If you visit a bookstore, whether physical or virtual, in search of a book on the microbiota, you will probably come across plenty of publications that take a range of different approaches. So what leads a journalist or writer to publish another book about the large community of bacteria living in the gut? To answer this question, we spoke to Cristina Sáez, a science journalist who, in conjunction with Spanish organization Fundación Alicia, has recently published a book on the subject called La ciencia de la microbiota [The science of the microbiota].

Available in Spanish and, from September, in Catalan, La ciencia de la microbiota (published by Libros Cúpula) takes a practical and accessible approach to the importance and functions of the gut microbiota, the 39 trillion bacteria that live in the digestive tract. Combining scientific rigor, modern illustrations, recipes and interviews with world-renowned experts, the book is based on the premise that we must look after those microorganisms so they can look after us.

As well as contributing to different media outlets, Cristina has been part of the editorial team at Gut Microbiota for Health for many years. Now, she has switched places from her usual role so we can ask her some questions about the book.


What’s different about this book’s contribution compared to others?

There are many, many books available that discuss the gut microbiota, including some that take a scientific approach and focus on explaining, for instance, the microbiota’s functions in the body. Many use a type of language that is not always accessible to the wider population and others are not as rigorous as they could be.

You also have options that provide recipes or guidance about how to take care of yourself through diet. When discussing with Fundación Alicia, we realized that lots of books emphasized diets that made recommendations using trendy words such as “superfoods” or “super energy”. In most cases, they were mentioning exotic ingredients and did not have scientific evidence to back up recommending their consumption. We have to bear in mind that microbiota science is still in the early stages. There are many studies, most of which are carried out with a small number of participants or in mice, and their conclusions cannot be declared valid until they are replicated in humans.

Our book is different because it aims to be for everyone—those who want to take care of themselves—but it does not provide a miracle solution. It just provides readers with easy and clear access to scientific evidence and what we know about how to take care of the gut microbiota, and transposes that to our everyday lives. For instance, in terms of diet, we try to stay away from miracle diets and super foods and make science-based choices. In other words, there is nothing better than following the Mediterranean Diet, based on fruit, vegetables, pulses, whole grains, tubers, nuts and dried fruit, and seeds, which is what the microbiota “likes”.

Our gut bacteria like fiber, fiber and more fiber. We joke a little in the book about how they like our grandmothers’ recipes and what we mean with that is that the best thing for the microbiota is locally produced food, which it has become accustomed to over many generations. Also, seasonal food, which has far more nutrients and organoleptic properties than food that has been in cold storage for months or which has travelled by plane from the other side of the world. And finally, traditional recipes.


You give lots of advice in your book. If you had to give us your top three recommendations, what would they be?

If I had to give three pieces of advice for taking care of the gut microbiota and ensuring it takes care of us, this is what I would say.

  1. Eat well. Follow the Mediterranean Diet, with a diet based on fruit, vegetables, pulses, whole grains, seeds, tubers and nuts and dried fruit. That should be the basis of what you eat.
  2. Take care of yourself. What does that mean? Do some exercise on a regular basis. It’s no good going for a run one day and then not doing it again for two weeks. You should try and get at least seven hours’ sleep, which is the ideal daily amount for good health, especially after the age of 40. And keep stress in check!
  3. Finally, a good way of taking care of our gut microbiota is by having a good social life. The more friends we have and the more time we spend with them, the more hugs we will get (which also produce serotonin and oxytocin). The more time enjoyed with our families and loved ones, the more bacteria we will exchange that will enrich our internal community. And if we also take a walk in the mountains and get in touch with nature—and the huge number of bacteria inhabiting that space—so much the better.

So the top three is simple: eat well, take care of yourself and surround yourself with good people.


What do you think about the future of microbiota research?

I think gut microbiota research is a fascinating field and that we are going to increasingly discover more and more relationships between our gut dwellers and their connection with both our health and our illnesses. Some really interesting fields have opened up, especially around the gut-brain axis. How can it be that our gut bacteria influence how we feel and what we think about? How can they be behind some of the major illnesses currently afflicting the Western world, such as Alzheimer’s, dementia more generally or depression?

This fascinating field will provide increasingly interesting results and we will know more about the role of those bacteria in our health. We will gradually learn about what to do to make them better, more balanced and more diverse and thus learn to modulate that community of microorganisms to treat symptoms and disease. We will have to wait quite a few years for that to happen, however, until much of the research being done now, which is producing some very promising initial results in small groups of volunteers or in mice, can be replicated and applied in the clinical setting.