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Anxiety Diarrhea: What Causes It and How to Cure It

Written by Dr. Michael Ruscio, DC on July 13, 2022

Written by Dr. Michael Ruscio, DC on July 13, 2022 — Reviewed by Hilary Watts

Follow These Ways to Overcome Anxiety-Related Gut Upset

• What Causes Anxiety Diarrhea?|
• The Gut-Mood Connection|
• 3 Gut-Related Steps to Beat Anxiety Diarrhea|
• Alternative Approaches|
• Cognitive Behavioral Therapy|
• Can Traditional Antidepressants Help?|
• Say Goodbye to Anxiety Diarrhea|

If you’ve ever received distressing news and needed to rush to the bathroom, you know that feeling anxious or nervous can have a direct effect on your digestive system.

Anxiety diarrhea is a delicate topic, but definitely worth addressing as there are some relatively simple steps you can take to make things better.

First let’s have a look at what’s going on when your emotional state affects your bowels. There’s increasing evidence of a direct link between your gut and brain, and that addressing gut health is a great way to deal with anxiety symptoms. We’ll investigate this link and discover some ways to address both the digestive issues and underlying anxiety.

What Causes Anxiety Diarrhea?

Though it’s not entirely certain why acute anxiety prompts a sudden need to poop, one theory is that it’s the result of a heightened reaction to fight or flight response hormones (such as adrenaline) produced when we feel under sudden threat [1, 2].

Fast intestinal transit times have been noted in people with chronic anxiety, and people with anxiety are more than twice as likely to have diarrhea compared to the general population [3, 4]. This excessive gut motility has been associated with chronic diarrhea in those with irritable bowel syndrome (IBS-D), but also in those without this health condition [5].

Another way that stressful situations and anxiety may cause diarrhea and other abdominal symptoms is via the stimulation of mast cells (histamine-producing immune cells). This means anxiety may create abdominal symptoms via the same immune system route that food allergens do [6].

For some people, prolonged and chronic levels of adrenaline can have the opposite effect of decreasing gut motility, making bowel movements more sluggish.

The bottom line is that anxiety and other stressors may influence bowel habits in either direction (e.g., diarrhea or constipation) [4].

The Gut-Mood Connection

We know that our gut microbiome — the collection of trillions of microorganisms in our gut — has a powerful impact on the brain, and vice versa. 

While it’s not always clear whether the anxiety or gut imbalances come first, it’s likely that many gut symptoms, such as anxiety-related diarrhea, are facilitated by a two-way gut microbiota-brain communication. The so-called gut-brain axis connects your central nervous system to your gut’s nervous system (also known as the enteric nervous system) via the vagus nerve [7, 8].

If the gut microbiome is unhealthy, the brain-gut connection may become disrupted and you may have increased levels of anxiety. Several systematic reviews/meta-analyses have found that anxiety often coexists with IBS, inflammatory bowel disease, and celiac disease [9, 10, 11, 12, 13, 14].

Unfortunately, these studies of prevalence cannot indicate whether anxiety and gut disorders are causally linked, nor can they determine which came first [15, 16]. Suffice it to say, people with gut dysfunction are more likely than healthy people to have anxiety, and it’s possible that gut imbalances could contribute to anxiety and vice versa [17].

For example, fascinating research in mice has shown that a chemical produced by bacteria living in the gut can alter brain function and make the animals exhibit more anxious behaviors [18].

In turn, stress and anxiety can unbalance microbes in the gut, initiating a series of biochemical reactions that impact the central nervous system [19].

Understanding that the gut affects our mental state (and the other way around) opens the door to the possibility that improving gut health may also help fight anxiety symptoms, such as anxiety diarrhea.

In practice, we’ve found that many patients who have gut issues develop anxiety — and that healing the gut often leads to improvements in anxiety. 

Below we’ll walk you through how to heal your gut to lessen your anxiety. But if you need a more hands-on approach, reach out to one of our highly experienced clinicians to get your symptoms under control.

