String theory first emerged in the 1960s as a possible way to solve one of physics’ biggest problems: combining quantum mechanics, which governs the smallest particles, with general relativity, Einstein’s theory describing gravity and the large-scale structure of the universe. Scientists have long struggled to unite the two because the equations often spiral into mathematical infinities when gravity is included at quantum scales.

String theory offers a potential way around that problem. In the theory, every particle, including the hypothetical graviton that would carry the force of gravity, comes from different vibrations of tiny strings. The mathematics also requires the strings to exist in at least 10 dimensions rather than the four dimensions humans experience.

One major obstacle remains. Testing string theory directly would require energies so extreme that researchers would need a particle collider as large as a galaxy.

Bootstrap Physics and String Theory

Since direct experiments are impossible with current technology, physicists are exploring other methods. One promising strategy is known as the “bootstrap” approach. Instead of assuming a detailed theory from the start, scientists begin with a few broad principles they believe nature must obey and then determine what laws naturally emerge.

In a new study titled “Strings from Almost Nothing,” accepted for publication in Physical Review Letters, researchers from Caltech, New York University, and Institut de Fisica d’Altes Energies in Barcelona used this strategy to investigate particle behavior at extremely high energies. Starting from just a couple of assumptions about how particles scatter during collisions, they unexpectedly arrived at the core features of string theory.

“The strings just fell out,” says Clifford Cheung, professor of theoretical physics and director of the Leinweber Forum for Theoretical Physics at Caltech. “We didn’t start with any assumptions about strings at all, but then the solution contained the cornerstone signatures of strings.”

Although the findings do not prove string theory experimentally, Cheung says the results are striking because many different mathematical outcomes could have been possible. Instead, the calculations pointed toward only one solution.

The Infinite Tower of Particles

One of the most important features to emerge from the calculations is known as the string spectrum. In the late 1960s, Italian theoretical physicist Gabriele Veneziano at CERN developed a mathematical function describing a mysterious “tower” of particles seen in collider experiments. The particles appeared in a sequence where mass and spin increased in orderly steps.

“At Veneziano’s time, particle colliders were seeing this spray of junk come out of the collisions, particles of different masses. It was fascinating and nobody had any idea what was going on. Veneziano wrote down a function to describe all the masses, revealing an infinite tower of particles,” Cheung says.

Researchers later realized this pattern resembles the harmonics of a vibrating string. When a violin string is plucked, it produces a main tone along with a series of overtones. String theory proposes that particles arise from similar vibrational patterns.

In 1974, Caltech physicist John Schwarz and French physicist Joël Scherk recognized that string theory could also include gravity. That discovery created one of the first meaningful links between string theory and general relativity.

“Like all particle physicists in that era, we had no prior interest in gravity. String theories are well-behaved at very high energies, unlike Einstein’s general theory of relativity, which survives as a low-energy approximation. Therefore, even though much was not yet understood, we were very excited that some version of string theory could provide a unified quantum theory of everything,” Schwarz says.

According to string theory, different vibrational modes generate different particles. A photon, for example, comes from an open string vibrating in its simplest mode, while the graviton is thought to arise from a closed vibrating string.

Why Quantum Gravity Breaks Down

The new study focused on scattering amplitudes, mathematical expressions describing the outcomes of particle collisions. When scientists use general relativity to calculate collisions at extremely high energies near the Planck scale, the math stops working properly and produces infinities.

“If you take general relativity and scatter at very high energies at the so-called Planck scale — that is roughly 19 orders of magnitude greater than a proton’s mass — you get a result that makes no sense. Everything completely breaks down,” Cheung says.

String theory avoids these infinities through a property called ultrasoftness. At extremely high energies, the strings effectively spread interactions out, preventing the violent behavior that normally causes the equations to fail.

“In a string theory framework, as you increase the energy transfer between particles, you will see a swift fall off in the probability that the particles will scatter. It’s like the particles don’t even want to scatter off one another, but rather pass freely,” Cheung says. “The scattering amplitudes don’t go to infinity. It’s better behaved.”

The researchers used this ultrasoft behavior as one of their starting assumptions. They also included another condition called “minimal zeros,” which limits the number of points where scattering probabilities vanish.

