Discover why taking care of your gut means taking care of your entire body — from your immune system to your mood.

For a long time, the gut was thought to be responsible only for digesting food. Today, we know its role goes far beyond that. Inside it lives a complex ecosystem of microorganisms — the gut microbiota — that directly influences key aspects of our health. Taking care of it not only improves digestion, but can also help you feel more energetic, less inflamed, and emotionally more balanced.

Adriana Martín Peral – Neolife Nutrition Unit

What Is the Microbiota and Why Does It Matter?

The gut microbiota is the collection of trillions of microorganisms — bacteria, viruses, fungi, and others — that live in your intestines. Although it may sound strange, these tiny inhabitants play a crucial role in your health.

Among the microbiota’s main functions are:

• Digesting food and producing nutrients such as B vitamins and vitamin K
• Training the immune system
• Producing neurotransmitters such as serotonin (90% of which is produced in the gut!)
• Protecting against harmful pathogens

This is why the gut is often called “the second brain.” There is a direct connection between the gut and the brain, known as the gut-brain axis, which allows what happens in one to affect the other.

The Microbiota and Its Impact on Mental and Immune Health

The connection between the gut and the brain has been one of the most fascinating scientific discoveries in recent years. What was once considered solely a digestive organ is now recognized as a complex system that communicates directly with the brain through what is known as the gut-brain axis. This communication pathway allows changes in the gut microbiota to influence not only digestion, but also emotional state, behavior, and even the way our body responds to disease.

In the field of mental health, various studies have shown that an imbalance in the gut microbiota — known as dysbiosis — may be linked to disorders such as anxiety, depression, and chronic fatigue. This is because many intestinal bacteria participate in the production of key neurotransmitters such as serotonin, which is responsible for generating feelings of well-being and happiness. In fact, it is estimated that more than 90% of the body’s serotonin is produced in the gut, which explains why digestive discomfort is often accompanied by emotional disturbances.

On the other hand, the microbiota plays a crucial role in the functioning of the immune system. Approximately 70% to 80% of the body’s immune cells are located in the gut, making it a true defense center. When the microbiota is balanced, it helps train the immune system to respond appropriately to viruses, bacteria, and toxins. However, when this balance is disrupted, it can lead to a state of chronic low-grade inflammation that, over time, weakens our defenses and increases the risk of developing autoimmune diseases, allergies, recurrent infections, and even metabolic conditions such as obesity and type 2 diabetes.

In addition, the modern lifestyle — characterized by low-fiber diets, excessive consumption of ultra-processed foods, frequent antibiotic use, lack of sleep, and high levels of stress — has a direct negative impact on the microbiota. These factors reduce bacterial diversity, promote the growth of harmful microorganisms, and alter the protective functions of the gut. For this reason, caring for the microbiota should not be seen merely as a strategy to improve digestion, but as a fundamental tool for strengthening the immune system, balancing the mind, and preventing disease.

How to Care for Your Microbiota: Practical Guide

Taking care of your microbiota does not have to be complicated. Despite its biological complexity, this intestinal ecosystem responds very positively to simple lifestyle and dietary changes. What you choose to eat, how you manage stress, and how much sleep you get can shape your microbiota day by day, strengthening its diversity and promoting beneficial bacteria. In other words, every daily decision is an opportunity to nourish your health from within.

One of the fundamental pillars of maintaining a balanced microbiota is the regular consumption of fiber-rich foods. Fiber acts as food for the good bacteria in the gut, allowing them to grow, multiply, and perform their functions properly. This type of fiber, known as prebiotic fiber, is naturally found in:

• Garlic
• Onion
• Asparagus
• Leeks
• Artichokes
• Whole grains such as oats
• Less ripe fruits, such as green bananas

Unlike regular fiber, prebiotic fiber not only regulates intestinal transit, but also directly nourishes the microbiota, helping improve its diversity and stability.

Alongside prebiotics, fermented foods have special value for gut health. These foods contain live bacteria, known as probiotics, which can temporarily colonize the intestine and support digestive, immune, and metabolic functions.

• Kefir
• Plain unsweetened yogurt
• Sauerkraut
• Kimchi
• Artisan kombucha are some accessible and effective examples

Including them regularly in your diet can help restore microbial balance, especially after antibiotic treatments or prolonged periods of stress and poor eating habits.

In addition to diet, other lifestyle factors significantly influence the microbiota. Chronic stress, sedentary behavior, lack of sleep, and excessive consumption of ultra-processed foods are silent enemies of intestinal health. Stress, for example, alters intestinal motility and can change bacterial composition within just a few days, causing digestive symptoms such as bloating, gas, constipation, or diarrhea. Sleeping well, staying physically active, and finding time to disconnect are essential habits that work together to protect the balance of the intestinal ecosystem.

Conclusion

Taking care of your microbiota is not a fad or a passing trend. It is a real investment in your long-term health. Starting with small, sustainable changes — such as adding more vegetables to your meals, avoiding added sugars, or choosing fermented options instead of industrialized products — can make a big difference in how you feel and how your body functions. Remember that a healthy gut not only improves digestion, but also strengthens your defenses, helps you manage stress more effectively, and enhances emotional well-being.

