Sweeteners, seagrass, and sterilised plastic

How sweeteners could cause risk of cardiovascular disease, and a new antibiotic found in trees.
27 September 2022
Presented by Will Tingle
Production by Chris Smith.


A spoon with white sugar on it


In the programme this week, we look at the plastic that sterilises itself, why sweeteners are worse for you than sugar, and how will seagrass react to climate change?

In this episode

Breast cancer awareness pink ribbon

00:45 - New personal breast cancer screening device

An award-winning, innovation helps women perform breast self-examinations to screen for cancer

New personal breast cancer screening device
Debra Babalola, Imperial College London

James Dyson - of cyclonic vacuum cleaner fame - runs an international design award competition that's intended to inspire the next generation of design engineers. In his words, it's a "chance for budding inventors to make a name for themselves." The results from the latest round have recently been announced, and the UK's winner was an entry from a team at Imperial College and the Royal College of Art. The concept they've come up with is called "Dotplot", and it's a handheld device to help women perform breast self-examination. Debra Babalola told Chris Smith what inspired them to come up with the concept in the first place, and how it works...

Debra - Dotplot is all about eliminating the confusion and the misconceptions around performing breast self checks. There are lots of tools out there to help people monitor different aspects of their health. But when it comes to breast health in particular, there aren't any at home solutions or devices that people can use to keep on top of what is going on within their breast tissue. And it's quite important, obviously, because breast cancer is so prominent. And of course, as the earlier you detect any developments within your breast, the better and people are relying on things like pamphlets and demonstrations and tutorials, which are quite limited in the guidance that they could provide. And so there's lots of different methods out there. It can be really confusing. People don't really know what they're supposed to be checking or where they're supposed to check or how they're supposed to do it. So we just wanted to make that process as clear as possible.

Chris - And how have you done that?

Debra - So we've developed Dotplot, which is a tool that women can use to check their breasts each month. It basically brings together a handheld device and a mobile app, and it will guide you through the self-check step by step. So what we have is that you would put in your general health information on the app. So like your menstrual cycle, your age, your height, that kind of thing, to help predict the best time for you to be doing these self checks. And then you will build a map of your upper chest or your torso using the device, you would select your breast shape, put your bra size and then use the device to rescale the baseline model that we've got over a standard torso. And once that's all set up, we will guide you through the self check by flashing on the point that you need to press the device on. And then once you've checked over that point, you'll go onto the next part of your breast. And then the next part, and the next part until you've covered all of the regions that need checking over.

Chris - So I'm thinking I've got a mobile phone in one hand, your gizmo in the other hand that I'm gonna use to do the self check. How big is the device that actually does the registration and the analysis of your tissue as you move it over your body?

Debra - Well, it fits within the palm of your hand and is similar to the size of an average bar of soap.

Chris - And that is talking to your mobile device.

Debra - Yes, it is by Bluetooth.

Chris - And so what the phone is doing is processing and telling the device record now, and the device is doing exactly that to make the measurements.

Debra - So the device is, what's kind of speaking to the phone. So the device will be emitting sound waves, which will then be used to take readings of the breast tissue. So you press it against your chest, it will take the reading and then that will be recorded on the phone.

Chris - How do the soundwaves tell what's underneath the surface of the skin?

Debra - Your breast tissue kind of acts as a filter and because the device will be pre-trained on, say, like a thousand women. And so we would've trained it to say, okay, this is what this, the readings will be like, if there is a lump present or if there isn't anything present. And so, depending on what the density of your tissue is underneath that point, that you're checking over the readings will be different.

Chris - Is it a bit like when you go for a baby scan and we use ultrasound, it's using sound waves and looking at the echoes that come back to work out the underlying profile of the tissue.

Debra - Exactly. That's it. Yeah. It's very similar to ultrasound. It just uses a different frequency.

Chris - How good is it at picking up the architecture of the tissue?

