Immunity gets a boost from a surprising place — breakfast

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0:41It sounds so simple. They had no idea. But now the data's peaking. I find this not only refreshing, but at some level astounding. Nature.

0:56Welcome back to the Nature Podcast. This week, how having breakfast can boost immunity. And lessons from the 40th anniversary of Chernobyl. I'm Maren Hansberger. And I'm Nick Petrich-Hell.

1:17eating is good for you according to science well more specifically having food may give some immune cells known as t cells a boost in other words the best time to get an infection may be after breakfast something like that if you're going to go out at least be well fed This is Greg Delgoff, author of a new paper in Nature that's looked at how T-cells respond to feeding. There's the old adage like, feed a cold, starve a fever, that kind of thing. And we think there's some value in this. Now, T-cells are a group of white blood cells that coordinate the body's immune responses, activating in reaction to threats.

2:02If they come across something that's not supposed to be there, like a bacterium, virus, or even a tumour, they respond to it and begin to call in the troops, sending chemical messages to other immune cells and dividing rapidly themselves. This is something known as activation. And if it sounds like it would require a lot of energy, you'd be right. The activation and kind of the training up of your immune system is incredibly demanding. That's why when we get sick, we get tired, we get fatigued. That is your body demanding that energy to allow your immune system to thrive. As there is such a well-known energy demand, researchers know a lot about long-term dietary changes in relation to the immune system.

2:50But less is known about the very short term, like if you've had breakfast or not. So Greg and the team recruited people to have their blood taken before breakfast so they had fasted overnight, and then again after they'd had six hours to go and eat what they liked, often breakfast and lunch, to test their post-meal or post-prangeal state. Now, these people were not infected with a virus, they were not vaccinated against anything, this was just looking at their resting immune repertoire. And what we found were striking metabolic differences between those two different populations of T cells, the ones that were before breakfast and the ones that we saw after lunch.

3:33After lunch the T-cells were better able to take up sugars, had more fats and more efficient mitochondria. Not only that but they could also more easily divide and proliferate to make the clonal immune army that you need to tackle infections. Ultimately Greg and the team think that the T-cells had a boosted ability to respond to threats. In mouse studies they were able to give animals vaccinations and monitor their responses in detail.

4:13The mice also offered the team the ability to identify the exact mechanism that cause this effect. They found that circulating particles that carry fats in the blood, called chylomicrons, seemed to be key, as this effect relied on their presence. And they also showed that the T-cells in mice that had been fed recently had a greater capacity to produce proteins. The team also wondered whether this effect could boost immune therapies, like chimeric antigen receptor or CAR T-cell therapies, where receptors are engineered to improve T-cells' abilities to root out threats. And what we found was that the CAR T-cells we manufactured after lunch lasted longer and were more effective.

5:09So this is a direct therapeutic implication where we should be standardizing and thinking about what patients eat before we isolate their blood to manufacture these T-cells. So that's something that we're very excited about moving forward in the future. I think this is really an exciting study and very original. This is Lionel Apatow, an immunologist at Indiana University who is not involved in this work. His research includes CAR T-cell therapies, so he found this aspect particularly interesting. This is really like a well-controlled experiment because the cells were harvested from the individual after fasting, then had a meal, and then after six hours, again, harvesting the cells again and testing their anti-cancer properties.

5:58And the results are quite striking, actually. The cells from the fed mice showed a greater ability to prevent tumour relapses. In other words, more anti-cancer effects. Lionel did note that the authors largely focused on CD8 T-cells, a particular subgroup of the immune cells. In some experiments, they did look at CD4 T-cells, but are noted for their anti-cancer effects. So he'd like to see more work on that in the future. Overall, as activation of T-cells is known to be energy-demanding, this effect made sense to Lionel. But the fact it happened so quickly was certainly new. I guess the results per se is not surprising.

6:42To me, what is surprising is actually the timing. such a short time like six hours like definitely not a long time and still that has profound consequences on t-cell immunity he also pointed out that one limitation of the study is that people were able to eat whatever they liked for those six hours which made it a bit difficult to know what exactly is causing the effects shown in the study greg also acknowledges this but he suggests that this could actually be considered a strength. Some people ate cookies and some people ate rice and some people ate salads and some people had hamburgers. And while we weren't statistically powered to determine the differences, what we were able to say is that it happened every time.

7:28So we knew even across all 30 or so donors that we had tested, we always saw the postprandial effect. It was telling us this is a good thing, right? That a meal matters and you can have whatever you want right there may be some things that are better or not as good but you're going to get this effect regardless so the breadth of the effect was really exciting still in future work greg and the team are going to do studies with more controlled diets to find the key components of nutrition that can improve the t-cells abilities understanding this could allow researchers to design food interventions to boost vaccinations or immune therapies it may be some time before we discover what exact hamburger enhances our immunity but for now greg thinks that this study should prompt researchers to reassess how diet influences the immune response this is something that we really don't ask patients or donors anything about we don't really say when have you eaten last and what did you eat and that may make a big difference of how effective those t-cells are so i think for just from looking from doing science on humans, this is going to be important to understand.

