The mind-gut connection and how to improve it

June 14, 2023

Providence Women's Health Team

[6 MIN READ]

The mind-gut connection and how to improve it

Ever felt a pit in your stomach or had a gut feeling about something? If so, you’ve listened to signals from a source you may not expect: your enteric nervous system, or ENS. Although lesser known than its central counterpart, the enteric nervous system plays a critical role in our bodies and our overall health. Often referred to as “the second brain,” this network hidden in the walls of your digestive system communicates with the brain in your head — and is changing the way scientists approach treatments for mental health disorders.

This month, as part of our women’s health series, we’re shining a light on this gut-brain connection and its impact on mental well-being. We’re talking with Melanie Santos, M.D., FACOG, FPMRS, medical director of pelvic health for St. Jude Medical Center in Fullerton, California. Santos is a urogynecologist who specializes in treating women with incontinence and other pelvic floor disorders, but she’s also familiar with many of the other health issues women face throughout their lives.

What is the mind-gut connection?

Dr. Santos: Most people are familiar with the body’s central nervous system, made up of the brain and spinal cord. The network extends from the brain to the body’s major organs through nerves, neurons (nerve cells) and neurotransmitters (chemicals that help pass along signals from nerve cells). But there’s another part of the nervous system located in our gut. It’s called the enteric nervous system. This system’s network of nerves, neurons and neurotransmitters extends along the digestive tract — all the way from the esophagus to the anus.

The enteric nervous system’s main role is in controlling digestion, but a 2004 study shed light on its link to the mind. The study found that the stress response in mice was reversed with the introduction of healthy bacteria. Since the study was published, researchers around the world have studied the connection and what it could mean for the treatment of mental health conditions.

Today, we know the connection between the brain and the gut can affect everything from digestion to our moods to the way we think. We know that microorganisms in the gut (known as microbes or, collectively, as the microbiome) not only help break down components of the food we eat, they also send signals to the central nervous system that trigger mood changes. This may explain why many people with irritable bowel syndrome (IBS) and other bowel problems, like frequent constipation or diarrhea, develop depression and anxiety. (And why gastroenterologists sometimes prescribe antidepressants or antianxiety medications to IBS patients.)

The gut microbiome also helps regulate the body’s immune response. If the immune system is “switched on” for too long, which can happen when gut bacteria are out of balance, it can lead to inflammation, which is associated with a number of chronic cognitive conditions, including Alzheimer’s.

Other brain disorders, including schizophrenia, bipolar disorder and Parkinson’s disease, are also associated with changes in the microbiome that lead to inflammation, suggesting diet can play a role in protecting against them.

How can women improve their gut health?

Dr. Santos: When you consider that stress and anxiety can contribute to your digestive health, and that what you digest can impact your stress and anxiety, it makes sense that any actions you take to improve your gut health will help your overall health, too.

First, make sure you’re digesting your food properly after a meal. That means you need to be in a relaxed state so your body can produce the gastric juices required to absorb the vitamins, minerals and nutrients from food that are necessary to support a healthy brain and body.

You also, of course, should stay away from processed foods and eat as many gut and mental health-boosting foods as possible. These include:

Fiber, which improves memory and overall mood while decreasing inflammation and oxidative stress. Foods high in fiber include fruits, vegetables, beans and legumes.
Vitamin D, which reduces gastrointestinal inflammation and regulates the microbiome. Foods with vitamin D include orange juice and egg yolks.
Protein, which contains nitrogen that limits the number of bad bacteria in a microbiome. Eating foods high in protein, like eggs, milk, yogurt, chicken, nuts and fish, can also decrease feelings of depression because it produces serotonin, the hormone that regulates mood. (Incidentally, the gut is known to store 95% of all serotonin in our bodies.)
Omega-3 fatty acids, which help lower cholesterol, reduce cravings and increase memory. Good sources of omega-3s include walnuts, oily fish like salmon and flaxseed.
Cocoa, which can improve microbiome health. Cocoa is found in chocolate products. It’s also rich in polyphenols, which are compounds that are naturally found in plant foods and benefit the microbiome.

In addition, it’s important to find time to exercise, which can help reduce stress and improve both your physical and mental health. Be sure to drink plenty of water to help boost digestion. A good goal is between six to eight glasses of water each day.

Finally, studies have found that taking probiotics — live bacteria commonly found in yogurt and other fermented foods — can help improve the microbiome and improve mental health, including reducing symptoms of anxiety and depression. Other studies have found that taking prebiotics, which are fibers that are fermented by the microbiome, can reduce levels of cortisol, a stress hormone.

Building a healthy gut

More research is needed on the mind-gut connection and its relationship to mental health. But one thing’s for sure: The healthy lifestyle choices we’ve been advising for decades still hold true. Eat a nutritious diet, get enough exercise and drink water — the building blocks of a balanced gut and a healthy mind.

Contributing Caregiver

Melanie Santos, M.D., FACOG, FPMRS, is medical director of pelvic health for St. Jude Medical Center in Fullerton, California. She’s board certified in urogynecology, obstetrics and gynecology.

Dr. Santos attended medical school at the Albert Einstein College of Medicine. She completed an internship and residency at Stanford University Medical Center and a fellowship at Emory University School of Medicine.

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