Energy drinks curb, and biting back against beetles
In this edition of The Naked Scientists: A new test to detect Alzheimer’s disease long before symptoms first appear. Also, the study showing Earth can sequester only a tenth of the carbon we thought it could. And, how drones, traps and sniffer dogs are protecting the UK’s timber industry from beetle attack...
In this episode
00:55 - Nations mull energy drinks ban for younger teenagers
Nations mull energy drinks ban for younger teenagers
Amelia Lake, Teesside University & FUSE
The government in England plans to ban under-16s from buying high-caffeine energy drinks. Health ministers say products - such as Red Bull and Monster - fuel obesity, disrupt sleep, and make it harder for children to concentrate in school. Some countries have already gone down this path, and others, like Australia, are watching closely and may follow. If a new law is passed, shops, cafes, and even online retailers will no longer be permitted to sell these drinks to younger teenagers. It’s a move that could affect thousands of young people and aims to tackle childhood obesity head-on. Amelia Lake is a professor of public health nutrition at Teesside University, and is also part of a research centre called FUSE- a group of universities which examines issues around public health…
Amelia - An energy drink is different to a regular soft drink because it contains caffeine and the threshold is more than 150 milligrams of caffeine per litre.
Chris - What does that mean though? Because Coca-Cola, Pepsi, they've got caffeine in them, haven't they?
Amelia - A cup of coffee might contain 80 milligrams of caffeine in a cup of coffee, a cup of tea about 50 milligrams of caffeine, a cup of cola 30 to 40 milligrams of caffeine. And then energy drinks, we are looking at those bigger cans, we're looking at 160 to 200 and sometimes even higher milligrams within that one can. So those larger cans, that is about two espressos worth of coffee in a can.
Chris - And the calories, how many calories are in a can of these energy drinks?
Amelia - Okay. So if we think about one of the larger cans like Rockstar Monster, they have around 230, 240 calories. So similar to cans of pop because they've got sugar in them.
Chris - Who is drinking them?
Amelia - These drinks have been one of the fastest growing sectors of the soft drink market, and that is globally. So this is a global issue and it's a global story. These are global companies and this is a big proportion of their global sales. About 1/3 of 13 to 16 year olds are having them once or more a week, also 11 and 12 year olds. So we know it's happening in younger children as well.
Chris - But occasionally during the week is arguably much less bad than if someone's got a regular habit. So is there evidence that there is extreme intake or that there's a rising trend towards more consumption?
Amelia - There is evidence globally around rising trends. There's evidence internationally, for example, I've just looked at data from Finland where it has been increasing year on year. And also the gender gap that there once was between boys and girls has completely narrowed, which is really interesting and is down to the marketing and advertising of these drinks. Given the fact that it is the fastest growing sector, the concern globally is that this is particularly in younger age groups and in under 12s. So looking at 10, 11 year olds.
Chris - And what sorts of health harms might be arising from this rising trend of use?
Amelia - We have reviewed the international evidence and we have found that there has been physical health outcomes associated with them. And that is what you might expect, stomachache, headaches, dental health impacts, cardiac issues, obesity in relation to increased calorie intake. And then in terms of the mental health factors associated with the intake of them, it is a whole range of issues through anxiety, increased stress, increasing depressive symptoms. And also the caffeine in these drinks impacts sleep, which is hugely important when it comes to every age group, but particularly adolescents and that growing brain and that growing body.
Chris - Do you think it's a symptom of lifestyle in general and other pressures on young people rather than just the prima facie cause here? Because a colleague of mine in Australia said that what she's seeing there is increasing numbers of young people who are staying up half the night playing computer games, socialising online, playing with smartphones, so they don't rest properly. They feel sleepy the next day, don't have time for breakfast. So on their way to school, they snag down a couple of tins of this stuff. It wakes them up, gives them a bit of energy because it's got calories in it. Then they crash at school later, having been up half the night, can't concentrate. But then come the evening, having slept it off, they feel perkier again. So they rinse and repeat and it's a vicious cycle.
