Author Archives: support

Exploring the Restorative Effects of a Nature Walk on Attention and Cognitive Function

Research conducted by psychology researchers from the University of Utah is adding empirical weight to what American authors John Muir and Henry David Thoreau espoused over a century ago: Spending time in natural surroundings not only nourishes the heart and soul but also benefits cognitive function. Amy McDonnell and David Strayer are at the forefront of this research, which utilises electroencephalography (EEG) to measure participants’ attentional capacity in natural versus urban settings.

Published in Scientific Reports, their study conducted at the university’s Red Butte Garden reveals that a walk in nature enhances executive control processes in the brain beyond the benefits typically associated with exercise alone. This finding contributes significantly to the growing scientific literature on how natural environments positively impact physical and mental health. Reflecting this increasing interest, the University of Utah has established the Nature and Human Health Utah research group to explore these themes further and propose practical solutions.

The researchers suggest that humans have a deep-seated affinity for nature rooted in our evolutionary history—a concept known as biophilia. This innate connection is increasingly threatened by dense urban environments characterised by constant technological stimuli such as cell phones, cars, and computers. According to Strayer, the modern urban jungle contrasts sharply with the therapeutic qualities of natural settings, highlighting a critical need to preserve access to nature for public health.

Strayer, a psychology professor known for his previous work on multitasking and distracted driving, has spent the last decade investigating how nature influences cognitive processes. McDonnell, who conducted the latest research as part of her doctoral dissertation, continues this line of inquiry as a postdoctoral fellow at the University of Utah. Their study, conducted in 2022 at Red Butte Garden, involved 92 participants who underwent EEG recordings before and after a 40-minute walk.

Participants first engaged in a mentally taxing cognitive task—counting backwards from 1,000 by sevens—to deplete their attentional reserves. They were then assigned either a nature walk through Red Butte or an urban walk through the university’s medical campus. The EEG data showed that those who walked in nature exhibited improved executive attention on subsequent tasks compared to those who walked in an urban environment. This improvement in executive control, essential for tasks requiring concentration and problem-solving, underscores the unique cognitive benefits of natural settings.

What distinguishes this study from much of the existing research in the field is its rigorous methodology, particularly its reliance on objective EEG data rather than subjective self-reports. EEG allowed the researchers to precisely map brain activity associated with attentional processes, revealing distinct enhancements in executive control among nature walkers.

McDonnell explained the technical aspects of their approach, detailing how each participant wore a cap fitted with electrodes to capture brain activity. This setup facilitated recording subtle electrical signals across the scalp, providing detailed brain maps highlighting the specific neural mechanisms influenced by environmental exposure.

While the study found significant benefits for executive control, particularly in the prefrontal cortex—an area critical for decision-making and problem-solving—it noted less pronounced effects on alertness and orientation. This specificity suggests that different components of attention may respond differently to environmental stimuli, an area ripe for further investigation.

Looking ahead, McDonnell and Strayer aim to refine their findings to identify which natural settings optimally enhance cognitive function and determine the necessary duration of exposure for maximal benefits. Their ultimate goal is to inform urban planning and design practices that promote mental and physical well-being by incorporating elements of natural environments.

Strayer emphasised the broader implications of their research, highlighting how understanding the cognitive benefits of nature could lead to innovative urban interventions. By integrating nature-inspired elements into urban landscapes, cities could support and enhance public health outcomes, counterbalancing the cognitive stresses imposed by modern urban living.

Continuing their work at Red Butte Garden, the researchers are investigating how cellphone use during walks may influence cognitive responses. Strayer views this ongoing research as complementary to his broader interest in distraction and attention, framing them as interconnected facets of mental functioning. He posits that while urban environments may overload cognitive resources, natural environments offer a refreshing reprieve, allowing the brain to reset and operate more efficiently.

McDonnell and Strayer’s research underscores the profound cognitive benefits of spending time in natural environments, supported by robust EEG evidence. Their findings not only validate the intuitive appeal of nature but also provide scientific insights that could reshape urban planning paradigms, fostering healthier and more resilient communities in an increasingly urbanised world.

More information: Amy S. McDonnell et al, Immersion in nature enhances neural indices of executive attention, Scientific Reports. DOI: 10.1038/s41598-024-52205-1

Journal information: Scientific Reports Provided by The University of Utah

Over 150,000 Deaths Linked to Heatwaves by 2019: First Global Mapping

A study led by Monash University has mapped global heatwave-related mortality from 1990 to 2019, revealing over 153,000 additional deaths per warm season, with nearly half occurring in Asia. The research, published in PLOS Medicine and led by Professor Yuming Guo, analysed daily death and temperature data from 750 locations across 43 countries. It found a significant increase in heatwave-related deaths, particularly in Southern and Eastern Europe, polar and alpine regions, and areas with higher incomes.