Debra - So right now we haven't actually tested it on human tissue at the moment, but we have done it on breast models that we've made within the labs. And then we've embedded lumps between three millimeters to eight millimeters within the models of the breast tissue. And it's been able to identify every lump and also find differences between areas that do have lumps and then areas that don't, and that's that 90% accuracy for detecting whether there is a lump present, but the next step would then be testing on women.

Chris - How deeply do you think it will be able to see into the tissue? Because obviously women come in different shapes and sizes. There are some with very small breasts, some women have very large breasts and that could be a challenge. Couldn't it get it to see deeply enough?

Debra - Yeah, definitely. But I think that's also why we want women to be applying pressure to their breasts as well. So it kind of flattens the area that the distance that the sound waves will need to cross, but also we are trying to do it. So no matter how big your breasts are, it can reach the front of your ribcage.

Chris - You mentioned earlier that you put in your menstrual cycle. I mean, that's important, isn't it? Because breasts and breast tissue go through cycles of growth and then shrinkage during the menstrual cycle, which can be confusing. It can make your breasts feel lumpy from time to time. So is there not a danger with this that it could make some people into the worried well?

Debra - So we ask for the details of your menstrual cycle. So we can tell you the best time for you to do it. So most GPS recommend that you do a self check, like a few days after you've had your period, because then all the chemicals and hormones are more relaxed within your breast tissue and that they tend to be less lumpy. So that's kind of why we want to take that information so we can predict the best time for you to prevent, you know, picking up any lumps that aren't really problematic. And that's also why we compare monthly readings just to make sure that if there are, you know, changes that you need to be aware of, well, we flag those. And if it is just a lump, that's, lumpy because your breasts are lumpy during the month, it is not likely that you'll pick that up in the following month.

Chris - So you would effectively get a profile, which it can compare one month with the next, and if you've got an area that might be a bit sinister, it's gonna say, well, that hasn't changed. This is the one to look at. And then I suppose you could take that to your GP and say, I'm a bit worried about this area. Could you have a look as well?

Debra - Yeah, that's exactly it. That's exactly what we would do. So yeah, you're comparing them and they were highlighting any changes and encouraging people to go into, get them checked clinically. If the changes do persist,

Chris - Given that you've got this working potentially for one very important part of the body, there are others that also we're encouraged to self-examine men are encouraged, especially young men to examine their testicles, to make sure they haven't got testicular cancer. It strikes me that you could do the same thing with that, couldn't you?

Debra - Absolutely. Yeah. That is one of the goals. I think once we've got the technology working really well for detecting lumps within your breast tissue, we definitely want to adapt it to early detection of other cancers and diseases as well. So yes, that is, that is the goal.

Crystals of sugar

07:43 - Are sweeteners worse for you than sugar?

A new study has linked sweeteners consumption to an increased risk of cardiovascular diseases

Are sweeteners worse for you than sugar?
Mathilde Touvier, NutriNet-Santé cohort

Much of the food and drink we consume these days contains artificial sweeteners. They most commonly appear in sugar-free soft drinks, tabletop sweeteners for our teas and coffees, and dairy products like yoghurt. These chemicals and additives allow food companies to make products which have a sweet taste without pumping them full of sugar. But now a study published in the British Medical Journal connects a high rate of consumption of these sweeteners with cardiovascular diseases among 171,000 French participants. James Tytko spoke with Mathilde Touvier, Doctor in Epidemiology in Public Health, and principal investigator of the NutriNet-Santé cohort.

Mathilde - During the follow up of about 1,500 incidents of cardiovascular diseases occurred. And to give you an idea in the group of the highest consumers in this cohort, there was the equivalent of 346 incident cases for 100,000 participants a year followed compared to the equivalent of, 314 cases in the non-consumer group. But really the important point here is that the association between artificial sweeteners and increased cardio disease risk was robust and statistically significant in analysis models.