Amelia - It is, absolutely. And our qualitative evidence actually supports that. So we know that that is what is happening, whether or not the energy drinks are at the crux of this and putting a sales restriction in place isn't going to magic wand that away. But there is a lot to be discussed around, for example, devices in bedrooms and just the importance of sleep. But using caffeine as a means of combating that sleep deprivation, adults do it. But now we're seeing younger and younger children do it. And there is a strong link between these drinks and computer gaming culture.
Chris - How practical is it to intervene in the way that the government are proposing to though? Because we've seen a number of things like sugar taxes and junk food interventions and healthy eating legislation's got more bits of policy around it than almost any other sector of science or health science. And it clearly doesn't work very well because of rising trends in terms of obesity, for example. So do you think that regulating these drinks in this way is practical and going to translate into any particular benefit?
Amelia - So if we go back to your question about policy, my colleague Dolly Van Tolleken and her PhD explored how many pieces of obesity legislation we'd had in the last 30 years, and there was nearly 700. And had it curbed obesity? No. So that's an interesting point. Around using things like the sugar drinks levy, that has been vastly successful and we do have some excellent evaluation of that. I think in this case, a sales restriction on energy drinks. First of all, we are not, with the sugar tax, the UK was a pioneer. With this, we're not a pioneer. Latvia, Lithuania, Poland already have restrictions in place. And those are for under 18s. Norway, it comes into place in January, that's for under 16s. So we're seeing a trend, there's a global trend in terms of restricting by age. We already restrict by age for many other things. So, you know, cigarettes, alcohol. In fact, we restrict by age for lots of things to do with children that don't actually have a scientific evidence base. They can't go in and buy aerosols or knives or crossbows or, you know, fairly sensible things, but yet they can walk in and buy a can that contains the equivalent of two shots of espresso.
08:43 - New Alzheimer's test aims to catch disease much earlier
New Alzheimer's test aims to catch disease much earlier
George Stothart, University of Bath
Alzheimer’s disease is a progressive brain condition that slowly erodes memory and thinking. It often creeps up on people unnoticed for up to twenty years. But by the time symptoms do appear, treatments can usually only slow the decline by a modest amount. But researchers in Bath and Bristol believe they may have found a way to detect Alzheimer’s much earlier. Their three-minute brainwave test can spot memory problems in people with mild cognitive impairment, a condition that often precedes Alzheimer’s. The study has been led by cognitive neuroscientist George Stothart from the University of Bath…
George - Currently, we have to wait for people to turn up at their doctors and say to the doctor that they think something's up. Now, unfortunately, that can take a very long time to reach that tipping point for people. So often it's taken a crisis to occur in that person's life, that they perhaps they found that they can't do their job anymore, or they have got lost when they've left the house. The problem with that, from a medical point of view, is by the time that's happening, the disease has already done an awful lot of damage to that person's brain. And it's really too late to start doing anything about that disease. And so we want to be able to pick up that disease much, much earlier. So we've developed a new test, which is called Fastball. And it's a very quick three minute test that's entirely passive. So what that means is the participant doesn't have to do anything. All we ask them to do is watch a screen. And on that screen, we play some images very rapidly, three images per second, it's quite quick. And what we do is we repeat some of those images from time to time. Now, whilst they're watching these images, they wear a special cap, which measures their brain activity. It's called an EEG cap. And we can measure their brainwaves with that cap. Now what happens when one of those images repeats is the brain has a little recognition signal that it elicits, and we can detect that with the EEG cap. So we use the EEG cap to measure people's recognition memory. And by doing that, what we've been able to show in our experiments is that people with Alzheimer's disease show really reduced recognition memory. And in our paper that's just come out recently, we've shown that this memory is also reduced in people at very high risk of Alzheimer's disease. So people who don't yet have a diagnosis, but are quite likely to get one in the next few years.
