Your gut bacteria directly impact your health in many ways, from helping build your immune system and influencing your weight and risk of certain diseases, like diabetes, obesity, and autoimmune, heart, and colon diseases, to affecting your brain, and in turn, your mental health and behavior. Gut health plays a significant role in mental health, and science shows there’s a clear link between your diet and your mental health.
You Have a “Second Brain” in Your Gut
In addition to the brain in your head, you also have a brain in your gut, called the enteric nervous system. This second brain consists of a network of some 500 million nerve cells and 100 million neurons lining your gut, esophagus to anus. Just like the brain in your head, the brain below uses over 30 neurotransmitters, including dopamine and serotonin. In fact, the bowels produce 95 percent of the body’s serotonin.
The gut microbiome is a vast community of trillions of microorganisms, consisting of bacteria, fungi, viruses, and other microscopic organisms that play a crucial role in maintaining your overall health. As well as allowing nutrients to enter the body and keeping opportunistic pathogens out, their activities also influence your brain and mental health.If you want more of an explanation of what the microbiome is and how your unique one is formed, read “How Gut Microbes Keep Your Brain Young.”
How Your Gut and Brain Communicate
The enteric nervous system isn’t capable of thought as we know it, but it does communicate directly with the brain in your head through a bidirectional system known as the gut-brain axis (GBA). The GBA is an intricate network constantly exchanging information between your central nervous system and gut microbiota. The gut and the brain exchange signals via various pathways, including neural, endocrine, and immune mechanisms. The GBA is a chemical pathway.
The microbiome also influences brain activity through the vagus nerve, which runs from your neck to your abdomen connecting internal organs to the brainstem. It’s the body’s major parasympathetic nerve responsible for governing basic vital functions, like gag reflex, heart rate, sweating, blood pressure, digestion, and vascular tone. The vagus nerve is a physical pathway between the gut and brain.
Other means of influence:
Research on the gut brain connection is growing, and while the exact mechanisms are still being studied, there is substantial evidence to suggest that the health of your gastrointestinal system can impact your mental well-being in several ways:
Neurotransmitter Production: The gut microbes can produce neurotransmitters, such as serotonin and dopamine, which are involved in regulating mood and behavior. An imbalance in gut bacteria can potentially affect the production of these neurotransmitters.
Immune System Function: A significant portion of your body’s immune system resides in the gut. An unhealthy gut can lead to chronic inflammation, which has been linked to mood disorders, like depression and anxiety. Inflammation in the gut can trigger inflammation in the brain, contributing to mental health issues.
Nutrient Absorption: A healthy gut is essential for proper nutrient absorption. Nutrient deficiencies, particularly those related to vitamins and minerals, like B vitamins and magnesium, can affect brain function and mental health.
Stress Response: The gut-brain axis also plays a role in regulating the body’s stress response. Chronic stress can disrupt the balance of gut bacteria and negatively impact gut health, contributing to mood disorders.
Regulation of Immune Responses: An imbalance in gut bacteria can lead to the activation of the immune system. This can influence brain function and contribute to mental health conditions, like depression, anxiety, and even neurodegenerative diseases.