Lillian Wilson

Gut Feelings by Alessio Fasano

Discover why the microbiome might possess the answers to human health with the book ‘Gut Feelings.’

Gut Feelings

In the intricate riddle of human health, there is a very important player that many do not notice – the microbiome. This vast community of microorganisms has a profound influence on various aspects of our health. From digestive processes to immune responses, and even impacting mental health, the microbiome’s significance is undeniable.

In this review, we will delve into the pages of ‘Gut Feelings’ by Alessio Fasano, a book that uncovers the potential of the microbiome to revolutionise how we perceive health and disease.

Author’s background

Alessio Fasano, a renowned pediatric gastroenterologist and scientist, leads the Center for Celiac Research at MassGeneral Hospital for Children (MGHfC) in Boston.

Alessio Fasano (r)

Established in 1996, the centre focuses on research, clinical expertise, and advocacy for gluten-related disorders like celiac disease. Trained in Italy, Dr. Fasano founded the Pediatric Gastroenterology and Nutrition division at the University of Maryland. He discovered the prevalence of celiac disease in the US, and his research identified ‘zonulin,’ tied to autoimmune diseases.

What is the book about?

‘Gut Feelings’ by Alessio Fasano explores the world of the microbiome – a community of tiny organisms living inside and interacting with our bodies. The book highlights how this field could revolutionise our approach to staying healthy and preventing diseases.

The book is divided into three main sections, each offering unique insights:

I. The Wisdom of a Microscopic Species: This section delves into the evolutionary biology of microorganisms, explaining their adaptability and highlighting the importance of our ancestral microbiome. It explores factors influencing the human microbiome’s development, decoding the connections between our genetic makeup and the intricate microbial ecosystem.

II. The Microbiome’s Role in Disease: The authors discuss the crucial role of the microbiome in various health conditions. They elaborate on the connections between the microbiome and gut inflammatory disorders, obesity, autoimmunity, neurological and behavioural disorders, environmental enteropathy, and even cancer. This section underscores the profound influence of the microbiome on our overall well-being.

III. Manipulating the Microbiome to Maintain Health: The book explores strategies for leveraging the microbiome to support health and prevent diseases. The authors delve into innovative approaches, such as utilising microbiome composition for disease prediction and interception.

Table of contents

  • Preface
  • I. The Wisdom of a Microscopic Species
  • 1. Evolutionary Biology Explains Bacterial Adaptability
  • 2. The Ancestral Microbiome
  • 3. Early Factors Influencing the Human Microbiome
  • 4. Cracking the Codes: From the Human Genome to the Human Microbiome
  • 5. Beyond Bacteria: Those Other “Omes”
  • 6. The Microbiome Hypothesis: The Epigenetic Role of the Microbiome
  • II. The Microbiome’s Role in Disease
  • 7. The Microbiome and Gut Inflammatory Disorders
  • 8. The Microbiome and Obesity
  • 9. The Microbiome and Autoimmunity
  • 10. The Microbiome and Neurological and Behavioral Disorders
  • 11. The Microbiome and Environmental Enteropathy
  • 12. The Microbiome and Cancer
  • III. Manipulating the Microbiome to Maintain Health
  • 13. From Association to Causation: A New Approach to Microbiome Composition and Function in Disease Development
  • 14. Preventive Medicine: Monitoring the Microbiome for Disease Prediction and Interception
  • 15. Treatments for Disease: Prebiotics, Probiotics, Synbiotics, and Postbiotics
  • 16. Microbiome Research in Gut-Brain Axis Diseases: Psychobiotics
  • 17. Artificial Intelligence, Synthetic Biology, and the Microbiome
  • 18. Maintaining a Resilient Microbiome through Old Age
  • Epilogue: Why Studying Our Microbiome Is Important for Our Future
  • Acknowledgments
  • Index

Key takeaways from ‘Gut Feelings’

1The role of microbiome in the development and treatment of diseases

The human microbiome’s central role in disease spans various conditions, including inflammatory diseases like irritable bowel syndrome (IBS) and allergies, where microbiome composition and function are pivotal. IBS highlights the intricate interplay between genetics, triggers, and altered gut barriers. Allergies connect early microorganism exposure with dysbiosis, intestinal permeability, and immune responses, influencing the balance between tolerance and reactions. Diverse studies reveal complex interconnections among microbiota, immunity, and clinical outcomes, offering potential therapeutic directions.

