Gut- Brain Story

Authors

Krithika Tharan

Synopsis

In the quest for holistic well-being, the intersection of the gut, the brain, and our emotions has long been a mystery. For decades, scientists have focused on the brain’s influence on the body, but emerging research is now highlighting the profound impact that our gut and its microbiome have on not just digestion, but also mental health, emotional regulation, and overall hormonal balance.

This book, “The Gut-Brain Story , delves deep into the fascinating world of gut health and its powerful, often underestimated, influence on both our minds and bodies. It takes you on a journey through scientific exploration and practical applications that reveal how our gut is much more than just a digestive system; it is a second brain that influences our mood, immune responses, and even our ability to heal from chronic pain and stress.

The goal of this book Is to provide readers with a comprehensive understanding of the gut-brain axis the complex communication network linking the gut and brain and the role of the gut microbiome in shaping not just our physical health, but our emotional and psychological well-being. Each chapter explores a unique aspect of this connection, from the way stress impacts our hormones and fertility to how movement, diet, and daily rituals can restore balance and foster healing.

The chapters are designed not only to present Innovative scientific knowledge but also to offer practical steps that readers can take to optimize their gut health and, in turn, improve their mental clarity, emotional stability, and overall vitality. Whether you are dealing with stress, hormonal imbalances, autoimmune diseases, or simply seeking to enhance your overall wellness, the insights provided here can guide you toward a deeper understanding of the intricate relationship between your gut, mind, and body.

This book is not just for those interested in science and health professionals, but for anyone looking to take charge of their health in a meaningful, sustainable way. By understanding the intricate pathways through which our gut affects our thoughts, moods, and behaviors, you can make informed choices that promote a healthier, more balanced life.

I invite you to explore the transformative power of the gut-brain connection and to begin your own journey toward wellness. May this book serve as a valuable resource, offering both knowledge and actionable insights that empower you to heal, feel better, and live a more vibrant life.

Welcome to the world of gut health and emotional healing where the path to wellness begins from within.

Chapters

  • The Healing Connection: How the Gut, Mind, and Emotions Shape Our Wellness
  • The Restless Mind: Gut, Sleep & Emotional Pain
  • The Silent Orchestra: Microbes, Mood, Metabolism & Miracles
  • The Motherhood Axis: Gut, Hormones & the First 1000 Days
  • Bodies on Fire: Healing Pain Through the Gut–Mind Axis
  • When the Gut Becomes the Mind: The Biology of Emotion, Inflammation & Healing
  • Rewiring the Gut–Brain Axis: Vagus Nerve, Rhythm, and Daily Rituals
  • When Stress Becomes Biology: Vagus, Thoughts, and the Hamster Wheel
  • Movement, Microbes, and Mood: Escaping the Chair Trap
  • Gut-Hormone Harmony: PCOS, Stress, Thyroid & the Second Endocrine System

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Author Biography

Krithika Tharan

Krithika Tharan is a Nutritional Psychologist, TEDx Speaker, and Founder of Hepta Academy and Hepta Senz, integrating psychology, nutrition, and behavioral science to drive holistic wellness. A certified Zenlp Master Practitioner and corporate trainer, she empowers professionals through evidence-based programs that enhance mental resilience and productivity. Recognized among Vikatan’s Top 10 Vella Manithargal for social impact, Krithika has authored acclaimed books on diet and travel and delivered over 300+ media sessions. Her mission is to help organizations cultivate healthier, purpose-driven teams that align wellbeing with peak performance.

References

Chapter 1: The Healing Connection: How the Gut, Mind, and Emotions Shape Our Wellness

1. Progress S.W. (2018). Polyvagal Theory: Social engagement and vocal tone signal safety, triggering calm reflexes. Psychological Science.

2. Foster J.A., McVey Neufeld K.A. (2013). Gut-brain axis pathways. Physiological Reviews.

3. Dinan T.G., Cryan J.F. (2017). Psych biotics as adjunct therapy for depression. Psychopharmacology.

4. Bravo J.A., et al. (2011). Gut bacteria influence mood through vagus nerve. Proceedings of the National Academy of Sciences (PNAS).

Chapter 2: The Restless Mind: Gut, Sleep & Emotional Pain

1. Cryan J.F., Dinan T.G. (2012). Gut microbes influence emotion through immune and neural routes. Nature Reviews Neuroscience.

2. Miller G.E., Raison C.L. (2016). Chronic stress and inflammation: Implications for the regulation of immune and emotional processes. Psych neuroendocrinology.

3. Hebbian Learning. (2020). Neuroplasticity and cognitive rewiring in emotional regulation. Frontiers in Neuroscience.

4. Kirmayer L.J. (2004). Psychosomatic pain and emotional responses to stress. The Lancet Psychiatry.

Chapter 3: The Silent Orchestra: Microbes, Mood, Metabolism & Miracles

1. Braniste V., et al. (2014). Germ-free mice have leaky blood-brain barrier; microbiota restoration tightens it. Science Translational Medicine.