8:36That was Greg Delgoff from the University of Pittsburgh in the US. You also heard from Lionel Apatow from Indiana University, also in the US. For more on that story, you can check out the links in the show notes. Coming up, as calls for an increase in nuclear power production get louder, we hear about the lessons that should be learned from the 40th anniversary of the Chernobyl disaster. Right now, though, it's time for the Research Highlights with Dan Fox.

9:04Physicists have, for the first time, detected cosmic rays using the trail of radio waves they left behind in Antarctic ice. Researchers analysed data from 208 days of operation of the Ashkarian radio array, based at the South Pole. There, detectors placed on strings down five boreholes up to 200 metres deep recorded 13 instances of radio emissions rippling through the ice. By analysing the shape, direction and rate of these signals, they found that the events were compatible with being caused by a cosmic ray hitting the ice and creating a cascade of particles that emits a radio shockwave, a process known as the Ashkarian effect.

9:48Because radio emissions travel farther in ice than light does, an in-ice radio array can efficiently cover much more volume than observatories that rely on optical signatures. These observations lay the groundwork for spotting elusive high-energy neutrinos in follow-up detectors planned to cover volumes of more than 100 cubic kilometres. You can find that research in physical review letters.

10:18It seems even ants enjoy a spa day, as a species of harvester ant from the US has been observed visiting the nests of a smaller species that seem to groom their hulking visitor. Pogonomyermax barbatus, also known as red harvester ants, have been seen backing up to the entrance of a nest belonging to a much smaller species of Dorymyermax ant. Once in position, the harvester ant freezes in place as one or more tiny workers emerge from the nest and started crawling all over its body. The Dorymyermax ants would even lick and nibble between its mandibles, presumably freeing them of parasites or bacteria.

10:57The behaviour mirrors that of cleaner fish that are often seen helping larger fish stay parasite-free. But in both insects and fishes, it's not always clear whether these sessions actually benefit the larger species, and further observation will be needed to understand the effects on a colony's health. Find that research in Ecology and Evolution.

11:2640 years ago last Sunday, during a test of Reactor 4 at the Chernobyl nuclear power plant in Ukraine, a chain of events was set in motion that resulted in the worst nuclear disaster the world has ever seen. The shadows cast by this event and by the later Fukushima nuclear disaster in Japan led many to turn away from nuclear power. But now, many countries and companies are calling for nuclear to play a bigger role in the world's energy mix, to help move away from fossil fuels and to meet an increasing demand for electricity. But there's much that needs to be considered. This week, Nature has a Worldview article written by Alexandra Bell, president of the Bulletin of the Atomic Scientists, an organization that addresses global security and public policy challenges that are posed by accelerating technological advancements.

12:13In her worldview, Alexandra calls for discussion about the risks facing nuclear power, both in the future and the risks that existing facilities are facing right now. This is something that's been brought into sharp focus by things like the Russian shelling of the Zaporizhia nuclear plant during the country's illegal invasion of Ukraine. And separately, a drone strike also caused extensive damage to the protective shell encasing the remains of Chernobyl's reactor 4, which risks destabilizing the site and jeopardizes the plans to decommission the remaining radioactive material. I spoke with Alexandra about what society needs to consider as we move into a nuclear energy future, and I began by asking her about her memories of the Chernobyl catastrophe.

12:55This disaster happened when I was little, but I distinctly remember watching the evening news and being worried about what was happening, the tension that I felt from my parents in the room, not the least of which because they had been worried about the Three Mile Island disaster than the partial meltdown that had happened there in 1979, but also my mother's family in Finland and watching this radiation spreading ever northwards. And after the disaster at Chernobyl, what was the shift that we saw in the world's attitude towards nuclear energy? In the aftermath of Chernobyl, I think you saw worldwide fear and skepticism about the safety of reactors.

13:34Of course, what happened at Chernobyl was really a cascade of calamities caused by bad safety measures, by improper leadership over that facility. You had that skepticism from the global community about nuclear power in general, but you also had international institutions putting in better safeguards, better norms and behaviors, demands for transparency around issues like this. So you saw sort of a balance of some countries continuing to invest in civil nuclear technology and some backing off. And you saw this replay itself in the aftermath of the Fukushima disaster in Japan, where countries thought if this is the kind of reactor disaster that can happen as a result of natural disasters, maybe we should be rethinking our investments.