3 Gut-Related Steps to Beat Anxiety Diarrhea 

While there‘s likely no “perfect” gut health prescription to specifically keep anxiety diarrhea under control, the following three self-care steps will improve the robustness of your gut in general. In turn, this could improve your chances of damping down generalized anxiety disorders and anxiety diarrhea more specifically.

Step 1: Remove the Foods That Don’t Suit You

Research suggests that common dietary sensitivities, such as sensitivity to gluten, might exacerbate anxiety symptoms, including anxiety diarrhea. Removing these triggers from your diet, at least temporarily, gives your gut an opportunity to heal and your anxiety symptoms to improve. 

For example, one 2016 pilot study explored the effects of a six-week gluten-free diet (GFD) in 41 subjects diagnosed with IBS-D (irritable bowel syndrome with a major diarrhea component). Half of these subjects tested positive for a gene that increases the risk of gluten allergy, while the other half were negative for the same gene. The results showed that [20]:

Cutting out gluten not only significantly reduced bowel symptoms like diarrhea, but also anxiety and depression in both groups.

• Those who tested positive for the gluten allergy gene had bigger improvement in depression, vitality, emotions, and fatigue. 

In another study, researchers wanted to see if a low FODMAP elimination diet would improve anxiety, depression, and quality of life in patients with IBS and diarrhea. A total of 92 patients were randomly assigned to consume either a low FODMAP diet or a diet based on standard IBS recommendations. After four weeks, the results showed [21]:

• The low FODMAP diet significantly improved anxiety as well as stool consistency, urgency, and anxiety.
• Other benefits seen in the low FODMAP group included significant improvements in abdominal pain, bloating, quality of life, activity impairment, body image, and depression compared to the standard IBS diet.

Getting Started on FODMAPs

A low FODMAP diet doesn’t have to be the first diet you jump on. For dealing with anxiety and gut issues, many of my patients find an ancestral-focused Paleo-style diet that removes highly processed foods and foods we are commonly intolerant or sensitive to (like wheat and gluten) to be adequate. 

That said, a low FODMAP diet probably is the better fit for symptoms that don’t respond to the Paleo diet and include more severe anxiety diarrhea, bloating, and digestive upset. The key to this diet is finding your own specific tolerance to a group of carbohydrates and prebiotics (FODMAPs) that can otherwise feed an existing overgrowth of bacteria.

Different people will have different tolerances to FODMAPs and over time this will almost certainly change. This means as your gut heals you can introduce more carbohydrates and prebiotics in the future, while still keeping digestive tract symptoms, like anxiety diarrhea, at bay. 

Step 2: Take Probiotics

Due to their balancing effect on the microbiota, taking probiotics may be another strategy to help deal with anxiety and diarrhea.

In one preliminary study, a total of 83 patients with anxiety and depression (eight also with IBS) were given a multi-strain Lacto/Bifido probiotic for two months. The results showed significant improvements in depression and anxiety, quality of life, and GI symptoms including diarrhea [22].

A 2021 systematic review also identified five studies that showed probiotics were effective for improving diarrhea, and one study showing probiotics improved anxiety [23].

Probiotics also stand up quite well for the alleviation of broader anxiety symptoms, and this is especially the case in clinically anxious people [24, 25]. However, dietary interventions are even more effective, so they should be the first choice for anxiety management [26]. 

One possible reason for the beneficial effect of probiotics could be that they help heal a leaky gut [27]. Increased intestinal permeability allows bacterial toxins to leak into the bloodstream and contributes to anxiety [28].

Which Probiotics Work Best?

Most of the studies of probiotics for anxiety and improved mood have used probiotics from the Lactobacillus/Bifidobacterium category, so based on this you’d likely choose a high-quality, multi-species Lactobacillus/Bifidobacterium blend [29, 30, 31].

This doesn’t mean another type of probiotic won’t be helpful for anxiety diarrhea though, and you probably don’t have to search for a super-specific type of bacteria for anxiety. In fact from my clinical experience, a blend of species is probably best to cover all bases. 

In the clinic we’ve found a Lactobacillus/Bifidobacterium blend, combined with Saccharomyces boulardii and soil-based probiotics, are an effective and well-tolerated combination. 

