Picture this: you’re driving on a mountain road, when you suddenly hit a thick patch of fog. You respond instinctively. Your vision sharpens, and you narrow your eyes to make out the shape of any oncoming cars.

Human beings handle these quick changes very well, but if it were a self-driving car – at least one with a current artificial intelligence (AI) system behind the wheel – things could easily end in disaster.

Today’s AI vision systems are extremely accurate when visibility is good. On a clear, sunny day a self-driving car can recognise pedestrians, road signs and other vehicles with precision. However, they are extremely vulnerable to environmental changes. If it rains, or gets dark or foggy, standard AI systems become blind, incapable of detecting obstacles that a human driver would spot with ease.

Our research at the University of Valencia proposes a possible solution: instead of exposing AI models to millions of images of every possible road condition, we decided to imitate biology. But biologically speaking, why can humans see so well under such a wide range of conditions?

Leer más: Human vision: what we actually see – and don’t see – tells us a lot about consciousness

The brain’s ‘volume control’

In our brains, neurons do not work alone. They use a truly fascinating form of adaptation that neuroscientists call divisive normalisation.

To understand this (without getting into mathematics) we can picture it as an automated “volume control” system, with neurons working in a team. Let’s say one neuron is looking at a very dark area of the field of vision, such as a black car at night. The neighbouring neurons turn up the “volume” of this weak signal, amplifying the small details to make them more visible.

If we look at a bright light, the same thing happens in reverse. The brain turns down the volume to prevent us from being dazzled.

This mechanism is what allows us to adapt and see clearly in a very wide range of conditions. But in the search for speed and accuracy, modern AI systems have neglected this biological inspiration.

Leer más: AI systems and humans ‘see’ the world differently – and that’s why AI images look so garish

AI in the driving simulator

In our study, we processed images using some of the most widely used AI models, adding layers to simulate the brain’s “volume control” mechanism. In basic terms, we forced their neurons to communicate with one another and adapt to their environment, just as our own brains do.

We wanted to see if imitating biology would make cars safer. To do this, we submitted both standard AI models and our brain-inspired modification to a series of tests. Using databases from real driving in European cities, night driving images from Switzerland, and several different virtual driving simulators, we were able to compare responses to difference levels of fog, darkness and light variation.

The results showed that imitating our own brains worked. After being trained, the two types of AI models could drive perfectly well, but once fog and darkness came into the equation, the unmodified one began to fail. It lost the ability to distinguish cars from buildings, and even from the road itself.

The AI system that was equipped with our brain-inspired mechanism, on the other hand, was robust. Even in fog or complete darkness, it performed more than 20% better than its unaltered counterpart.

We analysed, from the inside, how this new system perceived the world and found that it was doing exactly what we expected. It was capturing and enhancing the details of vehicles hidden in the fog that would otherwise be invisible. As a result, its performance became more stable in the face of changing weather conditions.

Leer más: The next generation of driverless cars will have to think about what’s on the road, not just see it

Learning from nature

Getting society as a whole to trust AI poses major challenges, and the safety of passengers and pedestrians in self-driving cars is a major aspect of this. It is not enough for smart systems to work under ideal conditions. We need them to be completely safe in the real world, and to safeguard the lives of all road users in all weather conditions.

Our research shows that the key to making artificial intelligence safer, more robust and more adaptable may be closer than it seems. There is no need for more powerful computers or vastly greater amounts of data. Sometimes, all we need is to look at the millions of years of evolution that have shaped our own brains.

In many cases, nature has already solved some of the problems that artificial intelligence faces today. We just need to learn from it.

A weekly e-mail in English featuring expertise from scholars and researchers. It provides an introduction to the diversity of research coming out of the continent and considers some of the key issues facing European countries. Get the newsletter!

Pablo Hernández Cámara receives funding from the Spanish Ministry of Science, Innovation and Universities.

Picture a sweltering summer’s day. Now imagine enduring the heat while eight months pregnant. Uncomfortable, to say the absolute least.

But in pregnancy, heat is more than just a nuisance, as for many women it can trigger early labour. A premature baby – meaning one born before 37 weeks of gestation – faces a significantly higher risk of mortality, as well as health complications that can affect them for the rest of their lives.