Comparing temperatures from 1850–1990 to 2013–2022, global surface temperatures have risen by 1.14℃, projected to increase by 0.41-3.41℃ by 2081–2100 due to climate change. This warming trend intensifies heatwaves in frequency, severity, and geographical spread. The study underscores that heatwaves contribute to a mortality burden averaging 236 deaths per ten million residents per warm season.

The study, which collaborated with Shandong University, the London School of Hygiene & Tropical Medicine, and other global institutions, highlights regional disparities in heatwave impacts. Tropical climates and lower-income regions saw a decline in heatwave-related mortality from 1990 to 2019. However, the findings stress the urgent need for tailored adaptation strategies and risk management at all government levels.

Professor Guo emphasises that while previous studies on heatwave-related deaths have been limited in scope, their research provides comprehensive evidence of significant global mortality impacts over the past three decades. Heatwaves induce severe thermal stress on the body, leading to organ dysfunction and heat-related illnesses like heat exhaustion, cramps, and stroke, exacerbating pre-existing chronic conditions and potentially causing premature death and psychiatric disorders.

More information: Qi Zhao et al, Global, regional, and national burden of heatwave-related mortality from 1990 to 2019: A three-stage modelling study, PLoS Medicine. DOI: 10.1371/journal.pmed.1004364

Journal information: PLoS Medicine Provided by Monash University

Understanding Immune Responses: Insights into COVID-19 Resistance among Certain Individuals

Scientists have recently unveiled significant insights into why some individuals avoid COVID-19 despite exposure to the virus. Published in Nature, this groundbreaking study, led by researchers from the Wellcome Sanger Institute, University College London (UCL), and Imperial College London, took a novel approach. Using single-cell sequencing, the study examined immune responses among healthy adult volunteers in the world’s first COVID-19 human challenge study. Unlike previous research focusing on symptomatic patients, this study concentrated on individuals with no prior COVID-19 history, offering a unique opportunity to observe immune responses in an immunologically naïve cohort. Participants were deliberately exposed to SARS-CoV-2 and monitored extensively, with detailed analyses conducted on blood and nasal samples using single-cell sequencing, generating a dataset encompassing over 600,000 individual cells.

Key findings from this study have highlighted previously unidentified immune responses involved in rapid virus detection and clearance. Individuals who successfully cleared the virus exhibited subtle innate immune responses rather than the typical widespread immune activation observed in severe cases. These responses included heightened activity of specific mucosal immune cells in the blood and decreased inflammatory white blood cells. Researchers also identified a gene, HLA-DQA2, crucial in preventing sustained viral infections among participants. Those with higher HLA-DQA2 activity levels before exposure showed enhanced resistance to the virus, establishing a foothold. These findings offer a promising potential for developing targeted therapies and vaccines that mimic these natural protective mechanisms.

In contrast, individuals who developed prolonged SARS-CoV-2 infections exhibited a rapid immune response in the blood but a slower response in the nasal passages, allowing the virus to persist locally. The study also identified common patterns in activated T cell receptors across participants, offering insights into immune cell communication crucial for developing targeted therapies. These insights enhance our understanding of COVID-19 immune responses and pave the way for potential treatments and vaccines that mimic natural protective mechanisms.

Dr Rik Lindeboom from the Netherlands Cancer Institute, a co-first author, underscored the significance of studying immune responses in adults encountering a new pathogen under controlled conditions. This approach enabled researchers to dissect immune responses without confounding factors like comorbidities or varied infection times. Dr Marko Nikolić, senior author from UCL and honorary consultant in respiratory medicine, highlighted the study’s contribution to elucidating early events determining virus clearance or establishment. The findings provide a comprehensive view of immune responses, which could inform the development of therapies targeting not only COVID-19 but other infectious diseases as well.

Dr Sarah Teichmann, senior author and co-founder of the Human Cell Atlas, highlighted the study’s relevance to mapping critical immune cells essential for combating infections. Integrated with ongoing Human Cell Atlas efforts, this knowledge promises to illuminate how different individuals respond to pathogens and vaccines. Shobana Balasingam from Wellcome’s Infectious Disease team noted the study’s importance in advancing our understanding of COVID-19 responses, particularly in differentiating natural and vaccine-induced immune reactions. The findings underscore the need for expanding such studies to diverse settings to develop tailored therapeutics and vaccines suitable for global populations, particularly those in low-resource environments where infectious diseases are endemic.

This study deepens our understanding of immune responses critical in COVID-19 prevention and lays the groundwork for future research into infectious disease dynamics and immune system interactions.

