The Gut-Brain connection: how our food influences our mental health

Have you ever noticed butterflies in your stomach when you feel excited or nervous?

Or observed how you lose your appetite during periods of stress?

Or had those moments when you’ve had to tun to the toilet as an attack of nerves hit in?

These are all indications of our brain communicating with our gut, and is a connection is formed by the longest nerve in the body, the vagus nerve. It works as a bidirectional highway, sending signals back and forth according to what is happening at either point.

You might be wondering what this connection is for? Why is it that we have this ‘second brain’ that somehow gives us an additional outlook on how we’re feeling.

The human body is wired for survival: this means that our most powerful system is the one that detects danger, prepares us for attack, and keeps us alive, aka the nervous system.

Before work-life balance became a thing, before exams, before deadlines, our main source of danger was wild animals out to attack us, and we needed to be able to run, very very fast, to get away from whatever was about to attack us. To achieve this, when we feel stress (and actually our body can’t distinguish between a lion running towards us or an exam that we haven’t studied for), all of our non-essential systems get temporarily shot down, to preserve resources and redirect all our energy for survival.

The gut is one of those ‘non-essential’ systems in times of acute stress. The last thing we need to be thinking about is where the nearest toilet is when we’re running away from a wild animal (so we can thank our beautifully adapted bodies for that at least).

The butterflies in your stomach? That’s the blood flow being redirected away from your gastrointestinal wall, causing irregular contractions in the gut wall.

The loss of appetite? That’s the adrenaline suppressing your desire to eat, so that you don’t waste energy on digesting food while you’re fighting for your life.

When functioning under normal conditions, ie. when we are not in a state of survival, the vagus nerve sends information from the gut back up to the brain about the health of the gut and the microbiome. Aside from digesting our food, the gut, and specifically the microbiome, is responsible for producing up to 90% of our neurotransmitters that determine our mood, our motivation, our focus and our ability to relax.

These neurotransmitters, such as serotonin (the ‘happy hormone’), dopamine (the ‘motivator), and GABA (the ‘calming’ or ‘zen’ neurotransmitter), are hormone-like messengers that stimulate the vagus nerve, passing the signal onto the brain to control our mood. These neurotransmitters are made by specific strains of bacteria in the gut, and are these days often referred to as ‘psychobiotics’ because of the effect they have on our mood.

Lactobacillus rhamnosus: Known to lower anxiety by influencing GABA receptors in the central nervous system, helping to induce a calming effect.

Bifidobacterium longum: Helps alleviate depression and stress by reducing the cortisol response and supporting neuroplasticity.

Lactobacillus plantarum: Assists with anxiety by boosting serotonin and dopamine levels while lowering cortisol.

These strains of bacteria require specific nutrients and the right environment in order to thrive, which we can create by adjusting our diet specifically to nourish and feed these bacteria. Fermentable carbohydrates and non-digestible fibres such as berries, leeks, onions, green bananas, legumes, green tea and dark chocolate all feed these strains, increasing your body’s ability to produce these all-important neurotransmitters. We also need a solid foundation of protein, specifically containing the amino acids tryptophan, (found in turkey, eggs, cheese, oats, and seeds), and phenylalanine and tyrosine (found in meat, fish, dairy, and legumes) for dopamine & norepinephrine (motivation & focus).

As well as feeding already established colonies of these bacteria, we can increase numbers in our microbiome by eating probiotic or fermented foods, such as kefir, natural live yogurt, sauerkraut, kimchi and kombucha, which all contain lactobacillus and bifidobacteria species.

This idea of psychobiotic therapy to treat depression has been replicated in clinical trials, successfully reducing signs in affected adults.

If you suffer from anxiety or depression, you can work with one of our expert practitioners at Remedy Clinic to uncover the underlying drivers that are causing this imbalance. Please don’t hesitate to get in touch with your questions.