“Remarkably, consistency requires scattering amplitudes not only to interact but also to not interact at special kinematic points called ‘zeros.’ The assumption of ‘minimal zeros’ demands the sparsest number of such vanishing points mathematically allowed by the equations,” Cheung says.

Using only these assumptions, the team showed that the resulting mathematics naturally reproduced the defining characteristics of string theory, including its famous spectrum of particle masses and spins.

“The precise details of string theory emerged automatically, including the infinite tower of massive spinning particles that form the ‘harmonics’ of the string that the theory is famous for,” says co-author Grant N. Remmen (PhD ’17), the James Arthur Postdoctoral Fellow at New York University.

Reviving an Old Idea With Modern Tools

Cheung compares the bootstrap approach to solving a sudoku puzzle. A few simple rules are provided at the start, and those rules eventually guide you to one unique solution.

“The deep irony is that this bootstrap idea that we’re pursuing now with modern tools and modern ideas is super retro. It’s an old idea,” Cheung explains. “The original discovery of the Veneziano spectrum, and John Schwarz’s work, took a similar approach. They didn’t start with string theory models but rather the solutions came out of basic principles.”

The study also builds on earlier work by Caltech physicist Steven Frautschi and UC Berkeley physicist Geoffrey Chew, who pioneered the bootstrap approach in particle physics during the 1960s. Their work provided some of the earliest hints of the infinite particle spectrum later connected to string theory.

“The bootstrap idea had become obsolete but now people like Cliff are reviving and modernizing it,” says Hirosi Ooguri, the Fred Kavli Professor of Theoretical Physics and Mathematics at Caltech and the Kent and Joyce Kresa Leadership Chair of the Division of Physics, Mathematics and Astronomy. “We now have a better understanding of the basic assumptions we can make, as well as stronger techniques for translating these assumptions into properties of scattering amplitudes and other observables.”

The study “Strings from Almost Nothing” received funding from the US Department of Energy, the Walter Burke Institute for Theoretical Physics, the Leinweber Forum for Theoretical Physics, the James Arthur Postdoctoral Fellowship at New York University, and the Next Generation EU. Additional authors include Francesco Sciotti of Institut de Fisica d’Altes Energies in Barcelona and Michele Tarquini, a graduate student at Caltech.

The discovery began when Aaron Bean, a professional horticulturalist who was helping band birds on a large outback property in Queensland, noticed an unusual plant growing in the landscape. He photographed it and later uploaded the images to iNaturalist after regaining phone service.

That simple upload set off an extraordinary chain of events.

Among the millions of observations shared on the platform, the photos eventually caught the attention of botanist Anthony Bean from the Queensland Herbarium. He immediately recognized the species as Ptilotus senarius, a rare plant that had not been documented since 1967 and was widely considered extinct in the wild.

Anthony Bean had actually described the species himself a decade earlier.

“It was very serendipitous,” said Thomas Mesaglio from the UNSW School of Biological, Earth and Environmental Sciences, who documented the rediscovery for the Australian Journal of Botany.

“Aaron Bean is an avid iNaturalist user who opportunistically took some photos of a few plants that were interesting on the property.”

Rare Australian Plant Rediscovered

Ptilotus senarius is a delicate shrub with purple pink flowers that resemble small feathered fireworks. The species grows only in rugged terrain near the Gulf of Carpentaria in northern Australia.

Before this rediscovery, no confirmed sightings had occurred for nearly 60 years. Scientists believed it may have joined the roughly 900 plant species that have disappeared from the wild globally since the 1750s.

With Aaron Bean’s photographs, Anthony Bean’s expertise, and help from the property owner in collecting a specimen, researchers were finally able to confirm that the species still survives. Rather than being classified as extinct, the plant has now been moved to the critically endangered list, allowing scientists and conservation groups to focus on protecting it.

“It’s one of these situations where everything had to fall into place and there was a bit of good fortune involved,” Mesaglio said.

How Citizen Science Is Changing Research

The rediscovery is part of a growing pattern in science. Increasingly, members of the public are photographing plants and animals they encounter and uploading them to online databases such as iNaturalist. In some cases, these observations are revealing species thought to be lost. In others, they are helping scientists identify organisms completely new to science.

For researchers like Mesaglio, citizen science platforms have become essential tools.

Australia’s enormous size and biodiversity make it impossible for scientists to survey every region themselves. Access can be even more difficult because about one third of the continent consists of privately owned land.

