Are ultramarathon runners really at increased risk of bowel cancer?

Source: The Conversation – UK – By Justin Stebbing, Professor of Biomedical Sciences, Anglia Ruskin University

Izf/Shutterstock.com

Exercise is a cornerstone of good health and evidence shows it can even help prevent cancers returning following treatment. But new findings are raising an unexpected question: could very high-volume endurance training carry its own risks?

At the 2025 American Society of Clinical Oncology meeting, researchers from Inova Schar Cancer Institute reported that a surprising number of dedicated marathon and ultramarathon runners had precancerous growths in their colons. Among 100 athletes aged 35 to 50, 15% had advanced adenomaslesions that can develop into bowel cancer – while 41% had at least one adenoma.

The study is small and not yet peer-reviewed, but the signal is strong enough to have captured global attention. Here’s what the findings really mean, why experts urge caution in interpreting the results, and what runners should watch for.

At first glance, it seems counterintuitive. Decades of evidence show regular exercise lowers cancer risks, including bowel cancer, and improves outcomes after a cancer diagnosis. This study doesn’t overturn that science. Instead, it suggests a narrow group of young, very high–volume endurance athletes might face unique bowel stress that could increase their odds of developing precancerous changes over time.

Young people with colon cancer has been called a new epidemic, and we don’t really understand why it’s increasing so much.

The Inova study deliberately excluded people with known genetic conditions or bowel disease to focus on runners who otherwise seemed low risk. Yet their screening found more advanced lesions than expected for that age group – a pattern outside experts, commenting in the New York Times, described as worth investigating, not a final answer.

How might heavy endurance training contribute to bowel changes? One theory focuses on temporary blood flow reductions to the gut during prolonged, intense exercise. Distance runners are familiar with runner’s colitis – cramping and occasional bleeding after long runs. Repeated cycles of low–oxygen stress, inflammation and tissue repair in the bowel could, theoretically, encourage adenoma development in susceptible people.

The Inova team highlighted this mechanism based on observations and runners’ reports of gut symptoms, though the study didn’t directly measure blood flow, oxygen or inflammation markers. It also didn’t isolate other lifestyle factors that might matter, such as dehydration strategies, anti–inflammatory drug use, specific nutrition practices, or very low body fat levels.

Just as important is what this study doesn’t establish. It doesn’t prove marathons or ultramarathons cause bowel cancer. It doesn’t show most young–onset bowel cancers occur in runners – doctors not involved in the study emphasised that most younger patients with these cancers aren’t endurance athletes. And it doesn’t address whether more moderate exercise carries similar risks.

The comparison point – the expected rate of advanced adenomas in the late 40s – comes from broader population studies, not from a matched control group. That makes the observed difference notable but still preliminary.

The research is clinically grounded, but its size and design mean it should be seen as a starting point for larger studies rather than a basis for changing general exercise guidance.

Still, there are practical lessons for endurance athletes and doctors. First, persistent blood in stool, changes in bowel habits, unexplained stomach pain, or iron–deficiency anaemia shouldn’t be dismissed as “just running”.

In a community where gut complaints are common and often normalised, it’s easy to miss warning signs. The lead oncologist argued that young runners with bleeding after long runs should be offered screening – a stance grounded in the fact that colonoscopy can remove precancerous lesions and prevent cancers developing. This is more cautious than current guidelines for average–risk adults but aligns with individualised, symptom–driven care.

Second, the study reinforces the difference between exercise as medicine and exercise as extreme sport. For cancer prevention and overall health, the strongest evidence supports regular, moderate–to–vigorous activity, not necessarily repeated ultra–endurance feats.

A yellow arrow pointing to a polyp in the large intestine.
Polyps can be removed during colonoscopy.
WendyJo/Shutterstock.com

Careful attention needed – not panic

Recent conferences highlighted data showing structured exercise after bowel cancer treatment improves long–term outcomes, underlining that physical activity remains one of the most powerful, low–cost tools in cancer prevention and care. This runner study doesn’t contradict that larger story. It flags a potential exception at the extreme end of training that needs careful attention, not panic.

If future research confirms a link, what might change? Screening recommendations could evolve for a clearly defined group of high–volume endurance athletes, perhaps starting colonoscopy earlier than the current age–45 threshold for average–risk adults.

Athletes and coaches might adapt training, nutrition and recovery to protect gut health – paying attention to hydration, heat stress, gradual progression, and avoiding unnecessary anti–inflammatory medication around long efforts.

Sports medicine and gastroenterology clinics might work together on protocols for evaluating gut bleeding in runners, narrowing the gap between “common” and “concerning” symptoms. But these steps depend on replication in larger, diverse groups and understanding which components of endurance life – intensity, duration, heat, altitude, nutrition – matter most.

For now, a balanced message serves the public best. Endurance running is a profound source of meaning and health for many people, and quitting running isn’t the lesson from a single small study.

The key is keeping the proven benefits of exercise in view while being clear–eyed about potential risks at extremes. Listen to your body’s signals, especially bleeding. Treat red–flag symptoms as medical, not merely athletic. And discuss personal risk factors and family history with your doctor.

As science probes this signal further, the likely outcome isn’t a blanket warning but more nuanced guidance: who might need earlier screening, when to investigate symptoms, and how to train hard with the gut in mind.

The study’s real contribution may be cultural as much as clinical: it gives runners and doctors permission to ask a question they’ve too often waved away, and to catch dangerous lesions before they become cancers.

The Conversation

Justin Stebbing does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. Are ultramarathon runners really at increased risk of bowel cancer? – https://theconversation.com/are-ultramarathon-runners-really-at-increased-risk-of-bowel-cancer-263564

Brain chemistry reveals psychiatry’s false divisions – new study

Source: The Conversation – UK – By Sameer Jauhar, Clinical Associate Professor, Imperial College London

Fahroni/Shutterstock.com

For decades, psychiatrists have treated psychosis as if it were separate conditions. People experiencing hallucinations and delusions might be diagnosed with schizophrenia, bipolar disorder, severe depression and related diagnoses, and receive completely different treatments based on diagnosis. But new research suggests this approach may be fundamentally flawed.

Our latest study, published in Jama Psychiatry, reveals that the brain changes driving psychotic symptoms are remarkably similar across these supposedly distinct mental health conditions. The findings could change how doctors choose treatments for the millions of people worldwide who experience psychosis.

Psychosis itself is not a disease, but rather a collection of generally deeply distressing symptoms, where people may struggle to distinguish reality from normal perception. They might hear voices that are not there, hold false beliefs with unshakeable conviction, or find their thoughts becoming jumbled and incoherent. These symptoms are new in onset, and terrifying – regardless of whether they occur alongside depression, mania, or without these mood symptoms.

We studied 38 people experiencing their first episode of psychosis with mood symptoms, comparing them with healthy volunteers. Using sophisticated brain scanning technology, we measured the synthesis of dopamine – a brain chemical tied to motivation and reward – in different regions of the brain.

We found that while most people with manic episodes showed higher dopamine synthesis in emotion-processing areas of the brain compared to those with depression, there was a common pattern across all participants: higher dopamine synthesis in thinking and planning regions were consistently linked to more severe psychosis symptoms (hallucinations and delusions), regardless of their official diagnosis.

