There is no doubt that the idea of gut health having systemic effects on human physiology is an ancient one, as countless health enthusiasts today pronounce with reference to supposed quotations from Hippocrates .1 But in the nineteenth century, a critical mass of doctors, psychiatrists, novelists, artists, ethnographers, politicians, and religious leaders all began to consider that digestive function principally influenced both emotion and cognition, often dynamically engaging with such ideas across wide disciplinary divides. Such reflections on the relationship between the digestive system and the mind spread far beyond medical journals and clinical practices, representative of the new popular enthusiasm for scientific thought in nineteenth-century cultures, which resulted in a broad range of genres through which evocation of the gut was imaginatively expressed.
This book is about that shifting focus on gut health in its relation to the mind and emotion, as epitomized in the English -language expression that refers to intuition as āgut feeling ā. But it is also a book about the emergence of this medical concept throughout literary, artistic, religious, nationalist, and ethnographic forms of representation. Embedded in this expression is the notion that the gut is the first part of the body to respond to the environment, producing an emotional sixth sense that then governs rational thought processes. This concept is not so foreign to our current physiological models in which the intestinal tract from mouth to anus is described as an exterior organ that mediates between the outside world and the internal viscera , with the intestinal epithelium providing an immunological gateway between self and other.2 But our current medical models too have recently been undergoing an important shift toward even greater systemic emphasis on the importance of digestive function and intestinal microbiota.
In fact, we are living in an exciting moment for ideas about the digestive system since there is currently an explosion of scientific research in relation to the āgut-brain axis ā, suggesting that the gut microbiome may have a much larger role in human physiology than was previously realized, influencing not only gastrointestinal health itself, but also obesity , metabolic health,3 the immune system ,4 cognitive function, mental illness , and neurodegenerative diseases .5 In alternative health communities over the past ten years, there has been an immense growth of popular interest in matters relating to the gut, as evidenced by the emergence of functional medicine in the USA, which has a strong focus on intestinal balance as the key to health and longevity . The opening pages of the work Unconventional Medicine, by the American functional health clinician Chris Kresser (one of the most influential figures of that movement) begins with the story of a child patient whose profound behavioral problems were found to correlate with severe intestinal bacterial imbalance, managed finally by a drastic change of diet .6 The success of the bestselling book Gut, the Inside Story (2014) by the German gastroenterology PhD student, Giulia Enders , is a clear indication of how much questions of intestinal health are now seen as central among readers of books about health.7 Popular interest in questions relating to the āgut-brain axis ā proposed by increasing numbers of scientific researchers has been stimulated in recent years by the publication of articles on the web-based Nature.com 8 and in The Lancet .9 It has now become common to hear even popular health enthusiasts cite the fact that there are more microbial cells in our bodies than the cells of the human body itself.10 The implications of how we understand our āselvesā is clearly suggesting a new vision of the human as multi-genomic , individualized as much by the composition of our gut micro-organisms as by our personalities, constituted as much by the life-forms living inside us as by our own genetic inheritance. There has also been a growth of interest specifically in ideas about the relationship between gut function and mental health, as a result of scientific work that has shown that the vagus nerve mediates neurotransmitter balance via the enteric nervous system, which was popularized in a series of recent articles in the web-based Psychology Today .11
Central to this area of scholarship, which has boomed since the turn of the twenty-first century, is the importance of transnational team research, as biochemists , neurologists , endocrinologists, immunologists , gastroenterologists , and microbiologists from different parts of the world work together on questions such as the potential links between the gut and depression , cognitive decline, or mental illness . In our book, we have taken a similar approach toward our humanistic inquiry into nineteenth-century ideas about āgut feeling ā. Bringing together eleven scholars with wide interdisciplinary expertise, this volume examines literal and metaphorical digestion in a range of spheres in nineteenth-century life and asks why digestive health mattered for modern culture. Focusing on Northern America and Europe from the perspectives of literary studies ; history of science and medicine; art history; politics; ethnography ; and religious studies, we have targeted three central questions: Which meanings were given to the digestive system in the writings and culture of this period? How did these meanings differ between particular national contexts or transfer across them globally? How do these findings help us better understand the relationship between the body and the mind?
By looking at digestive health from a historical and cultural perspective, this volume offers distinctive insights into an emergent area of medicine that now so emphatically integrates the body, the mind, and the emotions . However novel the new gut-brain axis science may seem, in fact many individuals who engaged with medical thought in the nineteenth century drew intuitive conclusions of a similar nature. And just as today we see the gut taking center stage in popular health movements, so too in the nineteenth century it was an area of medicine particularly amenable to vulgarization. Of course, nineteenth-century explanations of the role of digestion in cognition, emotion, personality, and general health were speculative and often widely imaginative in contrast to the well-formulated mechanistic models suggested by scientists today.
But we should not fall prey to the easy tendency to mock the past as a means of elevating our present achievements. Without the creative cultural imagination of āgut feeling ā elaborated in the culture of the long nineteenth century, it seems unlikely that medical researchers would ever have thought to look for ways in which digestion regulates other physiological functions, including those within the brain, or notice evidence of it doing so. Scientists do not operate in a vacuum but are embedded in cultural traditions and discourses, using both their left and right brain hemispheres to produce hypotheses that are triangulations of both deductive and inductive processing, both logical and intuitive reflection.12
Until now there has been little attempt to contextualize current ideas about the gut in scientific thought via a retrieval of older cultural discourses of āgut feeling ā. In fact, there has been strikingly little contribution to the emerging reimagination of gut health from scholars in the humanities. Since 2000, there has been a growing interest in food studies, a field populated mainly by historians and sociologists , which considers issues such as anorexia, obesity , and the social significance of eating practices.13 Literary and cultural studies scholars have also shown great interest in corporality in recent decades, such...