The gut-brain connection
If you’ve ever had ‘butterflies’ or felt your stomach 'flip', you already know that your brain has a direct line to your gut. This intimate bi-directional relationship between the brain and the gut means that not only can you feel what’s happening in the brain in your gut, i.e. nerves, butterflies, IBS symptoms, but what’s happening in our gut has a profound affect on your brain, leading to disorders such as poor cognition, anxiety and depression [1].
There are several ways in which this happens.
The gut microbiome: Gut bacteria.
The immune system: Including GALT (Gut associated lymphatic tissue).
Neurotransmitters: Chemical messengers.
The vagus nerve: Major nerve between gut and brain.
The gut microbiome
The microbes in your gut directly affect our brain chemistry in so many ways. They make chemicals which affect the brain; they make short chain fatty acid which regulate things like your perception of hunger, and maintain the blood brain barrier (the barrier which protects the brain by filtering what can get to it). AND certain microbes can make Lipopolysaccharide (LPS) toxic when passing through the gut wall, causing systemic inflammation, including brain inflammation and all the symptoms that come with it. LPS has been associated with severe depression, Alzheimer’s and schizophrenia [2].
So when our microbiome becomes dysregulated the result can be mood disorders, loss of cognition, brain fog as well as weight gain.
You can help optimise your microbiome. It likes a lot of fibre, resistant starch, such as sweet potatoes and potatoes, and polyphenols (plant chemicals). Get as much diversity and colours of plants across the week (aim for 25-30 different plants). It dislikes toxins, including alcohol, junk food, and stress.
The immune system
The immune system ‘headquarters’ sit behind the one cell thick wall that is the the gut lining. It communicates with gut microbes through the wall in order to learn about the external environment and identify any potential threats. Once a baddie is identified the immune system mounts an inflammatory response [3].
Eating an unhealthy Western-style diet sets off alarm bells and causes widespread inflammatory damage. Food sensitivities or intolerances can disrupt the microbiome and lead to gut permeability (leaky gut’), the immune system is activated as ‘foreign’ particles escape out of the gut and enter the bloodstream. Imbalances can lead to brain fog (a symptom of brain inflammation) and mood disorders, long term this can result in more serious brain conditions such as depression, Alzheimer’s, dementia as well as numerous other health conditions.
What you can do. What we eat and drink is constantly being monitored by our immune cells. Alcohol is toxic and highly inflammatory for both gut and brain health, you’ll know this so very well if you’ve had a hangover. Caffeine can promote anxiety and panic disorder, depending on how you personally metabolise caffeine. AND the brain is 60% fat, so make sure you are eating enough good fats to support brain health.
Neurotransmitters
Produced in both the gut and the brain, these are the chemicals which control feeling and emotions, like serotonin and Gamma-aminobutyric acid (GABA). Serotonin, which affects happiness as well as our body clock and sleep, is mainly produced in the gut.
Other jobs it performs are gut motility an important part of good digestion. An impaired gut means impaired happiness and sleep as well as poor digestion. A poor functioning gut could be the reason why you you feel down AND serotonin converts to melatonin (which helps you get to sleep) so now you have low mood and poor sleep [4][5].
GABA is responsible for inhibiting neural excitability and so controls anxiety, helps the body to relax and sleep well. It is produced by the gut microbes (Lactobacillus and Bifidobacterium), and so when we have a poor microbiota we can feel more anxious, on edge and unable to cope. A lack of GABA production can be one of the reasons people reach for external inhibitors, such as alcohol to make them feel calmer and help them to relax [6][7].
The Vagus Nerve
The vagus nerve is the major nerve that runs between the gut and the brain and transmits information about stress levels and how the body should be responding, moving between sympathetic (fight or flight) and parasympathetic (rest and digest) states.
If you’re spending a large part of your day stressed, angry, overwhelmed, and/or anxious the body de-prioritises digestion, in favour of inflammatory processes, increased blood pressure, quickening of your heart rate and the availability of sugar in case you need to run, defend yourself and potentially get injured. This is why chronic stress can lead to digestive problems as well as contributing to a whole range of modern health issues. The effects of stress on the health of the physical body cannot be over emphasised. People often find IBS symptoms ease on holiday and this could be part of the reason why [8].
Ways you can stimulate the Vagus nerve to budge it back over to the parasympathetic state:
Abdominal breathing exercises.
Being outdoors in green country space.
Social enrichment (being around others and avoiding isolation).
Singing, humming, playing music.
Cold exposure (e.g. cold water swimming, cold showers etc.)
Laughter (i.e. ‘belly laughter!’).
Exercise.
Knowing more about how this works can be such a game changer. For many years now, people have been told that their mood disorders are caused by a chemical imbalance and given a medication to rebalance the chemistry. But what is causing this chemical imbalance is really the important and interesting part of the puzzle. And think about how many people are told that they have IBS by their GP, essentially “there’s nothing we can do”, “it’s in your head” etc.etc.
Being aware of how this works at a physical level gives us a much better chance of improving our long term health by rebalancing our bodies. Feeding them the right foods, getting outside, exercising, reducing stressors and optimising sleep. Taking a holistic approach to gut and brain symptoms together makes perfect sense. They are so closely connected. Everything in the body is connected which is why it’s so crazy that we’ve divided it into separate systems and treat them independently, our bodies are just so much more complicated than that.
Get in touch if you’d like help healing your gut and regaining a clear mind.
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