More information: Rik G. H. Lindeboom et al, Human SARS-CoV-2 challenge uncovers local and systemic response dynamics, Nature. DOI: 10.1038/s41586-024-07575-x

Journal information: Nature Provided by Wellcome Sanger Institute

Regular Consumption of Kimchi Linked to Reduced Obesity Risk

Kimchi, a beloved staple of Korean cuisine, is not just a dish, but a cultural icon. Its unique preparation involves the fermentation of vegetables like cabbage and radish, combined with seasonings such as onion, garlic, and fish sauce. This fermentation process not only preserves the vegetables but also enhances their nutritional value, making kimchi a low-calorie, high-fibre, and vitamin-rich food. The presence of microbiome-friendly lactic acid bacteria and beneficial polyphenols further contribute to its health benefits.

Recent experimental studies have spotlighted certain strains of bacteria found in kimchi, such as Lactobacillus brevis and L. plantarum, which exhibit potential anti-obesity effects. To explore this further, researchers investigated whether regular kimchi consumption might correlate with reduced risks of overall and abdominal obesity, both significant health concerns.

The data for this study were meticulously collected from the Health Examinees (HEXA) study, a robust research initiative involving a substantial sample size of 115,726 participants (36,756 men and 78,970 women, average age 51). This community-based, longitudinal study is part of the larger Korean Genome and Epidemiology Study, which aims to identify environmental and genetic factors influencing chronic conditions among Korean adults over 40. The comprehensive nature of this study ensures the reliability of the findings.

Participants’ dietary habits were assessed using a 106-item food frequency questionnaire, which captured their consumption patterns over the previous year. Various types of kimchi, including baechu (cabbage), kkakdugi (radish), Babak, dongchimi, and others, were quantified based on typical portion sizes.

Anthropometric measurements such as height, weight (used to calculate BMI), and waist circumference were recorded. Obesity was defined by a BMI exceeding 25, while abdominal obesity was indicated by waist circumferences of at least 90 cm for men and 85 cm for women. Notably, 36% of men and 25% of women in the study were classified as obese.

The study’s findings revealed a unique ‘J-shaped’ association between kimchi consumption and obesity. While higher kimchi consumption was associated with increased intake of energy, carbohydrates, protein, fat, sodium, and rice, moderate consumption showed significant benefits. Participants who consumed up to three daily servings of kimchi demonstrated an 11% lower prevalence of obesity compared to those consuming less than one serving daily. This ‘J-shaped’ association underscores the importance of moderation in kimchi consumption for health benefits.

Among men, consuming three or more daily servings of baechu kimchi was associated with a 10% lower prevalence of obesity and abdominal obesity. In women, consuming two to three daily baechu kimchi was linked to an 8% lower prevalence of obesity, while one to two servings correlated with a 6% lower prevalence of abdominal obesity.

Lower-than-average consumption of kkakdugi kimchi showed around a 9% lower prevalence of obesity in both sexes. Daily intake of 25 grams among men and 11 grams among women was associated with an 8% to 11% reduction in abdominal obesity risk compared to non-consumers.

The study’s observational nature precludes establishing causation, and limitations include potential inaccuracies in self-reported dietary intake and the study’s applicability primarily to Korean populations. Concerns over kimchi’s sodium content were noted, although the potassium content in fermented vegetables may mitigate these effects.

Researchers caution against excessive kimchi consumption due to its potential to increase obesity prevalence, particularly highlighting its role as a significant source of dietary sodium. They recommend moderate consumption to maximise the health benefits associated with its nutritional components.

More information: Hyein Jung et al, Association between kimchi consumption and obesity based on BMI and abdominal obesity in Korean adults: a cross-sectional analysis of the Health Examinees study, BMJ Open. DOI: 10.1136/bmjopen-2023-076650

Journal information: BMJ Open Provided by BMJ Group

Orienteering: A Powerful Ally Against Dementia, Enhancing Both Brain and Physical Health for Speedy Participants

The sport of orienteering, a unique blend of physical exercise and challenging navigation tasks, has the potential to offer more than just physical benefits, as recent research by kinesiologists at McMaster University suggests. This study indicates that the more intense the orienteering activity, the greater the cognitive benefits, potentially serving as a powerful tool in the fight against cognitive decline, dementia, and serious diseases such as Alzheimer’s. This research, a continuation of a 2023 study, delves into the mental effects of orienteering at various levels of intensity, offering a glimmer of hope for the future of cognitive health.

The researchers chose orienteering as their focus because it requires participants to rapidly navigate a series of checkpoints across unknown terrain using only a map and compass. Orienteering demands focused attention and quick decision-making based on spatial information, which engages the hippocampus—a part of the brain particularly vulnerable to age-related decline. Degeneration in the hippocampus can negatively impact learning, memory, and spatial cognition. “Remarkably, even a single session of orienteering improved spatial memory in our study participants,” says lead author Emma Waddington, a graduate student in the Department of Kinesiology at McMaster, who conducted the study with colleagues from Western University. “This suggests that even occasional participation in orienteering could enhance spatial abilities and potentially delay their decline with age.”