Decades of research has documented the link between exposure to heat and preterm births. However, most studies have been limited to a single city or country, using different methods that yielded results which were difficult to compare.

So how many premature births are actually caused by heat in different parts of the world? Are all pregnant women equally vulnerable? Our new study, published in Environment International, provides the most comprehensive answers to these questions to date.

13 countries, 36 million births

We analysed 36.6 million births that took place during the summer in 250 towns and cities, across 13 countries (Australia, Brazil, Canada, Chile, Ecuador, Estonia, Israel, Italy, Japan, Paraguay, Spain, Switzerland and the United States) between 1979 and 2019. This is the most extensive multi-site analysis conducted on this topic to date.

To estimate the relationship between temperature and the risk of preterm birth, we used cutting edge statistical models that allowed us to see the delayed and non-linear effects of heat exposure in the days leading up to delivery.

The findings are clear: the risk of preterm birth increases linearly as temperatures rise. On days of moderate heat, this risk increases by 2.8%. On days of extreme heat, the increase reaches 3.8%.

855 extra premature births per million

Translating these risks into specific figures provides a clearer picture of the scale of the problem. We estimate that 1.41% of all premature births occurring during the summer are attributable to heat. In absolute terms, this equates to 855 extra premature births per million births.

The magnitude is comparable to that of other well-established factors. For example, it far exceeds the contribution of maternal smoking in low and middle-income countries, and is on a par with that of malaria. And heat is already a major environmental risk factor for reproductive health.

The differences between countries are also revealing. Paraguay has the highest rate, with 1,347 preterm births per million, while Switzerland has the lowest, with 628. Spain falls in the upper-middle range, with 1,080 per million. This variability suggests that climate, the level of socio-economic development, and each country’s capacity to adapt significantly influence the vulnerability of pregnant women.

Leer más: Cooling poverty is making extreme heat more dangerous for millions

Not all pregnancies have the same risk

One of our study’s most significant findings suggests that heat may not affect all women equally. Young single mothers with lower levels of education who are in a vulnerable socio-economic situation may be at greater risk of heat-induced preterm birth.

Female foetuses also appear to be more susceptible than male foetuses. However, most of these subgroup analyses were not statistically significant, so further research is needed to confirm them.

There are specific mechanisms behind these differences. People who are economically disadvantaged are more likely to live in particularly hot areas due to the urban heat island effect. They are also more likely to work outdoors, and to lack access to air conditioning or other means of protection against the heat. Social inequality and climate inequality overlap, and the most vulnerable pregnant women pay the highest price.

Heat also speeds up births at term

Perhaps the most surprising finding of our research is that the effect of heat is not limited to preterm births. We have also observed a significant increase in the risk of delivery in pregnancies that would be considered clinically normal, between weeks 37 and 42. Specifically, extreme heat increases the risk of delivery in weeks 37-38 by 3.66%, and in pregnancies of 39 weeks or more by 2.97%.

This means that heat can act as a trigger for labour in foetuses that, under other circumstances, would have continued to develop normally. The most sensitive gestational window is from week 31 to week 40, spanning late preterm and early term births.

Root causes

There are many biological mechanisms at play here. Heat can raise body temperature and trigger uterine contractions. The dehydration caused by heat also disrupts the electrolyte balance and reduces blood flow to the placenta. Furthermore, heat triggers inflammatory processes and oxidative stress, which can compromise foetal development and accelerate cervical ripening.

Pregnant women are particularly vulnerable because their bodies generate more heat than usual due to foetal growth, while also having a reduced ability to dissipate that heat because of weight gain.

Leer más: Women experience extreme heat differently to men. And they’re adapting to it in creative ways

Global warming

These findings are particularly worrying in light of climate change. Over the coming decades, heatwaves will become more frequent, more intense, and will last longer. If we fail to act, the burden of preterm births attributable to high temperatures will only increase, undermining decades of progress in neonatal and child health.

A proper response requires action on several fronts. In the clinical setting, health systems must incorporate heat as a risk factor in antenatal care, particularly for socially vulnerable women. In the urban sphere, it is urgent to develop adaptation strategies – green spaces, climate shelters, early warning systems – that protect pregnant women during episodes of extreme heat. And at the policy level, these findings must be translated into ambitious emissions reduction targets.

