Nutrition
Gut Feelings By Tanya Huber
You know that ‘ gut feeling ’ you sometimes get , or those butterflies in your tummy ? Those feelings are actually a real thing , and come about because of the link between your gut and your brain .
In the last couple of years , there has been extensive research on the connection between our brains ( the central nervous system ) and our gut . The gut-brain axis is the term that has been coined to describe this connection . So , what exactly is the gut-brain axis ? Simply put , it is a two-way communication pathway between the gut and the brain . More scientifically , it is a bi-directional communication channel between the enteric nervous system ( ENS )* and the central nervous system ( CNS ). Due to these pathways being bi-directional , communication is able to be passed from the gut to the brain and vice-versa . * The ENS is part of the peripheral nervous system ( PNS ), which is found in our gastric system .
The reason we need a two-way communication channel is because our body is complex and has several systems in place to maintain the homeostasis , the body ’ s need to maintain a certain state of equilibrium , in order to keep it functioning optimally and to maintain life . One of these systems is the gutbrain axis . Our brain needs to receive signals from the gut in order to do its job , and vice-versa . For example , when we require energy , the hormone ghrelin is released to stimulate hunger , and this triggers behaviours like that rumble we hear in our stomach .
When we eat , the hormone leptin is activated , and this will signal to the brain that we are full .
How the Gut-brain Axis Works
There are a number of biological networks that are involved in the two-way communication between the brain and gut . These biological networks include the neural system , the endocrine system , the immune system and metabolic systems .
• The Neural System : The vagus nerve , the longest and most complex nerve that connects the brainstem to the rest of the body , is the main pathway between the gut and the brain . The communication occurs through the autonomic nervous system , which controls automatic functions in the body . Within this system are two separate sub-systems , the parasympathetic ( PNS ) and sympathetic ( SNS ) nervous systems .
The PNS controls the digestive tract , respiration and heart rate functioning . It is also known as the “ rest and digest ” system . The SNS is responsible for activating the “ fight or flight ” response in the body that increases one ’ s alertness , blood pressure , heart rate and rate of breathing . The activation will occur in the presence of a stressor . These neural systems have an important role in gut function : When the SNS is activated , all the blood will move from the gut and into the peripheral muscles ( in order for us to “ fight or flight ,” and thus digestion is halted . When the PNS system is activated , the functionality of the gut is also compromised .
• The Endocrine System : This systems produces hormones that are secreted by glands . Our GI tract has many glands that produce hormones that are transported in the blood to our brain . One of the main hormones secreted in the gut and then transported to the brain is Peptide YY , which is released after we have eaten , in order to stimulate satiety , which basically means to tell us that we ’ re full and should stop eating .
• The Immune system : About 70 % of our immune system can be found within the GI tract ! This is why having a healthy gut is so important for our immune health . Many of these immune cells also play a role in the gut-brain axis .
• Microbiota-gut-brain axis : Research has suggested that the gut microbiome plays an important influence on the gut-brain axis . The gut microbiome is made up of trillions of microorganisms that live in our digestive tract . These microorganisms are mainly different species of bacteria , but there is also a diverse ecosystem of many different species of yeasts , viruses , protozoa , archaea and parasites . Unbeknown to us , these microorganisms are working symbiotically with the body to maintain a healthy body and mind . But that ’ s a topic ( that involves lab rats in germ-free environments ) for another day !
Images : Shitterstock & Pexels
Tanya Huber is a Johannesburgbased dietitian with a passion for mindful eating , women ’ s health and helping people to be the best version of themselves . Her practice focuses mainly on weight-loss , chronic disease such as high cholesterol and diabetes , Polycystic ovary syndrome ( PCOS ) and mental health . She believes in changing habits and reforming one ’ s mindset in order to have a healthy relationship with food , because food is life – literally and figuratively . More info at www . tanyahuber . com .
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