This discovery challenges some aspects of modern psychiatric practice. Currently, treatment decisions rely heavily on diagnostic categories that may not reflect what is actually happening in people’s brains. Two people with identical symptoms might receive entirely different drugs simply because one was diagnosed with bipolar disorder and another with depression.

Our study shows dopamine dysfunction is not uniform in psychosis. Moving beyond trial-and-error prescribing requires matching treatments to underlying biology rather than diagnostic categories alone.

A psychiatrist and his patient.
These findings could help us move away from one-size-fits-all prescribing.
Yurii Maslak/Shutterstock.com

Towards precision psychiatry

The implications could be profound. Rather than basing treatment solely on psychiatric categories, doctors might soon use biological markers to identify which drugs will work best for individual people. This approach, known as precision psychiatry, mirrors how oncologists already tailor cancer treatments to the genetic makeup of specific tumours.

For people with psychosis, this could mean faster recovery and fewer side-effects, by switching from drugs that do not work. Finding the right treatment often involves months of trying different drugs while people continue to suffer from debilitating symptoms.

Our research suggests people whose psychosis involves strong mood symptoms might benefit from drugs that target emotion-processing brain circuits, while those without mood disorders might need drugs that work differently on thinking and planning regions. Some people might even benefit from treatments that address cognitive problems alongside hallucinations and delusions.

This does not mean psychiatric diagnoses are worthless. They remain crucial for organising healthcare services, facilitating communication between professionals, and determining access to treatment. But they may no longer be the best guide for choosing medications.

The study involved a relatively small number of people, and the findings need to be replicated in larger groups before changing clinical practice. Still, this research represents a significant step towards a more scientific, biology-based approach to treating one of psychiatry’s most challenging symptoms.

As our understanding of the brain advances, the rigid categories that have dominated psychiatry for decades are beginning to blur. If the brain (and mother nature) does not respect diagnostic boundaries, neither should our treatments.

The Conversation

Dr Jauhar reported personal fees from Recordati, LB Pharmaceuticals, Boehringer Ingelheim, Wellcome Trust, Lundbeck, Janssen, and Sunovion and nonfinancial support from the National Institute for Health and Care Excellence, British Association for Psychopharmacology, and Royal College of Psychiatrists outside the submitted work.

Robert McCutcheon receives personal fees from Boehringer Ingelheim, Janssen, Karuna, Lundbeck, Newron, Otsuka, and Viatris outside the submitted work.

ref. Brain chemistry reveals psychiatry’s false divisions – new study – https://theconversation.com/brain-chemistry-reveals-psychiatrys-false-divisions-new-study-263319

How a church row over a pre-Christian ritual reflects an ancient Italian village’s battle for survival

Source: The Conversation – UK – By Aurora Moxon, Postdoctoral Fellow, University College Cork

High in the Aspromonte mountains in the toe of Italy’s boot lies the ancient Calabrian village of Bova. Over the last two millennia, a series of invaders and settlers have left their mark on the Aspromonte, including the ancient Greeks – influencing a way of life from farming to language.

Protected by the absence of roads until the mid-20th century, remnants of this Greek culture survive in Bova. The Greco-Calabro language, spoken day-to-day only by local goatherders and the elderly, includes words and phrases from ancient Greek. And for centuries, locals have created “Persephoni” – woven symbols of Persephone, the Greek goddess of spring, to celebrate the season’s arrival and invoke an abundant agricultural year.

Made from olive leaves woven onto canes and decorated with local wildflowers, fruit and goat’s cheese, these figures represent an important ritual to mountain people whose lives have depended on the land for centuries. Gradually, as Christianity was adopted by the Romans, these figures were absorbed into Catholic rituals by these local people.

From the 1990s, the Persephoni figures attracted attention as interest in the Greek cultural influences of the area grew. Then, in 2013, the local bishop refused to allow Persephoni to enter Bova’s cathedral after being informed these structures were folkloric puppets (pupazze) – a move that threatened this longstanding tradition with pre-Christian roots.

The procession of the Persephoni into Bova’s cathedral.

Challenging ideas of what is ‘modern’

As well as researching food, farming and ecotourism in the Aspromonte mountains, I investigate the negative effects of stereotypes of this area – and how contemporary local practices challenge ideas of what is “modern”. As part of this study, I visited Bova and spoke to villagers about their way of life.

Some told me how, in 2014, they successfully put pressure on the church to restore their cherished Persephoni tradition. They explained to the bishop the importance of the Persephoni, and the church’s blessing for this ancient tradition – which prompted him to relent and allow the figures back into Bova’s cathedral.

A decorated woven symbol of Persephone made of leaves, flowers and red ribbon.
A decorated Persephone figure ready for the procession.
Aurora Moxon, Fourni par l’auteur

However, as I witnessed earlier this year, the current priest’s message reiterated the church’s distance from what it calls “folklore” – despite the thousands of visitors the Persephoni attract to Bova, a village that is losing its young people every year to other towns and cities. Journalists and anthropologists continue use the term “puppets” to describe the Persephoni, which puts emphasis on a more pagan intepretation.

In nearby Locri, archaeologists have unearthed terracotta reliefs called pinakes (depicting the goddess of spring and the agricultural seasons) at the site of a shrine to Persephone. Referred to as the “flower-faced maiden” in the Homeric Hymns – a collection of 34 Greek poems addressed to the ancient gods – it’s not hard to understand why locals believe their celebration of Persephone has Ancient Greek origins.

Carrying their Persephoni around Bova on Palm Sunday and receiving the priest’s blessing before taking them into mass is one of the most important moments of the religious year for locals here. It’s the culmination of a month of long evenings spent plaiting pairs of olive leaves from local trees and attaching them to cane skeletons. Two metres tall, the largest Persephone is carried by Bova’s mayor.

On the eve of Palm Sunday, people decorate their Persephoni with fruits and flowers picked from local hillsides, and the following morning, goat’s cheeses called musulupu are added on. Some of these cheeses take the form of men and women, others are circular with “teats”. Like Persephone, they symbolise fertility and new birth.

Every year, thousands of people visit Bova to watch the procession, after which the local people hand out chunks of musulupu and ’nguta (a biscuity cake with hard-boiled eggs baked into the mix) in the town’s main square.

Population decline, cultural loss

Like much of Italy’s south, especially its mountainous areas, Bova has long suffered the effects of emigration. Today, inhabitants are attracted to jobs and the lifestyle in towns along Calabria’s built-up coast. In the 1970s, Bova’s population numbered 1,401; today it hovers around just 400.

Young Bovese feel compelled to leave the region once they have finished school. Agropastoralism, a form of subsistence farming involving the cultivation of crops and raising livestock, does not appeal to many youngsters, and yet a number of villagers continue to work as goatherders and small-scale farmers. Once landless, they now find themselves in a position to buy up abandoned land.

Goatherders milk their capre Aspromontane, an indigenous breed of goat, to make the cheeses attached to the Persephoni, pressing them into intricately carved wooden moulds. These goatherders use words from Greco-Calabro to describe their goats: zzarì means “grey coat”, for example, and zzerògasto means “hard to milk”.

While the Greco-Calabro language is a source of pride, the historic association of this language with herders and landless peasants has contributed to its decline.

Today’s grandparents discouraged their children from speaking it, as the language had become a marker of shame and perceived backwardness. This is part of a wider problem that sees the denigration of southerners in Italy – particularly in rural areas – as backward terroni, meaning “people who are the dirt beneath our feet”.