We have formulated high-quality supplements from each of these three categories of probiotics, which can be conveniently found on our online store. 

Step 3: Harness Herbal Antimicrobials

Herbal antimicrobials, like berberine, are sometimes recommended as part of a gut-healing program if dietary changes and probiotics don’t bring about significant enough resolution of symptoms. For people with anxiety diarrhea, they may be particularly beneficial.

One 2015 randomized controlled trial randomly assigned IBS patients with diarrhea as a main symptom to receive 400 mg/day of berberine hydrochloride or placebo for eight weeks. The results showed that berberine supplementation significantly reduced diarrhea frequency and anxiety after eight weeks of treatment, compared to placebo [32].

Abdominal pain, urgency, depression, and quality of life also significantly improved in the berberine group compared to placebo. These results help solidify the gut-brain connection and suggest that an underlying gut bacteria imbalance may be at play in those with anxiety. 

Alternative Approaches for Anxiety Diarrhea

Though no studies addressed the effect of alternative or complementary therapies on anxiety diarrhea directly, some do find benefits for people who have IBS-D and anxiety symptoms at the same time. For example:

• Meditation was beneficial in a small trial involving 16 IBS patients who practiced relaxation response meditation (RRM) for six weeks. The results showed that mediation significantly improved IBS symptoms (diarrhea, flatulence, belching, bloating) compared to the control group, while 39% of subjects reported improved anxiety [33].
• Yoga plus deep-breathing exercises were more effective than loperamide (Imodium) in IBS patients after two months of twice-daily sessions. Whether people in the study took loperamide or did yoga, they saw significant improvements in IBS-D symptoms and anxiety, but the yoga group saw greater improvement in bowel symptoms [34].
• Traditional Chinese medicine (more specifically moxibustion, which involves burning processed mugwort herb on specific acupuncture points on the body) improved IBS-D symptoms more effectively than a sham version of the treatment. After six weeks, the results showed that the TCM group had significantly greater improvement in diarrhea frequency and bowel urgency [35].

Many mind-body techniques, including the ones mentioned above are safe, easy to do at home, come at little or no cost, and can be implemented alongside dietary changes, making them a great choice for resolving anxiety-related symptoms. 

Cognitive Behavioral Therapy (CBT) for Anxiety

CBT can help anxiety and it can also be useful in IBS, so it’s another treatment worth considering for anxiety diarrhea [36].

One study found CBT combined with drug therapy significantly improved IBS-D symptoms and quality of life compared with drug therapy alone. However, the symptoms appeared to return after CBT was discontinued [37].

Another study found that CBT plus exercise significantly improved IBS-D symptoms compared to a control group after six, 12, and 24 weeks. Additionally, the CBT appeared to significantly improve thinking patterns and coping styles of people with diarrhea symptoms [38].

Can Conventional Antidepressants Help?

One systematic review and meta-analysis suggested that traditional antidepressants, including tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), and serotonin-noradrenaline reuptake inhibitors (SNRIs), help quell gut symptoms (especially diarrhea), as well as ease depression and anxiety more generally [39].

Antidepressants can have their side effects however, and these include significant disruption of the gut microflora [31]. For this reason I wouldn’t recommend traditional antidepressants as a first-line choice for anxiety diarrhea.

However, if you’re already on these medications or need them temporarily to get through a bad time, don’t beat yourself up. Taking probiotics and improving your diet alongside will help to mitigate the downsides.

Say Goodbye to Anxiety Diarrhea

Diarrhea is a distressing reality for many people with anxiety. To break through the cycle of anxiety, upset stomach, and more anxiety, you can bolster your gut health, helping to normalize the gut-brain connection. 

A Paleo or low FODMAP diet combined with probiotics is an effective way to do this for most people, but if this combination doesn’t work effectively enough, herbal antimicrobials, CBT, meditation, or other relaxing therapies like yoga could also help.

You can read more about the vital role of gut health on both physical symptoms and mental health in Healthy Gut, Healthy You. Or for more personal help you could consider a consultation with one of our highly experienced practitioners at the Ruscio Institute for Functional Healthcare.

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.