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Probiotics Can Reduce Stress and Improve Mood. Here’s Why

Nootropics (supplements that increase cognitive ability) are all the rage these days, especially in Silicon Valley where nootropic supplements (and pharmaceuticals) are often taken as performance enhancers.

I’ve already written on this blog about my experiences with the popular nootropic theanine, however, the focus of today’s post is whether probiotics can improve cognitive performance and reduce stress. In other words, are certain strains of bacteria emerging as the new nootropics?

Most of the focus for probiotics has been on gut health, and to date, almost all of the studies on the brain boosting potential of probiotic strains have been done in mice. In preparation for this post, our research team found two compelling studies, both in humans, which could signal good news for those exploring how the health of the microbiome plays a role in our mental health.

Microbiome research accelerating

Our regular readers know that we been write a good bit about the microbiome. I wrote recently about how exercise can increase microbial diversity, while Jennifer put together a compelling piece on how gut bacteria can influence tumor growth.

Jennifer’s post looked at two commercially available strains of probiotic, B. Longum and B. Breve, and how administration helped slow tumor growth in mice who had previously grown tumors at an accelerated pace.

B. Longum Journal of Translational Psychiatry study

It turns out that certain strains of bacteria can actually enhance cognitive ability while lowering the stress hormone cortisol.

Dubbed “psychobiotics,” these probiotic strains could be part of the way we treat anxiety and depression in the future, as well as chronic conditions like IBS, which are tied to imbalances in the gut-brain axis.

One of those strains, Bifidobacterium longum (B. Longum), is the focus of my post today. B. Longum is one of the leading probiotic strains associated with cognitive enhancement.

As Jennifer notes in her tumor post, the science surrounding the microbiome is new and emerging, and as such, many of the studies have been performed on mice.

However, the first study I want to focus on here looked at the impact of a specific strain of B. Longum (1714) on brain activity patterns, cognition, and the stress response in humans. The double blind and placebo controlled study appeared in the Journal of Translational Psychiatry. This wasn’t a probiotic blend, the authors only evaluated the impact of just this single strain of bacteria: B. Longum 1714. 1

It’s also worth noting that the authors used male subjects, as menstrual cycle can impact cortisol levels, and prior use of probiotics excluded subjects, most of whom ended up being medical students.

This was also a small study at just 22 participants.

B. Longum impact on stress

The findings on stress were interesting.

Study subjects taking B. Longum had a lower amount of stress in response to a stressful event as well as lower levels of daily reported stress. Cortisol levels dropped after administration of B. Longum 1714.

The psychobiotic effect on the acute stress response is complemented by a reduction in daily perceived stress that is consistent with previous findings that a probiotic intervention can affect subjective everyday stress.

B. Longum impact on cognitive performance

Subjects administered B. Longum 1714 showed subtle improvements in visuospatial memory as well as enhanced prefrontal cortex activity (the part of the brain linked to willpower) based on an electroencephalogram (EEG) test, which I believe are normally used to monitor electrical activity in the brain for seizure risk. To give a visual, this means that the subjects had the metal disks you see in the movies attached to their scalps and the corresponding brain waves recorded.

So, bottom line, B. Longum, or at least B. Longum 1714, was shown to reduce stress and modestly improve beneficial brain activity.

B. Longum American Journal of Gastroenterology study

For a couple years, the Translational Psychiatry study (“TS study”)stood alone. But a study was published in 2019 which seems to back up the findings of the TS study.

B. Longum 1714 reduces social stressors

Published in the American Journal of Gastroenterology, researchers evaluated again the impact of B. Longum 1714 on mental health, with the focus this time being social stress. In the study, which was placebo controlled and double blinded, those administered B. Longum 1714 showed less stress and greater resiliency in response to a social isolation / rejection simulation designed to induce stress. Improved performance was confirmed using brain imaging.

To quote the study authors:

During the resting state, B. longum 1714™ induced an increase in theta band power in the frontal and cingulate cortex and a decrease in beta-3 band power in the fusiform cortex, hippocampus, temporal cortex, and cerebellum. Although no significant change of SF36 was noted after the 4-week probiotic intake, the increase in theta band and decrease in beta-3 band power found in the resting state was associated with increase in perceived energy/vitality levels, as assessed by the SF36.

My Experience with B. Longum

I have noticed some of the benefits cited by these studies when dabbling with B. Longum probiotics

Some form of B. Longum is found in a ton of commercially available probiotic blends, usually alongside a number of Lactobacillus strains.

As such, I have taken B. Longum in numerous courses of probiotics, and to be honest, never noticed much of a cognitive impact. The only strain that showed nootropic potential for me was the B. Longum Moringa BB536 strain. Note this is not the strain used in the two studies I cite above. To date, I have had a hard time finding a product inline that uses B. Longum 1714.

When I isolated B. Longum and took it alone, I noticed pyschobiotic benefits, such as enhanced mood and an overall sense of calm and well being.

The results were subtle, but undeniable.

The authors of the study Jennifer cites in her tumor post use B. Longum alongside B. Breve. There are commercially available formulas of Bifidobacterium probiotocs that use both these strains alongside B. lactis and B. bifidum, and I’ve tried them, but I found greatest efficacy with the Moringa BB536 strain.

Closing thoughts

It is well established that the gut and brain communicate. Through what is known as the “enteric nervous system,” our digestive health impacts on our mental health. Although the exact mechanisms are yet to be teased out, it isn’t a complete shock that certain strains of bacteria, such as B. Longum, can reduce stress and boost mood in humans. 3

John O'Connor

John O'Connor is the founder of Gene Food, host of the Gene Food Podcast and a health coach trained at Duke's Integrative Medicine Program. Read his full bio here.

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