How stress halts digestion and disrupts the microbiome: a scientific look at the gut-brain axis

Світлана Бурмей
5 days ago
3 min read

Біговий захід GoMove в Ужгороді за підтримки Ediens

When we feel fear or anxiety, we often get a “sucking feeling” or “butterflies in our stomach.” From an evolutionary perspective, our brains never existed without signals coming from the gut. However, in today’s world, chronic stress has become the main enemy of our digestive system.

Why do we lose our appetite or, conversely, experience pain and bloating when we are stressed? How does stress affect bacteria, and how can bacteria protect us from depression? Let's look at this through the prism of neurobiology and microbiomics.

1. Physiology of stress: why the gut “shuts down”

Renowned neuroscientist Robert Sapolsky perfectly explains the mechanism of stress using the example of a zebra and a lion. When a zebra is being chased by a predator, its body mobilizes all the energy from its storage sites and instantly delivers it to its muscles. At this point, the body stops all long-term optimistic projects that are not critical to survival at that very moment.

Digestion is an incredibly energy-intensive process that “costs a fortune.” If you’re trying not to become someone’s lunch, you definitely don’t feel like digesting your own breakfast. So your body shuts down your digestive tract completely. The first step in this scenario is familiar to everyone: before an important speech or exam, your mouth becomes dry because saliva stops being produced.

Turning off your digestive system for two minutes isn't a big deal, but if you're in a state of chronic psychological stress for months, you risk getting a whole bunch of gastrointestinal disorders.

2. The real cause of ulcers: what do bacteria have to do with it?

For a long time, it was believed that stress directly caused stomach ulcers. However, scientists later made a revolutionary discovery: the bacterium Helicobacter pylori is responsible for ulcers , which punch holes in the walls of the stomach. But why, then, are ulcers so closely linked to stress?

The secret is that our stomachs usually do a good job of repairing their walls before bacteria can cause serious damage. But when you are in a state of chronic stress, the body turns off the repair (restoration) processes. The body, as it were, says: “Let’s do it tomorrow, because now a predator is chasing us!” It is psychological stress that turns off the defenses, allowing bacteria to destroy the mucous membrane.

3. How stress drives the microbiome crazy

Stress not only stops intestinal motility, it also dramatically changes the lives of our bacteria. It is known that some bacteria multiply much faster in the presence of stress hormones. Chronic inflammation caused by stress affects the behavior of microbes, provoking dysbiosis and increasing the permeability of the intestinal barrier.

At the same time, there is a feedback loop. Our microbiome is a chemical factory that directly controls our mood. Beneficial microorganisms (for example, bifidobacteria and lactobacilli) produce short-chain fatty acids (butyrates) and gamma-aminobutyric acid (GABA), which are involved in the production of serotonin, the hormone of happiness. If the population of these bacteria dies due to stress, we lose neurotransmitters, which leads to depressed mood, anxiety and even depression.

This connection is particularly evident in studies of post-traumatic stress disorder (PTSD) among the military. According to statistics, PTSD does not develop in all, but only in a part of people (about 30%) who have experienced trauma. Studies by Ediens show that people whose gastrointestinal tract and immune system are functioning adequately have a significantly higher resistance to PTSD. Microbiome imbalance is now considered an early marker of anxiety and depression.

4. How to break the vicious circle and help yourself?

Stress destroys the intestines, and a sick intestine generates even more stress for the brain. To get out of this state, you need to act systematically:

Avoid “blind” probiotics:
You shouldn't buy drugs at random. For precise treatment, modern 4P medicine uses in-depth genetic analysis of the microbiome . This allows you to choose individual solutions.
Specialized pharmabiotics:
To combat the effects of nervous tension, there are targeted biological products with proven clinical effects. For example, the Metabolic. Antistress complex was created specifically to support the body under psychological stress: it optimizes digestion, strengthens immunity, and reduces the negative impact of stress on the gut-brain axis.
Personalized nutrition:
When you’re stressed, bacteria need the right food. Eating a variety of fiber-rich foods (legumes, fruits) and fermented foods will help promote the growth of beneficial bifidobacteria and lactobacilli, which will protect your nervous system from the inside out. At the same time, limit artificial sweeteners, which encourage the growth of unwanted microbes.

Remember, your mental health isn't just limited to your head. By keeping your microbiome in balance, you're creating a solid biological shield that will help your psyche weather any storms life throws at it.