Gut feelings: Could the health of your gut be influencing your mood?

We’ve all experienced ‘gut feelings’ and often rely on these when making big decisions. How many times have you asked someone “what’s your gut telling you?”. We also talk about our gut when describing our emotions. We get “butterflies in our stomach” when we’re nervous or excited and a “gut wrenching feeling” when we’re scared or worried.

These kinds of sayings have been around for a long time so maybe our ancestors intuitively knew there was a link between our gut and our brain long before scientists started looking into this. The science is catching up though and there’s now a whole body of research showing that our gut and brain do in fact talk to each other via the ‘gut-brain axis’. More on this later. First, let’s take a closer look at what’s going on in your gut.

A city of bugs

Did you know that you have trillions of microbes living in and on your body? Gross right?! Well actually, these little guys play a huge role in our health and we literally couldn’t live without them.

We have microbes (bacteria, fungi, viruses) throughout our entire gastrointestinal tract but the majority of them set up home in our large intestine. Under the right conditions, these microbes live symbiotically with us as their hosts and if we look after them, they will do the same for us. Think of yourself as a landlord to a city of bugs. Provide them with a nice, safe place to live with all the amenities they need and they will take good care of their home. Don’t look after the place and fail to keep up with the maintenance and they’ll either move out or they’ll rebel and start trashing the place!

Diversity is key

Our microbiome has a hugely powerful influence on our overall health. They take on the jobs that we as humans just can’t do on our own, like digesting our food and extracting and absorbing the nutrients from it; training and maintaining our immune systems (70% of our immune system is our gut!); extracting energy from our food (which influences our weight); regulating our blood sugar levels and hormones that control our appetites; communicating with other organs, including the brain. Quite an impressive CV!

Different species of bugs have different roles to play so diversity really is key when it comes to optimal health. Think of your gut as a tropical rainforest, a diverse ecosystem housing millions of different species which ensures that no one species becomes dominant and that there is the resilience to survive, even if one species is wiped out.

How does gut health influence mental health?

Our guts are often referred to as our second brain and for very good reason. They actually have their own nervous system called the enteric nervous system (ENS) which communicates with our central nervous system (CNS) via the vagus nerve. This is the main communication channel between our gut and brain and it’s this that we refer to as ‘the gut-brain axis’.

Messages can travel in both directions however, it is thought that about 80-90% of the signals are being sent from our gut to our brain, so the health of our gut really can have a profound influence on the health of our brain.

For instance, key mood regulating neurotransmitters such as serotonin (the happy one), dopamine (the pleasure one) and GABA (the calming one), are produced in the gut with the help of our gut bugs. If these are out of whack, production of these chemicals and the messages they send to our brain can also become out of whack affecting our mood, feelings and emotions.

Another way that the gut may contribute to our mental health is through inflammation. Our gut has a layer of mucus which acts as a barrier to the outside world. It’s like the bouncer at an exclusive club with a very selective entry policy. The only things getting through into our bloodstream should be nutrients and other beneficial metabolites, and those things that could be harmful to us such as undigested food, toxins and bacteria, should be denied entry and stay in the gut. If this barrier becomes compromised or ‘leaky’, these uninvited guests can slip through causing our immune system to launch an attack which means the release of inflammatory chemicals.

We know that inflammation is implicated in mental health conditions such as depression, anxiety, dementia and schizophrenia, and studies have shown increased markers of ‘leaky gut’ in those suffering with depression. It’s possible then, that this neuro-inflammation actually starts in the gut and that focusing efforts on improving gut health, could in turn help improve mental health.

It can also work the other way around. Let’s take stress as an example. When our body is under stress, it deprioritises functions that aren’t seen as essential, such as digestion. That’s why it’s so common for people to experience gut related symptoms such as irritability, constipation or bloating when they’re stressed.

It’s a bit of a chicken and egg situation as to whether poor gut health contributes to poor mental health or vice versa and there is certainly evidence for both. This is a fascinating area of research though and one that is fortunately growing all the time so watch this space!

Things can affect your gut

Sadly, many things that are all too common in our everyday lives can have a negative impact on our gut health. From medications (including antibiotics and over the counter painkillers like ibuprofen), exposure to xenobiotics from things such as pesticides and heavy metals, lack of quality sleep, being sedentary and stress, to poor diet, particularly one that is high in sugar, saturated fat and additives such as sweeteners, emulsifiers and other chemicals that have no place in our bodies (i.e. the typical Western processed diet!).

How to optimise gut health

It is possible to improve the composition of your microbiome and that has the potential to improve your mental health. A 2018 study looked at 17 people who were suffering from IBS, chronic constipation or chronic diarrhea who received a fecal microbiota transplant (transferring the stool of a healthy individual to the large intestine of a person with a health condition…..I know! Yuck!). 12 of the 17 reported significant improvements in their mental health symptoms including depression, anxiety and sleep, irrespective of any changes in their gut symptoms!

The good news is that you have the power to control the health of your gut without going to that extreme and it’s possible to change the composition of your microbiome relatively quickly. Making dietary changes has been found to have the biggest impact on influencing gut health so, in addition to avoiding the factors mentioned above, here’s my top dietary tips that your gut bugs will love you for:

Increase fibre intake

If you asked your gut bugs what their favourite food is, it would be fibre! As humans we can’t digest fibre so it arrives in our large intestines intact providing the main food source for our microbiomes. As fibre is broken down and fermented, short chain fatty acids are produced which promote healthy gut movement and function, regulate blood sugar balance and appetite, reduce inflammation and oxidative stress, and maintain the health of our gut barrier. The problem is that most of us are not eating enough fibre so our bugs are going hungry and our health is suffering as a result.

We should all be aiming for around 30g of fibre per day which would look something like; 5 portions of veggies, 2 portions of fruit, 3 portions of wholegrains, and 1-2 portions from things like legumes, nuts or seeds. A word of caution if you’re not getting anywhere near this amount at the moment……increase slowly and drink plenty of water or you may end up with some unintended gut related consequences!

Increase PREbiotic foods

These are foods that contain certain compounds that encourage the growth of beneficial microbes. In other words, they provide food for your gut bugs which helps them grow in numbers and diversity. Good sources of prebiotics include onion, garlic, leeks, asparagus, apricots, pomegranate, almonds, cashews, legumes and many more.

Increase PRObiotic foods and drinks

These contain large amounts of live, beneficial microbes (mainly bacteria). Think fermented foods and drinks that rely on microbes as part of the process, such as live yoghurt, sourdough bread, kimchi, sauerkraut, pickles, miso, kefir and kombucha. Don’t however think that it means you can drink endless amounts of beer and wine. Not all fermented foods and drinks contain probiotics!

Increase polyphenol rich foods

Polyphenols are special chemicals found in plant foods that are known to have many health benefits. They include anthocyanin found in berries (this is what gives them their beautiful red, purple and blue colours), resveratrol in red wine and grapes and flavanols in dark chocolate. Other great sources of polyphenols include coffee, black and green tea, flaxseeds, extra virgin olive oil and herbs and spices.

The bottom line is, eat a wide variety of plant-based foods and you will be serving your gut well!

Health really does start in the gut and this is why I often recommend stool testing to my clients, as understanding what is going on in the gut can provide the missing piece of the puzzle when it comes to optimising mental wellbeing.

If you’d like more information about the state of the art, comprehensive stool testing I offer, please get in touch for a chat.