For the study, recently published in the journal PLOS One, groups of active, healthy young adults with no prior orienteering experience navigated a course on the McMaster campus. Some participants walked the course, while others ran. A control group exercised vigorously without any navigation tasks. Researchers used blood samples to measure participants’ lactate levels, an indicator of exercise intensity, and brain-derived neurotrophic factor (BDNF), which promotes brain plasticity. They also tested memory performance before and after the sessions. The findings showed that running increased lactate, BDNF, and memory performance more than walking, with notable benefits for spatial memory in those running while orienteering.

Losing the ability to navigate and find one’s way is among the earliest and most common symptoms of Alzheimer’s disease, affecting half of all individuals, even in the mildest stages. “With no known cure for dementia, preventative measures that can help stave off age-related cognitive decline are essential,” says Jennifer Heisz, Canada Research Chair in Brain Health and Aging at McMaster University, who supervised the research. Modern-day reliance on GPS-guided vehicles may mean that many people rarely use their natural wayfinding skills, potentially leading to deficits in spatial memory and a diminished sense of direction. Orienteering could help revive these skills, Heisz notes. Exploring the long-term effects of orienteering on human cognition and its impact across different age groups remains a vital area for future research.

More information: Emma E. Waddington et al, Orienteering combines vigorous-intensity exercise with navigation to improve human cognition and increase brain-derived neurotrophic factor, PLoS ONE. DOI: 10.1371/journal.pone.0303785

Journal information: PLoS ONE Provided by McMaster University

Early Life Heat and Cold Exposure: Effects on Brain White Matter Development

A recent study involving over 2,000 preadolescents suggests that exposure to heat and cold during early life may significantly impact the microstructure of white matter in the brain, particularly for children residing in economically disadvantaged neighbourhoods. Published in Nature Climate Change, the research underscores the vulnerability of foetuses and young children to extreme temperatures, highlighting implications for their long-term neurodevelopmental health. Led by the Barcelona Institute for Global Health (ISGlobal) and IDIBELL, in collaboration with Erasmus University Medical Center Rotterdam (ERASMUS MC) and the Centro de Investigación Biomédica en Red (CIBER), the study examines associations between temperature exposure and brain structure, using data from the Generation R Study in Rotterdam.

In the current climate emergency context, the study illuminates the alarming vulnerability of children to temperature fluctuations. Their developing thermoregulatory systems, still maturing during early life stages, make them particularly susceptible to these variations.

Mònica Guxens, a researcher at ISGlobal, Erasmus MC, and CIBERESP, explains, “The developing brain of foetuses and children is highly susceptible to environmental exposures. While preliminary evidence suggests that exposure to heat and cold can affect mental well-being and cognitive performance, studies evaluating structural brain changes due to these exposures are limited.”

The study, led by Guxens, focused on the white matter structure in preadolescent brains to pinpoint vulnerable periods to temperature exposure during early life. The researchers used advanced MRI techniques to assess brain connectivity by analysing water diffusion patterns in white matter. Specifically, they measured mean diffusivity and fractional anisotropy—markers of white matter maturation and integrity.

The findings reveal that exposure to cold during pregnancy and the first year of life and heat from birth to three years old correlated with higher mean diffusivity in preadolescents. This suggests slower maturation of white matter, which is crucial for efficient communication between brain regions. Laura Granés, IDIBELL and ISGlobal researcher and study first author, notes, “White matter fibres facilitate brain communication, and our study indicates that exposure to extreme temperatures may delay this process.”

The study highlights that the most significant changes in brain connectivity parameters occur during early childhood, underscoring the vulnerability of this developmental phase to environmental influences. Carles Soriano, co-author and researcher at IDIBELL, UB, and CIBERSAM, adds, “Our results suggest that temperature exposure during rapid brain development stages may have enduring effects on white matter microstructure.”

Interestingly, no association was found between early life temperature exposure and fractional anisotropy at ages 9-12. The researchers propose that mean diffusivity may provide a more reliable indicator of white matter development than fractional anisotropy.

Further analysis, stratified by socioeconomic status, revealed that children from poorer neighbourhoods exhibited heightened vulnerability to temperature exposure. These children showed similar susceptibility windows to cold and heat but starting earlier, possibly influenced by housing conditions and energy poverty.

Potential mechanisms linking temperature exposure to neurodevelopmental outcomes include disrupted sleep patterns, placental dysfunction, hormonal changes such as increased cortisol production, and inflammatory responses. Guxens underscores, “Our findings highlight the pressing need for robust public health strategies to protect vulnerable communities, particularly amidst ongoing climate challenges.”

The study’s findings underscore the critical impact of early life temperature exposure on brain development, emphasising the urgent need for targeted interventions and policy initiatives to safeguard children’s health in a changing climate landscape.