Extreme heat is no longer just a matter of comfort. It is a question of public health, social equity and climate justice. And pregnant women are on the front line.

Dominic Royé is financed through the Ramón y Cajal programme (RYC2023-042824-I) and by GAIN, the Xunta de Galicia's innovation agency.

Ana M Vicedo-Cabrera receives funding from the Swiss National Foundation, Mobiliar Cooperative, Wellcome Trust, and the Federal Office of the Environment (Switzerland).

Coral Salvador receives funding from the Xunta de Galicia, and currently receives funding from the Swiss National Science Foundation (SNSF).

Aurelio Tobias y Carmen Íñiguez no reciben salarios, ni ejercen labores de consultoría, ni poseen acciones, ni reciben financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y han declarado carecer de vínculos relevantes más allá del puesto académico citado.

While some of us enjoy curling up with a good book, others prefer watching a series or playing videogames. But from the perspective of neuroscience, reading is much more than just entertainment.

This is especially true for children and teenagers. In the young brain, reading stimulates specific cognitive processes that can make a major difference in adult life.

Reading is important during adolescence because it is a stage where the brain is still developing. Throughout this stage, there is an intense reorganisation of the neural networks that strengthen reasoning, planning and behavioural control.

One of the key brain structures in this process is the prefrontal cortex, a region associated with what are known as executive functions, which are responsible for sustaining attention, inhibiting distractions and controlling information processing. Certain experiences during this stage can catalyse cognitive development, and help to consolidate these abilities.

Leer más: Teens discover books on social media. What will the under-16s ban do to their reading?

Understanding a long text activates many of the mental processes that the adolescent brain is still constructing: sustaining attention over a prolonged period, recalling prior information, making connections between ideas, forming predictions, spotting inconsistencies and actively constructing the meaning of the story. Far from being a passive activity, reading involves considerable cognitive effort.

Precisely because of this cognitive demand, reading does not always generate the same immediate engagement as other, more passive activities. While many digital leisure activities offer instant gratification and a constant stream of new stimuli, reading requires an initial period of concentration and engagement before the narrative reward becomes apparent.

Reading and flow states

As reading skills become more established, something interesting happens: reading begins to flow. As the processes of decoding words, accessing their meaning and integrating the information needed to understand the text become automatic, cognitive effort diminishes and readers are able to become immersed in the story.

Attention then shifts away from deciphering sentences and towards understanding the narrative world and the characters. This is the point where reading becomes, for many people, a pleasurable activity.

And regular reading doesn’t just bring enjoyment: it also boosts cognitive development. In fact, its link to progress during adolescence is particularly significant, and even outweighs other factors like parents’ educational attainment.

It also helps us to interpret other people’s thoughts and emotional states and to understand and analyse our own mental processes, evaluate information, and distinguish between strong and weak arguments. By strengthening our critical thinking skills, it protects against fake news and misinformation.

Not all leisure activities activate these processes as deeply.

Leer más: Thinking aloud: what happens when children read for pleasure in classroom clubs

Does it matter what you read?

Literary fiction, such as novels or other stories featuring unpredictable characters and ambiguous situations, is particularly effective in fostering an understanding of the mental and emotional states of others, as it immerses the reader in complex social worlds. Informative or educational books, on the other hand, contribute more to the development of reasoning.

The ideal thing is to read what you most enjoy. Nevertheless, reading more varied and high quality texts will develop a wider range of different skills.

Leer más: Does listening to audiobooks improve learning?

And what if you don’t like reading?

Not everyone finds reading inherently appealing. Psychological research suggests that, when it comes to demanding activities, starting early and practising frequently can be key to making them ultimately rewarding. Reading is no exception.

If you are exposed to reading at an early age, you are likely to develop positive feelings towards books. And if your early experiences were negative – you were forced to read things that did not interest you, or struggled and found reading boring – motivation will be much lower.

That is why it is so important that in classrooms and homes we have access to all kinds of books, and that we can choose what to read, read together, and find stories that resonate with our interests and concerns.

