Have you heard the expression “you are what you eat”? This overused saying is often used in the context of how your diet impacts your overall health. It turns out that this saying may not be far off due to an often-unrecognized civilization living within you. Scary, right? The microbiome, also known as the colonies of bacteria typically found in the gut, also has the ability to signal to your brain. It is a bidirectional signaling process, meaning that signals will travel both to and from the brain. Have you ever craved a doughnut? We have reason to believe that these cravings are due to a bacterium that goes by the name of Citrobacter rodentium. The reader should imagine this as the devil on your sugar as it says “a doughnut will give us the energy that we need” while it conveniently disregards the eventual sugar crass that will deplete your energy reserve. The method of signaling used by bacteria such as the example above is primarily through the vagus nerve that innervates the digestive system, heart, and brain.
Some other functions of this vagus nerve digestion, heart rate, mood, and taste through the parasympathetic nervous system. For example, let’s say one did consume that delectable doughnut that proved too much of a temptation. One may observe an increase in heart rate and a pleasure response in the brain. The pleasure response is your brain rewarding you. “Congrats,” it’s saying. “We told you to do something and you did it!” The American diet encourages overconsumption of sugar and salt that can lead to health problems. However, your body is adaptable. Survival of the fittest applies even when it comes to these microscopic organisms in your gut. You can decide which to keep and which to kill. The Critrobacter rodentium asks for sugar because that is what it feeds on to survive. Less sugar equals less “bad” bacteria. As such, one should work with their health care provider to find goals that work well for you. Balance is key to maintaining a healthy population in one’s microbiota. I do not pretend to never eat sugar. In fact, I quite enjoy my cafeteria’s choice of desserts, but finding your balance is crucial to learning your own body. While it is difficult to eliminate a family of bacteria, it is overpopulation of a singular type that causes issues. Diversity is important! Unless you would like to consider a poop transplant, which is a very real thing known as a fecal microbiota transplant, I hope that you also value diversity in your own body. It is a complicated system that needs nutrients to function properly.
An example of a good bacteria is lactobacillus. “Wait a second, lacto… like lactose in milk?” Ding, ding ding! Lactobacillus is often found in fermented foods or dairy products like greek yogurt. Bacteria do not distinguish between culinary cultures. There are many foods found around the globe that highlight good bacteria including kimchi, fermented cabbage, kombucha, sauerkraut, and miso. However, Mediterranean food is particularly wonderful because they focus on plant-based foods with healthy fats like those found in olives. “Okay, so now I should just eat greek yogurt 24/7?” No, diversity of foods is just as important to allow one to enjoy eating things. Envision a garden. One don’t just want one weed to override all the beautiful greenery. Instead, one would want different colors and designs. The same can be said for the gut. So eat that doughnut with the realization that some bacteria inside of the intestinal tract will be very excited for the sugar, but don’t forget to give some tender love and care to the other bacteria too!
How does all of this relate to neuroscience? During development, the nutritional needs are at an all-time high and more important than ever. By erasing good bacteria with artificial and over processed foods, some of these bacteria are non-recoverable leading to deficits in digestion and brain signaling. More research is being conducted to discover the lasting impacts of nutrition deficiencies on the microbiome that can lead to later health problems. One can understand that without an “angel”, good bacteria stick up to the devil on the other shoulder. Brain signals would be overridden by a strong craving for sugar. As such, it is safe to say, it’s not all in your head. It also happens to be in your gut.
King Lab at Creighton University 