More information: Laura Granés et al, Early life cold and heat exposure impacts white matter development in children, Nature Climate Change. DOI: 10.1038/s41558-024-02027-w

Journal information: Nature Climate Change Provided by Barcelona Institute for Global Health

Night-time Heat Heightens Stroke Risk

A recent investigation by researchers from Helmholtz Munich and Augsburg University Hospital has revealed a significant link between nocturnal heat and increased stroke risk. The study, which drew upon extensive data and was led by Dr Alexandra Schneider, underscores the pressing need for preventive measures as climate change leads to more frequent and intense hot nights.

The study, which spanned 15 years and included approximately 11,000 stroke cases treated at Augsburg University Hospital, revealed a notable seven per cent rise in stroke risk following periods of extreme nocturnal heat. Dr Cheng He, the study’s lead author, highlighted that elderly individuals and women face heightened susceptibility, with clinics predominantly diagnosing strokes with mild symptoms post hot nights.

Moreover, the research team noted a concerning trend: from 2013 to 2020, the risk of stroke associated with elevated nocturnal temperatures saw a marked increase compared to the preceding period (2006-2012). Prof. Michael Ertl, overseeing the Stroke Unit at Augsburg University Hospital, noted a rise from two additional annual stroke cases in the earlier period to 33 extra cases annually in recent years.

The implications extend beyond epidemiology, prompting recommendations for adaptive strategies in urban planning. The researchers advocate for mitigating urban heat islands and enhancing healthcare preparedness. These initiatives are crucial for safeguarding public health against escalating nocturnal heat impacts.

Furthermore, the study’s findings are pivotal for hospitals, enabling better anticipation and allocation of resources in response to weather forecasts predicting hot nights. Prof. Markus Naumann, Director of the Neurological University Hospital in Augsburg, stressed the importance of proactive staffing to manage potential influxes of stroke patients during such periods.

The term “tropical nights,” defined by the Hot Night Excess Index (HNE), quantifies nocturnal temperature anomalies. It measures deviations above a threshold (14.6 °C in this study), which signifies temperatures surpassed during only the warmest five per cent of nights within the study period. The HNE index provides a metric to gauge the intensity of nocturnal heatwaves, aiding in understanding their impact on health outcomes.

Looking ahead, the research aims to translate these findings into practical applications, informing public health strategies and urban policies aimed at mitigating the adverse effects of nocturnal heat. Dr. Schneider underscored the importance of early implementation of preventive measures, stressing their potential to mitigate future health risks associated with climate change-induced nocturnal temperature rises.

The study by Helmholtz Munich and Augsburg University Hospital not only illuminates a critical nexus between nocturnal heat and stroke risk but also underscores the need for proactive measures in urban planning and healthcare. These measures are crucial in countering the health impacts of climate change-driven temperature shifts.

More information: Cheng He et al, Nocturnal heat exposure and stroke risk, European Journal of Nutrition. DOI: 10.1093/eurheartj/ehae277

Journal information: European Journal of Nutrition Provided by Helmholtz Munich

Comprehending Cardiac Dysfunction: A Deeper Look into Heart Issues

Recent research has unveiled a significant discovery in the field of heart health. It has been found that heart failure induces lasting physiological stress, potentially contributing to recurrent health issues. This is not just a temporary effect, but a ‘stress memory’ phenomenon that persists in hematopoietic stem cells, the cells responsible for blood and immune cell production, particularly macrophages crucial for heart health. During heart failure, the DNA modifications of these stem cells are altered, affecting the transformative growth factor beta (TGF-β) pathway. Suppressed TGF-β levels hinder macrophage production, exacerbating heart failure and associated complications. The implications of this ‘stress memory’ are profound, offering a promising strategy for mitigating recurrent heart failure, with potential applications in the early detection of stress accumulation.

Global efforts towards sustainable development goals, including improved health and well-being, yield positive outcomes, with life expectancy projected to rise by approximately 4.5 years by 2050. Public health initiatives have significantly reduced disease incidence and mortality rates, particularly for cardiovascular diseases. Despite these advances, heart disease remains the world’s leading cause of death, affecting an estimated 26 million people through conditions like heart failure.

Researchers in Japan have focused on understanding the mechanisms underlying heart failure recurrence and associated organ deterioration. Their investigations suggest that stress accumulated during heart failure, specifically in hematopoietic stem cells, may play a pivotal role. Project Professor Katsuhito Fujiu from the University of Tokyo’s Graduate School of Medicine highlights the role of these stem cells in the bone marrow and responsible for immune cell production. Studies in mice with heart failure reveal epigenetic changes in DNA, including suppression of the TGF-β pathway in hematopoietic stem cells, leading to dysfunctional immune cell production.