“If you are the property owner or you’re someone who has permission from the owner to be there then suddenly it opens up this whole new world,” Mesaglio said.

Scientists Want Better Biodiversity Data

Researchers are now encouraging more people, especially landowners, to participate in citizen science projects and collect high quality observations.

In New South Wales, the Land Libraries project run by the state government’s Biodiversity Conservation Trust provides training and equipment to help landowners document wildlife and plant species on their properties and upload the information to citizen science platforms.

Mesaglio supports expanding these kinds of programs, both because they improve scientific access to remote or private areas and because they help build public interest in conservation.

“Engaging landholders themselves with science and the natural world and getting them more passionate about diversity makes them far more likely to be interested and invested in protecting that diversity,” Mesaglio said.

Tips for Using iNaturalist

Mesaglio says detailed observations are especially valuable to scientists.

For example, a single close up image of a flower may not be enough to identify a species if many related plants have similar looking blooms. Taking additional photos of leaves, bark, stems, or the entire plant can provide critical clues.

He also encourages users to include information that may not appear in photos, such as soil conditions, nearby vegetation, or whether pollinators were present.

Even details like how a plant smells can help researchers determine what species it is.

“The more information you can provide and the more context you can provide, the more potential uses that that record will have in the future.”

In separate research, Mesaglio found that iNaturalist had already been cited in scientific papers involving 128 countries and thousands of species, underscoring the platform’s growing role in global science.

With millions of observations continuing to pour in, scientists believe there are many more discoveries waiting to be uncovered.

The breakthrough relies on tiny “molecular antennas” that funnel electrical energy into insulating nanoparticles. By using this method, researchers at the Cavendish Laboratory at the University of Cambridge created the first LEDs ever built from these previously “unpowerable” materials.

Their findings were published in Nature.

Molecular Antennas Power Insulating Nanoparticles

The research centers on lanthanide doped nanoparticles (LnNPs), materials known for producing exceptionally stable and highly pure light. They are especially valuable because they emit light in the second near infrared region, which can travel deep into biological tissue. This makes them attractive for medical imaging and sensing technologies.

Despite their optical advantages, these nanoparticles have one major drawback. They are electrical insulators, meaning they cannot easily carry electric current. That limitation has prevented scientists from using them in electronic devices such as LEDs.

Researchers at Cambridge found a way around that obstacle, a feat previously thought impossible under normal conditions. By attaching specially selected organic molecules to the nanoparticles, the team created a system capable of transferring electrical energy into the insulating material.

“These nanoparticles are fantastic light emitters, but we couldn’t power them with electricity. It was a major barrier preventing their use in everyday technology,” said Professor Akshay Rao, who led the research at the Cavendish Laboratory. “We’ve essentially found a back door to power them. The organic molecules act like antennas, catching charge carriers and then ‘whispering’ it to the nanoparticle through a special triplet energy transfer process, which is surprisingly efficient.”

Organic Hybrid LEDs Achieve Over 98% Energy Transfer

To make the technology work, the scientists built a hybrid material that combines organic molecules with inorganic nanoparticles. They attached an organic dye called 9-anthracenecarboxylic acid (9-ACA) to the surface of the LnNPs.

Inside the newly designed LEDs, electrical charges are directed into the 9-ACA molecules instead of the nanoparticles themselves. These molecules act as molecular antennas that absorb the incoming energy and enter an excited “triplet state.”

In many optical systems, triplet states are considered “dark” because their energy is often lost. In this new design, however, the triplet energy is transferred to the lanthanide ions inside the nanoparticles with more than 98% efficiency. That process causes the insulating nanoparticles to emit bright, highly pure light.

Ultra Pure Near Infrared LEDs With Low Power Use

The resulting devices, called “LnLEDs,” operate at a relatively low voltage of about 5 volts. They also produce electroluminescence with an extremely narrow spectral width, giving them much purer light output than competing technologies such as quantum dots (QDs).

“The purity of the light in the second near-infrared window emitted by our LnLEDs is a huge advantage,” said Dr. Zhongzheng Yu, a lead author of the study and postdoctoral research associate at the Cavendish Laboratory. “For applications like biomedical sensing or optical communications, you want a very sharp, specific wavelength. Our devices achieve this effortlessly, something that is very difficult to do with other materials.”