Chris - How specific is it for Alzheimer's disease? So if I, for instance, had some other reason why I had a memory deficit or some other chronic condition that was eroding memory, how specific is your test to say, yes, Chris has got Alzheimer's versus Chris has some other memory deficit?
George - That's a really good question. And it's one we're in the middle of answering. Now we don't have the answer to it yet, but we are in the middle of two very large scale studies. We're recruiting patients from neurology clinics with all sorts of different neurological problems. And that will give us exactly those accuracy numbers so that we can tell whether it's sensitive and specific to Alzheimer's disease, or whether it's just a general marker of memory impairment. Now, my prediction, my hope is that it is specific to Alzheimer's disease. And the reason I think it will be is because we built this test from the bottom up. The starting point was to identify which area of the brain is impacted very early on in Alzheimer's disease. And it's a little part of the brain buried deep in the middle of the brain called the perirhinal cortex. And so we built the task to rely very heavily on that brain area.
Chris - And how sensitive is it? So in other words, if I came to you with some undetectable clinical features to me, I don't think there's anything wrong with me. How good are you with this test at telling me I'm going to get Alzheimer's disease? And how much lead time can you bring with this?
George - We don't know how accurate it would be in the scenario you've described, because what you're describing there is a screening tool, picking up impairment in people without any symptoms at all. It takes a long time to run studies like that, because you have to test people and then you have to wait 10 or 20 years for them to develop the disease. And you have to test enough people in the first place that enough people go on to develop that disease. So we don't have the answer for that yet, but our two large studies will tell us how accurate and sensitive we are at detecting established Alzheimer's disease, but also in detecting Alzheimer's disease in those at risk. So those with what we call mild cognitive impairment, or there's another group called subjective cognitive impairment. And these are people who say to their doctor they're having problems with their memory, but when they come and do the traditional pen and paper tests, they score fine. So they're an important group to look at as well.
Chris - And when you test these people, how good is your test at hitting the nail on the head? So in other words, your test agrees with a neurologist or an elderly care expert, how often?
George - We had a paper in 2021, which had Alzheimer's classification accuracy. And that showed that we could get up to about 90, 92% accuracy in telling whether someone had Alzheimer's disease versus a healthy older adult. So that's good accuracy and sensitivity, but clinically that's not much use because those patients had already been diagnosed. So we want to be more accurate than that earlier on. To do that, we need to test, as I mentioned before, large numbers of people, a proportion of whom then go on to develop Alzheimer's disease. So we will learn that accuracy number from our current study in a few years time as we follow them up.
Chris - Is the longer term ambition here that if you can get this giving you a really long lead time, with the drugs that we foresee coming, we've only really tested those on people with already manifest Alzheimer's problems and got limited benefits from them, slowing down the condition, haven't we? People are saying, well, if we could intervene earlier, maybe the gains would be bigger.
George - Absolutely. Earlier diagnosis brings so many benefits. I mean, it brings benefits, potential benefits for the patient, given greater certainty, given them the opportunity to make lifestyle interventions, modifications, which has been shown to slow disease progress. But also, as you say, the drug development and the ability to use disease modifying therapies earlier. And also, who knows how that might improve and help the actual drug development itself. So not only will the drugs that we have work better, but could it be that we actually improve the development of those drugs in the first place by doing better stratification of patients into clinical trials and better characterization of patients in these clinical trials.