This stress-induced ‘memory’ persists over time, as demonstrated by experiments in which bone marrow transplanted from mice with heart failure perpetuated dysfunctional immune cell production and increased susceptibility to heart failure and organ damage in recipient mice. Fujiu describes this phenomenon as ‘stress memory’, wherein the effects of heart failure stress continue to influence the body long after the initial episode, potentially exacerbating future health challenges.

Excitingly, the identification of these epigenetic changes in the TGF-β pathway has opened new avenues for therapeutic interventions. Project Professor Katsuhito Fujiu from the University of Tokyo’s Graduate School of Medicine suggests innovative treatments that could potentially revolutionize the management of heart failure. These treatments aim to prevent stress memory accumulation during heart failure hospitalization, such as supplementing active TGF-β to restore normal signalling and correcting the epigenome of hematopoietic stem cells. These strategies hold the promise of not only preventing recurrent heart failure but also intercepting its development before significant symptoms arise, offering a beacon of hope for the future of heart health.

The research team aims to develop diagnostic tools capable of detecting and mitigating stress memory in human patients. Their ultimate goal is to enhance early intervention strategies, transforming the management of heart failure by addressing underlying physiological stressors before they manifest clinically.

More information: Yukiteru Nakayama et al, Heart failure promotes multimorbidity through innate immune memory, Science Immunology. DOI: 10.1126/sciimmunol.ade3814

Journal information: Science Immunology Provided by The University of Tokyo

UC Irvine Study Reveals Heat Waves’ Harmful Effects on Vital Organs

Researchers from the University of California, Irvine, have uncovered the molecular origins of heat stress’s detrimental impact on the gut, liver, and brain in elderly individuals. These findings highlight the prospect of developing targeted prognostic and therapeutic strategies. The interconnectedness of these organs forms a complex communication network that spans from the gastrointestinal system to the nervous system. Understanding this gut-liver-brain axis is critical for safeguarding human health, as it influences various physiological processes such as appetite regulation and mental health.

Published in Scientific Reports, a Nature Portfolio journal, their study on mouse models represents a pioneering effort to elucidate the molecular mechanisms underlying heat stress’s effects on this vital biological dialogue. Saurabh Chatterjee, corresponding author and professor of environmental and occupational health at UC Irvine’s Program in Public Health, underscores the impact of inflammation on cognitive decline and age-related diseases. He explains, “Investigating how heat stress disrupts gut-liver-brain communication enables us to better protect our increasingly vulnerable aging population.”

Employing RNA analysis and bioinformatics, Chatterjee and his team identified heat stress-induced changes in gene expression in the brain and liver of elderly mice. Notably, they observed a significant increase in ORM2 production—a liver-derived protein—in heat-stressed mice compared to unstressed controls. This finding suggests organ dysfunction induced by heat stress. The researchers hypothesize that elevated ORM2 secretion may be a compensatory response linked to gut inflammation and dysfunction.

Moreover, the potential impact of ORM2 on brain function through a compromised blood-brain barrier underscores the intricate interplay between multiple organs. This finding not only deepens our understanding of the molecular mechanisms of heat-related health challenges but also opens up new avenues for future research and therapeutic developments. The study also highlights ORM2’s potential as a biomarker for targeted interventions, offering a glimmer of hope in mitigating liver disease exacerbated by heat exposure.

Chatterjee underscores the urgency of their findings, stating, “Our discoveries are not just academic, they have immediate practical implications. With climate change contributing to escalating temperatures and recurrent heat waves, our aging population faces increasing risks of acute and chronic heat stress, threatening their health. The time to act is now.” In conclusion, the UC Irvine study not only sheds light on the molecular underpinnings of heat stress’s impact on vital organs but also offers a foundation for innovative approaches to mitigate its adverse effects on health, particularly in older adults.

More information: Subhajit Roy et al, Periodic heat waves-induced neuronal etiology in the elderly is mediated by gut-liver-brain axis: a transcriptome profiling approach, Scientific Reports. DOI: 10.1038/s41598-024-60664-9

Journal information: Scientific Reports Provided by University of California, Irvine

Unlock the Secret to Better Kimchi with Ancient Techniques

Fermented foods like kimchi have been integral to Korean cuisine for thousands of years. Since ancient times, Korean chefs have used onggi — traditional handmade clay jars — to ferment kimchi. Today, most kimchi is made through mass fermentation in glass, steel, or plastic containers, but it has long been claimed that the highest quality kimchi is fermented in onggi. Kimchi purists now have scientific validation, thanks to recent research from David Hu, professor in the George W. Woodruff School of Mechanical Engineering at Georgia Tech, and Soohwan Kim, a second-year PhD student in Hu’s lab.

