Articles

Evidence based

Evidence Based

This article is based on scientific evidence, written by experts and fact checked by experts.

Our team of licensed nutritionists and dietitians strive to be objective, unbiased, honest and to present both sides of the argument.

This article contains scientific references. The numbers in the parentheses (1, 2, 3) are clickable links to peer-reviewed scientific papers.

Healthy Gut, Healthy Brain: How to Use Mood Boosting Probiotics

Written by Dr. Michael Ruscio, DC on September 13, 2021

Written by Dr. Michael Ruscio, DC on September 13, 2021 — Reviewed by Dr. Hannah Hamlin

How Mood Boosting Probiotics Can Help Mental Health

• Probiotics for Depression, Anxiety, and Stress|
• Why Probiotics Work|
• What Probiotic Strains Are Best|
• Adding Probiotics to Your Life|

For decades, we looked at mental health primarily by looking at the brain, and not the rest of the body. More recently, we have discovered that mental health is tied to the health of our whole body, particularly our digestive health. While many people have had great success with only using therapy and/or psychopharmaceutical drugs, there are still many people who are struggling. 

Now with more recent studies, we have even more evidence that the brain and gut are connected. For some people a missing piece of their mental health care is their gut health. In this article, we will discuss how mood boosting probiotics can be an important addition to a comprehensive mental health treatment plan. We will look at the gut-brain connection and why probiotics work to improve mood in depression, anxiety, bipolar and other mental health conditions, in some people. 

Mental health is complex, and treatment is different for every person, so we want to be clear that the use of probiotics is a support, not a replacement, for other forms of mental health treatment. Good mental health care can also include medications, talk therapy, cognitive behavioral therapy, trauma work, mindfulness practices, and many other interventions.   

Let’s look at some of the research on the benefits of probiotic bacteria for depression, anxiety disorders, and stress.

Probiotics for Depression, Anxiety, and Mood

Probiotics have been found to improve moods, especially for those with depression [1]. Probiotics likely help improve mood because they help support a healthy microbiome — the balance of bacteria and microbes in the gut that help digest food and create a healthy gut. In the next section, we’ll discuss the strong connection between the gut and the brain, and thus mood. First, let’s look at some summaries of the research on how probiotics can help with depression, anxiety, and stress. 

Research studies have looked at probiotics effectiveness in improving general mood as well as improving diagnosed mental health disorders. 

Probiotics seem to have the most positive effect on people who have depression, anxiety, and increased situational stress. Research does not yet show a mood boost in people who are overall healthy. However, improved mood is a “side effect” of probiotics that I often hear about from my patients.

Anxiety and Stress

In studies regarding anxiety and stress, the results are mixed. The largest meta-analysis (where the results of multiple randomized control clinical trials are studied) showed no significant improvement in reducing subjective stress levels in healthy people [2]. However, in smaller studies involving people with anxiety and/or stress, probiotics had a generally positive effect. 

One study involving students facing exam stress found that those who took a multi-strain probiotic had lower scores on the perceived stress scale, depression/anxiety stress scale, and state-trait anxiety inventory, as well as lower cortisol (stress hormone) levels than those in the placebo group [3].

In terms of general anxiety and panic anxiety, studies show improvements, but they are preliminary and more research needs to be done [4, 5, 6]. They do agree that improvements in the gut-microbiome, sometimes from probiotics, sometimes from other interventions, often does improve anxiety [7].

Depression

The best evidence for probiotics improving mood has been found in depression [1, 8]. Studies looking at the mood boosting capabilities of probiotics have found that:

• Depression scale scores for depressive disorder were improved in people with major depressive disorder [8].
• A meta-analysis showed that probiotics have a moderate to large positive impact on people with mild to moderate depression [9].
• Psychiatric patients who took probiotics had improved scores on the Hamilton Rating Scale for Depression [10].

Why Probiotics Work: The Gut-Brain Connection 

You may be thinking, “But, I don’t have any issues with my digestive system, so my gut has nothing to do with my moods.” This may be true for some people, but mood disturbances and other non-gut-related symptoms are very common among patients with digestive conditions, including SIBO and IBS [11, 12, 13, 14, 15].

In fact, some people have gut imbalances that present with non-digestive symptoms only, such as depression, anxiety, and brain fog [16]. For this reason, it may be worth looking at your gut health if your mental health symptoms persist.

The brain and gut are linked through something called “the brain-gut axis.” Essentially, the brain affects the gut and vice versa.

We will explore three main components of why probiotics seem to work to boost mood:

• The gut and brain communicate in both directions.
• The microbiome supports the communication between the brain and gut.
• Inflammation and leaky gut negatively impact the brain and our moods.  

