Long Island Registered Dietitian Explains the Gut-Brain Connection: Prevent Disease and Improve Mental Health with Good Nutrition

As a Registered Dietitian who practices holistic nutrition therapy, I find that most people think their bodies are divided at the neck without any connection between the brain and the body.  Not so. Researchers have found that a nervous system in our guts (our “second brain”) communicates with the brain in our head. Together, “our two brains” play a key role in both mental and physical health. This two-way communication system is called the gut-brain axis.

So how do our two brains talk to each other? The vagus nerve is a primary pathway connecting the two, providing a bidirectional information highway. But the vagus nerve isn’t the only way the brain and gut communicate. Our intestines are home to trillions of bacteria and microbes that form the gut microbiota. The gut microbiome is so enormous that there are 10 times more microbes in your gut than there are cells in your body.

A great deal of the recent research has focused on the gut microbiome. The microbiota, the inhabitants of the microbiome, have been termed the “peacekeeper” between the gut and the brain. Recent advances in research have described the importance of gut microbiota in disease prevention and health promotion. Both an altered or unhealthy microbiome and/or the absence of diversity can play a central role in human health.

A Harvard Health article says it’s critical to pay attention to this relationship as anxiety and digestive problems can be intricately linked. GI and digestive disorders, like IBS, GERD, and gastritis, as well as food sensitivities can affect a person’s mental and physical health. 

The key is to develop a healthy gut microbiome through individualized nutrition interventions. Diet is the long-term solution since healthy species can replace unhealthy ones in 24 hours. Fiber, found only in the plant kingdom, is the food for healthy bacteria: vegetables, fruits, whole grains, and starchy vegetables. The issue is processing – selecting minimally processed as often as possible and ultra-processed occasionally.

Though probiotics, prebiotics and symbiotics are often helpful, they do not replace the unhealthy species that are living and growing in your gut.  It is what you eat that feeds the healthy microbes and starves the unhealthy ones. Try including fresh fruit and vegetables along with whole grains such as brown rice and whole grain bread, and starchy vegetables such as sweet potato, peas and beans. Fermented food, likewise, can be beneficial.

What you eat can have a profound effect on the composition of your microbiome – both the presence of healthy species and diversity of species. 

The bottom line, as Carrie Dennett, MPH, RDN, states in the Environmental Nutrition article, is “[o]ur diets influence the composition and health of our gut microbiota, and eating a diet rich in different types and sources of fiber will help support microbial diversity.”

For more information:

Dennett, Carrie, MPH, RDN. “What is the Gut-Brain Connection?” Environmental Nutrition, September 2021. 

Carabotti, Marilia et al. “The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems.” Annals of gastroenterology vol. 28,2 (2015): 203-209.