If you’ve ever seen “The Office,” you know that the connection between Michael Scott and Dwight Schrute is an iconic cornerstone of the show. The characters are opposites, yet they balance each other out and act as a support system for one another. Their bond — oddly enough — is like the relationship between our gut and brain.
We may be most familiar with our brain sending signals to our gut when we’re either hungry or feeling stressed. But the gut is constantly sending its own set of signals to the brain, says Bryant University’s Kristin Scaplen, Ph.D.
“A healthy, or even unhealthy, gut has direct implications on the brain and behavior,” says Scaplen, a neuroscientist and assistant professor within the School of Health and Behavioral Sciences’ Psychology department. “Making sure you have a really diverse and healthy microbiome inside your gut can help reduce the risk of developing a variety of conditions, both physical and mental.”
Gut-brain communication
Our brain, which is part of the human nervous system, speaks to the body through electrical signals and neurotransmitters. Made up of two main parts — the central nervous system (the brain and spinal cord) and the peripheral nervous system (the rest of the body) — the system also includes the enteric nervous system, which was discovered in the 1980s and manages how the body digests food.
“The enteric nervous system is a specialized network of neurons that lives inside the lining of our digestive tract,” Scaplen says. “It has approximately 500 million neurons that work, for the most part, independent of the central nervous system. You could almost think about the enteric nervous system like a second brain.”
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To communicate, the gut and brain use the vagus nerve, which originates in the brainstem and ends in the abdomen. While activity is bidirectional, Scaplen notes that 90 percent of the time, interactions move up, not down. She adds that because microbiota within the gut produce neurotransmitters as well as the beginnings of neurotransmitters, these chemical messengers can move up to the brain.
“Maintaining a healthy diet leads to a healthy gut microbiome, which leads to a healthy brain. A microbiome imbalance could impact brain function and behavior,” Scaplen says, highlighting that an imbalance could trigger neurotransmitter disruption, stress response, and chronic inflammation. “If you think about gut inflammation, those inflammatory signals are also headed up to the brain. Inflammatory signals in the brain influence nearly all aspects of brain function and can lead to dysfunction. Chronic neuroinflammation can lead to neuronal damage and death.”
Exploring the unexplained
While there are things we know about the gut-brain connection, there’s still a lot that we don’t understand and need to explore, says Scaplen. She notes that many individuals with anxiety and depression have stomach issues, and there's some suggestion that an unhappy gut could contribute to these disorders and others.
Additionally, there are some links between the gut impacting brain development.
“There has been some suggestion that individuals who are on the spectrum have disruptions to their microbiome. We can't necessarily say that this is causative, right, but there's this relationship where they seem to be deficient in some aspects of their gut,” Scaplen says, noting that the gut could impact the risk and progression of Parkinson's disease and Alzheimer's disease and that, for Alzheimer's disease, sticking to a Mediterranean diet can slow cognitive decline and reduce risk.
In addition to diet, researchers are exploring ways to assist those with an unhealthy gut microbiome. One of the ways involves a medical procedure where a stool sample from a person with a healthy gut microbiome is transplanted into the colon of a person with an unhealthy gut microbiome, allowing the introduction of healthy microbes.
“There have been some really positive results in that way,” Scaplen says. “One study did this fecal transplant with people who were suffering from major depressive disorder and saw some significant improvements across treatment.”
A happy, healthy gut and brain
According to Scaplen, our goal should be maintaining a healthy diet and lifestyle — quick fixes are not going to work.
“What you are eating is impacting your gut and that is ultimately impacting your brain,” Scaplen says, noting that foods and drinks with probiotics (think: yogurt, cottage cheese, kombucha) can help lead to a happy, healthy gut; this collection of live bacteria and yeasts help fight off unfriendly microbes and boost immunity against infections.
Because of all this, Scaplen says now is an exciting time within neuroscience.
“We've been focused on how neurons communicate and how their activity ultimately influences our behavior, thoughts, and perceptions, and now we're starting to look more broadly and holistically to other supporting cells in the brain and how they influence neurons and their processing, as well as layering in the gut in an attempt to understand how the entire person works together to function well,” Scaplen says.
To learn more about the gut-brain connection and the brain as a whole, celebrate International Brain Week with Scaplen by visiting one of Brain Waves RI’s brain fairs this March. As the organization’s vice president and chair of a new education pilot program for Brain Waves RI, Scaplen says the upcoming fairs will feature activities, games, and other opportunities to promote overall brain health.
• Brown Brain Fair: 10 a.m. to 2 p.m. on March 15. 345 Brook St., Providence.
• Pawtucket Brain Fair: 10 a.m. to 2 p.m. on March 22. 1005 Main St., Pawtucket.