Medical Imaging and Optical Communication Potential

The technology could lead to a wide range of future applications. Because the LEDs emit extremely pure near infrared light, they may enable new medical devices capable of seeing deep inside the body.

Tiny injectable or wearable LnLEDs could potentially help doctors detect cancers, monitor organs in real time, or activate light sensitive drugs with exceptional precision.

The narrow and stable light emission could also improve optical communications systems by reducing interference and allowing larger amounts of data to travel more clearly and efficiently. In addition, the technology may support highly sensitive detectors capable of identifying specific chemicals or biological markers.

First Generation Devices Already Show Strong Results

The research team has already achieved a peak external quantum efficiency greater than 0.6% for their NIR-II LEDs, an impressive result for an early generation device. The scientists also say there are clear paths for improving performance even further.

“This is just the beginning. We’ve unlocked a whole new class of materials for optoelectronics,” added Dr. Yunzhou Deng, postdoctoral research associate at the Cavendish Laboratory. “The fundamental principle is so versatile that we can now explore countless combinations of organic molecules and insulating nanomaterials. This will allow us to create devices with tailored properties for applications we haven’t even thought of yet.”

The work received support in part from a UK Research and Innovation (UKRI) Frontier Research Grant (EP/Y015584/1) and Postdoctoral Individual Fellowships (Marie Skłodowska-Curie Fellowship grant scheme).

Researchers at Washington University in St. Louis are working on a possible solution. A team led by Gang Wu, professor of energy, environmental & chemical engineering in the McKelvey School of Engineering, has developed a new catalyst designed for an anion-exchange membrane water electrolyzer (AEMWE). This technology uses electricity from renewable sources to split water into hydrogen and oxygen, producing clean hydrogen fuel in the process.

New Platinum-Free Hydrogen Catalyst

Wu’s group focused on replacing expensive platinum-based materials commonly used in hydrogen production systems. Their approach uses renewable electricity generated from sunlight, wind, or water to power the separation of hydrogen from water molecules.

“Going from water to hydrogen is a very desirable way we are able to store energy for different applications,” Wu said. “Hydrogen itself can be used as an energy carrier and is useful for different chemical industries and manufacturing.”

To build the catalyst, the researchers combined rhenium phosphide (Re₂P) and molybdenum phosphide (MoP). Together, the two materials created a highly effective composite that improved the hydrogen extraction process. The rhenium component helped hydrogen attach to and release from the catalyst surface, while the molybdenum sped up the splitting of water in the alkaline electrolyte.

Durable Performance for Clean Energy

The team paired the new catalyst with a nickel iron anode and found that the system performed better than a leading state-of-the-art cathode, including one based on PGM materials. According to Wu, the catalyst also operated for more than 1,000 hours at industry-level current densities of 1 and 2 amperes per square centimeter. That makes it one of the most durable platinum-free cathodes developed so far for anion-exchange membrane water electrolyzers.

“Our findings allowed us to rationalize the critical role of engineering the hydrogen-bond network at the catalyst/electrolyte interface in designing high-efficiency, low-cost AEMWEs,” Wu said. “Our catalyst showed the lowest resistance across the studied potential range, which suggests the fastest hydrogen adsorption kinetics among the studied catalysts. This newly achieved performance and durability metrics make our catalyst one of the most promising membrane electrode assemblies for practical anion-exchange membrane water electrolyzers.”

Potential for Large-Scale Hydrogen Production

Although the experiments were carried out at laboratory scale, the researchers plan to continue studying whether the technology can be expanded for industrial use.

The work was financially supported by G. Wu’s startup fund at Washington University in St. Louis.

In a study published in Nature Neuroscience, researchers from Inserm and the University of Bordeaux at the NeuroCentre Magendie, working with scientists at the Université de Moncton in Canada, reported a major step forward in understanding dementia. Their results showed a direct cause and effect link between faulty mitochondrial activity and cognitive symptoms associated with neurodegenerative disease.

Brain Energy and Memory Loss

The team created a highly specific tool that allowed them to temporarily increase mitochondrial activity in animal models of neurodegenerative disease. When they boosted the brain’s energy machinery, memory problems improved.

