Psychobiotics: Supporting Brain Health Through the Gut 

It’s not all in your head. The way you think, feel, and respond to stress has a lot to do with your brain, yes, but it’s also heavily influenced by what’s happening in your gut. Right now, trillions of bacteria and other microorganisms are living in your digestive tract. If your microbiome is balanced, there is a diverse range of species living there, all doing important jobs. Some are secreting signals that communicate with your brain through what’s known as the gut-brain axis, or more specifically, the microbiota-gut-brain axis [1]. These are psychobiotics: beneficial microbes that can support your mental well-being [2].

Although research is still emerging, these microbes have captured the attention of neuroscientists because they appear to have a meaningful influence on mood, memory, stress resilience, and cognitive function [2]. As brain health can be supported from many angles, here, we are going to break down what we know about the microbiota-gut-brain connection and how to promote better brain health with psychobiotics.

Your Gut and Brain Are in Constant Conversation

Anecdotally, we talk about “gut feelings” all the time. So maybe it won’t surprise you that there is actually some solid science behind this phenomenon, and that communication between the gut and brain works in two directions [3].

Your brain sends signals that influence digestion, your appetite, and gut function. At the same time, your gut continuously sends information back to your brain through a sophisticated communication network known as the gut-brain axis [1,3].

This network relies on several interconnected systems, including:

• The vagus nerve, which acts like a communication highway between your digestive tract and brain [4].
• The immune system, which can influence brain health through inflammatory signals.
• Hormones that help regulate stress and metabolism.
• Chemical messengers produced by both your body and your gut microbes.

When the gut microbiome is in balance it can produce or influence compounds involved in healthy brain function, including serotonin, GABA, and short-chain fatty acids [5]. While these substances don't simply travel from your gut into your brain, they do help shape the signaling pathways that connect the two systems.

Probiotics vs Psychobiotics 

Like squares and rectangles, all psychobiotics are probiotics, but not all probiotics are psychobiotics.

Probiotics are beneficial bacteria, in general. When beneficial bacteria inhabit a certain area of the body, they work symbiotically with your system, and push out or prevent colonization of unwanted species of bacteria.

There are probiotic supplements to target oral health, vaginal health, gut health, and more. Depending on the region you intend to support, probiotic supplements contain different, specific species or “strains” of microorganisms that have demonstrated the most observable benefits to that area in scientific studies.

For a long time it has been understood that when probiotic species outweigh potential pathogens in the gut, the “host” is more likely to experience more complete digestion, better nutrient absorption, bowel regularity, and normal immune function. 

Psychobiotics are a subset of probiotics that live in the gut, but play a specific role in supporting healthy communication between the gut and the brain. This means that the more psychobiotic species are introduced and established in the gut, the more signals are potentially circulated in the body for a positive mood and healthy brain function.

The growing body of evidence from this area of research is rather exciting because it reinforces something we've long believed: brain health isn’t limited to what’s happening in your head. Your brain is deeply connected to the health of your entire body, including your digestive system.

Rather than acting through a single mechanism, psychobiotics appear to influence several biological pathways simultaneously, shining a spotlight on the interconnections between body and mind.

How Can Gut Bacteria Affect Your Brain?

Are you still surprised to hear that microorganisms too small to see can have a big influence on how you think or feel? There are several ways this communication occurs, and understanding them may help it all make more sense.

1. The Vagus Nerve

The vagus nerve is one of the body's longest cranial nerves and the primary communication highway between the brain and the gut. It extends from the brainstem through the chest, and down into the digestive tract.

Certain beneficial bacteria may stimulate this nerve, sending signals that influence mood, stress resilience, and other aspects of brain function [6].

2. Supporting Healthy Neurotransmitter Activity

Some gut microbes help produce compounds involved in neurotransmitter signaling, including GABA and serotonin-related molecules [5,7]. GABA is a calming signal, and serotonin is linked to balanced positive feelings.

Although these chemicals don't directly cross from the gut into the brain in significant amounts, there are receptors for these chemicals all around the body [5]. By influencing the broader communication network connecting the gut, immune system, and nervous system, they may ultimately support feelings of well-being.

3. Helping Regulate the Stress Response

There’s another axis in the body that we rely on heavily for stress management: the hypothalamic-pituitary-adrenal (HPA) axis.

Early research suggests certain psychobiotic strains may help support a balanced stress response by influencing this system [8]. That's one reason they've become an area of interest for researchers studying stress, anxiousness, and emotional resilience.

4. Supporting a Healthy Inflammatory Response

Approximately 70% of your immune system is located in your gut [9].

When the gut microbiome becomes imbalanced, it can contribute to an imbalanced inflammatory response, a process that has been associated with changes in mood, cognition, and overall brain health [10].

We often emphasize that chronic inflammatory imbalances are a major threat to long-term brain function. Supporting a healthy gut microbiome may be one important strategy for helping maintain healthy inflammatory responses throughout the body.

Can You Get Psychobiotics from Food?

Sort of, but there are caveats. Fermented foods naturally contain live bacteria, including probiotic species. Some examples of fermented foods are:

• Yogurt
• Kefir
• Kimchi
• Sauerkraut
• Kombucha 

In a well-known clinical trial from Stanford, healthy adults who ate a 10-week diet rich in fermented foods saw a measurable increase in the overall diversity of their gut bacteria, along with a drop in markers of inflammation in their blood [11]. That's a meaningful finding, because a more diverse gut microbiome is generally considered a sign of a healthier one.

The caveat, though, is that most fermented foods contain a broad, unpredictable mix of bacterial strains, and food-based amounts can vary a lot from one batch to the next. The clinical research specifically behind psychobiotics, comes from studies using exact strains at exact doses, which is hard to guarantee in a jar of kimchi, but can be encapsulated pretty reliably [8]. 

That's not a reason to skip fermented foods. They're still a great resource for maintaining gut diversity in general, but it is a different (although complementary) approach to a targeted psychobiotic supplement [12].

The Bigger Picture

Your gut and brain are partners. They are constantly communicating through an intricate network of nerves, hormones, immune signals, and beneficial microbes.

While psychobiotic research is still in its early stages, the evidence continues to suggest that nurturing a healthy gut microbiome may be one more way to support a healthier brain. Specific strains of probiotics influence signals that can impact the way you think and feel, and supplementing these strains in the form of psychobiotics may benefit your brain health.

Remember, you're not stuck with the brain (or the microbiome) you have today. Every meal, every night of quality sleep, every workout, and every healthy lifestyle choice can help create an internal environment where both your microbiome and your brain can thrive.

These statements have not been evaluated by the FDA. This article is for educational purposes and isn't a substitute for medical advice. Talk to a doctor before starting any new supplement, especially if you're pregnant, nursing, or managing a health condition.

References

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3. Mosquera, F. E. C., Lizcano Martinez, S., & Liscano, Y. (2024). Effectiveness of psychobiotics in the treatment of psychiatric and cognitive disorders: A systematic review of randomized clinical trials. Nutrients, 16(9), Article 1352. https://doi.org/10.3390/nu16091352
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