16:46 - Earth's carbon storage capability 10% of previous estimates
Earth's carbon storage capability 10% of previous estimates
Joeri Rogelj, Imperial College London
Climate scientists say that Earth may be able to sequester far less carbon than current models assume. The findings - which have been published in Nature - suggest our planet’s long-term carbon storage capacity is - realistically - maybe only a tenth of what we thought we might be able to lay our hands on. This matters, because, if part of our strategy to combat climate change relies on sequestering at least a proportion of the carbon dioxide we emit, that rescue package just shrank by 90%. Joeri Rogelj authored the study; he is at Imperial College London…
Joeri - So we know that climate change is happening and we know very well what we need to do to stop that from becoming worse. And that is we need to stop adding carbon dioxide to the atmosphere. Now, there is a variety of ways in which we can reduce the amount of carbon dioxide that we emit. The most important way is, of course, to stop producing carbon dioxide by stop burning fossil fuels. But another additional way of doing this is to capture CO2, carbon dioxide, and to pump it underground. And the estimates of how much of that carbon dioxide we could be pumping underground until recently were really enormous. Tens of thousands of billion tonnes of carbon dioxide. And what we are trying to do with this study is to see whether all of this technical potential is actually practically available. If we take into account some aspects like where it could be risky or where it would be undesirable to actually be pumping CO2 underground.
Chris - So you're saying, ignoring the practicalities for a minute, assuming we could do this and we capture carbon dioxide and we wanted to, and we were going to put it underground, how much could we really put underground compared to what people think we could, is sort of where you were coming from?
Joeri - Exactly. So we very much rely on what people have done before. So what we do is not starting from a fundamentally different point. We start from this technical potential of how much space there is underground in our Earth's crust to store carbon dioxide. But then we start removing those areas where we think the risk is too high. For example, we start removing those areas that are too close to where people live. Because pumping things underground means that there is a risk that this carbon dioxide starts to seep into the groundwater and so on. We also exclude areas that are currently protected. We exclude areas that are too deep or areas that are too deep in the ocean. Or equally, we look at areas that maybe might be managed by indigenous groups and where we therefore do not want to disturb nature or the environment. And if we start doing that, we start to see that lots of the technical, physical potential that is available starts to be excluded. And we ended up with an estimate that is significantly smaller than the hypothetical global estimate for storage that would be available.
Chris - What does your number look like then? And how does it compare with what we thought we had at our disposal?
Joeri - The number is still big, 1460 billion tonnes of CO2. So just to put this in context, right now, on an annual basis, our entire global economy is emitting 40 billion tonnes of CO2 into the atmosphere. It would take more than 30 years of current global emissions to reach this entire 1400 billion tonnes.
The important thing, however, is that this is almost a factor 10 smaller than our starting estimate, that does not take into account these different risk factors or areas where we would not necessarily want to be pumping CO2 in the ground.
Chris - Another way of looking at it is to say, well, how much climate change in terms of temperature escalation does that offset? And for how long?
Joeri - Yeah, that's right. So every ton that we emit in the atmosphere adds to global warming. We also understand that if we remove carbon dioxide from the atmosphere and then permanently store it somewhere so that it doesn't enter the air anymore, then global warming will be reversing. There are some uncertainties around this, but to first order, we understand that this will happen. And so we can estimate what removing 1460 billion tonnes of carbon dioxide means in terms of reversing global warming. Now, if we would use that space that we have calculated exclusively to remove CO2 from the atmosphere, this would add up as a central estimate to roughly 0.7 degrees of warming that can be reversed. This estimate is an absolute ceiling for what this storage space can deliver, because it assumes that every ton stored is indeed removed from the atmosphere and is not used to, for example, capture carbon dioxide from fossil fuels that are still being burned, but instead of being released into the atmosphere are then stored again on the ground. And it also assumes that while we are removing carbon dioxide from the atmosphere, there are no other activities ongoing that still continue to emit carbon dioxide in atmosphere. So the 0.7 degrees, the central estimate is an absolute ceiling.
Chris - And it's not very much, is it? It's quite a low ceiling. When you think that we think with what we've already done, we've well and truly breached that. So we couldn't even reverse what we've already done if we use all of what you think is there at our fingertips and sequester that carbon back into the ground.
Joeri - Currently, we are roughly at 1.4 degrees of global warming. We would currently not have kind of the safe storage space to fully reverse this. We would have roughly the space to maximum reverse half of this. I do want to highlight here that our estimate really provides today's estimate. And I would believe that if we really start trying, we will find ways to improve this. But that doesn't mean that today we need to kind of trust that we will be able to remove more. So that's why we call this a prudent limit. We say this is the amount that you should count with today until proven otherwise.