For those who feel that “reading isn’t their thing”, it is important to remember that initial difficulty does not indicate a lack of ability – indeed, it is actually part of the learning process. With experience, reading comprehension becomes easier and less demanding, so it is best not to give up before it starts to become enjoyable. Even those who struggle most with reading can benefit from it.

Ultimately, reading journeys, like life journeys themselves, are diverse, and skills can develop in many different ways over time. But it is especially important for children and teenagers. In adolescence, reading is more than a cultural practice – it trains attention, imagination, reasoning and complex thought at a time when the brain’s development is in full swing.

Choosing not to read doesn’t just mean missing out on a pastime. It also means renouncing a powerful tool for cognitive development, and for a well-rounded cultural, critical and civic education.

A weekly e-mail in English featuring expertise from scholars and researchers. It provides an introduction to the diversity of research coming out of the continent and considers some of the key issues facing European countries. Get the newsletter!

Javier Roca receives research funding from the Spanish State Research Agency, the Valencian Regional Government and the University of Valencia.

Pilar Tejero Gimeno receives research funding from the Spanish State Research Agency, the Valencian Regional Government and the University of Valencia.

Eva Mª Rosa Martínez, Lucía B Palmero Jara y Marina Pi-Ruano no reciben salarios, ni ejercen labores de consultoría, ni poseen acciones, ni reciben financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y han declarado carecer de vínculos relevantes más allá del puesto académico citado.

When it comes to losing weight, the fear of “ruining your metabolism” is widespread. Indeed, many people who have lost weight and then put it back on feel that every failed attempt leaves them worse off than before, with more fat, less muscle, greater hunger, lower energy, and an ever-diminishing ability to lose weight again.

For those looking to lose weight, the so-called “yo-yo effect” has become an almost constant threat. According to this view, losing and regaining weight is not only frustrating but also dangerous. It even leads some people to believe that they are better off not trying to lose weight at all.

However, a critical review published in The Lancet Diabetes & Endocrinology calls for a reevaluation of this idea. The authors review the available evidence on “weight cycling” – repeated cycles of weight loss and regain – and conclude that there is no solid evidence that this phenomenon, in itself, causes long-term clinical harm in people with obesity.

Nuance is important here. This does not mean that regaining weight is desirable, nor that every diet is a good idea. It highlights something more specific: current evidence does not support the claim that losing weight and then regaining it “breaks” the metabolism or necessarily leaves a person worse off than before.

This finding is important because the fear of the yo-yo effect can become a barrier to seeking help, making changes, or resuming healthy habits after regaining weight. And given that obesity is a chronic and recurrent condition, suggesting that every failed attempt causes irreversible damage can lead to feelings of guilt, despair and resignation.

Leer más: How does your body lose weight? An obesity doctor explains why one size doesn’t fit all in weight loss

What we know – and don’t know – about weight cycling

Part of the confusion stems from the way many observational studies have been interpreted. People who have been through multiple cycles of weight loss and regain tend to have greater difficulty maintaining their weight loss, as well as a higher amount of excess body fat and more years of exposure to obesity. More metabolic abnormalities are observed in these groups, but it is not always easy to distinguish causes from effects.

To put it another way, the fact that a person with poor metabolic health has been on more diets does not prove that the diets caused that deterioration. The opposite may be true: greater excess body fat, a longer history of being overweight, or prior presence of risk factors could all be the reason for both a higher number of weight-loss attempts and poorer health outcomes.

Unjustified fear of muscle loss

One of the most widespread fears when starting a diet is the loss of muscle mass. When losing weight, the body does not just lose fat; it can also lose some lean body mass. The fear associated with the yo-yo effect stems from the fact that, when weight is regained, fat is regained rather than muscle, leading to an increasingly unfavourable body composition.

However, according to the recent Lancet review, the available data does not consistently show a disproportionate and permanent loss of lean body mass attributable to weight cycling in itself. The outcome depends on many factors, including the final weight achieved, the amount of protein in a person’s diet, the type of intervention, the level of physical activity and, in particular, the presence (or absence) of strength training.

