"The first thousand days of nutrition determine pathologies such as hypertension or type 2 diabetes."

Lucía Galán Bertrand (Oviedo, 1978) knew she wanted to be a pediatrician since she was five years old. At that age, she suffered a serious illness that kept her hospitalized for many days. Although more than 40 years have passed, she remembers every morning and night she had to spend there, unable to be accompanied by her parents and being restrained so her IV could not be removed. Pediatric care had little to do with today's care , and she feels that doctors didn't realize that she, and other children, could hear and understand everything, and that this could mark her forever.

The day she was discharged, she told her parents that when she grew up she wanted to be a children's doctor so that no one would have to go through the same thing again. From that, she learned a lesson that has shaped her professional career as a doctor, as she met the healthcare workers she would like to be like, and also those she wouldn't. Since then, she has dedicated her life to caring for children, including through outreach.

Maybe his name doesn't sound familiar to you, but if I tell you that he is Lucía, my pediatrician , changes everything. She has 1.2 million followers on Instagram alone. This outreach journey began almost by chance about 12 years ago. In her office, she used to hand out articles and lists of tips for parents , until one day a neighbor encouraged her to put it all together in a blog, which she later also published on social media.

In her work as a popularizer, she has published seven books, as well as numerous children's stories , which adds up to more than 80 editions in total. The latest to come out has been an updated version of The great book of Lucía, my pediatrician (Planeta, 2025) a guide for child and adolescent health, five years after the first edition.

QUESTION: Five years after publishing "The Big Book of Lucía, My Pediatrician ," the 25th edition of your book came out this month, with several updates. What are the most notable?

ANSWER. There were many topics in the big book that needed updating because the data or the situation had changed, as many things have happened to us socially in the last five years, including a pandemic . There were chapters that needed rewriting so that parents would have all the updated information.

Taking advantage of this exhaustive review, I've expanded the entire mental health section, covering depression in childhood and adolescence and anxiety disorders. I've also covered nutrition because it's an area where parents are asking for more information, in a clearer and more concise way.

I've also addressed relatively common illnesses that generate many questions and fears. For example, types of hernias in childhood, bronchiolitis and the new vaccine, measles, Kawasaki disease , and shaken baby syndrome , as well as personalized letters to provide emotional support.

Q. One of the book's chapters is about vaccines, and recently we've been hearing about diseases that we've been neglecting because we didn't get vaccinated, such as measles. Have there been any steps backward?

A. The anti-vaccine movement is something that has always existed, since the beginning of commercialization; it's not something new for us. It's a trend that evolves in waves, and in the wake of the pandemic, we saw a segment of the population quite reluctant toward certain vaccines , and that led to a lack of confidence in the rest.

This is something we healthcare professionals must emphasize: vaccines save between two and three million lives each year, and the vast majority of them are children; they are one of the greatest medical advances in human history.

Fortunately, in Spain, we enjoy very high vaccination coverage, above 95%, which guarantees herd immunity. This means that even if some minors are not vaccinated or have a condition that prevents them from generating these defenses, the vast majority are protected thanks to the immunity of others.

We have indeed seen a drop in coverage in some countries, and this, combined with migration and globalization, where we travel more and there are no borders, has led to measles outbreaks , not only in Spain but also in the rest of Europe and the world, such as the United States . And the more cases there are, the greater the risk of serious consequences and death, and we have already had to mourn some cases in unvaccinated children.

So it's not something that keeps us on alert; it's not a health emergency, but it's something we should never ignore, because we periodically encounter waves with very clear consequences for the health of children, who are, moreover, the ones who cannot make decisions.

Q. Some of the reasons anti-vaccines argue are that vaccines cause serious illnesses or even autism. Is this a reality you experience in your practice? How can these kinds of hoaxes be combated?

A. We have over a million children analyzed in independent studies worldwide, and all of these studies have come to the same conclusion: vaccines do not cause autism . This comes from Dr. [Andrew] Wakefield , who published a study with a paltry number of patients in The Lancet , a very prestigious journal. Ten years later, it was discovered that it had been fraudulent research with a clear conflict of interest, since Mr. Wakefield held a patent on his own vaccine, and families had been coerced into providing those results. The scandal was such, the biggest in the history of medicine, that his medical title was revoked, and he is no longer allowed to practice in the United Kingdom. The decision to withdraw that article from the journal came ten years later, and this caused tremendous damage to the entire community.

Do we still hear this in consultations? Yes, unfortunately. But also on social media and sometimes in the media. To combat it, we must do it at the consultation level, one-on-one. We need to try to understand where these fears and beliefs come from. And from there, with active listening and without judgment, because the moment the parent feels attacked or singled out, they won't come back, and if they don't, the one who loses is the child. I adopt an attitude of active listening , and I offer them verified information, with a very clear and forceful, but at the same time very calm, discourse.