Although the findings are still early and were observed in animal models, they point to an intriguing possibility: mitochondria may not simply break down after brain disease begins. Instead, their failure may help drive the symptoms that appear as dementia develops.

That idea could reshape how scientists think about future treatments. If brain cell energy failure contributes to memory loss, then restoring mitochondrial function may one day become a strategy for slowing or reducing symptoms.

Why Mitochondria Matter in the Brain

A mitochondrion is a small structure inside the cell that helps generate the energy required for normal function. This matters especially in the brain, which consumes a large amount of the body’s energy.

Neurons depend on that energy to send signals to one another. When mitochondrial activity drops, neurons may no longer have enough power to work properly. Over time, that energy shortage could weaken communication in the brain and contribute to memory and thinking problems.

Neurodegenerative diseases involve the gradual decline of neuronal function, followed by the death of brain cells. In Alzheimer’s disease, researchers have long observed that mitochondrial problems appear alongside neuronal degeneration, often before cells die. Until recently, however, it was difficult to determine whether mitochondrial dysfunction helped cause the disease process or merely appeared as a result of it.

A Tool Designed to Recharge Mitochondria

To explore that question, the researchers developed a tool that can temporarily stimulate mitochondrial activity. Their reasoning was simple but powerful. If increasing mitochondrial activity improved symptoms in animals, that would suggest mitochondrial impairment can come before neuron loss and contribute directly to cognitive decline.

Earlier work by the research teams had already identified a role for G proteins, which have the specific role of enabling the transfer of information within cells, in regulating mitochondrial activity in the brain. In the 2025 study, they built an artificial receptor called mitoDreadd-Gs. This receptor was designed to activate G proteins directly inside mitochondria, which in turn stimulated mitochondrial activity.

When mitoDreadd-Gs was activated in the brain, mitochondrial activity returned to normal levels. Memory performance also improved in mouse models of dementia.

A Possible New Target for Dementia Research

“This work is the first to establish a cause-and-effect link between mitochondrial dysfunction and symptoms related to neurodegenerative diseases, suggesting that impaired mitochondrial activity could be at the origin of the onset of neuronal degeneration,” explains Giovanni Marsicano, Inserm research director and co-senior author of the study.

The results do not mean that a treatment is ready for patients. The work was performed in animal models, and much more research is needed to determine whether similar approaches could be safe, durable, and effective in humans.

Still, the findings add momentum to a growing shift in dementia research. Scientists are increasingly looking beyond the familiar hallmarks of Alzheimer’s disease, such as amyloid plaques and tau tangles, to examine how energy production, metabolism, inflammation, and cellular stress may shape the disease from its earliest stages.

Recent research has continued to strengthen that broader view. A recent Mayo Clinic study linked disruptions in mitochondrial complex I, a key part of the cell’s energy system, to Alzheimer’s disease progression and potential treatment response. Reviews published afterward have also described mitochondrial failure as an early and potentially central feature of Alzheimer’s biology, not merely a late consequence of brain damage.

“These results will need to be extended, but they allow us to better understand the important role of mitochondria in the proper functioning of our brain. Ultimately, the tool we developed could help us identify the molecular and cellular mechanisms responsible for dementia and facilitate the development of effective therapeutic targets,” explains Étienne Hébert Chatelain, professor at the Université de Moncton and co-senior author of the study.

What Comes Next

The next major question is whether longer term stimulation of mitochondrial activity can do more than improve memory symptoms. Researchers now want to know whether restoring mitochondrial function could slow neuron loss, delay disease progression, or possibly help prevent damage before it becomes irreversible.

“Our work now consists of trying to measure the effects of continuous stimulation of mitochondrial activity to see whether it impacts the symptoms of neurodegenerative diseases and, ultimately, delays neuronal loss or even prevents it if mitochondrial activity is restored,” added Luigi Bellocchio, Inserm researcher and co-senior author of the study.

For now, the discovery offers a striking message: memory loss may be tied not only to dying brain cells, but also to living neurons that are running short on energy. By learning how to recharge those tiny engines, scientists may be opening a new path in the fight against dementia.

The discovery offers a rare direct look at one of the largest structures in existence and could help researchers better understand how galaxies grow and evolve over cosmic time.

The Universe’s Hidden Structure

Modern cosmology suggests that dark matter makes up roughly 85% of all matter in the Universe. Although invisible, dark matter is believed to shape a gigantic web-like framework made of long filaments. At the points where these filaments intersect, galaxies form and shine brightly.