23:21 - UK fights bark beetle invasion with sniffer dogs and drones
UK fights bark beetle invasion with sniffer dogs and drones
Max Blake, Forest Research
Across Europe, bark beetles have left a trail of destruction; they attack and compromise spruce trees, which they have killed by the million. Now, these tiny creatures are increasingly invading the UK, arriving - it turns out - across the channel by air under their own steam. But scientists are racing to stop them. And armed with drones, traps, and now even sniffer dogs, they’re taking the fight directly to the beetles. Here’s Max Blake, head of tree health at Forest Research…
Max - Spruce really underpins our forest industry. Conifers, and spruce in particular, grow far better in our conditions to produce more valuable wood than any other tree. They are largely free from significant pests and diseases. But the risk that we're looking at here, Ipstibagraphus, is the most significant pest in Eurasia of spruce species. So it feeds on a few different species like Siberian spruce, a bunch of different species in Japan and China.
Chris - And when you say it feeds on them?
Max - So a male will begin to bore into the bark and it'll make a little nuptial chamber, attract a female, the female will come in and then begin to make what we call a maternal gallery, which will go vertically up the tree. And then usually if the male's lucky, he'll attract a second female and she'll go down the tree. And what you end up with is two very straight tunnels going up the tree. And the female will lay eggs on either side of this tunnel. And that's where the larvae come from. And the larvae will begin to eat, radiating out from that. So you get this remarkable pattern coming out from these galleries. And what they're feeding on is tissues in the tree which transport nutrients up and down from the roots to the leaves and vice versa.
Chris - Do they compromise the tree then? So once they start doing this, does this kill the tree, just stunt the tree? What's the impact?
Max - They will eventually kill the tree. So when there's enough of these galleries produced by enough beetles, they'll girdle all of these tissues. And it's kind of like having all of your blood vessels suddenly blocked up. Now, typically it doesn't really do that. So what it normally does is it feeds on storm damaged trees, trees that have been particularly drought stressed, things like that. So trees that can't really defend themselves. Normally that phloem network is very well defended because of course it has to be. This is the main thing that's keeping that tree alive. So they're able to flush those galleries with resins which kill the beetles if they're healthy.
But if they are weakened, then that's sort of when it can come in. So it was unprecedented for us when we found Ipstipographa satchiphae breeding here in the UK back at the end of 2018. We didn't know why it was there. We eventually realised, and this was one of those realisations where your gut almost gets ahead of the direct evidence, and we were certain that they were able to fly over the channel from outbreak populations in Belgium, France, and probably northern Germany.
Chris - Does this mean all your fears are being realised? And what can we do? Now you've identified that these guys can come by air. What will you be doing about it?
Max - The fact that they can go on these air channels and fly far further than we ever thought possible looks on the one hand to be very scary. We also know that we need to jump in and catch populations when they're very small to have a better chance of eradicating them.
Chris - But that's difficult, isn't it? Because if they're small, they're hard to spot. So how can you find them? How do you know where to centre your attention?
Max - They are remarkably hard to find. So the exit holes and the entrance holes that they produce on the trees are about three millimetres wide. We've managed to find just single galleries by eye in entire woodlands just made up of pure spruce, which might be 10 or 20 hectares. It takes an awful lot of very painstaking work on the ground to go and find these. But the fact of the matter is that as our surveillance has increased, we're also looking at trying to be as efficient and as quick as possible. And that's where adopting some new techniques takes place.
Chris - So what do they look like, these new approaches?