But herders and small-scale farmers in the mountains are also often called backward by middle-class Calabrians in cities and coastal towns. The relentless association of Calabria – and the Aspromonte in particular – with organised crime exacerbates the marginalisation of this area.

Through their symbolic figures of Persephone, inhabitants of Bova assert the value of their deeply rooted rural identity and ancient agropastoral spirituality, insisting the Catholic church recognises this hybrid religious practice. The determination to preserve it speaks of resistance in the face of population decline and cultural loss.


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The Conversation

Aurora Moxon receives funding from the Irish Research Council. Aurora Moxon previously received funding from the South West and Wales Doctoral Training Partnership.

ref. How a church row over a pre-Christian ritual reflects an ancient Italian village’s battle for survival – https://theconversation.com/how-a-church-row-over-a-pre-christian-ritual-reflects-an-ancient-italian-villages-battle-for-survival-258852

La musique ne vous fait ni chaud ni froid ? Cela pourrait être dû au fonctionnement de votre cerveau

Source: The Conversation – in French – By Catherine Loveday, Professor, Neuropsychology, University of Westminster

Certaines personnes ne ressentent absolument rien quand elles écoutent de la musique. Les chercheurs ont en découvert la cause, logée dans le cerveau. Krakenimages/Shutterstock

Et si la musique vous laissait de marbre ? Alors qu’elle fait vibrer la plupart d’entre nous, 5 à 10 % de la population reste totalement indifférente aux mélodies. Ce trouble, appelé « anhédonie musicale », intrigue les chercheurs, qui en dévoilent aujourd’hui l’origine : un défaut de communication entre le cerveau auditif et le système de récompense.


Lorsque je demande à une salle remplie d’étudiants comment ils se sentiraient s’ils ne pouvaient plus jamais écouter de musique, la plupart sont horrifiés. Un bon nombre était encore en train d’écouter de la musique juste avant le début du cours. Mais il y en a toujours un ou deux qui avouent timidement que cela ne changerait rien à leur vie si la musique n’existait pas.

Les psychologues appellent cela « l’anhédonie musicale », c’est-à-dire l’absence de plaisir à écouter de la musique. Et un nouvel article publié par des neuroscientifiques espagnols et canadiens suggère qu’elle serait causée par un problème de communication entre différentes zones du cerveau.

Pour beaucoup d’entre nous, ne rien ressentirquand on écoute de la musique semble incompréhensible. Pourtant, pour 5 à 10 % de la population, c’est la norme.

Dans le cadre de mes recherches et de ma pratique auprès de personnes souffrant de pertes de mémoire, je leur demande souvent de choisir leurs chansons préférées dans le but de raviver chez elles des souvenirs marquants.

J’ai toujours été fascinée par le fait que certaines personnes me regardent d’un air perplexe et me disent : « La musique ne m’a jamais vraiment intéressé•e. » Cela contraste tellement avec la majorité des gens qui adorent parler de leur premier disque ou de la chanson qui a été jouée à leur mariage.

Des études récentes montrent des variations considérables dans l’intensité des émotions ressenties quand on écoute de la musique. Environ 25 % de la population est hyperhédonique, c’est-à-dire qu’elle éprouve un besoin presque obsessionnel de musique.

Les recherches dans ce domaine utilisent généralement le Barcelona Music Reward Questionnaire (BMRQ) (questionnaire de récompense musicale de Barcelone), qui interroge les personnes sur l’importance de la musique dans leur vie quotidienne : À quelle fréquence en écoutent-elles ? Leur arrive-t-il de fredonner des airs ? Y a-t-il des chansons qui leur donnent des frissons ?

Si le score obtenu est faible, alors on parle d’anhédonie musicale. Pour confirmer ce diagnostic, des chercheurs mesurent, en laboratoire, le rythme cardiaque, la température ou la sudation des personnes sondées, pendant qu’elles écoutent de la musique. Chez la plupart d’entre nous, ces marqueurs physiologiques varient en fonction de la musique écoutée, selon qu’elle nous touche beaucoup ou peu. Mais chez les personnes souffrant d’anhédonie musicale, l’effet physiologique est nul.

Une théorie a consisté à dire que le fait de moins apprécier la musique pourrait refléter une anhédonie plus générale, c’est-à-dire une absence de plaisir pour quoi que ce soit. Ces pathologies sont souvent liées à des perturbations au niveau des zones du système de récompense, telles que le noyau accumbens, le noyau caudé et le système limbique.

Il s’agit d’une caractéristique courante de la dépression qui, comme d’autres troubles de l’humeur, peut être corrélée à une absence de réponse à la musique. Cependant, cela n’explique pas l’anhédonie musicale « spécifique », qui touche des personnes qui prennent du plaisir avec d’autres récompenses, comme la nourriture, les relations sociales ou le cinéma par exemple, mais restent indifférentes à la musique.

Homme renfrogné devant un violon
Tous les enfants obligés de prendre des cours de musique ne remercient pas leurs parents une fois adultes.
foto-lite/Shuttersock

Une autre explication qui a été avancée consiste à dire que les personnes qui s’intéressent peu à la musique ne la comprennent tout simplement pas, peut-être en raison de difficultés à percevoir les mélodies et les harmonies.

Pour vérifier cette hypothèse, nous pouvons nous intéresser aux personnes atteintes d’amusie, un trouble de la perception musicale qui affecte la capacité à reconnaître des mélodies familières ou à détecter des notes fausses. Ce trouble survient lorsque l’activité est réduite dans des régions clés du cortex fronto-temporal du cerveau, qui gère le traitement complexe de la hauteur des notes et de la mélodie. Or, on connaît au moins un cas d’une personne atteinte d’amusie qui n’en aime pas moins la musique.

Quoi qu’il en soit, d’autres recherches montrent que les personnes souffrant d’anhédonie musicale ont souvent une perception musicale normale, ils reconnaissent les chansons ou distinguent sans problème les accords majeurs des accords mineurs.

Alors, que se passe-t-il ? Un article recense toutes les recherches menées à ce jour dans ce domaine. La récompense musicale semble être traitée par la connectivité existant entre les zones corticales auditives, situées au niveau du gyrus temporal supérieur, et les zones du système de récompense. Il arrive que ces zones soient intactes chez des sujets souffrant d’anhédonie musicale. C’est donc la communication entre les zones qui est gravement perturbée : les parties du cerveau chargées du traitement auditif et le centre de la récompense ne communiquent pas.

Les personnes qui réagissent normalement à la musique présentent une activité importante au niveau de cette connexion dans le cerveau, qui est plus élevée pour une musique agréable que pour des sons neutres. Une étude réalisée en 2018 a montré qu’il est possible d’augmenter le plaisir procuré par la musique en stimulant artificiellement ces voies de communication à l’aide d’impulsions magnétiques.

Cette nouvelle analyse pourrait permettre aux scientifiques de mieux comprendre les troubles cliniques dans lesquels les récompenses quotidiennes semblent réduites ou amplifiées, ce qui est le cas par exemple lors de troubles alimentaires, d’addictions au sexe ou aux jeux.

Ces résultats remettent également en question l’idée répandue selon laquelle tout le monde aime la musique. La plupart des gens l’aiment, mais pas toutes les personnes, et cette variation s’explique par des différences dans le câblage du cerveau. Parfois, cela résulte des suites d’une lésion cérébrale, mais le plus souvent, les individus naissent ainsi, et une étude réalisée en mars 2025 a mis en évidence l’existence d’un lien génétique.