Something similar happens with energy expenditure. The common belief is that every diet slows down the metabolism, but metabolic rate is heavily influenced by body size and composition. If a person weighs less, they also need less energy to keep their body running, and if they put on weight, their energy expenditure adjusts accordingly. This adaptation does not necessarily equate to a permanent metabolic breakdown.

Leer más: Muscle is important for good health – here’s how to maintain it after middle age

Keeping weight off

There is an important caveat here: debunking the myth of a “broken metabolism” does not mean we can trivialise weight regain. When a person loses weight, their blood pressure, blood sugar levels, lipid profile, mobility, sleep and quality of life can all improve. If they regain the lost weight, some of those benefits may diminish or disappear, returning the person to their original metabolic state. But that does not prove that losing and then regaining the weight has caused any additional harm.

This is one of the article’s key points. The main problem is not so much having tried to lose weight, but the difficulty of maintaining sufficient and healthy weight loss over time.

This nuance is also important in the era of new obesity drugs, including GLP-1 receptor agonists like Ozempic and other similar treatments. In many cases these medicines lead to significant weight loss, but coming off them can result in partial or complete weight regain. But it is an oversimplification to interpret this regain as proof that the treatment disrupts the metabolism – it more likely indicates that obesity requires long-term treatment strategies, just like other similar conditions.

No miracle diets

The conclusion should not be that yo-yo dieting is no big deal. It is often accompanied by frustration, guilt, a loss of self confidence, loss of healthy habits, and a deteriorating relationship with food. It may also rely on poorly thought-out methods, such as extremely restrictive diets, unrealistic goals, lack of proper support, or an exclusive, blinkered focus on the number on the scales.

We also should never suggest that regaining weight means someone has failed irrevocably. Many people who manage to maintain significant weight loss in the long term only do so after multiple unsuccessful attempts. When it comes to making healthy choices, change is rarely linear.

Leer más: Ultra-processed foods might not be the real villain in our diets – here’s what our research found

The best theoretical and practical approach is to replace the mindset of temporary dieting with that of a sustainable lifestyle. This means setting realistic goals, maintaining muscle mass, avoiding extreme restrictions, choosing filling and nutritious foods, getting better sleep, being more active, and seeking professional support where possible. In short, long-term adherence is more important than any other variable.

It also means understanding that body weight is regulated by powerful biological systems. After losing weight, the body may increase feelings of hunger, partially reduce energy expenditure, and promote recovery. This is not a sign of personal weakness, but an adaptive response. It is why maintaining weight loss usually requires a long-term approach, not just willpower.

A well-designed intervention should include sufficient protein, strength training, regular physical activity, dietary satisfaction, nutrition education, ongoing monitoring, and psychological or behavioural support where necessary. In some cases, it may also require drug treatment or bariatric surgery. The choice depends on the degree of obesity, comorbidities (the presence of several conditions at the same time), medical history, and each person’s individual preferences.

Fighting despair

Regaining weight does not mean your metabolism is broken. Nor does it mean it is not worth trying again. It simply means that your previous approach was not enough, was unsustainable, or you lacked the right support.

The new review does not exonerate fad diets, nor does it portray the yo-yo effect as harmless. What it does is debunk the more specific and counterproductive notion that losing and regaining weight will inevitably damage the metabolism.

When it comes to obesity, as in so many other areas, a failed attempt should not be seen as the end of the road, but as a guide for planning the next step.

A weekly e-mail in English featuring expertise from scholars and researchers. It provides an introduction to the diversity of research coming out of the continent and considers some of the key issues facing European countries. Get the newsletter!

Las personas firmantes no son asalariadas, ni consultoras, ni poseen acciones, ni reciben financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y han declarado carecer de vínculos relevantes más allá del cargo académico citado anteriormente.

In recent months, corruption allegations have increasingly surrounded figures close to Spanish Prime Minister Pedro Sánchez, from his wife and brother to former senior officials of his party and even former prime minister José Luis Rodríguez Zapatero.

Eight years ago, on June 1 2018, Pedro Sánchez became Spain’s prime minister after a successful vote of no confidence against the conservative government of Mariano Rajoy. The motion was triggered by the Gürtel corruption scandal, and was supported by a broad coalition of left-wing and nationalist parties.

