Does A Healthy Gut (Microbiome) Improve Mental Health? Research Suggests It May

Arguably the most intriguing albeit nebulous biological concept uncovered in recent years is that of the human gut microbiome and its connection to mental health. Gut microbiota (found in our gastrointestinal tract) are well-known to modulate numerous bodily functions, notably immune response, nutrient digestion, bowel regularity, and endocrine balance [1]. But now, the so-called microbiota-gut-brain axis has taken center stage.

Do gut microbiota have the capability to alter our mental health? Seminal evidence suggests they can (and do) [2].

Perhaps targeting the gut microbiome is prudent for supporting mental health? Here's what science has to say on the matter and how you can promote a beneficial composition of intestinal microbiota.

The Microbiota-Gut-Brain Axis And Mental Health (Disorders)

When the mind is unwell, the body typically follows a similar fate. In a world full of apprehension and uncertainty, mental health should be a priority for everyone.

Hitting the gym regularly and eating a balanced diet is a bulletproof way to lift your mood and quell stress, but there's more to the puzzle. The connection between physical health and mental health is nuanced and intricate. As time evolves, we are gaining insight into how the brain, body, and microbial communities within us coordinate stress response and related biological processes.

Burgeoning scientific and clinical evidence makes it clear that human gut microbiota serve as commensal or parasitic organisms; they can benefit or harm us, but we don't do much for them [3].

So, how do intestinal bacteria and other microbial species (e.g. fungi) regulate mental health? The microbiota-gut-brain connection/axis is a phenomenon unlike any other, and though it's readily apparent, many questions about how it works remain unanswered.

The good news is we now have an abundance of literature on the gut microbiome and are rapidly elucidating diverse roles of microbes in the human gastrointestinal (GI) tract [4]. Direct evidence of any remedial effect the gut microbiome has on mental health disorders is limited, but we can deduce putative therapeutic outcomes based on existing research.

Gut Bacteria And Neurotransmission

Research in recent years highlights that microbes, specifically bacteria of the Lactobacilli and Bifidobacteria genera, produce and/or consume a broad spectrum of mammalian neurotransmitters [5]. A pertinent example is that certain gut bacteria influence tryptophan metabolism and, by extension, serotonin neurotransmission [6].

When serotonin levels are low, depressive symptoms manifest [7]. Hence, most anti-depressant medications work by blocking serotonin reuptake at specific neurons within the central nervous system. Theoretically, gut bacteria that increase serotonin levels could be synergistic with, or complementary to, selective-serotonin reuptake inhibitors (SSRIs).

Other bacterial species alter gamma-aminobutyric acid (GABA) and glutamate neurotransmission [8]; dysfunctional GABA-glutamate pathways are a cornerstone of anxiety disorders (we've discussed this topic at length in another article). It's plausible that GABA-producing microbes could alleviate anxiety-like behavior, while glutamate-producing microbes may do the opposite.

Preliminary findings are promising, but more direct research is necessary to determine the anxiolytic and anxiogenic effects of specific gut bacteria.

Indirect Mental Health Benefits of Gut Microbes

Chronic health conditions like irritable bowel syndrome, inflammatory bowel disease, and leaky gut syndrome can drastically reduce quality of life and take a toll on people mentally. Probiotics, which are foods or supplements that contain beneficial microbes, have proven quite effective for addressing these issues and may therefore have a considerable impact on mental health [9].

The same can be said for individuals with a compromised immune system. The GI tract contains the majority of immune cells in the human body, and gut microbiota play an important role in the function of these cells [10]. Life is no fun if you're constantly ill, so probiotics could indirectly improve brain function by restoring a healthy immune system.

As you can see, the gut microbiome is a pillar of longevity and overall wellness. The following section will outline ways you can improve gut health.

How To Improve Gut Health: Prebiotics and Probiotics

Eating probiotic foods like sauerkraut, kimchi, and yogurt is a simple way to support healthy gut microbiota composition. But sometimes that's not enough, and extra help is needed — this is where probiotic supplements and prebiotics come into play.

Probiotic supplements typically come as capsules containing beneficial microorganisms that promote a healthy gut microbiome. Emerging research substantiates the efficacy of supplementing with probiotics for numerous indications [11]; taking probiotics may have profound implications for treating conditions like irritable bowel syndrome, major depression, and chronic anxiety.

In past decades, a major hindrance for probiotics was finding bacteria that could survive the acidic milieu of the stomach. Gastric juice is low in pH (i.e. highly acidic) and readily destroys/breaks down many substances, as well as living things such as bacterial species.

Thankfully, advances in biotechnology make modern-day probiotic supplements, like Transparent Labs Gut Health, viable by providing beneficial bacterial strains that readily survive in the stomach and colonize the GI tract.

Furthermore, the gut microbiome feeds on digestion-resistant starch and various fibers; these nutrients are "prebiotics" since they nourish gut microbiota. Prebiotics are especially rich in foods like sweet potatoes, green (unripe) bananas, tapioca, chicory root, aquatic greens, and Jerusalem artichoke.

Another practical option to get more prebiotics in your diet is to add a scoop of Transparent Labs Prebiotic Greens to a smoothie/protein shake.

Key Take-Home Points

• The human digestive tract contains over 1000 microbial species, primarily bacteria, and plays a vital role in overall physical and mental health.
• Eating a healthy diet with plenty of prebiotics and probiotic foods is key for stimulating the growth of beneficial gut microbes and eliminating harmful bacteria. Supplementing with probiotics may also be prudent to establish and maintain a robust gut microbiome composition.
• The link between gut health and anxiety/depression has opened up encouraging new ways of tackling psychiatric disorders. However, more research is necessary to connect the dots between the human microbiome and brain function.