The Brain and the Belly: How our gut health impacts mood and more

We all know that feeling; we eat something that doesn’t entirely agree with us, and the gas, bloating, cramping or nausea ensues. These symptoms are usually acute, quite obvious and in a few hours, they subside. What happens when the health of our gut is chronically compromised and leads to symptoms we didn’t even know were related such as mood disorders? Well… if we don’t know they’re related, chances are nothing is done.


Our gut (stomach and more importantly, our small and large intestines) is responsible for our immune function and our ability to breakdown and assimilate nutrients, but it also plays a role in neurotransmitter synthesis.  Neurotransmitters are chemical compounds produced by our bodies that deliver messages from our brain to the rest of the body and vice versa.  Common neurotransmitters that are involved in depression and anxiety include serotonin, dopamine, GABA (gamma-aminobutyric-acid) and norepinephrine. They are involved in different capacities depending on the person and whether depression or anxiety is more prominent. Generally, it has been estimated that about 95% of serotonin (the “happy hormone”) in the body is found in the gut. Click here for more details on what action each neurotransmitter has in our processes and behaviours. 

How can my diet impact my mood?

1. Protein: The neurotransmitters listed above are created from amino acids (the building blocks of proteins). Tryptophan - that famous sleep-inducing amino acid in turkey - is a precursor of serotonin. Tyrosine is the precursor of dopamine and norepinephrine. So, if we do not have sufficient complete protein intake, chances are we are not synthesizing these hormones to the degree we should be and our mood could be suffering the consequences. Animal sources of protein are complete in nature (containing all 8 essential amino acids); certain combinations of plant-based foods are required to make complete proteins.

2. Vitamins and Minerals: Amino acids are required to create neurotransmitters, but in order for the cascade of reactions to happen, nutrients such as magnesium, B vitamins and vitamin C are required as co-factors.  Here is a diagram of the pathways for all you science geeks out there.

3. Bacteria: The gut microbiota-brain axis is a newer area of research. Microbiota refers to the complex bacterial environment of our gastrointestinal system.  Each person is different based on environment, diet and possibly genetic predisposition.  A study in 2000 found that anxiety and depression were independent risk factors for IBS (irritable bowel syndrome) so, the relationship goes both ways; our brain impacts our gut health too. Gut bacteria can actually synthesize GABA (important for reducing anxious symptoms), serotonin and dopamine. Using probiotics is one way to foster a healthy gut microbiome as is consuming fermented foods (kimchi kombucha or sauerkraut).  Keep in mind, replenishing healthy gut bacteria is not necessarily for everyone, so consult an ND to see if it’s right for you. 


Disclaimer: This is not by any means an extensive list of neurotransmitters and processes; this description is simplified but still relevant to understanding how the gut can impact the brain! We are also aware the diet is not the only factor that is important with respect to mood; it is simply a piece of the puzzle to consider.



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Heather Robinson