That parliamentary majority then became the foundation of a new political cycle in Spain. Since then, Sánchez has governed through a complex alliance bringing together three different groups: his own Socialist Workers’ Party (PSOE), parties to its left (first Unidas Podemos and later Sumar), and a diverse set of peripheral nationalist forces, mainly located in the Basque Country and Catalonia.

This coalition proved more resilient than many expected. It has survived the pandemic, delivered major social and labour reforms, and secured enough parliamentary support for Sánchez to remain in office after the 2023 general election.

Yet the coalition has now become increasingly fragile. And for the first time since 2018, the source of instability may be the PSOE itself.

The first signs of weakness appeared among the parties to the left of the PSOE. The alliance that once revolved around Unidas Podemos fragmented, while its successor, Sumar, struggled to maintain unity among its constituent parties. The coalition’s second pillar, the nationalist and regional parties that support Sánchez in parliament, has also become more difficult to manage.

The consequences are visible. The government has not approved a new state budget since 2022, relying instead on extensions of previous budgets, and parliamentary defeats have become commonplace.

Despite these difficulties, the PSOE – and Sánchez himself – remained the coalition’s strongest asset. Sánchez consistently outperformed expectations, survived electoral setbacks, and maintained a central position in Spanish politics. While coalition partners generated uncertainty, the Socialists provided stability. That may now be changing.

Leer más: Why the rise of a new far-right party in Catalonia spells danger for the Spanish government

Corruption allegations

Over the past two years, a growing number of investigations and allegations have affected figures connected to the PSOE and Sánchez’s inner circle. The cases involve former senior party officials, members of the prime minister’s inner circle, and individuals close to the government.

Supporters of the government argue that these investigations are textbook “lawfare” – politically motivated use of the courts to undermine or directly attack enemies. There is evidence to support this view, as some of the corruption allegations have been brought forward by Manos Limpias (“Clean Hands”), a self-styled trade union with far-right links. Critics, meanwhile, maintain that the cases reflect legitimate judicial scrutiny of those in power.

Regardless of which interpretation prevails, the political consequences are already evident.

The attorney general was disqualified last year in a case involving the disclosure of confidential information. Sánchez’s brother is currently on trial over allegations related to his appointment to a public-sector post, and Sánchez’s wife is also under investigation. The most damaging case for the PSOE has been the Koldo scandal, which allegedly involved former ministers and senior party officials in a corruption scheme linked to the purchase of face masks during the pandemic.

Other controversies have only added to the pressure. PSOE member Leire Díez is accused of seeking information and exerting pressure on judges investigating corruption cases involving the party, with support of party officials.

While Sánchez himself has not been implicated in any of the cases, allegations of bribery, leaked recordings, favouritism and political interference have combined to create a perfect storm around him.

The latest blow came with the investigation into former Socialist prime minister José Luis Rodríguez Zapatero over his alleged links to Venezuela and the airline Plus Ultra. For the PSOE, the significance is not only judicial but also political. Zapatero remains the most prominent member of the party’s old guard. He is widely regarded as a totem of the Spanish left, and has consistently backed Sánchez.

Zapatero symbolises not only the PSOE but also the generation of Socialists who governed Spain between 2004 and 2011. He is remembered above all for expanding social rights, particularly through the legalisation of same-sex marriage and abortion reform. This image as a progressive leader has largely overshadowed memories of his austerity measures, spending cuts and agreements with the right-wing Popular Party (PP).

The allegations against him have resonated strongly on the left. Speaking in Spain’s national congress on May 20, left-wing Catalan leader Gabriel Rufián summarised the mood succinctly: “If it’s true, it’s shit. But if it’s a lie, it’s even worse.”

Leer más: NATO has deep divisions – but why is Spain its most openly critical member?

Losing control of the narrative

As a result of these allegations, the issue dominating public debate is no longer one chosen by the government. Housing, inflation and public services remain major concerns for Spanish voters, but corruption allegations have increasingly come to dominate political and media attention.

This represents a significant challenge for any government. One of the main advantages of incumbency is the ability to shape the political agenda. When governments lose that capacity, they often find themselves on the back foot, reacting to events rather than steering them.