Max - So we've been looking at the use of drones, that's quite obvious. So we use a lot of satellite data and a lot of helicopter photography. So we can go around quickly, photograph an area of spruce from the air, and we'll keep an eye on that over the years to see if there's storm damage or if there's any decline. But what helicopters struggle to do, obviously, because you don't particularly want to be flying a helicopter too close to any trees, is give us really high resolution data, and in particular, look beyond that to the ground floor. And that's where drones come in. So we're able to use drones to more quickly survey some of these areas. The other area that's got significant potential is using sniffer dogs. Sniffer dogs are fantastic at trying to detect ips in timber stacks. So if you've ever been to a forest, someone's fell parts of the forest or thin it, you can have these huge timber stacks, which are themselves very dangerous. Of course, each log will weigh a couple of hundred kilos. You don't want people clambering over that to try and find small galleries. And also a lot of it is inaccessible, but it's not inaccessible to a dog's nose.
Chris - So are dogs and drones going to cut it then? Do you think, are you confident with what you can do with these tools now? Do you think you can hold this in check? Or should we be looking for an alternative source for our telegraph poles?
Max - Yeah. So both dogs and drones have got a part to play in this. The programme of work is vastly larger than it was when we started this back in 2018. So we're in this very strange scenario where things are much worse than they seem. In other words, more beetles are coming over more regularly than we ever thought possible. But also things are much better because they do seem to struggle to actually persist here in some sites. So that is a really active area of research at the moment. We're trying to understand why they seem to be able to persist on some sites and don't on others. And then we can begin to look at long-term adaptation, especially thinking about that next outbreak instead of 20 or 30 years time.
What happens to bullets fired directly upwards?
Thanks to Yousef Hyder and Luis Rafael Moscote Salazar for the answer!
James - Celebratory gunfire is fairly widespread as you suggest, with examples across the world from the Americas to the Middle East.
Bullets leaving a gun barrel experience explosive acceleration. Depending on the firearm, a bullet fired straight upwards can rise several kilometres before gravity halts its climb and pulls it back down. Because bullets are often made of lead, which is very dense, falling bullets encounter relatively less air resistance and reach high terminal velocities, up to 180 metres per second.
At these speeds, they can penetrate the human skull. Yousef Hyder is a neurologist at the University Hospitals in Birmingham. I asked him what the effect of such an impact could be.
Yousef - The bullet will damage the skull and impact on the brain itself, but then following on from that you'll get secondary effects. So they'll be bleeding inside of the skull, which we call intracranial hemorrhage, and then the actual brain itself will start to swell up. When that happens, the pressure inside of the skull will start to rise. So because the skull is basically a rigid box, it can only handle so much pressure and eventually the body is not able to compensate for that and the pressure will start to spike up exponentially. What can happen is herniation, which basically means that the brain is being pushed out of its normal position and it can even move through openings in the skull. Basically, parts of the brain which are very critical for health, like the areas that control breathing and your heartbeat, those will get squashed and that's when it becomes life-threatening.
James - A penetrating injury is thus very serious. But aside from these most extreme cases, less severe damage could also lead to lifelong consequences for a patient.
Yousef - So if the bullet's falling in such a way that it's tumbling and it's not at such a high speed, then it can impact the head without causing a penetrating injury but still definitely can cause severe trauma. It can knock a person unconscious and it can cause what we call concussion as well. They are prone to having very long-term effects, months and even a year later, long-term headaches, problems with balance, sleep, thinking, even emotional problems, all because of this injury.
James - So how common are these injuries? Well, my thanks here goes to Luis Rafael Moscote Salazar, director of the Colombian Clinical Research Group in Neurocritical Care. For his consultation when composing this piece, he conducted a literature review on this very question. He found that if you're unlucky enough to be struck, the mortality rate from a falling bullet is estimated at around 32%. One reason for this is that victims of falling bullets rarely have protective equipment such as helmets. After the Iraqi football team won the Asian Cup in 2007, celebratory gunfire killed three people. In Puerto Rico, New Year's Eve gunfire in 2004 caused 19 injuries and one death. So, Dr Moscot Salazar's conclusion?
Luis - My advice would be try finding a different way to celebrate.
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