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The Missing Link Between Stress and Gut Health? Gut Bacteria

Written by Dr. Michael Ruscio, DC on August 7, 2023

Written by Dr. Michael Ruscio, DC on August 7, 2023 — Reviewed by Aimee Gallo

Nurturing Your Gut Flora is the Key to Breaking the Vicious Cycle of Stress and an Inflamed Gut

• The Gut-Brain Axis|
• Gut Problems are Stress Problems|
• Stress and the Microbiome|
• Diet as a Hidden Stressor|
• Increase Your Gut’s Resilience|

Thanks to the intricate gut-brain axis, stress and gut health influence each other in profound ways. Chronic physical stress and emotional tension can disrupt the delicate balance of the trillions of microorganisms that live in our gut. Known as dysbiosis, this disruption of the gut flora can lead to intestinal inflammation and permeable gut lining. 

These effects can lead to a vicious cycle where an unhealthy digestive system creates further stress on the body via this two-way highway. Over time, the negative effects of stress on the gut’s ecosystem can contribute to the development of digestive symptoms like constipation, diarrhea, gas, and bloating. 

At its worst, stress is heavily implicated in digestive disorders like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Even conditions that are seemingly not gut-related, like autoimmunity, thyroid disease, and fibromyalgia, are linked to an unhealthy microbiome and a “leaky” gut. Many of these have an onset during periods of stress and flare during additional times of stress, such as with emotional trauma or a viral illness. 

Thankfully, research into this microbiota link between stress and gut health also gives us significant therapeutic insight into how to heal our gut bacteria and lower the systemic inflammation that contributes to chronic disease and stress. Introducing probiotics, (along with a therapeutic, anti-inflammatory diet) can help put a stop to this self-perpetuating cycle of stress and an unhealthy gut.  

Stress and Gut Health Talk via The Gut-Brain Axis

The interplay between stress and gut health is quite complex, largely due to the numerous different manifestations of stress in the body. However, stress can be broadly categorized into two types: physical and emotional. Physical stress largely comes from tangible stressors like an inflammatory diet or a gut pathogen, while emotional stress often originates in our brains. 

However, where stress starts is rarely where stress stays, thanks to a bidirectional highway called our gut-brain axis. 
Through this axis, our digestive tract communicates with our brain via the vagus nerve, the main component of our parasympathetic nervous system (PNS) and driver of our “rest and digest” functions. Its counterpart is the sympathetic nervous system (SNS), which controls our “fight or flight” stress response. Together, these systems make up the autonomic nervous system and are highly vulnerable to an imbalance once chronic stress enters the picture.

When stress keeps us in a sympathetic state for too long, our vagus nerve becomes suppressed, and our gut-brain communication starts to go haywire. Neurotransmitters and hormones act as chemical messengers between these organs by traveling along the vagus nerve. 

Chronic stress impairs this cross-talk by decreasing vagal tone and altering neurotransmitter and stress hormone production in the brain and in the gut (by disrupting the gut microbiome). In the brain, these chemicals can influence memory, mood, and even pain, which is why gut dysfunction can have such a strong effect on our mental health and stress levels [1, 2]. 

When in the gut, neurotransmitters hold influence over our digestive function by helping our brain regulate how quickly food moves through our GI tract through the muscular contractions called peristalsis [3]. This is part of the reason why sudden and frequent bathroom trips can accompany anxiety and stress, and why stress is highly implicated in other gut symptoms and diseases. 

Research shows that stress has numerous other adverse effects on our gut health [4]:

• Altered appetite and anorexia
• Decreases nutrient absorption
• Increases intestinal permeability (leaky gut)
• Disruption of mucus and stomach acid production
• Increased gut inflammation
• Delayed stomach emptying 
• Increase lower intestinal mobility (slowing in upper GI and increase in lower GI)
• Decreased blood flow 
• Bacterial overgrowth (like in SIBO)
• Increased pain perception
• Dysregulated mast cells and histamine production
• Altered intestinal neurotransmitter levels
  

To fully appreciate the connection between stress and gut health, the spotlight turns to the microbiome and how it is a crucial link between chronic stress and gut health. Before I get further into the microbiome, let’s pause to see how the effects of stress on the gut-brain axis may directly apply to you.

Gut Problems are Stress Problems

There’s a strong link between chronic stress and gut issues in the scientific literature, and stress management has made its way into mainstream treatment for gut conditions, like irritable bowel syndrome (IBS).

Stress is a well-known trigger of IBS symptoms, which often include gas, bloating, abdominal pain, and stool changes. As previously discussed, stress can alter levels of certain neurotransmitters, including serotonin, which can affect stool transit time (leading to diarrhea and/or constipation) and pain perception in those with this condition [5, 6]. 