The Conversation

Catherine Loveday ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’a déclaré aucune autre affiliation que son organisme de recherche.

ref. La musique ne vous fait ni chaud ni froid ? Cela pourrait être dû au fonctionnement de votre cerveau – https://theconversation.com/la-musique-ne-vous-fait-ni-chaud-ni-froid-cela-pourrait-etre-du-au-fonctionnement-de-votre-cerveau-263588

Un pulmón de cerdo trasplantado a un humano se suma a corazones, riñones e hígados en el avance de los xenotrasplantes

Source: The Conversation – (in Spanish) – By Lluís Montoliu, Investigador científico del CSIC, Centro Nacional de Biotecnología (CNB – CSIC)

Minicerdos (_minipigs_) de Göttingen modificados genéticamente. Ellegaard, CC BY-SA

Los xenotrasplantes de órganos de cerdo a seres humanos siguen avanzando. Tras validarse esta estrategia con riñones, hígados y corazones ahora un equipo de investigadores chinos lo ha logrado con pulmones de cerdo xenotrasplantados a un hombre cadáver, en muerte clínica. El pulmón ha sobrevivido nueve días funcionando.

Por qué son necesarios

El trasplante de órganos es uno de los avances médicos más espectaculares: permite seguir viviendo a centenares de miles de personas cuyos órganos fallaban o habían dejado de funcionar.

Solo en el año 2024 se realizaron 173 286 trasplantes de órganos en todo el mundo. La mayoría de ellos (110 021) fueron de riñón, seguidos de los trasplantes de hígado (42 494), corazón (10 286) y pulmón (8 236), los cuatro órganos que se trasplantan con más frecuencia.

España sigue siendo el país del mundo donde se realizan más donaciones y más trasplantes por millón de personas. Desgraciadamente, no todos los pacientes que necesitan alguno de estos órganos logra encontrar una persona compatible que acepte o pueda donárselos (como donante vivo, un procedimiento habitual en trasplante de riñón), o pueda aprovecharlos tras un accidente mortal o tras la muerte clínica de una persona. Se estima que en EE. UU. aproximadamente 17 personas fallecen cada día en las listas de espera, sin recibir el órgano que necesitaban.

Las donaciones de órganos, a pesar de haber aumentado, no logran compensar el incremento de solicitudes de trasplantes. Esta es la razón principal de la búsqueda de estrategias alternativas para suplir la carencia de órganos humanos, y este es el origen de la investigación en xenotrasplantes. Estos están pensados esencialmente para ganar tiempo en las listas de espera, hasta que los pacientes puedan ser trasplantados con un órgano humano.

Cerdos editados genéticamente

Los trasplantes de órganos de animales a seres humanos (xenotrasplantes), son esencialmente de cerdo. Pero no de un cerdo cualquiera. Son cerdos transgénicos, editados genéticamente. En laboratorio se realizan múltiples modificaciones genéticas para que sus órganos no sean reconocidos como extraños por nuestro sistema inmunitario.

De este modo, la edición genética busca ‘camuflar’ el órgano del cerdo para evitar el rechazo fulminante, a medio y a largo plazo que se produciría inevitablemente.

Son cerdos de la raza minipig, de pequeño tamaño, que llegan a pesar entre 70-80 Kg, compatibles con el tamaño de cuerpo y órganos humanos.

Los xenotrasplantes surgieron, como idea, hace más de 30 años. Se produjeron diversos cerdos transgénicos con varios genes porcinos anulados y varios genes humanos añadidos, para que sus órganos pudieran subsistir dentro del cuerpo humano. Durante muchos años los experimentos solamente se realizaron en primates no humanos, principalmente monos babuinos. Hasta que se dio el paso a probarlo en humanos.

Primeros experimentos: riñones en humanos

En septiembre de 2021 un equipo de cirujanos e investigadores de un hospital de Nueva York decidió conectar un riñón de uno de estos cerdos transgénicos a la circulación sanguínea en una pierna de una mujer cadáver, en muerte clínica cerebral, pero con latido cardíaco y respiración asistida. El riñón sobrevivió 54 horas sin mostrar signos de rechazo y produjo orina con normalidad.

Poco después conocimos otro caso similar, realizado en Birmingham (Alabama, EE. UU.) cuando a un hombre, también en muerte clínica, le trasplantaron los dos riñones de estos cerdos transgénicos. En este caso solo uno de los riñones funcionó las 74 horas que duró el experimento.

El primer riñón de cerdo transgénico trasplantado a una persona viva se realizó en 2024, y el hombre sobrevivió dos meses.

Tras estos primeros intentos se sucedieron otros xenotrasplantes de riñones con distintos tipos de cerdos editados genéticamente, con mayor o menor éxito. Hasta que recientemente se ha anunciado un ensayo clínico en el que se evaluarán 50 pacientes xenotrasplantados de riñón.

Los ejemplos del corazón

En corazones se ha seguido un camino similar al de los riñones. Primero se empezó con corazones de cerdos modificados genéticamente xenotrasplantados a cadáveres de personas en muerte cerebral. El primer avance significativo se produjo en enero de 2022 en Baltimore (Maryland, EE. UU.) al trasplantar un corazón de cerdo transgénico a un hombre, con una cardiomiopatía avanzada y otras comorbilidades por las que no era un candidato adecuado en las listas de espera. Nunca habría recibido un corazón humano.

El hombre proporcionó su consentimiento informado para el xenotrasplante y sobrevivió dos meses con el corazón de un cerdo latiendo en el interior de su tórax. En 2023, también en el hospital de Baltimore, otro paciente vivo recibió un corazón de cerdo transgénico. En este caso sobrevivió seis semanas.

En hígados también se han realizado algunos xenotrasplantes, primero sobre cadáveres y luego sobre personas vivas, y en algún caso el resultado ha sido exitoso.

Vencer el rechazo

Los síntomas de rechazo son la razón principal del fracaso de los xenotrasplantes, a pesar de que todos los pacientes reciben medicamentos para mantener la respuesta inmunitaria controlada y reducida. En otros casos pueden aparecer infecciones difíciles de tratar debido a la inmunosupresión a la que están sometidos.

Tras validar la estrategia de xenotrasplantes en riñones, hígados y corazones, los tres órganos que se trasplantan con mayor frecuencia, el siguiente reto era probarlo en pulmones, el cuarto órgano en relevancia para trasplantes. Y esto es lo que acaba de realizar un equipo de cirujanos e investigadores en Guangzhou (China).

Los resultados de este primer experimento de xenotrasplante de pulmón de cerdo transgénico sobre una persona cadáver, en muerte clínica cerebral, han aparecido publicados en la revista Nature Medicine.

Un cerdo con seis genes editados

En este caso, los investigadores han usado el corazón de un tipo de cerdo con seis genes editados, que xenotrasplantaron a un hombre de 39 años, en muerte clínica cerebral.

Solamente le introdujeron uno de los dos pulmones, el izquierdo. Dejaron el derecho intacto, para poder comparar el comportamiento y funcionalidad de ambos.

El pulmón xenotrasplantado funcionó durante nueve días, sin síntomas de rechazo agudo o infección, lo cual ya es un gran éxito médico. El tratamiento posoperatorio incluyó también diversas drogas inmunosupresoras. Sin embargo, los doctores detectaron un edema importante a las 24 horas en el pulmón xenotrasplantado, probablemente relacionado con el procedimiento quirúrgico del xenotrasplante.