Scientists think these filaments also act as intergalactic highways, channeling gas into galaxies and fueling the birth of new stars. Learning how this gas moves through the cosmic web is considered essential for understanding how galaxies develop.

But detecting that gas has been extremely difficult. Most intergalactic gas has only been observed indirectly by measuring how it absorbs light from bright objects behind it. Hydrogen, the most abundant element in the cosmos, emits only a very faint glow, making direct observations nearly impossible for older instruments.

Hundreds of Hours of Telescope Observations

The new observations were carried out by researchers from the University of Milano-Bicocca together with scientists from the Max Planck Institute for Astrophysics (MPA). The team used MUSE (Multi-Unit Spectroscopic Explorer), a powerful instrument mounted on the European Southern Observatory’s Very Large Telescope in Chile.

Even with such advanced technology, the project required one of the most ambitious MUSE observing campaigns ever conducted in a single region of the sky. Researchers gathered data over hundreds of hours to detect the faint filament clearly enough for detailed analysis.

The study, led by Davide Tornotti, PhD student at the University of Milano-Bicocca, produced the sharpest image ever captured of a cosmic filament stretching roughly 3 million light-years. The structure connects two galaxies that each contain an active supermassive black hole.

The findings were published in Nature Astronomy and provide a new way to study the physical properties of gas inside intergalactic filaments.

A 12-Billion-Year Journey Across Space

“By capturing the faint light emitted by this filament, which traveled for just under 12 billion years to reach Earth, we were able to precisely characterize its shape,” explains Davide Tornotti. “For the first time, we could trace the boundary between the gas residing in galaxies and the material contained within the cosmic web through direct measurements.”

To better interpret the observations, the researchers compared the data with supercomputer simulations of the Universe created at MPA. These simulations predicted what such filamentary structures should look like under current cosmological models.

“When comparing to the novel high-definition image of the cosmic web, we find substantial agreement between current theory and observations,” Tornotti adds.

New Clues About Galaxy Formation

The successful match between observations and simulations gives scientists greater confidence in their understanding of how gas is distributed around galaxies and how galaxies receive the material needed to continue forming stars.

Researchers now hope to identify many more of these faint structures in order to build a broader picture of how matter flows through the cosmic web.

Fabrizio Arrigoni Battaia, MPA staff scientist involved in the study, concludes: “We are thrilled by this direct, high-definition observation of a cosmic filament. But as people say in Bavaria: ‘Eine ist keine’ — one doesn’t count. So we are gathering further data to uncover more such structures, with the ultimate goal to have a comprehensive vision of how gas is distributed and flows in the cosmic web.”

Research from UC Davis Health found that people diagnosed with anxiety disorders had lower levels of choline in the brain than people without anxiety. The finding comes from a study published in Molecular Psychiatry, a Nature journal, and offers a rare look at the chemistry that may be connected to anxiety across several different diagnoses.

The researchers reviewed data from 25 previous studies that measured neurometabolites, the chemicals involved in brain metabolism. Altogether, the analysis included 370 people with anxiety disorders and 342 people without anxiety.

A Consistent Chemical Signal in the Brain

The standout finding was choline. People with anxiety disorders had about 8% lower levels of this nutrient in the brain compared with those in the control groups. The pattern was especially clear in the prefrontal cortex, a brain region that helps regulate thought, emotion, decision making, and behavior.

“This is the first meta-analysis to show a chemical pattern in the brain in anxiety disorders,” said Jason Smucny, co-author and an assistant professor in the Department of Psychiatry and Behavioral Sciences. “It suggests nutritional approaches — like appropriate choline supplementation — may help restore brain chemistry and improve outcomes for patients.”

Choline (pronounced kō-lēn) plays several important roles in the body. It helps form cell membranes and supports brain functions involved in memory, mood regulation, and muscle control. Although the body can make a small amount on its own, most choline must come from food.

Why Anxiety Disorders Matter

Anxiety disorders are among the most common mental health conditions in the United States. Richard Maddock, senior author of the study, is a psychiatrist and research professor in the Department of Psychiatry and Behavioral Sciences. He is also a researcher at the UC Davis Imaging Research Center, where scientists use magnetic resonance imaging (MRI) methods to study brain health.

