never seen saccharine. These recipient mice developed diabetes proving that the microbiome was actually driving the effect. This was a very big eureka moment for us leading to the publication of of our findings in nature in 2014. And as you can imagine, this generated a lot of discussion that spanned outside of the scientific and medical communities.

7:48And one must also mention that in this initial study, we've also performed a very small preliminary study in human volunteers who were given saccharine. and we found that half the people who were exposed to saccharine didn't care at all. They didn't change their blood sugar control. Their blood sugar levels were completely the same. But the other half of these individuals developed marked disturbances in their blood sugar control even after a week of exposure to this compound. None of the individuals in this small preliminary trial actually improved their blood sugar control. This was a very counterintuitive, but a very important moment in this type of study, because it told us something very fundamental, not only about artificial sweetness.

8:38It taught us that rather than quantifying foods or food components in their ability to induce changes in the human body or in the mouse body in this case, we need to start thinking about how to quantify the recipient, the people who actually consume these compounds. And this goes against the one-size-fits-all dietary paradigm that was prevalent for 50 years before this and led to the personalized nutrition concept which was developed. And artificial sweeteners in our hands were the very first example of these personalized microbiome-driven effects that dictate why one person would react to a given food while the other person would not react to the same exact food, even when it's consumed at exactly the same quantities.

9:31So imagine that you're saying that both Coca-Cola and our diet Coca-Cola is off the table and same for all the other manufacturers, but there'll be a lot of people saying, well, it's really hard to switch from that to water because I'm really used to all of these sweet tastes. Do you have like an easy tip for how to transition off those drinks for anyone who's listening? Well, most of us have done this when we were kids. I used to anyway have tea with about four spoons of sugar in it. when I first started having it. And gradually, you just dial it down so that you can go to three and then to two and then to one.

10:09And I think the same is true with these products. You need to wean yourself off, I think, that amount of sugar. And once you've done that, they're too sweet for me to actually have them now. We do have these thresholds for sweetness that we can manipulate ourselves and get used to more bitter tastes and sour tastes and fermented drinks and things like this are an important way. So I think teas, kombuchas, and diluting down these products gradually to get yourself off them in a few months is probably the way to do it. Professor Sarah Berry here. We've all experienced that familiar 3 p.m. slum, that moment where your energy dips and you find yourself aimlessly rummaging through the kitchen for a quick fix.

10:59Biologically, that typically happens because highly refined, soft textured processed foods can cause rapid, sharp peaks and subsequent drops in circulating blood sugar. Our data shows that these kind of sharp drops can actually leave you seeking out more energy, forcing you to ride a metabolic roller coaster that can drive people to consume an average of 300 extra calories later in the day. To address this challenge, the team developed the Zoe Gut Health Bar. It's a snack bar built with over 10 distinct plants formulated by our scientists to offer high plant diversity. When making this bar, our primary objective was to break the rollercoaster cycle.

11:40We prioritised the food matrix, leaving as many of the natural plant structures as intact as possible. Because the structure isn't broken down by heavy processing, the nutrients enter your system at a much more measured, predictable pace, supporting a steady release of energy. And we topped it with real dark chocolate or raspberries and goji berries, proving that prioritizing your gut health can also hit the exact right note you're looking for in a snack. Find out more about the gut health bar at zoe.com forward slash snack bar.