How Gut Inflammation Causes Anxiety

By Samantha Gilbert, FNC, CHNP, CNC     Last updated on February 11th, 2023

How Gut Inflammation Causes Anxiety

Can gut inflammation cause anxiety? Can the health of your gut microbiome really impact you on such a profound level?

The truth is that there are many variables that can occur within your gut that can lead to anxiety including bacterial and yeast overgrowth, parasites, worms, and other pathogens that cause leaky gut. Otherwise known as intestinal permeability, it is now well established that leaky gut is a major driver of chronic illness because it’s a constant source of inflammation, and anxiety is a symptom of this inflammation.

What is the Gut Microbiome?

The microbiome is a collection of many different types of organisms. Bacteria tend to dominate this particular ecosystem, but you also have viruses, fungi, protozoans, and a number of different types of organisms that exist within the human system.

The microbiome is defined as all of those organisms including their genetic elements. The ecosystem is how the host (in this case your gut) functions with these organisms. Different parts of the body have different versions of the microbiome such as the mouth, vagina, and skin to name a few. They each have their own ecosystem that in a perfect world, would play nice with one another and support the host with a robust and strong immune system.

Because most diseases (including anxiety) are derived from a dysfunctional ecosystem, we can fix the ecosystem, which puts you in a much better position on your wellness journey. So please know you have so much more control over your health and wellness than you probably realize.

To learn more about gut inflammation and the amazing microbiome, check out my podcast episode below with microbiologist Kiran Krishnan, Co-founder of Microbiome Labs. You can also find the Eat For Life podcast on Apple Podcasts, Spotify, Google Podcasts, or wherever you listen to podcasts!

How Does Gut Inflammation Cause Anxiety?

There is a bi-directional connection between the gut and the brain and when this connection is underdeveloped, I often see anxiety and other conditions such as depression, OCD, hyperactivity (especially in children), anger, violent behavior, and autism.

The gut is called the second brain for a couple of reasons:

  1. A lot of metabolic and neurotransmitter byproducts are produced in the gut that affect the brain in a very significant way and
  2. Because the enteric nervous system, which is a neurological system, lines the entire digestive tract.

The enteric nervous system is only second to the brain in terms of nerve endings. In fact, it’s got more nerve endings than the spinal cord does, so it’s a very dense neurological tissue and the gut and gut bacteria have direct access to this entire system. The enteric nervous system is directly connected to the brain through the vagus nerve. In other words, it’s a 2-way street of communication between the gut and the brain.

When it comes to anxiety, a couple of things can occur. One is that there is a dysfunction of the development of the neuronal tissue itself, so you’re not getting proper signaling back and forth between the gut and the brain, which can affect mood and behavior, and cause a lot of anxiety.

However, most of the time it is the wrong types of microbes that begin to inhabit the gut at high levels. Usually this is due to a poor diet of processed foods that are high in gluten, refined sugars, and other chemicals that are a major driver of leaky gut.

Good microbes produce really important neurotransmitters such as serotonin, dopamine, GABA (a calming neurotransmitter), and brain-derived neurotrophic factors. All of these are produced in the gut and have a profound effect on your ability to experience peace and calm.

Then we have opportunistic and pathogenic microbes that if allowed to proliferate, will produce neurotransmitters in the gut that go to the brain that can cause you to have anxiety or a panic disorder.

The Hypothalamic-Pituitary-Adrenal Axis Connection to Gut Inflammation and Anxiety

The Hypothalamic-Pituitary-Adrenal Axis (HPA axis) is a major neuroendocrine system that controls reactions to stress and regulates many processes including the immune system, digestion, sexuality, mood and emotions, and energy storage and expenditure.

In many ways, it is controlled by the types of microbes that exist in your gut.

The triggering of fight, flight, freeze is actually dependent to a certain degree on the types of microbes that exist in your gut and can be triggered much more often when you have a dysbiotic gut. When this happens, I often hear my clients tell me they have anxiety that emanates from their gut and makes them feel sick to their stomach. This is because the gut controls the tonality of the HPA axis.

In fact, your ability to handle stressful situations comes from the diversity and the complexity of your microbiome. For example, when we experience an external stressor such as an argument with a loved one, one of the first things that starts to kick off is the epinephrine to norepinephrine cascade.

The Effect of Adrenaline on the Gut Microbiome

One of the things that studies show on the microbiome is when you increase epinephrine (adrenaline) and norepinephrine (noradrenaline) in the body, you actually start proliferating certain pathogenic bacteria. These pathogenic bacteria that sit in your system are lying in wait so to speak because they’re waiting for your system to change in order to start proliferating. This is one of the ways in which stress can alter your microbial terrain and it’s something I commonly see in people with copper overload because copper lowers dopamine and increases norepinephrine.

Additionally, your adrenaline and heart rate goes up leading to lots of perfusion. The microbes in your gut start sensing this change, then they start to proliferate and begin to produce more toxins that make you feel more anxious.

Under normal circumstances, when there is lots of diversity in the microbiome and where pathogens aren’t being upregulated by your sense of stress, what tends to happen is you experience the stress and are able to manage it, then your body can come back to a state of normalcy.

But if you have a dysfunctional microbiome and your stress level goes up, your gut microbes also go up and they will keep producing toxins that make you feel more anxious and stressed. Even when that stressor goes away, your body is still being triggered because the microbes are now creating the stress response.

Do you have anxiety that seems to be connected to your gut?

If you feel you may have gut inflammation that is causing anxiety, I’d love to hear your story in the comments below. Many people struggle with gut inflammation, so please know that you aren’t alone.

Nutrition Counseling to Help You Thrive

To address gut inflammation and anxiety, I aim to identify and address the root biochemical causes and imbalances of your symptoms.

I offer a free 1:1 consultation to help you disconnect from the hype and the marketing jargon, and address the true source(s) of your discomfort. It’s time for your healing journey to truly begin.


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Xiaoxu Yang, Jun Lou, Weixi Shan, Jianhong Ding, Zhe Jin, Yanxia Hu, Qian Du, Qiushi Liao, Rui Xie, Jingyu Xu, Pathophysiologic Role of Neurotransmitters in Digestive Diseases, Frontiers in Physiology, 10.3389/fphys.2021.567650, 12, (2021).
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Ross M. Maltz, Jeremy Keirsey, Sandra C. Kim, Amy R. Mackos, Raad Z. Gharaibeh, Cathy C. Moore, Jinyu Xu, Arpad Somogyi, Michael T. Bailey, Social Stress Affects Colonic Inflammation, the Gut Microbiome, and Short-chain Fatty Acid Levels and Receptors, Journal of Pediatric Gastroenterology and Nutrition, 10.1097/MPG.0000000000002226, 68, 4, (533-540), (2019).


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