You have to try not to address all the fears and questions in a first consultation because many of these people have held these beliefs for many years, and you won't be able to dismantle them in half an hour. You have to build trust, and in my case, although I do have experience with families who are vaccine-hesitant or clearly anti-vaccine , once I do that and achieve that level of complicity and connection, I can work in a much more calm and direct way. Then, I tell them we're going to address the topic, ask them what worries them, what their greatest fear is, and provide them with documentation and information. This way, I've managed to vaccinate many children whose parents had initially decided not to.

Q. Has nutrition taken on a greater role for parents in protecting their children's health?

A. Yes, definitely. Nutrition has changed significantly since 20 years ago, when I started working as a pediatrician. It's one of the main topics of conversation in a pediatrician's office, whereas it wasn't before.

Not only do parents want to do it right, but they are already fully aware of the short-, medium-, and long-term impact of feeding their children properly. We now know the importance of the first thousand days (which encompass how we eat during pregnancy and up to the child's first two years of life). This will determine the presence or absence of serious diseases such as high blood pressure , type 2 diabetes , metabolic syndrome, and cardiovascular disease. During these first thousand days of nutrition, it's as if we metabolically program our bodies to have a greater or lesser chance of suffering from diseases in the medium and long term.

There is a growing social awareness that the fewer ultra-processed foods, the better, that we need to limit our consumption of added sugars in our diet, and that it's necessary to promote diets rich in fruits, vegetables, legumes, and high-quality protein foods, such as eggs or fish. As a source of fat, we should eat extra virgin olive oil , and to always drink water, we should banish juice, soda, or sugary drinks.

Q. There's been a lot of talk about attention-deficit/hyperactivity disorder (ADHD) for some time now, especially in children. Are there as many cases as it seems, or is the term being used lightly?

A. Often, people speak out of ignorance, and as soon as a child is a little more active than what the person considers normal, they are labeled with that label. This is something we hear every day and creates a huge amount of social stigma for children and families diagnosed with ADHD . It also creates a lot of fear and anxiety for mothers who then come in for a consultation with their eight-month-old baby because their neighbor has told them they might be hyperactive because they move their legs a lot.

What we need to be very clear about is that it's a neurodevelopmental disorder present in between 4 and 6% of the school population; it has clear criteria, and diagnosis should never be made before the age of 5 or 6. Regardless of whether children are active or not, there is a high percentage of 1-, 2-, and 3-year-olds who have a strong motor component and move around a lot. Furthermore, it's normal for a 2-year-old to be inattentive and have a certain degree of inattention; this is a result of their cerebral immaturity. But to say that it's ADHD is a bit of a stretch. Let's call things by their name and let professionals diagnose the existence or absence of a disorder, illness, or difficulty.

Q. What can you tell me about giftedness?

A. Giftedness is a condition present in a small percentage of the population (between 2 and 5%), both in children and adults, and has been given significant attention in recent years. Because of this, I believed it was appropriate to include it in the big book, as there are many myths and stigmas surrounding it.

These people manage the information they receive differently and in a branched manner, as they are capable of generating multiple ideas simultaneously. What concerns us about them is partly their academic performance, because a very high percentage of them, paradoxically, fail at school because they are bored at school and aren't diagnosed in time, which is why they sometimes exhibit disruptive behavior.

But so does their emotional situation , as they handle it differently than others. This creates many mixed feelings for children and adolescents, who already go through sometimes complicated times. They have the constant feeling of not fitting in, they can't find others with their same tastes and interests... They are more likely to suffer bullying precisely because of differences in their tastes, their behavior, or even their way of speaking.

Therefore, families should know that this is a condition that has a diagnosis, and when the school, family, or medical team clearly suspects it, a neuropsychological evaluation is indicated. As with other conditions, they have the right to curricular adaptations or additional support from schools if needed, as the law provides. Therefore, it's important to conduct the evaluation to explain to parents what it entails and, above all, so they can provide emotional support because the road to adulthood is not without its twists and turns. Being smart is one thing, and having high abilities is something much bigger and more complex that deserves our full attention as parents, healthcare professionals, and teachers.

The mental health of children and adolescents

Q. One of the new chapters focuses on mental health. Especially since COVID, many scientific studies show that it has worsened in adults and young people. What about children?

A. The pandemic has highlighted a real problem that already existed but was largely silenced: the mental health status of our children and adolescents, as well as the glaring lack of resources at these stages. Twenty percent of them have an anxiety disorder , which significantly diminishes their quality of life.

People think that just because children are children, they should be eternally happy and worry-free because they'll have those when they're older. The reality is that children also suffer from depression. The reality is also that suicide is one of the leading causes of unnatural death in children, and that bullying is the leading cause of suicide among them due to the anxiety and depression that lead to this persistent situation.