In a combined experimental and theoretical study, Hu and Kim measured carbon dioxide levels in onggi during kimchi fermentation. They developed a mathematical model to show how the gas was generated and moved through the onggi’s porous walls. By bringing the study of fluid mechanics to bear on an ancient technology, their research highlights the work of artisans. It provides the missing link for how traditional earthenware allows for high-quality kimchi. Their study was published in the Journal of the Royal Society Interface. “We wanted to find the ‘secret sauce’ for how onggi makes kimchi taste so good,” Hu said. “So, we measured how the gases evolved while kimchi fermented inside the onggi — something no one had done before.”

The porous structure of these earthenware vessels mimics the loose soil where lactic acid bacteria — known for their healthy probiotic nature — are found. While previous studies have shown that kimchi fermented in onggi has more lactic acid bacteria, no one knows exactly how the phenomenon is connected to the unique material properties of the container. First, Kim obtained a traditional, handmade onggi jar from an artisan in his hometown of Jeju, South Korea, a region famous for onggi. Back at Georgia Tech, Hu and Kim first tested the permeability of the onggi by observing how water evaporated through the container over time.

Next, they installed carbon dioxide and pressure sensors into the onggi and a typical, hermetically sealed glass jar. They prepared their own salted cabbage and placed it in both containers. They then used the sensors to measure and compare the change in carbon dioxide — a signature of fermentation. Hu and Kim also developed a mathematical model based on the porosity of the onggi. The model allowed them to infer the generation rate of carbon dioxide since the onggi lets carbon dioxide out gradually. They concluded that the onggi’s porous walls permitted the carbon dioxide to escape the container, accelerating the fermentation speed.

The onggi’s porosity also functioned as a “safety valve,” resulting in a slower increase in carbon dioxide levels than the glass jar while blocking the entry of external particles. Their data revealed that the carbon dioxide level in onggi was less than half of that in glass containers. They also found that the beneficial bacteria in the onggi-made kimchi increased 26% more than in the glass counterpart. In the glass jar, the lactic acid bacteria became suffocated by their carbon dioxide in the closed glass container. It turns out that because the onggi releases carbon dioxide at a small rate, the lactic acid bacteria are happier and reproduce more.

“Onggi were designed without modern knowledge of chemistry, microbiology, or fluid mechanics, but they work remarkably well,” Kim said. “It’s very interesting to get these new insights into ancient technology through the lens of fluid dynamics.” Onggi’s semi-porous nature is unique compared to other forms of earthenware. A clay container that leaks, but only slightly, is not easy to make. Terra cotta containers, for example, quickly leak water. “It’s amazing that, for thousands of years, people have been building these special containers out of dirt, but in many ways, they are very high-tech,” Hu said. “We discovered that the right amount of porosity enables kimchi to ferment faster, and these onggi provide that.”

While the use of onggi by artisans is dwindling, the research by Hu and Kim serves as a reminder of the value of these traditional methods. The study’s findings not only validate the artisan work but also inspire the development of energy-efficient methods for fermenting and storing foods. Moreover, the aesthetic appeal of onggi adds to their allure, making them a unique and beautiful addition to any kitchen.

More information: Soohwan Kim et al, Onggi’s permeability to carbon dioxide accelerates kimchi fermentation, Journal of The Royal Society Interface. DOI: 10.1098/rsif.2023.0034

Journal information: Journal of The Royal Society Interface Provided by Georgia Institute of Technology

Impact of Extreme Temperatures on Stroke Mortality in Low-Income Countries

A study led by Harvard T.H. Chan School of Public Health has identified a significant association between extreme temperatures and increased risks of death from both ischemic and hemorrhagic stroke. Scheduled for publication on May 22, 2024, in Stroke, the research underscores that this relationship is particularly pronounced in low-income countries compared to their high-income counterparts.

Lead author Barrak Alahmad, a research fellow in the Department of Environmental Health, highlighted the study’s implications for understanding climate change’s impact on stroke mortality. He emphasised that as temperatures become more extreme, fatal strokes are anticipated to rise, potentially exacerbating the disparity in stroke mortality between high- and low-income countries, with the latter likely bearing a disproportionate burden of climate-related health impacts.

Prior investigations into the correlation between extreme temperatures and stroke mortality have yielded inconsistent findings. Many studies have been confined to single cities or countries, predominantly in high-income regions, and few have differentiated between ischemic and hemorrhagic stroke subtypes. To address these gaps, the researchers leveraged the Multi-Country Multi-City Network, a global consortium in environmental health, to compile a comprehensive database spanning 522 cities across 25 countries. This dataset encompassed over 3.4 million ischemic stroke deaths and 2.4 million hemorrhagic stroke deaths reported between 1979 and 2019.