Este es un primer caso, un primer paciente, al que seguramente seguirán muchos más hasta poder optimizar la técnica y permitir la realización de futuros xenotrasplantes de pulmón, de forma segura y eficaz. Una prueba más de que los xenotrasplantes de órganos de cerdo a personas ya están aquí, empiezan a ser viables, y han venido para quedarse.

The Conversation

Los contenidos de esta publicación y las opiniones expresadas son exclusivamente las del autor y este documento no debe considerar que representa una posición oficial del CSIC ni compromete al CSIC en ninguna responsabilidad de cualquier tipo.

ref. Un pulmón de cerdo trasplantado a un humano se suma a corazones, riñones e hígados en el avance de los xenotrasplantes – https://theconversation.com/un-pulmon-de-cerdo-trasplantado-a-un-humano-se-suma-a-corazones-rinones-e-higados-en-el-avance-de-los-xenotrasplantes-263888

How cloves might help relieve pain and inflammation

Source: The Conversation – UK – By Dipa Kamdar, Senior Lecturer in Pharmacy Practice, Kingston University

Jamaan/Shutterstock

Cloves have long been a staple in kitchens and traditional medicine cabinets. Known for their warm, spicy flavour, they’re typically found whole or ground, and as clove oil or extract. But beyond their culinary charm, cloves are gaining scientific attention from researchers and clinicians for their potent analgesic (painkiller) properties. But could this humble spice rival ibuprofen or other commonly used painkillers?

Cloves, the aromatic flower buds of the Syzygium aromaticum tree, are native to Indonesia and widely used in global cuisines, especially in spice blends and festive dishes. Medicinally, they’re most commonly used in the form of clove oil. It contains eugenol, a compound with well-documented anaesthetic and anti-inflammatory effects.

Eugenol, the main active compound in cloves, is a naturally occurring plant chemical that works in multiple ways. It blocks certain chemicals and nerve responses that cause pain, including histamine – a chemical involved in immune responses, inflammation and allergic reactions – and noradrenaline, a neurotransmitter and hormone that can heighten pain sensitivity during stress.

Eugenol also inhibits the production of prostaglandins – substances that trigger inflammation and contribute to pain and swelling. This is the same biological pathway targeted by anti-inflammatory painkillers like ibuprofen. Because of these anti-inflammatory effects, eugenol could, in theory, be useful for conditions such as arthritis, although human evidence is limited. In an animal study, eugenol improved limb function in rats with osteoarthritis.

While research into its use for joint pain is still in early stages, most of the solid human evidence for cloves comes from dentistry.

Clove extracts are used in balms or diluted oils for muscle aches, brewed into teas for headaches, and applied as oil for toothache. Cloves have been a go-to dental remedy since at least the 13th century. Clove oil remains available in pharmacies for temporary toothache relief in adults and children over two years.

Studies suggest cloves may provide pain relief comparable to some conventional painkillers and topical anaesthetics. In dentistry, topical anaesthetics such as lidocaine or benzocaine are applied to the surface of the gums or skin to numb an area before treatment. They work by blocking pain signals from nerves near the surface – a mechanism thought to be similar to that of eugenol.

In paediatric dentistry, researchers compared clove oil, lidocaine gel and ice cones applied to injection sites in the mouth. Clove oil emerged as the most effective in reducing pain and anxiety among children, suggesting it could be a natural, cost-effective and well-accepted option to improve dental experiences. Another clinical trial in adults found clove gel to be as effective as benzocaine gel in minimising pain from dental injections, with no significant difference in pain scores.

These findings are supported by broader reviews, which show that topical clove preparations consistently outperform placebo treatments. In dental procedures, clove oil and gels not only reduce pain but also offer antiseptic and anti-inflammatory effects.

Beyond dentistry

There’s also evidence for using cloves in other types of pain relief. In one clinical trial, combining topical clove oil with lidocaine significantly reduced pain at episiotomy sites (the small surgical cuts made between the vagina and anus during childbirth to help deliver the baby) compared with lidocaine alone. These results suggest that clove oil may enhance the effectiveness of standard anaesthetics.

Cloves may also offer a range of other potential health benefits. Laboratory and animal studies indicate that eugenol and isoeugenol – a closely related plant compound with similar aroma and antimicrobial effects – have anti-inflammatory and antibacterial properties, inhibiting bacteria such as E. coli and Staphylococcus aureus.

Animal models suggest cloves may help protect the liver from damage and support its detoxification processes. Certain compounds, including nigricin (a naturally occurring clove constituent that appears to influence how cells handle sugar), have been linked to improved insulin sensitivity and glucose uptake, raising the possibility of better blood sugar control.

Eugenol has also shown cytotoxic effects (meaning it can kill or damage certain cells) against specific cancer cell lines in laboratory studies. However, these are early-stage findings, and no clinical trials in humans have yet confirmed its effectiveness or safety as a cancer treatment.

Side effects

While cloves are generally safe in culinary doses, concentrated forms such as clove oil should be used with caution.

Bottle of clove oil next to dried cloves
Ingesting larger amounts of clove oil or high-dose extracts can cause serious side effects.
Wirestock Creators/Shutterstock

In the mouth, clove oil may cause blistering, swelling, or lip irritation, and on the skin it can trigger burning sensations or rashes. Eugenol can be toxic in high amounts, and allergic reactions, though rare, are possible. Swallowing clove oil should be avoided, though small amounts used for toothache are generally harmless. Ingesting larger amounts of clove oil or high-dose extracts can cause serious side effects such as seizures and liver damage. High doses may also interfere with blood clotting, so anyone taking anticoagulants like warfarin should exercise caution. Animal studies have shown eugenol can lower blood sugar, so people with diabetes on insulin should monitor their levels closely.

Cloves may never replace ibuprofen across the board, but their proven effectiveness for topical and dental pain, combined with a suite of other possible health benefits, makes them a compelling natural option. For now, they remain best suited as a complementary remedy – but one with a long history, promising science and a rightful place in both the spice rack and the medicine cabinet.

The Conversation

Dipa Kamdar does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. How cloves might help relieve pain and inflammation – https://theconversation.com/how-cloves-might-help-relieve-pain-and-inflammation-262767

Five pieces of sleep advice that could be making your insomnia worse – a sleep therapist explains

Source: The Conversation – UK – By Kirsty Vant, Doctoral Researcher, Department of Psychology, Royal Holloway University of London

Shisu Ka/Shutterstock

We all know how much better we feel after a good night’s sleep. Science backs this up: high-quality sleep boosts cardiovascular health, immune function, brain health and emotional wellbeing. Unsurprisingly, many people are keen to improve their sleep – and “sleep hygiene” has become a go-to strategy.

Sleep hygiene refers to the habits and environmental factors that promote good sleep, such as keeping a regular bedtime, avoiding screens before bed, and cutting back on caffeine. These are sensible tips for healthy sleepers. But for people with insomnia, some sleep hygiene practices can backfire – reinforcing sleeplessness rather than resolving it.

As a sleep therapist, I’ve seen how good intentions can sometimes make things worse. Here are five common sleep hygiene strategies that may do more harm than good for people struggling with insomnia.