James - I read recently that around half of an average person in the UK's calorie intake is ultra-processed food and drink and that's food that's most likely to contain these artificial sweeteners.

Mathilde - Yes. In France, the proportion of energy brought by ultra-processed food is about 30, 35% so lower than in the UK or the US, for instance, which is more than 50, 58%. But yes, indeed participants who enter these cohorts also tend to have globally healthier health behaviors in, and also dietary intake. So we make the hypothesis that in real life, in a real population setting, and maybe in the UK, we would have even higher amounts of exposure to ultra-processed food. So maybe the associations in real life would be even stronger than the one we observe in the cohort yet it's still an hypothesis that we will never be able to verify. But yes, it would be possible to think about that.

James - It seems to me, there's a growing body of evidence to suggest that ultra-processed food is having a severely negative impact on public health. And a lot of these diseases are related, aren't they, to Obesity and cardiovascular disease, but yet they're still so prevalent in all of our diets. When are the food standards agencies going to do something about this public health disaster that it feels like we are sleeping walk into?

Mathilde - Research interest in ultra-processed food. And so the epidemiological studies about that are quite recent. We now have about 50 studies showing an association between ultra-processed food and adverse health outcomes. Yes, indeed. Evidence is accumulating. We still don't know exactly and precisely, within these ultra-processed foods, what are the substances, the types of additives or other substances and contaminants created during processing or contaminants from food packaging and so on which substances may cause problems. And so this is really what we want to investigate now, and to advance knowledge on this topic. Even if we don't know exactly where the problem comes from, from which substances and so on to reduce this overall intake, there are already some countries in Brazil, in France, which have already introduced this in their official recommendation. The fact that ultra-processed food intake should be reduced in the population. This is one type of action recommendation to the population, but the other one would be to act on the regulation of the products. It can't be to forbid ultra-processed food. This is why we need some precise research saying this type of molecule, this type of additive and so on may cause a risk for the population.

James - Are there any potential obstacles in the way of limiting the presence of these additives? I'm imagining some potential corporate interests that might slow the progress.

Mathilde - Even when scientific evidence is very, very strong, which is not the case for the moment. I mean not only with this study, but with the topic. When we begin to have more and more scientific evidence, there are often barriers from powerful lobbies and the food industry that don't want things to change and see these type of results that are not in line with their economic interests. So it's not always easy. We really had the case currently with the food label nutrient score, this food label provides an overall idea of the nutritional quality of the food product. And so it's very useful for citizens that don't have the time to read the labels, which are very complicated and so on. So here at the glance, you have the idea of the nutritional quality of the food with the very simple color label. And so there is a strong battle between science, which validated this logo with epidemial studies and experimental studies showing that participants are more inclined to select food healthier for their health. They understand the way that we could rank produce against nutritional quality, but yet various strong barriers by the food industries really don't want this logo to be put on back. So, and here, of course, with food additives, we have the same kind of opposition with some industries that don't want to remove these additives from their process. And so it's not always easy to win the battle of public health against economic interests.

A pair of plastic gloves

13:22 - A new self sterilising plastic

A new method of treating disposable plastics to reduce the amount of harmful diseases on them.

A new self sterilising plastic
Andrew Mills, Queen's University Belfast

The spread of infections in healthcare settings is a major problem. Dirty hands are one source, but equally, surfaces like gloves and aprons, and other single-use plastics can also pick-up and pass-on bacteria and viruses through contact. As he explains to Chris Smith, Andrew Mills, from Queen’s University Belfast, had the bright idea of adding something to plastic that reacts with light to produce a bleach-like substance on the surface that can wipe out contaminating microbes…

Andrew - I knew that there was an awful lot of disposable plastic materials that were used in the healthcare industry that provided a clean surface, but rapidly got contaminated. And of course, I also knew that one of the major ways that viruses and bacteria are transmitted in a healthcare environment is by landing on the surface. And then you touch that surface. So I wanted to imbue these plastic disposable materials with extra value, and that value will be the ability to self sterilize.

