You hear it all the time, especially when you need to make a big decision. “Listen to your gut,” your friends, family, or co-workers advise. But what does that really mean? Does the gut actually have anything worthwhile to tell you? Turns out, the answer is yes – your gut has a lot to tell you.
The Science of the Gut
The gut is harbors the majority of what scientists call the microbiome. This describes all of the microbial species on and in the human body, from skin to mouth to gut to reproductive and respiratory tracts. Another term we use is microbiota, which refers to the individual bacterial species in the biome specific to a certain part of the human body, for example, the intestines. Microbiota and the microbiome develop when we are babies and evolve and change over time.
These microbes are plentiful. Think about this: for every human gene, there are 100 microbial genes on and in our bodies. There are an estimated 500 to 1,000 species of bacteria in the human gut alone! The vast majority of these live in the large intestine, or colon. Many gut microbes are responsible for breaking down nutrients like carbohydrates, synthesizing vitamins, and creating enzymes. Overall, the microbiota plays an important role in normal, healthy human physiology and has a significant impact on health and disease.
The Connection Between Your Gut and Your Brain
Your brain, and in turn your mood, is affected by what happens in the gut and vice versa. You may have heard people refer to the gut as the “second brain.” Research has shown that alterations in intestinal microbiota affect anxiety-like behavior. Scientists observed that behavior changes resulted from inflammatory status and are associated with differences in the microbiota profile in the gastrointestinal tract.
What we have also discovered is that the gut functions through regulation of what is called the enteric nervous system, “the so-called brain in the gut.” Brain-gut interactions are dependent on signaling from the enteric nervous system (ENS) and from the brain (central nervous system, or CNS). All humans have experienced the brain-gut connection.
How You Can Foster a Healthy Brain-Gut Relationship
You can take steps to gain and maintain a healthy gut. Many people are familiar with the concept of probiotics. These are naturally-occurring, friendly bacteria, often from fermented foods like yogurt, kimchee, pickles, sauerkraut, etc. Add them to your diet.
Prebiotics are less well-known. They are specialized plant fibers that beneficially nourish the good bacteria that are already in the gut. While probiotics introduce good bacteria into the gut, prebiotics act as a fertilizer for the good bacteria that’s there. These plant fibers are not digested. Instead, prebiotics promote the growth of good bacteria in the gut.
Studies have shown that prebiotics and good bacterial gut balance play a direct role in health and disease, and the more diverse your diet is in vegetables, the higher the prebiotic effect. Sources of prebiotics include beans, dandelion greens, Jerusalem artichoke, jicama, raw oats and unrefined wheat, barley, and yacon.
Take good care of your gut – that way, when you listen to it, it will lead you in a healthy direction.
Peter Moses, MD, is a gastroenterologist at The University of Vermont Medical Center and professor at the Larner College of Medicine at UVM.