The symbolism is particularly striking in Sánchez’s case. His rise to power in 2018 came through a vote of no confidence in Mariano Rajoy’s PP, after it became mired in its own string of corruption scandals. Eight years later, his opponents are attempting to frame the PSOE through a similar lens.

The end of a political cycle?

At this point, some perspective is needed. Spanish politics has experienced remarkable continuity since 2018. Sánchez has remained in office longer than many observers expected, navigating a fragmented parliament and an increasingly polarised political environment.

The current left-wing government is one of the longest-lasting of Spain’s democratic period. Sánchez’ eight year tenure is second only to Felipe González, also of the PSOE, who governed from 1982 to 1996.

We also cannot ignore the possibility that some of the current wave of allegations could be politically or judicially motivated lawfare. The words of former PP prime minister José María Aznar, spoken after Sánchez secured a second term in 2023, still resonate on the right: “Whoever can do it, do it.” In other words, remove the government by whatever means are available.

Sánchez’s governments have achieved notable policy successes, including labour market reforms, increases in the minimum wage, and an active role in European and international affairs. More recently, the government has pushed ahead with the regularisation of more than 500,000 undocumented migrants.

Even his critics acknowledge Sánchez’s extraordinary capacity for political survival. Still, after eight years in office, some observers, particularly on the right, believe Spain may be approaching the end of a political cycle.

If this is the case, it is not solely the result of corruption allegations and judicial investigations. The parties to the left of the PSOE are weaker than they once were, and relations with parliamentary allies have become more complicated. Legislative productivity has slowed. The party has performed poorly in regional elections in Extremadura, Castile and León, Aragón and its former stronghold of Andalusia.

This does not necessarily mean that Sánchez’s government is approaching immediate collapse. The prime minister has little incentive to call a snap election, particularly when most opinion polls suggest that a coalition between the PP and far-right Vox could emerge as the alternative. Nor is it clear that voters have definitively turned against the Socialists. Spanish politics has repeatedly shown that public opinion can shift rapidly, especially during election campaigns. Nevertheless, the mood has changed.

For years, the PSOE functioned as the strongest pillar supporting Spain’s governing coalition. Problems usually came from junior coalition partners or parliamentary allies. Now, for the first time, the main source of uncertainty appears to be the party at the coalition’s centre.

Whether the current allegations ultimately lead to convictions, exonerations or political dead ends, their impact is already being felt. They have weakened the government’s control of the political agenda, increased tensions among coalition partners, and fuelled speculation about the durability of the ruling coalition established in 2018.

There are echoes here of the final years of Felipe González’s premiership in the 90s, which was marked by corruption allegations and the GAL scandal. Those last years are often remembered as the slow decline of a long Socialist government and the prelude to José María Aznar’s victory in 1996.

So, 30 years later, are we witnessing the final stage of the Sánchez era and the prelude to a new coalition of right-wing and far-right forces? It would be premature to answer yes. But the broad coalition that brought Sánchez to power seems more fragile today than at any other point over the last eight years.

A weekly e-mail in English featuring expertise from scholars and researchers. It provides an introduction to the diversity of research coming out of the continent and considers some of the key issues facing European countries. Get the newsletter!

Asbel Bohigues no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.

Iodine deficiency is often seen as a problem of the past, but this isn’t entirely true. During the 20th century, the iodisation of salt became one of the most effective public health interventions for preventing conditions caused by a lack of this mineral, including goiter (enlargement of the thyroid gland) and preventable damage to neurological development.

The World Health Organization (WHO) still views iodised salt as a safe and effective strategy, while UNICEF notes that it is the most widely used way of improving iodine intake worldwide.

However, the success of this simple measure means iodine has all but disappeared from public debate. And today, in several countries, signs of insufficient intake are once again being detected in certain groups, particularly in pregnant or breastfeeding women and people on restrictive or poorly planned diets.

What we are witnessing is not a dramatic resurgence of the most severe symptoms everywhere, but rather a silent risk of deficiency in contexts where vigilance has waned.