2. Dalile B., et al. (2019). SCFAs as neuromodulators. Nature Reviews Gastroenterology & Hepatology.

3. Kelly J.R., et al. (2016). Depression linked to altered gut flora diversity. Molecular Psychiatry.

4. Foster J.A., McVey Neufeld K.A. (2013). Gut-brain axis pathways. Physiological Reviews.

5. Frost G., et al. (2021). FFAR2/3 receptors in metabolic and emotional regulation. Gut Microbes.

Chapter 4: The Motherhood Axis: Gut, Hormones & the First 1000 Days

1. Dominguez-Bello M.G., et al. (2010). Microbial exposure in utero impacts immune development. Proceedings of the National Academy of Sciences (PNAS).

2. Qin J., et al. (2012). Dysbiosis in gut microbiome exacerbates inflammation and metabolic diseases. Nature.

3. Progress S.W. (2018). Polyvagal Theory and its role in regulating emotional responses. International Journal of Neuroscience.

4. Knezevic J., et al. (2020). The thyroid–gut axis and fertility. Nutrients.

Chapter 5: Bodies on Fire: Healing Pain Through the Gut–Mind Axis

1. Laborde S., et al. (2022). Slow-breathing protocols reliably increase HRV and vagal tone. Journal of Psychophysiology.

2. Pereira M., et al. (2021). The effects of gut microbial metabolites on pain and inflammation regulation. Endocrine Reviews.

3. Fasano A. (2011). Zonulin and intestinal permeability. Proceedings of the National Academy of Sciences (PNAS).

4. Dinan T.G., Cryan J.F. (2017). Psych biotics as adjunct therapy for depression. Psychopharmacology.

Chapter 6: When the Gut Becomes the Mind: The Biology of Emotion, Inflammation & Healing

1. Cryan J.F., Dinan T.G. (2012). Gut microbes influence emotion through immune and neural routes. Nature Reviews Neuroscience.

2. Miller G.E., Raison C.L. (2016). Chronic stress and inflammation: Implications for the regulation of immune and emotional processes. Psych neuroendocrinology.

3. Sarkar A., et al. (2016). The microbiome’s role in the regulation of mental health and emotional responses. Nature Reviews Microbiology.

4. Kelly J.R., et al. (2015). Microbiome modulation of the kynurenine pathway in mental health. Trends in Molecular Medicine.

Chapter 7: Rewiring the Gut–Brain Axis: Vagus Nerve, Rhythm, and Daily Rituals

1. Porges S.W. (2020). Safety perception governs inflammation and stress response. International Journal of Neuroscience.

2. Laborde S., et al. (2022). Slow-breathing protocols reliably increase HRV and vagal tone. Journal of Psychophysiology.

3. Dalile B., et al. (2019). SCFAs as neuromodulators. Nature Reviews Gastroenterology & Hepatology.

4. Kelly J.R., et al. (2016). Depression linked to altered gut flora diversity. Molecular Psychiatry.

Chapter 8: When Stress Becomes Biology: Vagus, Thoughts, and the Hamster Wheel

1. Progress S.W. (2018). Polyvagal Theory and its impact on stress. Psychological Science.

2. Mbiydzenyuy N.E. (2024). Stress-induced ovulation suppression and its gut connections. Frontiers in Neuroendocrinology.

3. Klusmann H., et al. (2023). The effect of stress on ovulation and the HPA axis. Neuroscience & Biobehavioral Reviews.

4. Saadedine M., et al. (2025). Stress and functional hypothalamic amenorrhea: A biological pathway. Stress.

Chapter 9: Movement, Microbes, and Mood: Escaping the Chair Trap

1. Bravo J.A., et al. (2011). Gut bacteria influence mood through vagus nerve. Proceedings of the National Academy of Sciences (PNAS).

2. Dempsey P.C., et al. (2016). Just 2 minutes of walking every 30 minutes reduces post-meal glucose by 34%. Diabetologia.

3. Katzmarzyk P.T., et al. (2009). Prolonged sitting raises all-cause mortality by 49%, independent of exercise. Medicine & Science in Sports & Exercise.

4. Foster J.A., McVey Neufeld K.A. (2013). Gut-brain axis pathways. Physiological Reviews.

Chapter 10: Gut-Hormone Harmony: PCOS, Stress, Thyroid & the Second Endocrine System

1. Baars A., et al. (2015). Bile acids, FXR, and TGR5 in metabolism. Nutrients.

2. Progress S.W. (2018). Polyvagal Theory and its role in regulating emotional responses. International Journal of Neuroscience.

3. Qin J., et al. (2012). Dysbiosis in gut microbiome exacerbates inflammation and metabolic diseases. Nature.

4. Knezevic J., et al. (2020). The thyroid–gut axis and fertility. Nutrients.

Published

December 17, 2025

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