Gut-brain connection: How a healthy gut fuels more than digestion

What if “gut feeling” wasn’t just a phrase, but instead held weight in mental health and neurological disorders? Many experts believe so.

Your gut health—specifically, the microbiome within your digestive tract—has been linked to mental health conditions such as anxiety and depression and could even indicate your chances of being diagnosed with Parkinson’s disease later in life.

Narendra Kumar, PhD, an associate professor of pharmaceutical sciences at the Texas A&M University Irma Lerma Rangel College of Pharmacy, has spent over a decade researching conditions that impact the gastrointestinal tract and their implications on the rest of the body. He said the brain must be fueled with the hormone serotonin—and almost 90% of it is produced in the gut. When serotonin levels get out of balance, it could set off a chain reaction, causing issues like anxiety, depression, digestive problems and other chronic conditions.

“The gut-brain axis controls our mood, cognition and memory, appetite and satiety, and neuron development,” Kumar said. “All of that often leads to better social interactions, which are often compromised in mental health.”

From slow digestion to brain disorders

Kumar explained that digestive issues, such as slow digestion in the stomach and small intestine, are common among people with mental health diagnoses because of the serotonin imbalance that characterizes mental health disorders. Research has shown that low serotonin levels in the gut can cause constipation, just as low serotonin the brain can lead to depression.

Notably, chronic constipation has also been linked to neurological disorders like Parkinson’s disease—sometimes serving as an early warning sign of underlying problems.

“Gut health is a precursor to brain health, and bowel movement can influence body movement,” Kumar said, adding that a healthy gut biome and regular physical activity can support the brain and body in more ways than one.

The search for balance

Because the gut microbiome is as unique as a fingerprint, Kumar said it can be difficult to restore completely once it becomes unbalanced. Probiotic rich foods can help maintain or even build the microbiome somewhat, but he said it’s always best to check with a medical professional and get individual advice based on what your body may be lacking.

He also suggests high fiber and low fat to maintain balance.

“A high fat diet triggers the immune system—and when the immune system is triggered again and again, it causes a condition called chronic low-grade inflammation,” Kumar explained. “When you have chronic low-grade inflammation, it can trigger your insulin system to go out of whack, and that leads to obesity.”

Persistent inflammation and obesity can eventually lead to type 2 diabetes and related conditions. Obesity has also been linked to mental health conditions, such as depression and anxiety, which can worsen serotonin production and exacerbate existing mental health conditions associated with serotonin deficiency, such as anxiety, depression, insomnia and dementia.

Beyond the immediate effects of poor nutrition, Kumar said diet can also impact long-term brain health. Research suggests that people who consume high amounts of saturated fat over a long period of time may face a higher risk of developing Alzheimer’s disease than those who eat a more balanced diet.

In addition to what you eat, an active and social lifestyle also plays a role in brain and gut health. Physical activity is widely recommended to treat chronic constipation because it can help speed up the time it takes food to move through the large intestine. Exercise and social activity also both increase serotonin production, which can improve digestion.

To combine exercise with social interaction, Kumar suggests joining a local running group or gym exercise classes.

“We’re big fans of Facebook these days. Everybody is linked up virtually, but use Facebook to your advantage,” Kumar said. “Make a group and say, ‘Let’s meet at 5 a.m. and go for a 5k,’ and give a meeting place. Use it as a tool and don’t rely on meeting virtually solely for social interaction.”

A two-way street between gut and mind

Kumar said the connection between the gut and brain goes both ways. A healthy lifestyle can strengthen both mental health and digestion, helping protect against disease and lowering the risk of mental illness.

When you eat nutritious foods and stay active, you nourish your gut microbiome and improve digestion, which leads to the release of signals that can boost mood and reduce anxiety. When anxiety is reduced and mental health is strong, there is less risk of disrupting gut function, leading to more comfortable digestion and improved nutrition absorption, further fueling your brain. Taking care of one system takes care of another and better serves the whole body, illustrating the powerful, two-way connection that bolsters overall well-being.