Chris - How?

Andrew - It's really neat. You can put pigment particles into them, really inexpensive. They are basic pigment particles used in paint, it's titanium dioxide, but in paint, they actually coat the pigment particles so that they don't actually do any photochemistry. That means they don't interact with light and then generate things on their surface that would do damage to the polymer because you don't want your paint falling off. But here we do. We want those pigment particles to actually absorb light and then destroy anything that's on its surface. So that's what we do. We use naked titanium dioxide particles, put them into plastic and they're able to destroy viruses and bacteria in particularly, most notable these days SARS-CoV- 2

Chris - Something similar has been done with self cleaning glass. Hasn't it? I think King's Cross station in London was one of the first places to do this where by adding dioxide particles to the glass, it then reacts with the ambient light to produce nasties that blitz the dirt. So you basically endowed a plastic bag with what they did at Kings cross.

Andrew - Exactly.

Chris - The difference is that at King's Cross station, the sunlight shines hopefully some of the year on the glass. Your plastics, if they're in a clinical setting, as you're advocating for, they're gonna have just artificial light. Is there enough energy in that light to make this work?

Andrew - That's a really good point. The interesting thing about these pigments is they really don't need very much to make them quite reactive and certainly reactive enough to generate the small level of bleach, which is effectively what it does on the surface to destroy a virus or a bacterium. You only need to damage them before they die. So the question is, is there enough? And the answer is, yeah, there's window light. And there's a bit of UV light that comes in there. But also a lot of fluorescent tubes, well all fluorescent tubes, actually emit a small amount of UV. And so when we were doing our trials, we were using room light, fluorescent lamps and very low UV light associated with that coming through windows. One of the things that really surprised us was both worked, but actually the room light one worked really well. We thought it was going to be so small because there really is like a micro watts centimeter squared of UV falling onto the surfaces, but actually they seem to use them very well. And then it was sufficient to destroy the kind of levels of bacteria and viruses that we were looking at.

Chris - The chemistry that's going on then? The UV light that's coming from, whatever source hits this titanium dioxide, how does it then turn into, you dubbed it bleach? What does it do when it hits the titanium dioxide to then produce something capable of destroying microorganisms?

Andrew - So when you shine light onto these pigment particles, you create bleach light molecules that can destroy viruses and bacteria.

Chris - And what sorts of microorganisms will they knock out in your plastics?

Andrew - We tried it with SARS- CoV-2 and it worked very well for them. And also the influenza virus. We looked at some other viruses as well. It actually worked for all of them.

Chris - Can you turn the plastic into a range of different things? Is it actually plastic that you could use the same way? We love using plastics, can you turn it into any kind of shape, size or characteristic within reason?

Andrew - You can and a lot of people have used the same technology to create things like mobile phone covers and keyboards for computers. We are not so much in favor of that because once you start handling it, you put on sufficient coating of all the sweat and the grease and whatever it is that you've got in your fingers, the then it overwhelms the ability of this material to keep itself clean, disposable plastic materials, where you are worried about the micro droplets that are coming from your breath, falling on it and then transmitting those viruses or bacteria to some other person. This is what this technology is targeting.

Chris - Is it easy to do Andrew? To make this? Because obviously one of the big attractions of plastics and one of the reasons it's such a scourge now is because it's really cheap. So does this enormously increase the cost burden of making these things? Or is it very easy to do?

Andrew - I'm sorry, I interrupt you because of my enthusiasm for it. We use extrusion to make these, there's nothing special about this. You just, when you're making this thing, instead of adding one pigment, you add our photo-active pigment. That's the only difference. And the photo-active pigment pigment is that used or behind it is that used in paint. So it's incredibly inexpensive. It will not add any great cost to a penny. Maybe, even less than that, to what the existing cost of that apron or that tablecloth or that curtain is at present. The beauty of this is that it has this extra value, this extra ability to keep you safe and well.