Gut microbiome imbalance has also been linked to obesity and metabolic shifts. Investigations into type 1 diabetes (T1D) indicate microbiome changes, notably the Firmicutes/Bacteroidetes ratio, preceding T1D, emphasising genetics, environment, and microbiome interaction.

What is more, recent studies spotlight the gut microbiome’s significance in cancer immunotherapy, especially with checkpoint inhibitors, revealing dysbiosis-induced inefficacy and linking responder microbiota with improved outcomes, highlighting the potential for personalised anticancer treatments.

2The unique gut-brain connection

The relationship between the human microbiome and our brain’s health is a fascinating discovery that is changing how we think about our bodies. Imagine there’s a connection between our gut and brain that’s controlled by tiny microorganisms in our gut – this connection is called the gut-brain axis. These microbes communicate with our brain and affect how it develops and works. They can even impact our mood, memory, and other brain functions. This discovery is a big deal because it shows that our gut health is closely linked to our brain health. These microbes can influence how our brain grows, how it works, and even how we feel. It’s like they’re sending messages back and forth between our gut and brain. This is important because it could help us understand and treat conditions like autism, anxiety, and even diseases like Parkinson’s. It also highlights how our diet plays a role in keeping both our gut and brain healthy.

3Autism and microbiome connection

Autism Spectrum Disorder (ASD) is a complex disease characterised by communication difficulties, social obstacles, and repetitive behaviours. While increased awareness and better diagnoses contribute to the growing cases of ASD, environmental factors are becoming more recognised as key triggers. ASD’s complexity leads to different treatment results, highlighting the need for personalised approaches based on specific biomarkers. In this intricate landscape, the gut microbiome’s role and its potential links to the brain open up new avenues for investigation.

The author cites research that shows that children with ASD often face gut and immune issues. The GEMMA (Genome, Environment, Microbiome, and Metabolome in Autism) study reveals the connections between genes, environment, gut health, and ASD. GEMMA’s pursuit promises not only insights into ASD’s origins but also the potential for personalised treatment approaches that could reshape how we understand and address this complex condition.

Overall rating & strengths and weaknesses, according to readers’ reviews

The book has gotten 3.96 ⭐️ on GoodReads.


  • Offers a wealth of information and up-to-date research on the microbiome.

  • Covers the microbiome from various perspectives and includes interviews with various experts in the field, providing a well-rounded view of the subject.

  • Presents scientific concepts while remaining engaging for those with a general understanding of diseases and pathophysiology.


  • While the book offers a wealth of references and research, it might not fulfil readers’ hopes of finding actionable insights or advice.

  • The book’s use of technical language and jargon might make it feel like a textbook, especially for readers who are not familiar with the subject.

Best quotes from ‘Gut Feelings’

“Besides a high intake of sodium, all the other listed risk factors linked to deaths and DALYs globally (low intake of whole grains, fruits, nuts and seeds, vegetables, fibers, and legumes) have a proved negative impact on gut microbiome composition and function and favor dysbiosis and inflammation.”
“There is now growing evidence suggesting that the gut microbiome and its metabolites participate in the formation of the BBB, and myelination, neurogenesis, and microglia maturation, from the prenatal period to senility. The microbiota can influence neuroinflammation by modulating microglia and astrocytes. Animal models suggest that the microglia, defined as “the immune system of the brain,” remain in an immature status if animals develop under germ-free conditions, but they can be rescued by the administration of SCFAs.”

Final takeaway

‘Gut Feelings’ by Alessio Fasano delves into the fascinating world of the microbiome and its profound impact on human health. Through the author’s expertise as a renowned pediatric gastroenterologist and scientist, the book uncovers the intricate connections between our genetic makeup, brain health, disease prevention and susceptibility, and the complex microbial ecosystem that resides within us.

This book is a must-read for anyone seeking a deeper understanding of the microbiome’s pivotal role in human health and the future of disease prevention and treatment.

Where to buy

You may purchase ‘Gut Feelings’ on Amazon at the best price. It is available in paperback, hardcover and Kindle versions, so you may choose an option that appeals to you the most.

Healthypedia FAQ

Yes, the book features interviews with experts in the field and presents real-world examples to illustrate its points.

The book discusses cutting-edge topics like artificial intelligence, synthetic biology, and their impact on microbiome research.

Although the book offers an understanding of the microbiome's influence, it does not provide precise lifestyle guidance tailored to every reader.

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