I’ve Got a Feeling:
Understanding the Gut-Brain Connection

At some point in your life, you’ve probably experienced the feeling of having “butterflies in your stomach,” or the notion of having a “gut feeling.” But where do these feelings actually come from? According to Yoko Kawashima, Functional Medicine Certified Health Coach at AAPRI’s Center for Functional Medicine, there’s a direct physiological and biochemical connection between your brain and your gastrointestinal (GI) system. Let’s take a look at how the brain affects the gut and vice versa.

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Did you know you have two brains?

As Yoko explains, your gut has its own nervous system—the enteric nervous system (ENS)—which is an extensive web of various types of neurons embedded in the wall of your GI tract, extending from the esophagus down through the stomach and intestines to the rectum. “The enteric nervous system plays a big role in the digestion process in your GI tract. There is a bidirectional highway called the vagus nerve, which connects your two brains—the brain in your head and your second brain in your gut,” says Yoko. “Those feelings of butterflies, or queasiness, are driven by the release of stress hormones that are perhaps perpetuated by psychological stress, which impact the neurons in your gut.”

The enteric nervous system is often referred to as the “second brain” because it relies on the same type of neurons and neurotransmitters that are found in the central nervous system. In fact, with more than 100 million nerve cells lining your GI tract, there are more neurons in the gut than in the entire spinal cord

What does the enteric nervous system do?

The second brain plays a key role in your overall health. Its main function is controlling digestion, from swallowing to the release of enzymes that break down food and the control of blood flow that helps with absorption of nutrients and elimination. The ENS also communicates with your big brain, which can trigger changes in your mood and emotions, and in particular how we respond to stress. 

In addition, “About 70 percent of our immune system is found in the gut, which means the enteric nervous system has a powerful impact on our health,” explains Yoko. “A common example is when our second brain sends us into ‘fight or flight mode’ when we’re under stress, and our digestion and motility stop functioning properly. This can lead to constipation, IBS symptoms, a disrupted gut microbiome—and can eventually lead to a weakened immune system.” Chronic stress can cause inflammation and suppress immune function. 

The second brain secretes a significant amount of serotonin and dopamine, which are both “feel good” chemical messengers used by the nervous system to regulate various bodily functions such as sleep, motivation, memory, and metabolism. Chronic stress causes serotonin and dopamine levels to decrease and cortisol levels to increase, which can disrupt digestion, brain activity, hormones, and mood—and it’s all connected through the gut microbiome

How functional medicine can help 

A functional medicine approach includes eating a healthy, balanced diet rich in anti-inflammatory foods, along with regular moderate exercise and a consistent strategy to manage stress, or “rest and digest,” says Yoko. “The standard American diet, which is high in trans fats, sugar, and processed foods is one of the main culprits in causing a breakdown in gut function that can lead to a decrease in brain productivity, too.”

Nutrients That Promote a Healthy Gut

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  • Fish Oil – Reduces inflammation in the gut and anxiety symptoms
  • Turmeric – Lowers overall inflammation in the brain, body, and gut
  • Adaptogens – Help to better manage stress
  • Vitamin D – Improves cognitive function and mental resilience; reduces inflammation in the gut and helps to reduce depression
  • Fiber – Lowers blood sugar levels, improves digestion
  • Fermented foods – Repopulates the gut microbiome with beneficial bacteria

Contact us to learn more

Our functional medicine team can help you identify issues with your gut/brain connection, and implement essential lifestyle changes to achieve better health. Contact the AAPRI Center for Functional Medicine to schedule a free 15-minute Discovery Call to learn more about how our program can help you get take control of your health.

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