20:19 - Will seagrass adapt to climate change?

The survival of seagrass could be tied more to their past than their future...

Will seagrass adapt to climate change?
Emmett Duffy, Smithsonian Institution

Seagrass is a vital source of carbon storage. In fact some species of seagrass are able to capture carbon 35 times faster than areas of tropical rainforest. Even so, seagrass only covers 0.2% of the seafloor and so maintaining its existence is paramount to fighting climate change and preserving species. Emmett Duffy, from the Smithsonian Institution, has been speaking to Will Tingle on the importance of seagrass to both marine ecosystems and humans alike, as well as the new research highlighting how climatic pressures could affect their populations going forward…

Emmett - I think of sea grasses as the Serengeti of the sea. These are big expanses of underwater grasslands that are also highly productive and support lots of wildlife, as grasslands do on land and the foundation of these ecosystems are sea grasses. These are not algae or seaweeds, but flowering plants with roots that invaded the sea millions of years ago. They are critical to ocean wildlife, lots of large animals - dugongs, manatees, sea turtles depend on sea grasses. They're also essential nurseries for fishes, and particularly in parts of the developing world. Many people in coastal regions get a large part of their protein from fishes and shellfish that live in seagrass beds. And finally, they, uh, soak up carbon that our industrial society is exhaling into the atmosphere. So there's a lot of interest in so-called blue carbon capture by sea grasses.

Will - In the research paper, it's stated that there are two populations of eelgrass, one found in the Pacific and one found in the Atlantic. What is sort of so notably distinct between these two populations and how was that difference found?

Emmett - Yeah, a big surprise from our research was finding how different the seagrass looked in the two oceans. Eelgrass is distributed globally around the Northern hemisphere. And so understanding what makes it tick is a global problem. And we needed a global team. So we got 50 of our colleagues around the world together to sample the eelgrass using the same methods. So it would be comparable and we measured both the size and density and shape of the eelgrass, but also the genetic structure. We've known that there is a lot of genetic separation among various populations of eelgrass, which occurs all over the Northern hemisphere. But we found that the seagrass in the Atlantic was consistently shorter and denser. It lives in what we would call Meadows, whereas in much of the Pacific it's closer to forests.

Will - And was there any noticeable difference between the genetic strength between the two populations?

Emmett - Yes. So eelgrass originated, it evolved originally in the Pacific ocean and there's lots of genetic variation there because that's its ancestral Homeland, so to speak. And then sometime during the Pleistocene between ice ages, the eelgrass moved through the Arctic and colonized the Atlantic. And that probably involved only a small number of plants because the genetic diversity of eelgrass in the Atlantic is much smaller than it is in the Pacific. And what we've found is that much smaller genetic variation in the Atlantic is associated with this meadow like growth form. And so probably what happened is that the pioneers who made it across the difficult journey through the Arctic were small stature plants. Meadow forming plants from the edge of the Pacific.

Will - So with these two separate populations. If one is less genetically diverse or complex than one other region, do you think that the population in the Atlantic may be at more risk from climate change or other dangers to their existence?

Emmett - What we know is that the growth form of the eelgrass in the Atlantic seems to be constrained to being relatively short. However, the good news is that eelgrass is highly adaptable. It lives in all kinds of environments from open ocean coasts to the inner Baltic Sea and from the Arctic to Baja, California, for example. So it seems to be able to adapt reasonably well to different climates. It should be able to make it very well if we can control water quality and overfishing,

Will - These seagrasses sound like essential parts of the ecosystem to protect if they're so vital to Marine ecosystems and to our own food supplies. So what is the best course of action that you or I could do to help preserve these seagrass colonies?