1. Spending more time in bed

When sleep isn’t coming easily, it’s tempting to go to bed earlier or lie in later, hoping to “catch up”. But this strategy often backfires. The more time you spend in bed awake, the more you weaken the mental association between bed and sleep – and strengthen the link between bed and frustration.

Instead, try restricting your time in bed. Go to bed a little later and wake up at the same time each morning. This strengthens sleep pressure – your body’s natural drive to sleep – and helps restore the bed as a cue for sleep, not wakefulness.

2. Strictly avoiding screens

We’re often told to ditch screens before bed because the blue light they emit suppresses melatonin, a hormone that helps regulate sleep. But this advice may be overly simplistic.

In reality, people with insomnia may reach for their phones because they can’t sleep – not the other way around. Lying in the dark with nothing to occupy your mind can create the perfect storm for anxiety and overthinking, both of which fuel insomnia.

Rather than banning screens entirely, consider using them strategically. Choose calming, non-stimulating content, use night-mode settings, and avoid scrolling mindlessly. A quiet podcast or gentle documentary can be just the right distraction to help you relax.

3. Cutting out caffeine completely

Caffeine blocks adenosine, a neurotransmitter that makes us feel sleepy. But not everyone processes caffeine the same way – genetics play a role in how quickly we metabolise it.

Some people may find a morning coffee helps them shake off sleep inertia (the grogginess you feel upon waking) and get active, which can support a healthy sleep-wake rhythm. If you’re sensitive to caffeine, it’s wise to avoid it later in the day – but cutting it out altogether isn’t always necessary. Understanding your individual response is key.

4. Trying too hard to ‘optimise’ sleep

The global “sleep economy” – encompassing everything from wearable trackers to specialised mattresses and “sleep-promoting” sprays – is worth over £400 billion. While many of these products may be well-meaning, they can contribute to a modern condition known as orthosomnia: anxiety driven by trying to perfect your sleep.

It’s important to remember that sleep is an autonomic function, like digestion or blood pressure. While we can influence sleep through healthy habits, we can’t force it to happen. Becoming obsessed with sleep quality can paradoxically make it worse. Sometimes, the best approach is to care less about sleep – and let your body do what it’s designed to do.

5. Expecting the same amount of sleep each night

Healthy sleep isn’t a fixed number of hours – it’s dynamic and responsive to our lives. Factors like stress, physical health, age, environment, and even parenting responsibilities all affect sleep. For example, human infants need to feed every few hours, and adult sleep patterns adapt to meet that need. Flexibility in our sleep has always been a survival trait.

Expecting rigid consistency from your sleep sets up unrealistic expectations. Some nights will be better than others – and that’s normal.

In my years as a sleep therapist, I’ve noticed how sleep privilege – the ability and opportunity to sleep well – can distort conversations around sleep. Telling someone with insomnia to “just switch off” is like telling someone with an eating disorder to “just eat healthy”. It oversimplifies a complex issue.

Perhaps the most damaging belief baked into sleep hygiene culture is the idea that sleep is entirely within our control – and that poor sleepers must be doing something wrong.

If you’re struggling with sleep, there are evidence-based treatments beyond sleep hygiene. Cognitive Behavioural Therapy for Insomnia (CBT-I) is the gold standard psychological intervention. New medications are also available, such as orexin receptor antagonists (suvorexant, lemborexant and daridorexant, for example) – drugs that block the brain’s wake-promoting orexin system to help you fall and stay asleep .

Insomnia is common and treatable – and no, it’s not your fault.

The Conversation

Kirsty Vant undertook consultancy work in 2024 from AGB Pharma who manufacture melatonin for use in children with ADHD.

ref. Five pieces of sleep advice that could be making your insomnia worse – a sleep therapist explains – https://theconversation.com/five-pieces-of-sleep-advice-that-could-be-making-your-insomnia-worse-a-sleep-therapist-explains-261682

Why I had to become a murder detective for my book about an 18th-century Jewish pedlar

Source: The Conversation – UK – By Tony Kushner, James Parkes Professor of Jewish/non-Jewish Relations, University of Southampton

An illustration of the crime from 1771. London Jewish Museum

This article contains details of antisemitism and violence that some readers may find upsetting.

It’s evening at a remote Sussex pub in 1734 and a vicious triple murder has just taken place. Jacob Harris – a Jewish pedlar, smuggler and possible highwayman – stands accused of slitting the throats of the publican, his ill wife and a female servant.

I’ve studied the case for my latest book, The Jewish Pedlar: An Untold Criminal History. The point of interest for me was not whether Harris was guilty (he probably was). Or even whether – despite the seriousness of the crime – he was a victim of English antisemitism in everything from the newspaper coverage to the way he was later remembered. I was more interested in a series of questions about Harris’s background and motivations.

Harris had many aliases including Hirshal Hirsh and James Daves, reflecting both his criminal tendencies and complex identity that was both continental Jewish and very local. How on earth did someone of German-Jewish origin manage to integrate himself into the close-knit smuggling fraternity of Sussex?

What was Harris even doing in Ditchling Common, many decades before there was anything approximating to a Jewish community in Sussex? And what motivated him to commit the murders?

Despite the potential for prejudice against Jewish people at the time, I concluded that in the criminal world, as long as someone was trusted and useful, their background did not matter. It was only when Harris fell out with a fellow smuggler leading to a fatal fight that his life fell apart. The quandary for me as a social and cultural historian was how to write anything like a biography of Harris when there are no direct quotes from him in the surviving archive.

Completing my 340-page study therefore felt like somewhat of an achievement. To do so required intricate detective work (and indeed the advice of a real retired detective) to interrogate every piece of contemporary evidence.

This included the sparse legal record of the murders, the first Sussex assizes (court) record to be kept in the National Archives at Kew; a contemporary diary from a local landholder; and copious reports in British newspapers which “borrowed” heavily from one another.

There was also a bill sent to the Treasury by the county of Sussex for the catching, imprisonment, trial, hanging and gibbeting of Harris (gibbeting involves placing a hanged body in a specially constructed iron cage at the scene of the crime). And there was a ballad which would have been written and sold at the gibbeting and has survived in various forms ever since.

Not one of these sources is straightforward, and this is also true of most of the authors and major players in contemporary responses to the murders.

The complexities of the case

Harris was not the only person in the case who had multiple names. There was also his first victim, the publican Richard Miles. His many names strongly suggest that he was on the wrong side of the law and almost certainly a fellow smuggler.

The lead justice of peace in the case, who later became an MP and major landowner, had also changed his name. As did the newspaper entrepreneur who was the only one who made explicit Harris’s Jewishness when reporting in his new title, Walker’s Weekly Post.

Even Sir Robert Eyre, the judge from London who sentenced Harris to be hanged and gibbeted, had a reputation for corruption, though I’m not saying it affected the decision in this case. I don’t doubt that Harris was guilty of the horrendous crimes he was charged with.

The gibbeted body

Having been found guilty in the county assizes at Horsham and hanged in that town, Harris’ body was then carted to the scene of the crime a good 15 miles away to be placed in the gibbet cage.

Illustration of a post surrounded by a crude wooden fence
Remnants of the gibbet post, illustration from Thomas Blaker, Burgess Hill as a Health Resort (1883).
Author provided

A history of a local Sussex family compiled over many generations suggests that his skull remained in the cage some decades later. The post from which the gibbet cage was hung remained in position for much longer and soon became known as “Jacob’s Post”. Despite his crimes and his Jewish origins, he became a local folk hero.