Iodine’s role in the body

Iodine is an essential micronutrient for the synthesis of thyroxine (T4) and triiodothyronine (T3), hormones that regulate metabolism, growth, and many physiological processes. Adequate intake during pregnancy and early childhood is particularly important for the normal development of the central nervous system and for the early stages of brain maturation.

In addition, the body’s needs increase during pregnancy and breastfeeding due to increased maternal production of thyroid hormones, greater renal excretion of iodine, and the transfer of this mineral to the fetus and the infant.

Why deficiency is on the rise again

The issue is not that people have stopped consuming salt, but rather that the type of salt they consume has changed, as have the sources of sodium in their diet. In recent years, iodised salt has been replaced in many households by “gourmet” or “natural” salts. These include sea salt, pink Himalayan salt, flaked salt and kosher salt, which are often perceived as more sophisticated or healthier, even though they are not always iodised.

In a way, iodised salt has an image problem. Compared to the culinary prestige of its trendy rivals, it has come to be viewed as something ordinary, outdated even.

Today, lot of our salt intake also comes from processed and ultraprocessed foods, meaning the use of iodised salt cannot be guaranteed. For this reason, the World Health Organization has called for coordination between policies that aim to reduce sodium intake and those that promote iodised salt.

The makeup of our diets has also changed a lot. Iodine is naturally present in all seafood, some dairy products and in eggs, though the quantity may vary from one region or food system to another. When a person reduces or cuts out several of these sources at once while not also consuming iodised salt or fortified foods, the risk of deficiency increases.

The result is that a basic, inexpensive, and effective micronutrient has fallen out of the spotlight just as certain groups are once again at risk of not getting enough iodine.

Plant-based diets

Vegetarian and vegan diets can be healthy, but they must take iodine into consideration. A 2023 review in the British Journal of Nutrition concluded that people following a plant-based diet, especially vegans, may find it hard to get the recommended amount of iodine from these foods alone.

This does not mean a plant-based diet is inherently lacking – and the solution is straightforward. Just as vitamin B12 is is commonly recommended for those who reduce their consumption of fish or dairy – or when people replace animal products with unfortified plant-based alternatives – so too should iodine.

Leer más: Vegan and vegetarian diets may lack certain nutrients – here’s how to get more of them

Pregnancy and breastfeeding

Iodine deserves special attention during pregnancy. There is strong evidence that a severe deficiency of this micronutrient can affect fetal development and thyroid function, which is why many organisations use specific thresholds to assess iodine status in pregnant women. The US National Institutes of Health states that a urinary concentration of 150–249 micrograms per liter (μg/L) in pregnant women is considered adequate for the general population.

But there is a caveat to this. Concerns about mild or moderate deficiency are legitimate, but there is no conclusive evidence as to the cognitive benefits of supplementing all pregnant women who show a mild deficiency. Reviews and trials have indicated that there is plausible biological concern, and some studies suggest an association with poorer outcomes, but controlled experiments have not unanimously shown clear improvements in infant neurodevelopment.

Nevertheless, several scientific societies have adopted a cautious stance. The American Thyroid Association, for instance, states that women who are planning to conceive, pregnant or breastfeeding should receive 150 μg of iodine daily in prenatal or multivitamin supplements, usually in the form of potassium iodide, to help meet increased requirements.

Why ‘more salt’ is not the answer

Another important clarification is needed here. Advocating for iodised salt does not mean recommending a higher salt intake. The WHO maintains its recommendation to reduce sodium intake due to its link with high blood pressure and cardiovascular disease. In terms of public health, the solution is not “more salt”, but less – though the salt we do eat should be iodised.

In fact, the WHO itself has emphasised that reducing salt intake and fortifying salt with iodine are compatible, provided the concentration of the mineral is properly adjusted and salt used by the food industry is also fortified.

This point is key because it avoids two common pitfalls: turning the issue into a nostalgic defence of table salt, or the other extreme of assuming that any reduction in sodium intake will automatically solve all health problems without any nutritional consequences. But it is possible to strike a balance between preventing cardiovascular disease and iodine deficiency.

A weekly e-mail in English featuring expertise from scholars and researchers. It provides an introduction to the diversity of research coming out of the continent and considers some of the key issues facing European countries. Get the newsletter!

José Miguel Soriano del Castillo no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.