The study reveals that extreme cold and hot days contributed significantly to stroke mortality. Specifically, for every 1,000 deaths from ischemic or hemorrhagic stroke, approximately 11 were attributable to extreme temperatures. The coldest and hottest 2.5% of days were associated with 9.1 and 2.2 excess deaths from ischemic stroke, respectively, and 11.2 and 0.7 excess deaths from hemorrhagic stroke, respectively. Notably, low-income countries experienced a higher burden of heat-related hemorrhagic stroke mortality compared to high-income countries. However, evidence linking cold temperatures to hemorrhagic stroke mortality in low-income countries was suggestive rather than conclusive. Interestingly, the study did not find a clear relationship between a country’s GDP and the risk of temperature-related ischemic stroke mortality.

The researchers hypothesised that factors such as better indoor temperature regulation and lower rates of outdoor work in high-income countries, coupled with poorer-quality healthcare infrastructure in low-income countries, may contribute to these disparities. They stressed the need for further investigation to elucidate the underlying drivers behind the heightened vulnerability of low-income countries to temperature-related hemorrhagic stroke mortality and to identify effective interventions.

The study’s limitations include its geographical focus, with rural areas and regions in South Asia, Africa, and the Middle East being underrepresented. Additionally, the study did not collect or analyse individual-level demographic data. Furthermore, the focus solely on stroke deaths underscores the necessity for additional research into the incidence of non-fatal strokes to comprehensively assess the overall burden of temperature-related stroke impacts.

Alahmad urged professional stroke societies to invest more in such research, particularly as climate change escalates, and to spotlight emerging environmental risk factors that could exacerbate strokes, already a significant contributor to global mortality rates. He emphasised the importance of expanding this research to inform better public health policies to mitigate the adverse health effects of climate change.

This study by Harvard T.H. Chan School of Public Health underscores the critical link between extreme temperatures and stroke mortality, highlighting the urgent need for targeted interventions, especially in low-income countries most vulnerable to climate change’s health impacts. As global temperatures continue to rise, understanding and addressing these risks will be essential in mitigating the future burden of stroke morbidity and mortality worldwide.

More information: Barrak Alahmad et al, Extreme Temperatures and Stroke Mortality: Evidence From a Multi-Country Analysis, Stroke. DOI: 10.1161/STROKEAHA.123.045751

Journal information: Stroke Provided by Harvard T.H. Chan School of Public Health

Higher Costs of Nature’s Decline Revealed

Researchers advocate for governments to adopt a novel approach to calculating the benefits of conserving biodiversity and nature for future generations. This method, proposed in the journal Science, aims to integrate the monetary value of ecosystem services, such as air and water filtration, crop pollination, and recreational value, into cost-benefit analyses for public infrastructure projects. The objective is to enhance the visibility of biodiversity loss and the benefits of nature conservation in political decision-making processes.

Current methodologies for valuing ecosystem services are criticised for their limitations in capturing how these values evolve. In contrast, the new approach considers the projected increase in monetary value as human incomes rise and the expected decline in biodiversity, treating nature as a progressively scarce resource. This economic principle acknowledges that people are willing to invest more in conserving nature as incomes grow. Additionally, it recognises that as ecosystem services become scarcer, their monetary value increases, a phenomenon fundamental to economics.

Professor Moritz Drupp, leading the study on sustainability economics at the University of Hamburg, emphasises that their formula provides governments with a tool to estimate future values of essential ecosystem services crucial for decision-making. The research underscores two critical factors influencing these adjustments: the annual rise in global income adjusted for inflation and the diminishing availability of biodiversity resources. These considerations argue for setting significantly higher present values of ecosystem services in contemporary cost-benefit analyses, potentially exceeding 130 per cent when accounting solely for income growth and over 180 per cent when also factoring in the impact on endangered species listed in the Red List Index.

The research team includes notable UK-based academics like Professor Mark Freeman from the University of York, Dr Frank Venmans from the LSE, and Professor Ben Groom from the University of Exeter. They highlight that current environmental valuation methods often undervalue nature over time compared to other goods and services. Their proposed uplift in ecosystem values aims to rectify this oversight and suggests its incorporation into future Treasury analyses supporting budgetary decisions.

Dr Venmans provides a specific example with coral reefs, predicting their decline due to climate change and emphasising the increased value of remaining reefs amidst rising household incomes. This scenario underscores the urgency for governments to reassess the long-term benefits of preserving ecosystems with enduring impacts. Professor Freeman underscores the urgency for governments to align the appraisal of ecosystem protection with other significant public investments, ensuring consistency across projects like HS2 and broader infrastructure spending.

The researchers stress that political decisions can mitigate biodiversity loss, underscoring the necessity for governments to comprehensively evaluate the ramifications of their policies today and in the future. Their work seeks to equip policymakers with robust tools to integrate the economic value of ecosystem services into decision-making frameworks, fostering sustainable development practices that safeguard natural resources for future generations. This comprehensive evaluation is crucial for making informed and responsible decisions.

More information: Moritz Drupp et al, Accounting for the increasing benefits from scarce ecosystems, Science. DOI: 10.1126/science.adk2086

Journal information: Science Provided by University of Exeter