Gardening Chemistry: Soil Microbes Good For Your Mental Health?


Home / Gardening Chemistry: Soil Microbes Good For Your Mental Health?

Serotonin is a molecule that makes us feel happier. Image courtesy of NIH.

The suggestion that gardening promotes mental health, and general well-being is older than the practice of psychiatry.

However, biochemical evidence seemed to be lacking. For example, we may ask the questions: Where is the agent (or molecule) that acts upon the serotonin receptors or GABA-receptors (gamma-amino butyric acid receptors) in the brain to produce this effect? Or, was  physical exercise the reason for the better mental health in those who experience improvement in mood?

Well, intriguing evidence has now surfaced that indicates certain soil microbes help relieve stress and combat depression. It is the ingestion of the microbes that promote well-being, and the microbes are viewed as possible adjuvants, substances that enhance the body’s immune response.

Although it seems to be a leap of faith to label the microbes as anti-depressants—the evidence points towards the conclusion of the microbes inducing better health.

Microbes, Humans, and Depression

The connection between microbes and human existence should not come as a surprise; it is a symbiotic relationship honed over a period of 500 million years. What may come as a surprise is the potential use of ‘bacterial agents’ as anti-depressants and anti-anxiety medications.

The conclusion that microbes are a source of anti-depressant behavior reaches for a psychiatric concept known as microbe-gut-brain axis. The ‘axis’ governs the manner in which the gut communicates with the brain. In essence, certain microbes will act as adjuvants; assisting the body’s natural chemistry.

In this case the bacterium in question is one that does not naturally occupy the gut. Mycobacterium vaccae, in this case, is shown to induce a sense of well-being and lessen anxiety in mice.

Mycobacterium Chemistry

What can be said of the chemistry involved is that mycobacterium alters gut chemistry. In essence, the bacterium aids in the production of any one of the following bio-active molecules: butyric acid, propionic acid and acetic acid.

The molecules are not known to be primary neuro-active agents but affect the way the gut communicates with the brain. The augmented gut tells the brain to produce more gamma amino butyric acid (GABA) or serotonin (the agents affecting anxiety or depression).

When compensating for a lack of GABA or serotonin, the bacterium acts like a typical ‘anti-depressant.’  Researchers have compared the bacterium to the anti-depressant imipramine.

Bacterium and Neurochemistry


Imipramine-antidepressant. Mycobacterium in soil behaves similar to Imipramine. Image courtesy of NIH

The ramifications of using a bacterium to improve mental health have implications for neurochemistry but may also explain the effectiveness of other pharmaceuticals and deeper concepts as well.

The concept of utilizing bacteria as an adjuvant is significant. However, the realization that the gut contains up to 90 percent non-native bacteria lends credence to the argument that dietary variations affect how individuals respond in both drug trials and allergens.

Genetics and Chemistry

Over long periods of time, variations in diet may  affect the genetics of isolated groups of individuals. Different populations respond to ‘biomolecules,’ in ways that are dictated by what is in their gut.

Given the diverse nature of bacteria, we can group individuals based on how their diet affected their children. People were born with  iron deficiency because, in their lineage, the gut chemistry was averse to certain factors that changed the biochemistry of their genetics.


Choosing Your Chemical Destiny

Ultimately, we as a species can choose how our future off-spring will deal with factors beyond their control—we can determine our destiny.

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