14:21But memories fade, time passes, technologies improve, energy demands go up. So you're now seeing a broad-based interest around the world in investment in civil nuclear technology. And that's really to deal with growing AI energy demands and energy demands of a growing global population in general. Right. So what lessons can we take from a disaster like Chernobyl as we go into this future where the world may be relying on a new era of nuclear energy to help us meet current and future energy needs? So something we're seeing today is a tech industry that's increasing the amount of footprint for data centers and the development of new technologies.

15:03They need power. And as the globe transitions away from a fossil fuel based economy, civil nuclear power is really going to be a bridge, hopefully, to investment in green technologies across the board. What you're going to see is investments in small reactors to power these data facilities and other infrastructure spread across lots of different countries, lots of different places. We need to make sure that there's a standardized level of safety for these reactors, that these tech companies understand the inherent dangers that come along with civil nuclear technology. I'm really interested in why nuclear is so promising in this regard, as opposed to something like solar or wind.

15:45Like, why is nuclear the big potential solution here? As we try to move away from fossil fuels, there is a view that nuclear energy can be a bridging technology. Wind, solar, obviously, are things that we're investing in. They're not quite at scale at cost effectiveness that we see with nuclear. Of course, they don't have the inherent dangers of nuclear. But nevertheless, you're going to see these investments go forward when they do, when these new reactors are going to be built, a new generation around the world. We need to make sure there are safeguards in place, standards in place. One, to make sure these operations are happening safely.

16:22Two, is that civil nuclear technology is unfortunately a nuclear weapons starter kit. So in addition to making sure the facilities themselves are safe, we have to make sure companies are investing in proliferation resistant technology so civil nuclear reactors cannot be turned into a nuclear weapons program. We've seen that happen before. It can happen. But we do have lessons learned now, very hard lessons learned about how to prevent such proliferation. But again, that's something that industry needs to be involved in and is something that governments need to be demanding. And what's happening in the regulatory space related to this potential predicted increase in demand for nuclear energy from the private sector?

17:01What trends are you seeing in conjunction with that? Well, from a regulatory perspective in the U.S. in general, what you've seen is a lowering of standards, a hope for this administration, at least, to rapidly expand civil nuclear reactor development, to quickly get facilities online. Unfortunately, the result of that is the lowering of these standards. You know, we really need to balance the need for this technology, for these energy demands with safety of communities around the world. We already know that poorly constructed, poorly managed nuclear facilities can create disasters. So we need to do everything that we can to avoid that.

17:42And what are the conversations that you're having with experts and policymakers about the threats posed by conflicts around the world to current civil nuclear facilities? Yeah, this is a difficult topic because in general, energy facilities that are used for military purposes are considered legitimate military targets. Unfortunately, civil reactors sort of sit in a gray space. There's an idea that they can be of dual use for both civilian power and for military operations. The issue at hand is the danger of attacking nuclear facilities in particular because of what could happen. It is necessary now, given the dangers of what we've seen at Chernobyl, what we've seen at Fukushima.

18:23We need to have a conversation about whether or not it is legitimate to attack these types of facilities, particularly civil nuclear reactors that are not ostensibly clearly a part of a military program. And we have institutions that can determine that, like the IAEA, and we're way overdue for a conversation. This is something that I talked about when I was inside the U.S. government, and certainly it's a subject for experts, for policymakers to be discussing now. It is past time for us to have a serious conversation, whether it's in Vienna at the International Atomic Energy Agency or in New York at the United Nations, about how we prevent such attacks in a way that makes sense for the entire international community.

19:07Finally, then, this week is marking the 40th anniversary of the Chernobyl disaster. So how can what happened then inform what happens today? So Chernobyl was really our worst case nightmare scenario when it comes to the potential dangers associated with a civil nuclear reactor. We certainly learned a lot of lessons about safety, about security of facilities, about transparency. In a crisis like this, we need to get information out as quickly as possible, fact-based, science-focused, not spin, not jargon, because accidents happen. And the truth of the matter here is that we are going to be investing in civil nuclear technology.

19:49But what we need, if we're going to make these investments, is full transparency, public oversight and regulation of the nuclear power industry. And we also need resilience and response mechanisms in case the worst happens. And we constantly need to be updating these norms, these regulations to make sure they're fit for purpose in a world that's constantly evolving as tech is constantly evolving. The stakes could not be higher when it comes to civilian nuclear power. We also desperately need to have a conversation about keeping civil nuclear reactors out of conflicts. Alexandra Bell from the Bulletin of the Atomic Scientists there.

20:29To read more about her thoughts on ensuring the safety of future nuclear power, you can head over to the show notes where you'll find a link to her worldview. And that's all for this time. We'll be back later in the week with The Briefing Podcast. But until then, if you've enjoyed the show, do let us know. You can leave a review on your podcast app of choice, or you can reach out to us on social media. We're at Nature Podcast. And of course, one email too. Podcast at nature.com. I'm Nick Petrich Howell. And I'm Maren Hunsberger. Thanks for listening.