Serotonin is also heavily implicated in mood, and research shows that those with IBS are three times more likely to experience anxiety or depressive symptoms [7]. 

Stress management is crucial in gut disorders, and research shows that meditation and other relaxation techniques improve mood, quality of life, and GI symptoms in those with IBS [8]. Mindfulness meditation can even help lower inflammation levels and modulate the immune system [9], which tends to be hyperactive in many gut disorders.

The effects of stress on gut health are by no means limited to IBS, as many other gut disorders are linked to chronic stress and a dysregulated nervous system [4, 10]:

• Nausea
• Constipation
• Gastroesophageal reflux disease (GERD)
• Irritable bowel syndrome
• Inflammatory bowel disease (IBD)
• Ulcerative colitis
• Peptic ulcers
• Gastritis
• Gastroparesis

An observational study with over 1,000 participants found that anxiety and/or mood disorders preceded the onset of a functional gut disorder (like dyspepsia and IBS) in a third of the individuals. Interestingly, two-thirds had a gut disorder that preceded a mental health concern [11].

Clearly, there is a tight, bidirectional link between stress and gut health. Addressing your stress levels if you have gut symptoms can do double duty by improving your mental stress and alleviating your digestive symptoms.

Microbes and Your Mood — How They Connect

The trillions of microorganisms that make up our gut microbiome are massively influential for not just gut health, but overall health. Unfortunately, these healthy “bugs” are also extremely vulnerable to stress and are likely where poor gut health starts when in the face of stress. Stress can shift our microbiome to an unhealthy state, called dysbiosis, that can wreak havoc on our gut health, dysregulate the gut-brain axis, and ignite an inflammatory cascade in the body [12, 13]. 

Research shows that dysbiosis occurs within a few days of experiencing stress [14]. During periods of prolonged stress, this can lead to long-term decreases in bacterial diversity (the type of organisms), decreased “good” bacteria, and an overgrowth of unhealthy bacteria [15]. 

When the gut microbiome is unhealthy, it increases inflammation levels in the digestive tract, which can weaken the lining and create intestinal permeability. Otherwise known as leaky gut, this loosening of the intestinal wall allows for bacterial metabolites to slip into the bloodstream where they can travel to the brain, causing a significant inflammatory response along the way. Through this process, stress-induced disruptions to the microbiome can lead to even more symptoms of stress, anxiety, and depression [16].

A review of six randomized controlled trials (RCTs) found that when one of these bacterial metabolites, lipopolysaccharide (LPS), was administered to healthy participants, they experienced dramatic increases in inflammatory markers and anxiety [17]. 

Disrupted gut flora can also influence the vagus nerve and the nervous system’s release of neurotransmitters, compounding the negative effects of rogue bacterial metabolites [16]. Dysbiosis is linked to numerous digestive and non-digestive conditions, including:

• IBS [18]
• Crohn’s disease [19]
• Ulcerative colitis [19]
• Colorectal cancer [19]
• Chronic pain [20]
• Fibromyalgia [20]
• Overweight/obesity [19]
• Allergies [19]
• Non-alcoholic fatty liver disease (NAFLD) [21]
• Atherosclerosis [22]
• Rheumatoid arthritis [22]
• Hypothyroidism [23]
• Type 1 diabetes [19]
• Type 2 diabetes [22]
• Austism [19]
• Multiple sclerosis [24]

This doesn’t include the many other diseases and conditions linked specifically to leaky gut syndrome. 

Interestingly, many of the above are also associated with chronic stress. If you have a chronic health condition or symptom, especially if you have gone through significant and/or prolonged stress, you may benefit from rebalancing your microbiome — even if you aren’t currently experiencing digestive symptoms. 

In my practice, I see that typically the easiest and most effective way to do this is through probiotics. When implemented alongside the fundamentals of a healthy lifestyle — like a regular exercise routine, mindful living, and a nutrition-packed diet — these therapeutic bacteria are invaluble for healing an overwhelmed gut.

Healthy Bacteria for a Stressed Gut

Probiotics exert their therapeutic effect by bringing the gut microbiome back into balance. By restoring the gut flora, these powerful bacteria help heal the gut-brain axis by:

• Improving serotonin metabolism [25]. 
• Increasing bacterial diversity [25]
• Fighting off harmful pathogens and toxic metabolites, like lipopolysaccharide (LPS)
• Healing the lining of the gut (reversing leaky gut syndrome) [26, 27, 28]
• Modulating the immune response and inflammation levels in the gut [27, 28, 29]
• Lowering systemic inflammation [30, 31]

These bacteria are highly effective at reducing symptoms of gut distress, helping to heal chronic GI disease, and alleviating stress and mental health issues. Through positive shifts in the microbiome, probiotics can lower the inflammatory burden in the body (not just the gut) and protect against the inflammation-induced effects of stress. 