To this day there is a heritage display on Ditchling Common to mark this momentous event in the district’s history.

Later Jewish criminals who were hanged became prized for their body parts by surgeons such as William Hunter (of the Hunterian museum in London) for racialised display. I didn’t want to treat Harris as this kind of object of study, but as a human being with family and friends (and no doubt enemies).

To discover more about Harris, his occupations and identity, I covered the period up to the second world war and followed Jewish pedlars and criminals in many different places from China to South America, from Sierra Leone to the Hebrides and from South Africa to the Caribbean. I also charted how the memory of Harris altered through time, from the Victorians who saw him as racially different and “naturally” criminal, through to a growing sensitivity towards his Jewishness in a post-Holocaust world.

It might be argued that at a time of growing hostility towards those of migrant origin and increasing racism, including antisemitism, what we don’t need now is a book on a Jewish criminal. I would argue that by trying to understand the individuality of these often remarkable – if often controversial – figures, it emphasises their fundamental humanity.

We cannot – and must not – expect any group of people to be perfect. As an asylum seeker (a former professional in Yemen) in an Essex hotel which has been subject to constant demonstrations in summer 2025 told The Guardian: “Yes, there are some refugees who do not behave respectfully or who do not follow the rules of the host society.” He added that this should not mean that all are regarded as such and that “every refugee has a story, and every human deserves dignity”.

In this respect in my book I certainly do not glorify Harris or downplay his crimes. I do, however, insist that he is not demonised as a “Jew murderer” as the Victorians would have it, and that see him instead as part and parcel of 18th century English rural life – a world far more diverse than we often assume.


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This article features references to books that have been included for editorial reasons, and may contain links to bookshop.org. If you click on one of the links and go on to buy something from bookshop.org The Conversation UK may earn a commission.

The Conversation

Tony Kushner does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.

ref. Why I had to become a murder detective for my book about an 18th-century Jewish pedlar – https://theconversation.com/why-i-had-to-become-a-murder-detective-for-my-book-about-an-18th-century-jewish-pedlar-262671

Winners and losers in a hotter ocean

Source: The Conversation – UK – By Will de Freitas, Environment + Energy Editor, The Conversation

Meet your winners. E. PUIG / shutterstock

The ocean is heating up – in some places, faster than scientists once thought possible. For the fish, crustaceans and plankton that underpin life in the sea, this means habitats will shift, food supplies will change, and predators may suddenly find their prey has vanished. This isn’t a simple story of loss, but of winners and losers in a lottery weighted by climate change.


This roundup of The Conversation’s climate coverage comes from our award-winning weekly climate action newsletter. Every Wednesday, The Conversation’s environment editor writes Imagine, a short email that goes a little deeper into just one climate issue. Join the 45,000+ readers who’ve subscribed.


Fish are already threatened by polluted seas and overfishing by humans. Climate change adds another threat by reshaping the very waters they depend on – testing their ability to adapt.

Sevrine Sailley, a marine ecosystem modeller at Plymouth Marine Laboratory, explains:

“As the ocean heats up, fish try to stay in the conditions they’re best suited to. Some species will move, but others can’t relocate so easily – for example, if they need to live in a certain habitat at a particular life-stage, such as in kelp that offers shelter for breeding fish.”

Sailley and her colleagues used a computer programme to simulate the oceans around the UK over the rest of this century. They looked at 17 key commercial species and identified some winners and losers:

“While sardines may thrive, with a 10% boost in Atlantic abundance, our model suggests mackerel could decline by 10% in the Atlantic and 20% in the North Sea.”

Warm-water species like bluefin tuna could do well, she writes, but “bottom-dwelling species like cod and saithe (pollock) face a tougher future. These fish prefer colder, deeper waters and have fewer options to escape warming seas due to depth limitations.”




Read more:
How climate change is making Europe’s fish move to new waters


Sudden changes

Those fish are typically responding to what’s happening below them in the food web. And these shifts don’t just play out slowly. They can unfold dramatically during events such as marine heatwaves, when the sea itself becomes layered in ways that choke the food web.

Ocean scientist Tom Rippeth of Bangor University described this process during an “unprecedented” heatwave in the seas around the UK two years ago. That summer, the already-warm surface was heating up faster than ever.

Smiley cod fish
This cod has nothing to smile about.
Miroslav Halama / shutterstock

“Those stratified seas”, Rippeth writes, “on the continental shelf around Britain and Ireland are some of the most biologically productive on the planet. They have long been an important area for fishing cod, haddock, mackerel and other species. Those fish eat smaller fish and crustaceans, which in turn feed on microscopic plants known as plankton.”

Those plankton depend on nutrients mixed up from the deep water into the surface layer. However, during the marine heatwave, Rippeth feared the high surface temperatures would mean stronger stratification, less mixing, and a diminished supply of nutrients.

Bad news for the plankton. And bad news that will ripple up the food web.




Read more:
An ‘extreme’ heatwave has hit the seas around the UK and Ireland – here’s what’s going on


What the jellyfish tell us

Few creatures illustrate these shifts more clearly than jellyfish. Marine conservation expert Abigail McQuatters-Gollop of the University of Plymouth says jellyfish numbers are increasing in certain regions, including the UK. For her, this is a signal of dramatic changes in the ocean food web.

Jellyfish tend to feed directly on plankton, so they’re pretty low in the food web. In fact, since they drift rather than swim, they’re technically plankton themselves. Yet they’re big enough (and scary enough, in some eyes) for humans to notice when their numbers rise, which makes them an eye-catching indicator that waters are warming.

“Warmer sea temperatures”, McQuatters-Gollop writes, “mean that jellyfish can now inhabit a wider range of habitats, with some species moving polewards into waters that were once too cold for them.”

This has changed how energy moves through the food web:

“The warmer-water zooplankton species which now dominate northern European waters are generally smaller and less nutritious than the cold-water species they have replaced.”

It also contributes to what scientists call a predator-prey mismatch.

“While the seasonal cycle of phytoplankton [tiny plants] is driven by sunlight and so hasn’t changed, the point in the year when some zooplankton species [tiny animals] are most abundant now arrives earlier, as shorter and warmer winters cause the eggs of some species to hatch sooner. This has meant a mismatch between the spring phytoplankton bloom and the annual peak abundance of the zooplankton that gorge on it.”

These shifts cascade upwards through the food web – one reason why those warm-water bluefin tuna are likely to prosper in UK waters, while cold-water cod and herring are set to struggle.




Read more:
Jellyfish alert: increased sightings signal dramatic changes in ocean food web due to climate change


Post-carbon

Last week, we asked if severe heatwaves have affected your holiday plans. Several readers said they had given up on summer holidays in hot countries entirely.

For instance Andrew Strong said: “We are not holidaying in Europe between June and September, not even in the UK! It’s too much.”

Next week, we’d like your thoughts on air conditioning at home. Do you have it? Do you want it? Do you see it as an unnecessary and frivolous waste of energy, or an inevitable response to increasing summer heat? (If you’re American or Australian, do you laugh at us backwards Europeans for even having this debate?).

