By Sarah Jackson, MS, RDN, CLT

Have you noticed that when you’re stressed, your digestive symptoms get worse?

This happens due to the gut-brain axis that is connected by hundreds of millions of neurons in the digestive system, which allows communication with our brain. The “second brain” housed in our gut, also referred to as the enteric nervous system, relies on the same types of neurons and neurotransmitters that are found in the central nervous system, which comprise of our brain and spinal cord. If you’ve ever felt “butterflies” before a big speech, you’ve felt this system in action! It’s important to note that the make-up of our gut microbiome also plays a role in this two-way communication system.

When the brain in our head experiences anxiety and stress, it can have a profound impact on our overall wellbeing, including our bodies ability to digest the food we eat. According to the American Psychological Association (APA), stress can affect digestion and what nutrients the intestines absorb. Gas formation attributed to nutrient absorption may worsen as a result. In the intestines, we have a tight barrier to protect the body from food related bacteria. This barrier serves to keep intestinal contents in, without leaking out. However, stress can weaken this barrier and allow gut bacteria to enter the body via intestinal permeability. It is noted that most of these bacteria are easily taken care of by the immune system and do not cause us acute harm, however, the constant low inflammatory action can lead to chronic mild symptoms, states the APA.

What chemically changes when we are stressed?

When we experience stress, various physiological changes occur, including an increase in certain glucocorticoids, such as cortisol and norepinephrine.

Cortisol is known as the”fight or flight” hormone that increases during emotional states of stress. This hormone prepares the body to flee or fight and thwarts other non-immediate functions, like (you guessed it), digestion. The body allocates resources, primarily blood, to the brain and large muscles, rather than digestion. Although this process came in handy for our ancestors when fleeing from lions, it can wreck havoc on on our digestive health today if left unchecked.

Chronic or prolonged stress can suppresses the immune system and alters almost every aspect of the digestive system, including:

• Esophagus contraction
• Irritation of stomach lining/worsening ulcer symptoms
• Stomach acid production (hypochlorhydria)
• Delayed gastric emptying
• Increase in colonic motility

In a study published in Gut, British Medical Journal (BMJ), researchers found that in the those with most common functional gastrointestinal disorders, IBS and Functional Disorders (FD), persistent alterations of autonomic responsiveness is likely to play a role in altered bowel habits and alteration in gastric emptying. Frankly put, those with pre-existing gastrointestinal disorders are likely to suffer the most from the stress induced, fight or flight response brought on by the autonomic nervous system.