Your gut has memory. Every choice you make either builds it up or weakens it. That is why caring for your microbiota is a smart and conscious way to care for your entire body, from the defenses that protect you to the thoughts that accompany you. Today is a good day to start.

BIBLIOGRAPHY

(1) Cryan, J. F., & Dinan, T. G. (2012). Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience, 13(10), 701–712.

(2) Dinan, T. G., & Cryan, J. F. (2017). The microbiome-gut-brain axis in health and disease. Gastroenterology Clinics of North America, 46(1), 77–89.

(3) Belkaid, Y., & Hand, T. W. (2014). Role of the microbiota in immunity and inflammation. Cell, 157(1), 121–141.

(4) Round, J. L., & Mazmanian, S. K. (2009). The gut microbiota shapes intestinal immune responses during health and disease. Nature Reviews Immunology, 9(5), 313–323.

(5) Kau, A. L., Ahern, P. P., Griffin, N. W., Goodman, A. L., & Gordon, J. I. (2011). Human nutrition, the gut microbiome and the immune system. Nature, 474(7351), 327–336.

(6) Valdes, A. M., Walter, J., Segal, E., & Spector, T. D. (2018). Role of the gut microbiota in nutrition and health. BMJ, 361, k2179.

(7) Giulia Enders (2014). La digestión es la cuestión. Editorial Uranito

(8) Michael Mosley (2017). El Código de la Comida: cómo tu flora intestinal puede cambiar tu vida. Editorial Urano.

La entrada Your Second Brain: How the Gut Microbiota Impacts Your Mind, Immunity, and Overall Health se publicó primero en Neolife.

For years, it was believed that the gut was simply a food-processing system.

However, in recent decades, scientists have discovered something remarkable: inside our intestines lives an ecosystem of trillions of microorganisms—bacteria, fungi, and viruses—that not only digest what we eat, but also affect our mood, immune system, and even our weight. This community is known as the gut microbiota, and its role in health is far more important than we ever imagined.

Arantxa Jiménez – Neolife Nutrition Unit

What Is the Gut Microbiota and Why Is It So Important?

The gut microbiota is the collection of microorganisms that live in your digestive tract. Each person has a unique composition, like a microbial fingerprint. These bacteria collaborate with our bodies in many ways:

• They help digest complex nutrients.
• They produce vitamins (such as vitamin K and some B vitamins).
• They train the immune system.
• They regulate inflammation.
• They influence the production of neurotransmitters like serotonin.

The Gut–Brain Axis: A Highway of Signals

Here’s where it gets fascinating: your gut and brain are connected through what’s called the gut–brain axis, a two-way communication network that includes the vagus nerve, the immune system, and chemical signaling.

About 90% of serotonin, the neurotransmitter linked to well-being, is produced in the gut.

An imbalanced microbiota (dysbiosis) has been associated with depression, anxiety, and even neurodegenerative diseases.

Gut bacteria can also influence your eating behavior and stress response.

Studies have shown that people with obesity have a different bacterial composition compared to those with a healthy weight.

Some bacteria extract more energy from food, while others influence insulin resistance or fat storage.

Moreover, a less diverse microbiota can contribute to a chronic inflammatory state—a key factor in metabolic diseases such as type 2 diabetes.

How to Take Care of Your Microbiota

There are many practical ways to maintain a healthy gut:

• Increase your fiber intake (fruits, vegetables, legumes, whole grains).
• Include fermented foods (kefir, natural yogurt, sauerkraut, kombucha).
• Avoid excessive refined sugars and ultra-processed foods.
• Avoid unnecessary antibiotics.
• Exercise regularly.
• Reduce chronic stress.

Probiotics (live microorganisms) and prebiotics (fiber that feeds those bacteria) can also be helpful, but it’s always best to consult a healthcare professional before taking supplements.

Conclusion

Your gut doesn’t just digest food—it also influences your mood, metabolism, and overall health.

Taking care of your microbiota means taking care of yourself. Eating well, staying active, and reducing stress aren’t just good ideas—they’re essential for maintaining a healthy internal ecosystem.

BIBLIOGRAPHY

(1) Revista eBioMedicine (2023). Gut microbiota and its metabolites in depression: from pathogenesis to – Revisión de metabolitos microbianos y aplicaciones terapéuticas. The Lancet+1PMC+1

(2) Santomauro D.F., Mantilla Herrera M., Shadid J., et al. (2022). Gut Microbiota Metabolites in Major Depressive Disorder—Deep Insights into Their Pathophysiological Role and Potential Translational Applications. Metabolites. Metabolitos como SCFA y triptófano en trastornos depresivos. PMC+1PMC+1 www.elsevier.com+139ytu+1

(3) Montoya-Moreno M. (2025). Microbiota intestinal y salud mental: una conexión emergente en la medicina Rev Med UAS, 15(1).

(4) CSIC (2023): Investigación de Yolanda Sanz sobre microbiota y salud mental.

La entrada Gut Microbiota: The “Second Brain” That Influences Your Mood, Weight, and Health se publicó primero en Neolife.