The Conversation

ref. Winners and losers in a hotter ocean – https://theconversation.com/winners-and-losers-in-a-hotter-ocean-263556

Les femmes dans la finance : déconstruire les stéréotypes pour faire progresser l’égalité

Source: The Conversation – France (in French) – By Gunther Capelle-Blancard, Professeur d’économie (Centre d’Economie de la Sorbonne et Paris School of Business), Université Paris 1 Panthéon-Sorbonne

Le secteur de la finance s’est largement féminisé. Mais, à mesure que l’on monte dans la hiérarchie, les hommes continuent d’être majoritaires. Ces inégalités prennent naissance dans des préjugés – parfois dès le foyer. Est-il possible de les combattre efficacement ? Comment ?


Longtemps, la finance a été considérée comme un bastion masculin. Et si les temps changent, les représentations peinent à évoluer. Golden boys, traders arrogants, dirigeants technocrates : les figures dominantes de l’imaginaire financier restent quasi exclusivement masculines. Or, dans la réalité, la majorité des salariés du secteur bancaire sont… des femmes ! Mais cette majorité est trompeuse. À mesure que l’on grimpe dans la hiérarchie ou que les postes deviennent plus rémunérateurs et stratégiques, leur part décroît nettement. Aucune femme, à ce jour, n’a dirigé de grande banque française.

Dans un contexte où des voix conservatrices s’élèvent, notamment aux États-Unis, contre les politiques de diversité sur fond de croisade antiwokisme, il importe de continuer à documenter, interroger et à comprendre les mécanismes comportementaux, culturels et institutionnels complexes qui façonnent les trajectoires socioéconomiques et, partant, les inégalités de genre.

Des différences souvent mal comprises

Les différences d’attitudes, de préférences et de valeurs entre les femmes et les hommes sont largement exagérées. Il serait temps d’en finir avec cette fable selon laquelle les hommes viendraient de Mars et les femmes de Vénus. Qu’il s’agisse de leur rapport à l’argent, de leur goût pour le risque et la compétition ou de leur volonté de pouvoir, les différences entre hommes et femmes sont souvent faibles, variables et fortement contextuelles. Et surtout, elles sont socialement construites.

Ces différences sont amplifiées par la prégnance de stéréotypes qui finissent par être intégrés, tant par les femmes que par les hommes. Il en résulte des inégalités persistantes au détriment des femmes en matière d’épargne, d’accès aux crédits et de participation sur les marchés boursiers. Les femmes pâtissent aussi lourdement des préjugés dans leur carrière et sont peu nombreuses à occuper les postes les plus prestigieux et les plus rémunérateurs. Et lorsque les femmes finissent par briser ce « plafond de verre », c’est souvent en adoptant des « codes réputés masculins » (en matière de prise de risque, par exemple) – ce qui remet d’ailleurs en cause certains récits sans doute trop simplistes autour des effets vertueux d’une féminisation des instances financières.




À lire aussi :
Financement participatif : les créatrices d’entreprise mieux traitées par le grand public que par les professionnels ?


Des stéréotypes qui viennent du foyer

Ces différences se nourrissent des préjugés qui prennent naissance dans les foyers. Ainsi, pendant longtemps, c’est le mari qui s’occupait de gérer le budget du ménage. Ce n’est plus le cas aujourd’hui : les enquêtes montrent au contraire que ce rôle est désormais dévolu majoritairement aux épouses. On en sait toutefois peu sur la gestion de l’argent au sein des couples.

À partir d’une base de données issue d’une banque française regroupant plus de 7 000 couples, on peut analyser la manière dont chacun des partenaires s’auto-évalue en matière de connaissances financières. Fait marquant, un biais de genre est observé dans la perception de ses propres compétences financières puisque la recherche montre que les femmes se sous-estiment plus souvent que les hommes. Pourtant, lorsque les conjoints sont présents ensemble au moment de l’évaluation, l’écart tend à se réduire de 18,7 %.

Ce phénomène suggère que la dynamique du couple peut atténuer ou renforcer les biais de genre. Et plus les couples sont engagés financièrement (épargne, investissement), plus l’écart de confiance tend à s’accentuer au détriment des femmes. Ces écarts ne sont pas anodins : ils conditionnent les prises de décision et les arbitrages patrimoniaux, et il peuvent renforcer les déséquilibres au sein du couple.

Une loi pour quels résultats ?

La finance, ce n’est pas que la gestion des comptes et du budget au sein des ménages. C’est aussi (et surtout) un secteur économique structurant, où les postes les plus stratégiques sont encore largement occupés par des hommes.

En France, la loi Copé-Zimmermann (2011) a imposé un quota de femmes dans les conseils d’administration, dans et hors du secteur financier, suivie plus récemment par la loi Rixain (2021) sur les comités exécutifs. Ces dispositifs ont eu des effets réels. Les conseils d’administration sont, à l’heure actuelle, à quasi-parité en matière de genre et la France est le leader en la matière. Il apparaît, en outre, aujourd’hui, que la loi de 2011 a eu un effet sur la performance extrafinancière des entreprises, qui s’expliquerait par la montée en puissance de femmes ayant eu des parcours professionnels souvent en prise avec les enjeux environnementaux et sociaux.

Si les quotas garantissent donc en général une quasi-parité dans les conseils d’administration (en termes de sièges), ils n’épuisent cependant pas la question des inégalités de genre à la tête des grandes entreprises. En particulier, la hiérarchie au sein même des conseils (présidences, comités stratégiques, etc.) reste très genrée et reproduit les stéréotypes conventionnels, les femmes accédant moins souvent aux fonctions les plus influentes.

Interroger les règles du jeu

Finalement, les inégalités observées ne traduisent pas des différences innées de compétences ou d’appétence pour la finance, mais bien des différences de socialisation, d’éducation et, consécutivement, de trajectoires. Les travaux issus de la recherche expérimentale et des enquêtes institutionnelles convergent : les écarts existent, mais ils sont amplifiés par les structures et les normes sociales. En d’autres termes, il ne suffit pas d’ouvrir les portes de la finance aux femmes. Il faut aussi interroger les règles du jeu, les modèles dominants, et les représentations qui pèsent sur les parcours.

Ainsi, et par exemple, il apparaît clairement aujourd’hui que les quotas à la tête des entreprises, pour importants qu’ils soient, ne suffiront pas à résorber les inégalités de genre aux niveaux inférieurs, à tous niveaux de qualification : le rôle et la prégnance des stéréotypes indiquent que la clé est dans une dynamique bottom up (plus que top down), conduisant les femmes à se projeter pleinement dans l’univers de la finance et des postes à responsabilités, et les hommes à se départir de leurs croyances en la matière. Bref, c’est à la base qu’il faut maintenant agir : dans les écoles, dans les familles, dans les institutions.


Les auteurs de cet article ont supervisé le numéro de la Revue d’économie financière d’avril 2025, « Femmes et finance ».

The Conversation

Antoine Rebérioux a reçu des financements de l’Agence Nationale de la Recherche (ANR).

Gunther Capelle-Blancard et Marie-Hélène Broihanne ne travaillent pas, ne conseillent pas, ne possèdent pas de parts, ne reçoivent pas de fonds d’une organisation qui pourrait tirer profit de cet article, et n’ont déclaré aucune autre affiliation que leur poste universitaire.

ref. Les femmes dans la finance : déconstruire les stéréotypes pour faire progresser l’égalité – https://theconversation.com/les-femmes-dans-la-finance-deconstruire-les-stereotypes-pour-faire-progresser-legalite-257589