When I come home to cook after a long day’s work, my primary goal is to feed no one but myself. However, I recently realized that this is a very self-centered view, because it ignores the many microorganisms with which I inevitably have to share everything that enters my gastrointestinal tract. Whether I want it or not, I always have to share my culinary concoctions with trillions of other individuals: the gut microbes. Recent scientific advances have revealed that pleasing the dauntingly complex ecosystem within us is partly shaped by the simple act of eating; thus, pleasing microbes might be even more important than pleasing ourselves, because the microbes perform services crucial to human health.
For the past year, I have spent most of my professional life exploring scientific approaches to food. Or, to be correct, I have explored the more hands-on approaches, such as those aiming to develop new techniques and products to promote advances in the culinary arts. However, once consumed, food affects us and leaves a lasting mark, whether it is prepared in a progressive gastronomy lab in Spain or on a farm in Norway. As such, a scientific approach to cooking must address how food affects the human body. Indeed, while we experience food emotionally, mentally and even spiritually, we also experience it physiologically – food is able to dictate the state of our five senses, and that of our overall health and well-being. Having investigated the hands-on culinary aspect of food science at Fundacion Alicia in Spain and in Dr. Amy Rowat’s at UCLA, I will spend this summer asking broader questions about food and health. More specifically, I am spending ten weeks as a Summer Research Fellow in the department for Gastroenterology at the world-leading medical institution Mayo Clinic in Rochester, MN.
Least said, four weeks at Mayo Clinic have complicated my understanding of food, providing me with a new set of prisms through which I view nutrition and health. As a consumer, I am every day exposed to a wealth of information on healthy foods. Eat more fiber! Eat blueberries and Kale! Eat your vitamins! Try eating yoghurt because it contains probiotics! The calls are endless. Although informative, these calls concern what we should eat, but fail to point out why we should eat it, and how the foods benefit us. In addition to providing direct benefits to the human body, most healthy foods are healthy because they directly affect our gut microbes, which in turn perform actions that are indirectly beneficial to the host. Contrary to popular belief, most healthy foods are beneficial not because they endlessly pump nutrients down your bloodstream, but because they cause changes to the gut microbial community, directing it to perform vital actions such as the synthesis of vitamins or the breakdown of the indigestible carbohydrates that comprise most plant foods.
The gut microbes should not be underestimated; we would not be the same without them. Tens of trillions microorganisms inhabit the human gastrointestinal tract, forming a dynamic and diverse community shaped by selection and competition. With the overwhelming majority found in the colon, the communities of microorganisms are referred to as the microbiota; the human microbiome is home to an enormous number of bacteria, approximately 10 million bacterial cells, outnumbering the human cells by an estimated 10-fold and the human genome by 150-fold. That’s a lot.
The microbiome encodes for a number of functions that makes the human genome look bleak in comparison. For example, the human gastrointestinal tract only encodes for 17 enzymes dedicated to the breakdown of carbohydrates; the microbiome contains at least 10.000 enzymes devoted to this task. The relative abundance of bacterial species and their specific genes is heavily controlled by diet; a recent study revealed that some Japanese individuals contained a gut bacteria very specialized for degrading algal cell walls, a bacterium otherwise only found in Japanese seaweed. Another study showed that diet instead of host phylogeny (evolutionary relatedness) can be a strong predictor for gut microbial community composition; for instance, herbivorous rabbit and rhinos have similar microbiomes, despite being extremely far apart in terms of phylogeny.
Changes in the normal microbiome has been associated with a number of disease states, including colon cancer, Irritable bowel syndrome, ulcerative colitis, diabetic gastroparesis, etc. As a result, it is clear that the gut microbiome is a dynamic ecosystem that has the power to affect our overall well-being. Since the microbiome responds to and is shaped by the daily perturbations presented by our diets, it seems that we are ultimately kings of our own castles. Although an oversimplified mechanism of action, we can carefully select what we eat to select for a healthy gut microbiome that maintains the overall health of our selves.
Over the next six weeks I will continue my research on the beautiful interactions between gut microbiota and diet composition, asking questions about their compounding effect on human health. In more specific terms, I will investigate the prospects of certain dietary compounds in treating common gastrointestinal health problems, while trying to understand the more general bidirectional relationships between changes in gut microbial communities and changes in host physiology. While I am learning that science is never as predictable as science itself predicts, I am also gaining invaluable insights into broader scientific approaches to food, the approaches which potentially have the power to affect the health of millions of people worldwide, including my own.
Whatever the implications, don’t forget that next time you eat breakfast (or any meal) you are feeding not only yourself but trillions of organisms within you; as that bite of cereal enters your mouth, it initiates the daily tending of the body’s microbial garden.