Written by Brittani Kolasinski - Clinical Nutritionist (BHSc NutMed), indulger and lover of all things food!
Have you ever noticed the changes to your appetite depending on your mood? Or the fluttering feeling in your stomach at the thought of public speaking, or those first date nerves? – well, it may or may not come as a surprise to you that our gut and brain are more closely connected than we first thought, and, the science is all confirming this; referring to it as our ‘gut-brain connection’. They’re even going so far as to call our stomach the ‘second brain’. With this is mind, let us chat about all things ‘gut and brain’ and look at how one affects the other and vice versa…
An Overview of digestion
Digestion begins well before food even touches our lips. The very thought of food, the sight, the smell while it's cooking - this all begins to stimulate salivary enzyme secretion within the mouth, which ultimately begins the process of digestion itself. This process is referred to as the ‘cephalic phase’. These enzymes help to break down the food as we chew and then swallow, enjoying every bit! This continues as it reaches the stomach, with hydrochloric acid and other enzymes combined with muscular movement to further break down these larger molecules to smaller ones. Following this it will enter our small intestine, which is where the majority of our absorption occurs, allowing our micronutrients and broken-down macronutrients (carbs, fats, proteins) to be absorbed into the bloodstream. Then they can travel throughout the body to their destinations providing our bodies with the fuel and nutrients it needs to function optimally.
Introducing your microbiome
From the small intestine, undigested fibres enter the large intestine which houses majority of our bacteria, referred to as the ‘microbiome’. These bacterias ‘feed’ (they actually ferment, but to think of it as feeding is probably more simple) on these fibres, creating energy for the bowels and other substances maintaining the health of our body as a whole.
In saying this, it is vital to eat a fibre-rich diet to ensure that the health of our microbiome is in-tact and promotes diversity of different strains of beneficial bacteria. In turn, a diet rich in simple sugars and processed foods actually feeds the ‘bad’ kinds of bacteria, promoting their growth. This can lead to issues with candida overgrowth (yeast infections/thrush), inflammation, weakened immunity and other concerns relative to our mental health such as depression and anxiety (Sonnenburg & Sonnenburg, 2014; Flint et al, 2014; Jameel et al, 2014; Brymora et al, 2011).
With new researchers stating that our gut bacteria may help to regulate and reduce conditions such as anxiety, poor mood, cognition and pain, it’s now thought that modulation of the colonies of beneficial bacteria within our bowels may be a strategy for treatment of more complex central nervous system disorders (Cryan & Dinan, 2012; Reardon, 2014).
Serotonin, for example, is a neurotransmitter responsible for feelings of happiness and it promotes bowel motility & digestive function. It's also the precursor to melatonin (required for sleep). It is one of the many products that our microbiome provide, in fact, 97% of our serotonin is produced in our guts! (Kim & Camilleri, 2000).
Impact of inflammation
When inflammation is present within the gut it creates these ‘gaps’ within the lining of our small intestine, allowing not just our broken-down macronutrients and micronutrients to get into the bloodstream, but also larger, toxic particles to enter that ideally should be eliminated via the bowels. When these are freely released into the bloodstream they can end up crossing our blood-brain barrier, resulting in neuro-inflammation. This can contribute to feelings of depression, as well as other more chronic conditions such as Alzheimer’s & dementia (Kelly et al, 2015; Eikelenboom et al, 2010).
The effects of stress
Stress will also impair digestion and results in inflammation. High stress can also deplete our levels of beneficial bacteria, and when our sympathetic nervous system (our fight or flight response) is enhanced our body will slow down other processes, such as digestion, menstruation in women, immune function and more (Moloney et al, 2014).
With the day and age we live in we are constantly stimulated and can go day to day in this mild, chronically stressed state. With working hard and long hours, being contactable via phone or email 24/7, bombarded with traumatic global news, time constraints and other relationship or family concerns to add to the mix, its no wonder our bodies are perceiving this constant stress as a threat, and therefore conserving energy from other functions (as mentioned above) to get you away from the threat itself, when sadly, the very threat is our constant hustle and daily life!
When we are eating in this stressed out state our digestive function is compromised. Less hydrochloric acid is produced for one, reducing our digestive capacity and resulting in heartburn, indigestion, bloating, discomfort and reflux. We might also be eating on the run or consuming ready-made meals which leaves out the whole first stage of digestion - the cephalic phase. For a large number of us this is a common daily occurrence and with the reduced digestive capacity, our absorption of nutrients is also reduced (Mönnikes et al, 2001).
These nutrients are needed for the body to function, by providing the cofactors for biochemical reactions to take place, for neurotransmitter synthesis – to optimise brain function and in turn help us to tolerate some of the stressors. Mindful eating is a brilliant practice that brings the focus back to our meal, the present time, how we are feeling while we eat, chewing slowly, enjoying every moment – not in front of the TV blinded to the mouth pleasure you're chowing down on (Dalen et al, 2010).
What else reduces stress?
-Movement - Studies have shown the benefits of exercise on reducing stress and improving brain function, memory and learning abilities. This is in part due to the production of BDNF (brain-derived neurotrophic factor) (Huang et al, 2014).
-Getting outdoors - Also referred to as ‘earthing’ actually has profound beneficial effects on our stress response, immune function as well as reducing inflammation (Oschman et al, 2015). Try taking your lunch break outside if you can, waking a bit earlier to get outdoors first thing in the morning, or even in the evening, walking barefoot through the park or just finding an inner-city garden to sit and let your mind wander.
-Meditation & relaxation – however that looks for each of us individually. Meditation & mindfulness has an impact on reducing inflammation, taking us out of this sympathetic nervous system dominant state and has also been shown to provide anti-aging benefits to our brains – incredible stuff! (Edenfield & Blumenthal, 2011; Hölzel et al, 2011; Jerath et al, 2006).
It makes a world of difference to take just 10 minutes out of your day, wake that little bit earlier to get in a walk, take time to sit and breathe deeply. It is vital to incorporate these soul-nourishing practices into the day, we are all worth the extra effort.
Take home notes:
For those food-loving, health conscious, eager-to-learn-more types you can find referenced articles, like this one, blog posts, recipes, food pics + more here: