It might sound ludicrous when you see the title: Probiotics for anxiety. 

But what if I told you anxiety is a gut disorder? Does the title sound a bit reasonable to you?

Rest assured, it is all in my article. I am Dr. Tun Min, a GP working in Northwest NHS UK. I have a special interest in the field of supplements, fibers, and probiotics relating to Gastrointestinal health.

How does your gut health affect anxiety?

Either stomach-churning before a job interview or butterflies in the stomach at the sight of a loved one, you might speculate that your emotions are tied to your gut.

It all started in 2004 with a study on two types of mice. One group had their germs and stomach artificially removed and the other didn’t. On exposure to a stressful experience, the germ-free mice showed an exaggerated response to stress as compared to the others. This sparked a great interest in the connection between the gut, gut microbes, and the brain, called the gut-brain axis.

The gut-brain axis

It is a bidirectional communication between your gut and your brain.

This crosstalk occurs in several different ways.

• Vagus nerve

More than 100 million nerve cells are embedded in your gut wall. This hidden second brain in your gut is called the enteric nervous system (ENS). The vagus nerve is the biggest nerve connecting your ENS and brain. It sends signals in both directions.

• Neurotransmitters

The gut and the brain also communicate through chemicals called neurotransmitters which can regulate feelings and emotions. For example, your gut bacteria produce a neurotransmitter called gamma-aminobutyric acid (GABA), which helps control depression and anxiety.

• Chemicals produce by gut microbes

When your gut bacteria ferment fiber, they produce metabolites called short-chain fatty acids which can cross the blood-brain barrier, and impact brain structure and function.

• Immune system

Gut microbes can modulate immune homeostasis. When your immune system is imbalanced, it can lead to chronic inflammation which is associated with many brain diseases like depression and dementia.

How do probiotics come into the picture?

You have probably known that your digestive tract harbors trillions of microbes which we call the gut microbiome. Studies have found that people with anxiety have different microbiomes. They have more harmful bacteria that produce inflammatory chemicals linked to anxiety and depression.

Probiotics are living microorganisms that you ingest to increase good bacteria and improve the diversity of your gut microbiome. 

They improve anxiety by stimulating the vagus nerve, producing neurotransmitters like GABA, and serotonin, reducing inflammation, and crowding out pathogenic bacteria.

So, can probiotics improve your mood?

Yes, they do.

It is crystal clear that a healthy gut begets a better resilience to stress and anxiety. 

So if you are keen on improving your gut-brain connection and raising the levels of beneficial bacteria in your digestive tract, why not try probiotics? You can incorporate probiotic-rich fermented foods into your diet or take the capsule.

Since you have a unique set of your microbiome, my best answer to “ Do probiotics calm anxiety?” is to find out for yourself.

What does the research say?

Already well-proved in animal studies

In 2018, PubMed Central published a systematic review of 22 animal studies and 14 human clinical studies looking at the impact of probiotics on anxiety. While researchers could not tackle conclusive evidence in human studies, they found that probiotics, specifically Lactobacillus and Bifidobacterium, significantly reduced anxiety-like behavior in rodents.

More human studies are needed

A  2020 review of research findings suggested that probiotics can improve mental health and psychological function in people with depression, anxiety disorders, and Alzheimer’s.

In 2021, researchers examined the effects of probiotics on anxiety, stress, and mood of 30 badminton players. Consuming probiotics significantly helped to alleviate stress and anxiety.

Generally speaking, human studies to date have small sample sizes, and the evidence is still limited to attribute to the novelty of probiotics as psychotropic intervention.

However, with further research, I can foresee more widespread use of probiotics in the management of mental health.

The most promising probiotics for anxiety

1. Lactobacillus rhamnosus

Lactobacillus rhamnosus was identified as an anxiolytic probiotic by both animal and human studies. It increases GABA, an inhibitory neurotransmitter that makes you more relaxed and reduces anxiety and stress.

2. Bifidobacterium longum

B. longum NCC3001 normalizes mouse anxiety-like behavior induced by chronic gut inflammation. The anxiolytic effect of B.longum is by activation of the vagus nerve.

3. Bifidobacterium breve

Bifidobacterium breve CCFM1025 significantly reduced depression- and anxiety-like behaviors and reversed gut microbial abnormalities in male mice.

4. Lactobacillus reuteri

Research shows that Lactobacillus reuteri can reduce anxiety symptoms in animals by reducing stress hormone levels and altering the expression of GABA receptors.

5. Lactobacillus Plantarum

In one study, researchers gave Lactobacillus plantarum DR7 to stressed adults.

They found that this probiotic alleviated stress and anxiety by increasing dopamine and serotonin, lowering stress hormone levels, and reducing inflammation.

6. Lactobacillus helveticus

The administration of  Lactobacillus helveticus and Bacteroides longum probiotics in humans showed improvement in psychological symptoms and a decrease in the stress hormone, cortisol.

Are there any side effects to taking these psycho-biotics?

Not really. These friendly bacteria have a good safety profile, and until now, no research has shown significant adverse outcomes with probiotics.

However, they are not for people with a fragile immune system. Since they are live bacteria, they can invade your bloodstream and harm your body if you are immunocompromised.

How to choose the best probiotic for anxiety?

One of the most frequent questions I get asked by my patients is, “How do I choose a probiotic of good quality?”

Like medications, the FDA does not strictly regulate probiotics. So consumers can’t always be sure of what they are getting. But there are a few important rules to consider when selecting a probiotic.

• Culture count or the total amount of bacteria per capsule 

A potent dose of 25-30 billion CFU (colony forming unit) is required to bring the health benefits of probiotics.

• Strains of bacteria 

A high-quality probiotic should include at least 8-10 strains of bacteria. Be aware to find the strains that are proven to be effective for the health benefit you desire. For example, if you are taking probiotics for anxiety, you should pay attention to including the lactobacillus and bifidobacterium strains I’ve mentioned above.

• Make sure your probiotic has a delayed release 

It is crucial because a delayed release can resist stomach acid and help deliver the probiotics to the intestines where they are most needed.

• Be aware of artificial reviews

To avoid this, you better buy quality probiotics from trustworthy brands reviewed by professionals.

Culturelle is one product that probably has the best Lactobacillus strain in the market. This particular product mainly consists of two Lactobacillus rhamnosus strains, GG and DSM plus L. paracasei DSM which are all most well known to support the gut-brain axis and help with maintaining the best chemistry environment in the brain thus helping with depression, mood problems, anxiety problems.

The addition of natural prebiotics, dietary fiber, and kiwi fruit makes the Lactobacillus strains even healthier which also adds benefits to gut health.

Garden of Life Dr. Formulated Mood+ 50-Billion Probiotics 60 Vegetarian Capsules

I advise this product mainly to those who prefer a shot-gun approach. Garden of Life products are known for high CFU content with multiple strains of probiotics.

The main benefit is that it gives all the benefits of probiotics for some people which, to be honest, a lot of people quite like. However, few people find it hard to tolerate the side effects, usually mild like stomach upset, constipation, and vomiting.

Having said that this contains a good CFU count of 25 billion with a mix of both Lactobacillus and Bifidobacterium species.

Personal advice 

Since most probiotics are relatively safe and impressive supplements for gut health with potential benefits on anxiety, taking them won’t hurt you. More research is ongoing to support probiotics as a psychotropic intervention, and so far, the results are encouraging.

However, probiotics are not a substitute for standard care like cognitive behavioral therapy and FDA-approved medications to treat anxiety.

It is also crucial not to suffer in silence and seek professional help if your fear and anxiety are getting out of control or you are having suicidal thoughts.