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The intricate, sensitive connection between the mind and the gut

by Deborah Lynn Blumberg

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When my husband, two-week old daughter, and I burst into the emergency room that night, I wracked my brain, trying to remember the last time I’d been able to go to the bathroom. I was so constipated I collapsed on a gurney doubled over in pain.

I’d been stressed since giving birth (the second time), and a medication I received during labor was making breastfeeding painful. I was already anxious about my return to work with two kids, an early daycare pickup, and childcare costs doubling. I was frustrated by a lack of sleep and regularly went for cheesy pasta casseroles and banana bread over vegetables.

When my symptoms started escalating—to stomach pains and heartburn, and later to achy joints and rashes—I made my way through more than a dozen doctors and medications searching for a diagnosis. Months later, I finally came to believe it had all started in my mind.

“When you’re stressed, your gut is a different gut,” says Emeran Mayer, a gastroenterologist, neuroscientist, and UCLA professor who studies how the digestive system and nervous system interact in health and disease. “The brain and the gut are so closely connected, you almost have to look at it as one unit.”

Emotions and the stomach are linked. I knew that. Like anyone, I’ve felt butterflies in my belly before speaking in front of a group. What I didn’t realize was the profound and long-lasting effect chronic stress can have on our gut, specifically by altering its composition, disrupting, and even disabling our microbiota—the 100 trillion microorganisms living in our stomach that help us process food and maintain a healthy immune system.

Microbiome research has exploded in recent years as scientists seek to better understand this microscopic ecosystem operating inside our bodies. “The Mind-Gut Connection,” Mayer’s recently published book on this topic, explores the constant dialogue between our brain, gut, and gut microbiota. It delves into what can go wrong when communication between the three breaks down, and how to help reverse ill effects.

The necessary communication starts in the brain. That’s where stress stimulates the release of a hormone called the corticotropin releasing factor (CRF), which triggers two messages to the body: one is a spike in the stress hormone cortisol. The other is a signal that travels through our autonomic nervous system to the gut where it can interfere with digestion and cause symptoms like belly pain, bloating, and irregular bowel movements. 

Nerve signals can also change the composition of the gut microbes, influence their behavior, and make the lining of the gut more permeable, eventually leading to a “leaky gut.” When this happens, gut microbes and food components gain access to the gut’s immune system, resulting in low-grade inflammation that can spread throughout the body. A leaky gut can increase the risk of developing a host of other health problems, including food allergies, autoimmune diseases, and possibly even depression.

When blood work showed I’d developed a sensitivity to more than a dozen foods I’d eaten my whole life without a problem, and my physical symptoms worsened over time, I became even more anxious. It was a vicious loop.

“Every emotion starting in the brain will be reflected in the gut, and anything that happens in gut will be reflected in some way at the brain level,” Mayer says.

Our gut is home to 60 to 80 percent of our immune system and 90 percent of our neurotransmitters, chemical messengers that help control mood. That’s one reason making sure our gut is healthy is essential, Mayer says.

“We have this fascination with healthy diets,” he adds, “but people forget that unless you’re in the right state of mind, the benefit of eating well is greatly reduced. Chronic stress can actually remodel our gut cells. Negative feelings aren’t just psychological,” he adds, “they can have a real effect on your entire body.”

Mayer and his colleagues recently published a study in the journal Microbiome that found a link between gut microbes and the sensory areas of the brain in patients with irritable bowel syndrome (IBS). IBS patients with altered microbiomes showed differences in their thalamus, basal ganglia, and the sensory motor cortex. It’s the first study to identify this connection in humans.


Read more: If you’re suffering from IBS, mindfulness might be able to help.


Almost all patients suffering from digestive disorders—and often anxiety—who make their way to Mayer’s office leave with two key mandates: start diaphragmatic breathing exercises and eat a Mediterranean diet.

“A lot of patients come to me in this state of chronic stress,” he says. To halt the stress response and start to heal the body, “you need mindfulness, a relaxed state and also a non-inflammatory, plant-based diet. The combination of these two is essential.”

He takes his own advice to heart and, during my recovery, so have I. Mayer practices deep breathing at least twice a day, when he wakes up and before bed, a routine I’ve worked into my days. Meditation also helps. [Editor’s Note: If you’re curious about meditation, try our Basics.]

“The good thing about breathing is, you can do it anywhere,” he says. “[T]echniques like breathing and meditation are really the simplest thing that you can do for your health, both mental and physical.

The author of this post is an editorial contributor to Headspace. These are their views, experiences and results and theirs alone. This contributor was paid for their writing.

Deborah Lynn Blumberg

Deborah Lynn Blumberg is an award-winning health and wellness and business writer and editor with over 15 years experience writing for publications including The Wall Street Journal, the Christian Science Monitor, and Barron’s. She tells the stories of the people and companies that are changing our world for the better, and has a special interest in integrative and functional medicine. Find her at DeborahLynnBlumberg.com.

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