Maddock has spent decades treating people with anxiety disorders and studying how these conditions affect the brain.

“Anxiety disorders are the most common mental illness in the United States, affecting about 30% of adults. They can be debilitating for people, and many people do not receive adequate treatment,” Maddock said.

Anxiety disorders include generalized anxiety disorder, panic disorder, social anxiety disorders, and phobias.

How the Brain Processes Fear and Stress

Anxiety disorders are connected to the way the brain responds to stress, danger, and uncertainty. Two key regions are often involved: the amygdala, which helps shape the sense of safety or threat, and the prefrontal cortex, which supports planning, decision making, and emotional control.

When this system is working well, the brain can usually separate manageable problems from serious threats. In anxiety disorders, that balance can shift. Everyday concerns may feel overwhelming, and the body’s stress response can become difficult to calm.

Brain chemistry also plays a role. Anxiety disorders have been linked to changes in neurotransmitters, including norepinephrine, which is part of the body’s “fight-or-flight” response. Norepinephrine is often elevated in anxiety disorders, and the UC Davis researchers suggest that this heightened arousal may increase the brain’s demand for choline.

In generalized anxiety disorder, for example, people may worry excessively about ordinary events and struggle to control nervousness or fear.

Measuring Brain Chemicals Without Surgery

Maddock and Smucny have long studied how brain chemistry is connected to mental illness using proton magnetic resonance spectroscopy, also known as 1H-MRS.

This technique is noninvasive and is performed with an MRI machine. Instead of producing a standard image of brain structure, 1H-MRS uses magnetic fields and radio waves to measure chemical levels in tissue.

Maddock had previously seen low choline levels in studies of people with panic disorder. That earlier work helped lead to the larger meta-analysis with Smucny. Even though the researchers expected to see reduced choline, the consistency of the result stood out.

“An 8% lower amount doesn’t sound like that much, but in the brain it’s significant,” Maddock said.

The study also found reduced levels of cortical NAA across brain regions after some exclusions. NAA is often considered a marker related to neuronal health and function. However, the clearest and most consistent signal was the reduction in choline-containing compounds across anxiety disorders.

Choline, Diet, and Mental Health

The researchers think that chronic fight-or-flight activity may raise the brain’s need for choline. If the brain cannot take in enough to meet that demand, choline levels may drop.

That does not mean choline supplements are a proven treatment for anxiety. Maddock emphasized that the question remains open.

“We don’t know yet if increasing choline in the diet will help reduce anxiety. More research will be needed,” Maddock said. He cautions that people with anxiety should not self-medicate with excessive choline supplements.

Still, the finding adds to growing interest in the relationship between nutrition and mental health. Choline is already known to be important for the brain and nervous system, and many people in the United States do not get the recommended daily amount.

“Someone with an anxiety disorder might want to look at their diet and see whether they are getting the recommended daily amount of choline. Previous research has shown that most people in the U.S., including children, don’t get the recommended daily amount,” Maddock said. “Some forms of omega-3 fatty acids, like those found in salmon, may be especially good sources for supplying choline to the brain.”

What Later Research Adds

Since the UC Davis work was published, the broader research picture has remained intriguing but not settled. Related dietary research in adults has suggested that higher choline intake may be linked with lower odds of depression, but the same study did not find a significant adjusted association with anxiety or psychological distress.

That makes the UC Davis brain imaging result especially interesting. It points to a measurable chemical difference inside the brain, but it does not prove that low dietary choline causes anxiety or that increasing choline will relieve symptoms. Controlled trials would be needed to test whether changing choline intake can alter brain chemistry or improve anxiety outcomes.

For now, the findings support a practical but cautious message: nutrition may be one piece of the anxiety puzzle, but it is not a substitute for professional mental health care.

Foods That Provide Choline

Choline is found in several common foods. Rich sources include beef liver, eggs (particularly the yolk), beef, chicken, fish, soybeans and milk, among others.

The study highlights a possible biological link between anxiety and a nutrient the brain depends on every day. It also raises a larger question for future research: whether improving choline status could help restore brain chemistry in people with anxiety disorders.

For now, researchers say the answer is not yet known. But the discovery gives scientists a clearer chemical target to investigate and gives people another reason to pay attention to the nutrients that support brain health.