It's a topic that must be addressed with all the rigor and sensitivity it requires, without trivializing it or causing social alarm, but rather informing families of the warning signs they should watch for if they notice a change in their child's behavior.

Q. In the book, you define adolescence as an airport runway. What's the best way to approach this stage in a healthy way?

A. With knowledge. I solve almost everything in life that way. Books have been with me throughout my life and, in fact, have saved me in many situations where I didn't understand what could be happening, both with patients and with my own children.

So I would encourage all parents to read because they will see themselves and their children recognized in countless situations. They will understand many of their behaviors, such as the need for intimacy, for getting closer to their friends than to their parents, for seeing them as the enemy... All of this is temporary; it's a real and literal metamorphosis that their body and brain are undergoing, and when you know the steps, the speed, and what's coming next, you experience it much more serenely. Reading brings a lot of calm, knowledge, and a sense of control, and this is a gift in motherhood.

Adolescence is a real metamorphosis and your body and brain are experiencing it.

Q. What is precocious puberty and what should be done in these cases?

A. Precocious puberty is a condition in which pubertal development occurs earlier than we consider normal. In girls, it can be normal for them to begin breast budding, which is the growth of the breasts, starting at age 8. If they experience it earlier, you should consult your pediatrician. It's also necessary to do so with pubarche, which is the appearance of pubertal growth before this age. Often, it will remain an isolated pubarche, and that doesn't necessarily mean it's precocious puberty, but it is a reason to ask.

In boys, it is defined by testicular growth, and this should never occur before the age of 9. So, if we see that boys start earlier, we should also go.

There is a small percentage of cases that begin puberty early, and in that case, they are referred to a pediatric endocrinologist for the appropriate evaluation. And in certain circumstances, puberty sometimes has to be delayed to prevent the child from entering puberty earlier than expected, with all the consequences this entails for their final height, for example, because they may end up much shorter, and also because of the emotional impact it can have.

Q. We're living in an era of ever-increasing information for parents, from books, information on the internet, and even social media. Is having access to so much a positive thing, or can it be overwhelming or even detrimental?

A. Information is always positive, but it has to be good. What I'm missing right now isn't having it, but critical thinking. People have access to so much, but they don't question it. Sometimes, faced with so much information, many parents lose their common sense and ignore their own instincts. I tell many of them that when in doubt, they should follow their instincts and look for professional, reputable sources they trust. So I think it's important that we educate our children on this.

Questioning what we receive and comparing information is a tremendously healthy exercise for the brain . I think we're used to this ultrasonic speed, to having the answer to everything at the click of a button, but there has to be a second step, which is to compare it with reliable sources.

Q. What are the most common reasons for consultation in pediatrics?

A. It depends on the child's age. In the first year, everything is a source of fear and anxiety. Parents then become incredibly concerned about weight gain, eating habits, strange noises, and whether it's really normal or not. The key question is , is this normal? They need to create two columns of what is and isn't normal. That's why I divide the big book this way, because I think it's the first crossroads they face.

From the first year onwards, they have much more experience, they know their baby better, and they feel more confident with feeding. This is when many children start school and the chapter on infections begins. Parents are very concerned about fever and how to manage it, about different illnesses, and everything they sometimes hear around them about them.

And when they're older, with their diet outdated, with many past illnesses, and the awareness that most of them are minor, they begin to worry a lot about everything related to their mental health, their behavior, their conduct.

Q. You mention fever, and in the book you say it's a symptom rather than a disease itself. When should we be concerned?

A. Fever is a warning sign from our body, most often secondary to an infection. When our body detects a foreign organism, the first thing it does is raise its temperature to eliminate the agent because viruses love to reproduce at lower temperatures. So, as it knows, what it does is raise the temperature to make viral replication difficult. On the other hand, this increase in temperature stimulates our immune system to produce the appropriate defenses to fight the infection.

I always tell children that fever is a friend, because it's really helping us fight the infection, and it gives us doctors a lot of information about what might be happening inside their body. When are we worried? When we have a baby under six months old who has a temperature of over 38 degrees. We always say they should consult a pediatrician because their immune systems are very immature, and sometimes they have serious infections with mild temperatures. It's the first symptom of an illness that can be serious in an infant under six months old.

From that age on, if the child is two years old and also has a runny nose, a cold, mild diarrhea, or a cough, it's normal for their temperature to rise slightly in the context of a respiratory or gastrointestinal infection. If the child's general condition is good—they're eating, happy, have a good color, and are drinking water—we give them two or three days before consulting the pediatrician. However, if during this time or after the three days have passed, the fever begins to get higher and the general condition is affected, it's time to consult the pediatrician.