Central and Enteric Nervous Systems

The gut-brain axis consists of the central nervous system and the enteric nervous system. The central nervous system is how we sense the environment around us. It links emotion and cognition in the brain, and it controls automatic functions such as breathing and heartbeat [17]. The enteric nervous system is in the gut and it regulates digestion among other functions [18].

The gut and brain send signals to each other through part of the central nervous system called the vagus nerve. The vagus nerve regulates stress response, including our fight, flight, or freeze response. The gut even sends neurotransmitters such as dopamine, serotonin, and norepinephrine made in the gut to the brain along this nerve [5, 19].

It is important for mood regulation that all parts of this intricate system are working well. For example, if the vagus nerve is dysregulated causing high stress, the signaling between the gut and brain is impaired. This can result in mood imbalances such as symptoms of depression or anxiety, but as you can tell, this can also cause GI issues such as constipation.

Gut Microbiome

A poor gut microbiome (the balance of bacteria and other gut microbes needed for our gut to function properly) can negatively affect our mood, as can be seen in the case of irritable bowel syndrome (IBS,) which often comes with gastrointestinal symptoms as well as depression and anxiety [20, 21].

The communication from the brain to the gut goes both ways, with the brain helping to regulate digestion and the flow of food through the gastrointestinal tract, leading to symptoms such as bloating, diarrhea, and constipation. 

It is very important that this brain-gut axis is healthy and working well, and the gut microbiome plays an important role in supporting that communication system [22]. With a poor microbiome, our brain may not even get the neurotransmitters it needs to function well, contributing to depression and anxiety [23]. Mood boosting probiotics help improve the microbiome which supports the function of the gut-brain axis [1].

Inflammation and Leaky Gut

You have probably heard a lot about leaky gut and how it can cause everything from stomach distress to skin issues, and it can also affect the brain. 

Simply defined, leaky gut is when the normally strong lining of the small intestines that prevents undigested food and toxins from getting into your bloodstream weakens, and this is often called intestinal permeability [24]. When these foreign bodies get into the bloodstream, the immune system attacks them, causing an immune reaction not only in the gut, but also often in the brain [25]. Leaky gut can happen for a number of reasons, very often from inflammatory foods and/or an imbalance of the gut microbiota. 

The inflammation, as well as the bacteria that leaks through the intestinal lining due to leaky gut has been linked to depression, anxiety, and other mood disorders [26]. This is why it’s important to support a healthy microbiome and good bacteria, which probiotic supplementation can do.

Which Probiotics Are Best for Mood?

In the world of psychobiotics (another name for probiotics or prebiotics that have an effect on mental health), [1] you may hear that one species or another of probiotics is the best to treat certain mental health conditions. However, we do not really have evidence to support that claim. 

Most studies on the effects of mood boosting probiotics have used a Lactobacillus/Bifidobacterium blend (a Category 1 probiotic). This does not mean that other categories of probiotics such as soil-based or saccharomyces boulardii do not work, it just means they have not been studied for this use yet.

Within the Lactobacillus/Bifidobacterium category, studies do not clearly show that any one species or strain works better than another.  

Some of the commonly used species in that category for research are Lactobacillus helveticus plus Bifidobacterium longum, Bacillus coagulans, Lactobacillus rhamnosus, Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum, Bifidobacterium breve, and Bifidobacterium infantis. While many strains and species have been used, no one has proven to be more effective than another. In fact, a multi-species formulation in this category has been found to be the most effective in decreasing depression [1, 27].

Adding Probiotics to Your Life

If you are thinking about trying probiotics for mood support, here is a quick guide:

1. Don’t change your current treatment plan without consulting with your mental health team. Probiotics are not a replacement for other forms of treatment.
2. Start with a Category One probiotic, a Lactobacillus/Bifidobacterium blend, since those were the most commonly used probiotic supplements studied (or you can start with a triple therapy probiotic approach that includes category one as well as category two and three probiotics). 
3. Use probiotics with an anti-inflammatory diet which can help improve leaky gut and balance out the gut microbiome. Dietary interventions have been shown to improve depression [28, 29]. Research has shown that anti-inflammatory diets can also be effective at improving the gut microbiome and thus mood [7]. In particular, a low-FODMAP diet has been shown to improve depression and anxiety [30].

If you are unsure about adding in probiotics on your own and would like more individualized help from our clinic, please fill out our contact form. We would be happy to help you improve your health and wellness. 

I hope this article has helped you learn more about how probiotics can help improve mental health, giving you another tool in your toolbox to better health and mental wellbeing.