Gut Microbiome and Mental Health

The Science of Psychobiotics

Your mental well-being relies on your gut-brain axis. Here's how to keep that two-lane highway to happiness functioning perfectly.

Check out this list of mental health conditions:

  • Anxiety
  • Depression
  • Stress-induced issues
  • Cognitive decline

All of these, their subcategories, and dozens of other psychological maladies can be caused or exacerbated by a "broken" gut-brain axis. Luckily, we can prevent and treat these issues with something called psychobiotics.

What are Psychobiotics?

"Psychobiotic" sounds like a song by Slipknot. Psychobiotics are actually a class of probiotics and prebiotics that improve mental health by influencing the gut-brain axis.

As a refresher, the gut-brain axis is the two-way communication network between your gut and brain. It links the central nervous system (CNS) with the enteric nervous system (ENS) via neural, hormonal, and immune pathways. There are lots of moving parts: the vagus nerve, neurotransmitters, gut microbiota, and metabolites like short-chain fatty acids (SCFAs).

The gut microbiome – those colonies of microorganisms that live in our G.I. tracts – plays a huge role by producing neuroactive compounds like serotonin, dopamine, and gamma-aminobutyric acid (GABA). Your gut bacteria also modulate inflammation and the stress response.

Certain gut bacteria are classified as psychobiotics. They use the gut-brain highway to influence mental health.

The Common Psychobiotic Strains

Here are the two power players:

  • Lactobacillus
  • Bifidobacterium

Studies show that people with various mental health issues tend to have lower levels of beneficial gut bacteria, including these psychobiotic strains.

The different psychobiotics and their sub-species influence mood and mental health in several ways. They produce neurotransmitters such as GABA, serotonin, and dopamine. They influence the HPA axis to control cortisol and ferment dietary fibers into SCFAs which squash brain inflammation. They even communicate with the brain via the vagus nerve, directly influencing mood and stress responses.

In short, just about every mental health issue we'd like to avoid is influenced by psychobiotics. So, should we just start taking probiotics? It might help a little, but it's very tricky. A better plan is to consume foods and supplements that directly grow and balance psychobiotics.

What to Eat and Take

You probably know what to eat: stuff that contains live cultures and other stuff to keep them fed. That's fermented foods (real yogurt, kefir, and sauerkraut), prebiotic-rich foods (fruits, veggies, nuts, whole grains, and legumes), and resistant starches.

If we had to crown a King Prebiotic, it would be beta glucan. When this specialty fiber reaches your gut, it's fermented by Lactobacillus and Bifidobacterium. This fosters their growth and produces SCFAs and neurotransmitters while stimulating the vagus nerve and regulating inflammation.

Beta glucan modulates the immune system by interacting with immune cells in the gut. This helps reduce systemic inflammation associated with mental health disorders like anxiety and depression. Psychobiotic strains work synergistically with beta glucan to reduce pro-inflammatory cytokines and support a balanced immune response.

Beta glucan also enhances the overall health of the gut environment by promoting the growth of psychobiotic bacteria, improving gut barrier integrity, and reducing "leaky gut," linked to neuroinflammation. A healthier gut environment allows psychobiotic strains to more effectively produce beneficial metabolites and neurotransmitters that impact the brain.

Some psychobiotic strains, like Bifidobacterium longum and Lactobacillus helveticus, preferentially utilize beta glucan as a food source, leading to more beneficial byproducts. Beta glucan even enhances the adhesion of psychobiotics to the gut lining, improving their colonization and longevity.

Oats, barley, yeast, and certain mushrooms contain beta glucan, but their cellular walls are thick, making it hard for your body to extract and utilize the good stuff. The best source of beta glucan is actually algae, particularly Euglena gracilis. Algal beta glucan has much thinner cell walls, making it easy to digest. Biotest Beta Glucan Immune-Boosting Fiber (Buy at Amazon) contains 600 mg of this form per serving.

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As a bonus, this same fiber has several fat-loss and metabolic health benefits.

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How does a ketogenic or carnivore diet address this?

Over time, ketogenic and carnivore diets reduce the diversity of gut microbiota (via lack of fiber, the primary fuel for Bifidobacteria and Lactobacillus) and increase the gut bacteria associated with inflammation and gut permeability.

At first though, these diets could help with some dysbiosis issues because you’re starving the sugar-eating bad bacteria. But a person can do that without going full keto or carnivore and avoid any long term problems. A low-carb person could also slip in some fermented foods. Strict carnivore would have a harder time. Weirdly, they have the same problems as vegans in the long run since the body isn’t made for either diet. Like all diets that remove or severely limit entire macros, supplementation would help avoid the negative effects.