Madison Simons, PsyD is a gastrointestinal psychologist in the Digestive Disease and Surgery Institute at Cleveland Clinic. This month, she answered our questions about the gut-brain connection and how our diet could have an effect on our mood.

Read the Q&A with Dr. Simons below.

WAM: The gut and the brain are related, so much so, that we often refer to the gut as the second brain. What does that actually mean?
Dr. Simons: The gut is home to thousands of different types of bacteria, which we refer to as the “microbiome.” Studies on the microbiome have found it to affect not only our digestive tract but also our overall health, how we respond to stress and adversity, and the likelihood of experiencing things like anxiety and depression. Similarly, the microbiome is affected by our diet, stress levels, and chronic medical conditions, even those affecting systems outside of the gastrointestinal tract like asthma, cardiovascular disease, or neurological conditions.

WAM: How can the gut with all those gastric juices churning and staying busy digesting food be related to how we feel emotionally? Isn’t our brain responsible for our emotions and outlook on the world?
Dr. Simons: When we feel stressed or perceive a threat in our environment, the brain sends a signal to activate the sympathetic nervous system. You might have heard this called the “fight or flight” response. In this state, our heart rate increases, breathing gets faster, and blood flows from our hands and feet into the larger muscle groups in our legs and trunk. The last priority when our body is gearing up to fight a predator or run away is digestion. For some people, stress may slow down digestion whereas for others it may cause the intestines to rapidly evacuate (think diarrhea!).

WAM: We know from research that approximately 98% of serotonin is produced in the gut, not the brain. Given serotonin is associated with helping control depression and anxiety, do we believe there is a biological connection between the gut and levels of mood disorders?
Dr. Simons: Absolutely. The diversity of the gut microbiome is consistently shown to be associated with mood disorders like anxiety and depression, though we do not yet understand exactly why. The relationship is likely bidirectional—changes in microbiome diversity seem to contribute to the onset of depressive symptoms but stress and depression also appear to impact the microbiome. These studies underscore the importance of treating the entire brain-gut axis: when we treat depression, we likely can help the gut and when we treat the gut, we are likely helping our mood.

WAM: What are your top 3 tips for caring for our gut health in order to keep the gut working optimally with the brain?
Dr. Simons: One of the most important things we can do to support our gut health is to eat a wide variety of fruits and vegetables to increase the diversity of the microbiome. If you have a hard time tolerating raw vegetables, try sautéing or pureeing them instead to vary the texture. You might notice increased gas or bloating when you try reintroducing these foods—that is okay and could be expected! It sometimes means your body needs more practice digesting those foods. In addition, finding ways to manage your stress can help to turn down that fight or flight response—get involved in activities you enjoy, spend time outside, connect with your loved ones, or work with a mental health provider. Practicing mindful moments, where you focus on the senses involved in a normal activity like washing your hands, making the bed, or folding the laundry may help you be more present in the moment. Lastly, I would encourage you to find ways to practice flexibility—with your thoughts, routines, and behaviors. I often work with patients on practicing imperfection, which helps when we can no longer live life the way we expected. Practice buying a product without reading as many reviews, sending a text without correcting a typo, or hanging a picture without measuring first.  Other small ways to practice flexibility include taking a different walking route, loading your dishwasher in a different way, or pairing a different outfit together. The more creative, the better!