Emmett - The biggest threat to eelgrass and other sea grasses throughout most of the world is coastal development and particularly poor water quality. These plants need a lot of light, so they need clear water and they only grow, uh, for, in most places in relatively shallow water. And we've seen success stories in Chesapeake Bay, in the United States, in Tampa bay, in the United States and a few other places where controlling runoff and pollution of the water has allowed the sea grasses to rebound and grow back again. So the best thing we can do is keep the water clear. And of course that has lots of other benefits as well.

Klebsiella Pneumoniae Bacteria

25:52 - Antibiotics that grow on trees

Antimicrobial compounds found in Australian Blushwood tree targets disease causing bacteria

Antibiotics that grow on trees
Jason Cullen, QIMR Berghofer Medical Research Institute

The announcement that scientists have uncovered a new family of antimicrobial compounds that are produced by the Australian blushwood tree is welcome news in the fight against a rising tide of antibiotic resistance. Very few new antibiotic drugs have been developed in recent years, for various reasons, meaning that we’re in increasing danger of succumbing to infections we can no longer treat. In tests, the new agents kill a broad swathe of disease-causing bacteria; they are also very effective at dismantling the protective “biofilm” that bacterial communities build to defend themselves from drugs and the immune system, meaning they can help make bacteria vulnerable to other antibiotics, and they boost the immune response and healing power of the tissue at wound sites. Speaking with Chris Smith, and from the QIMR Berghofer Medical Research Institute, Jason Cullen…

Jason - Essentially what these molecules do is they disrupt these biofilm structures, but then they can also stimulate a very good immune response, which enables a wound to sort of reset itself. And then you get a good wound healing response.

Chris - Tell us a bit more about these compounds then where do they come from?

Jason - One of our collaborators was quite interested in deriving therapeutics from the Australian rainforest. They came across these compounds initially as oncology agents, but, it turns out that they also work quite well in chronic wounds. They're derived from an Australian rainforest tree’s fruit and nuts.

Chris - What does the plant do with these compounds? Why does it make them?

Jason - They act as a bit of a deterrent to animals on the floor. So when the fruit drops off the tree, they'll eat the fruit, but then end up leaving the nut alone. But they may also have other benefits within the seed itself in order to stop any microbial sort of degradation of the nut.

Chris - How did you pursue it then? Once you had these compounds, how did you start to try to piece together what they could do against microbes?

Jason - Originally. It wasn't anything to do with microbes, but what my collaborators noticed is that one of these, similar looking compounds, which is being used to treat tumours. After it treated the tumour, you got this very nice wound healing response. There was also data from veterinary studies suggesting that this class of compound could actually close hard to heal wounds in animals. And so we set about just trying to understand if they would have some applicability in chronic wounds in the lab and ultimately help develop this for human applications.

Chris - So if it promotes wound healing, is it doing that just because it suppresses invading microorganisms that irritate the wound, or is it also doing something to the animal tissue that makes that more likely to heal?

Jason - Yeah, we think they work by a number of different mechanisms. One of them is that it appears to disrupt the bacterial biofilm. They're not actually antibiotic in a sense that they don't actually directly kill the bacteria, but they just disrupt these structures. And the other activities that we found here is that they can also stimulate a very good immune response. In addition to that, they seem to induce changes in these skin resident cells, which promotes a very good sort of wound healing response. So we think it's a mixture of all of these activities, which come together to help promote the closure of wounds.

Chris - Do they work against all classes of bugs or are they quite discreet because different horses run on different courses when it comes to antibiotics and some are very good at treating some classes of microbes and absolutely useless against others. Is this a comprehensive effect or are they quite focused?

Jason - We found that the actual main one that we're interested in can actually disrupt a lot of Gram-negative and some Gram-positive biofilms as well. Obviously they don't work on everything, but there's quite a broad selection that they do work on.

Chris - And the resistance problem. I mean, that's ostensibly why you are going down this path.

Jason - Yeah. So we think that these will help sort of circumvent the resistance problem because they're targeting bacterial virulence rather than the growth or survival of the bacteria. So in that sense, it sort of reduces the potential for the development of antibiotic resistance.


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