Many studies show that probiotics are highly effective in reducing the signs of stress, and may even play a role in the regulation of our stress hormone, cortisol. A 2020 meta-analysis, which offers the highest quality of research, found that probiotics reduced stress, anxiety, and depression in over 1,000 healthy adults [32]. 

By combining several types of probiotics together you can benefit from multiple types of health-promoting organisms. One study adopted the concept and combined a Lactobacillus/Bifidobacterium blend with a solid-based probiotic containing Bacillus spp. After administering this combination, along with l-glutamine, to 80 young adults the researchers saw a reduction in stress, anxiety, and depression, and a modulation of the stress response [33].  

Along with a healthy yeast, known as Saccharomyces boulardii, these bacteria make up the three arms of what I call a “triple therapy approach”. For your ease, you can find all three types in a bundle on my online store.

Diet as a Hidden Stressor

As previously mentioned, psychological stress isn’t the only type of chronic stress. Physical stressors include things like acute illness, alcohol consumption, mold toxicity, and, yes, your diet. Your body can’t tell the difference between physical and psychological stress — both can wreak havoc on your body when they go unchecked for too long [34]. 

Diet is of particular importance in gut health, as it is introduced directly into the gastrointestinal tract and thus has an immediate effect on the gut environment, including the intestinal wall and microbiome. If you are consistently putting unhealthy foods and toxins into your body, healing chronic stress and poor digestive health is going to be an uphill battle.

Some foods are overall agreed upon to be inflammatory in nature (and therefore stressful to the gut), like sugar, refined and processed foods, and low-quality, hydrogenated oils. Along with increased inflammation, these foods can disrupt the gut microbiome, leading to bacterial overgrowth, and worsen symptoms in gut disorders like IBS [35, 36, 37]. 

In the presence of a healthy gut, a small amount of these foods isn’t likely a big deal. But when consumed in excess or when introduced to an already inflamed and/or dysbiotic gut (ie. a stressed gut), they can amplify the problem [38, 39]. 

It’s not just these obvious foods you have to keep an eye out for if you are experiencing the effects of an unhealthy digestive system. Especially in the presence of leaky gut syndrome, a hyperactive enteric (GI) immune system can respond to “ordinary” foods as inflammatory, which can disrupt your gut health even further and worsen your symptoms.

Common foods that are seen as a threat include dairy, sugar, gluten-containing grains, corn, soy, and alcohol. Many of my patients report it’s some or all of these foods that seem to provoke their symptoms, and most respond well to removing them from their diet. 

It’s important to remember here that these foods aren’t necessarily the problem — their introduction into a hyperreactive and inflamed gut is the problem. Healing the gut should heal the response to these foods and make it more resistant to physical and mental stress. 

Increase Your Gut’s Resilience to Stress with an Anti-Inflammatory Diet

A diet that cuts out the above common inflammatory triggers and allows the body to heal (with the help of targeted therapies, like probiotics) is more than enough to get you started. I tend to lean toward starting with the least restrictive elimination diet first, then removing more food groups if your symptoms don’t fully resolve. 

I find this approach works best as it’s, a) easier to figure out which foods you are truly reacting to, and, b) it prevents you from getting stuck in a highly restrictive that may not be offering any further therapeutic benefit. Remember, the goal of an elimination diet is to enjoy more food by the end of it. 

A Paleo-style framework is one of the easiest and most effective places to start as it cuts out the foods listed above, but there are other options like low FODMAP and the autoimmune protocol (AIP). I walk you through how to build and complete your own personalized elimination diet here and here. 

However, an elimination diet can be daunting for some poeple, and adopting a Mediterranean eating pattern might be easier to implement. While it doesn’t eliminate all common food allergens, it’s fairly simple, enough to resolve symptoms in some people, and a great fallback when you can’t seem to stick with a more restrictive diet long enough to see results. If you get partial relief from the Mediterranean diet, you can always transition into one of the above short-term elimination diets for further relief.

Once you land on one that works for you, an anti-inflammatory diet can help heal your gut lining, restore the microbiome, and stop the self-perpetuating cycle of chronic stress and an unhealthy gut [40, 41, 42, 43].

Stress and Gut Health Relief  

Stress can be hard to get a handle on, but the way to hack it may be through healing your gut. By restoring your healthy microbiome with probiotics and cutting out “stressful foods” through an anti-inflammatory diet, you can get your stress and gut health under control. 

You can find more in-depth advice on how to address poor digestive health and inflammation-driven diseases in my book, Healthy Gut, Healthy You, or for hands-on help, reach out to us directly at our virtual clinic.

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.