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Preventing the 3.30 Slump. Fatigue and the Gut Brain Connection

Posted By Jennifer Bishop  
15:00 PM

Do you ever feel like nodding off at around 3 to 3.30 in the afternoon?

Well you are not alone. But what is the solution to this snoozy feeling in the afternoon?

Could it be your blood sugar, poor sleep, stress or could it be your gut brain connection?

Many factors around your lifestyle, diet, health and gender will affect this feeling. However, in the last few decades much research on the gut brain axis has revealed profound influences on  energy levels, general health, mental health and work performance and functioning.

The GBA (gut brain axis) is a two way super communication highway and it strongly influences your feelings of wellbeing as well as your energy and digestion and our microbiome. The microbiome communicates with the brain through the vagus nerve, affecting not just food intake but also mood and inflammation response, according to a 2014 Experimental Medecine Journal review.

Your microbiome can be determined from an early age due to breastfeeding. However, some elements of it can be altered within a 24-hour period just by changing your diet. If you had the power to improve your energy levels, fatigue, work productivity and sleep just by changing your gut microbiome wouldn’t you?


What Exactly is the Gut Brain Axis?

The gut-brain axis (GBA) consists of bidirectional communication between the central and enteric nervous system, linking emotional and cognitive centers of the brain with peripheral intestinal functions. Recent advances in research have described the importance of gut microbiota in influencing these interactions, including stress response, memory and anxiety.


The vagus nerve a large part of this axis, carries information between the brain and the internal organs and controls the body's response in times of rest and relaxation. The vagus nerve is the primary control for the parasympathetic nervous system, opposite to the sympathetic nervous system's fight-or-flight response.

This large nerve begins in the brain and branches out in multiple directions to the neck and torso, where it's responsible for carrying sensory information from the skin of the ear, controlling the muscles that you use to swallow and speak and influencing your immune system.

This video below details how the vagus nerve works

No wonder, increased stress levels, poor diet and lack of sleep can damage this massive nerve.



Fatigue and the Unhealthy Gut

An unhealthy gut may contribute to sleep disturbances such as insomnia or poor sleep, and therefore lead to fatigue, poor performance or over time, chronic fatigue. Numerous studies in the past two decades have demonstrated links between gut health and the immune system, mood, mental health, autoimmune diseases, endocrine disorders, skin conditions, and cancer.

Autoimmune disease such as Crohns Disease, Irritable Bowel Syndrome (IBS) and SIBO all alter the gut wall and nutrient absorption causing fatigue. Additionally, food intolerances, and allergies also represent a significant issue for up to 50% of the population. Each of these can contribute to feelings of illness, poor digestion and fatigue as well as sleep disorder.

IBS is an incredibly common disorder with about 10-15% of the population being diagnosed with it. This is significant as research reports that over half of these people  reported serious fatigue, low stamina in work and leisure and socially.

IBS is also related to insomnia, which includes difficulty falling asleep, waking frequently and feeling unrested in the morning And poor sleep predicts more severe gastrointestinal symptoms the following day.


Food Intolerances

Getting the right foods and avoiding those that you maybe allergic or more likely sensitive to are key. Food intolerances maybe another gut brain reaction causing fatigue. Dairy, lactose intolerance is estimated to affect up to 65% of the worlds population.

Gluten is the general name given to proteins found in wheat, barley, rye and triticale. Gluten is a term that refers to a family of proteins known as prolamins. These proteins are resistant to human digestion. Several conditions relate to gluten, including celiac disease, non-celiac gluten sensitivity and wheat allergy.


Serious Disease and the Gut Microbiome

Researchers are now exploring how changes in the gut microbiome are associated with serious diseases such as Multiple Sclerosis, Parkinson’s and Huntington’s Disease. The Florey Institute have found the first evidence of disrupted gut bacteria in Huntingtons Disease patients. Of course, fatigue is one of the common symptoms in these diseases also.

The research points to the urgent need for follow-up studies in humans to validate the findings. The study provides even more evidence that the gut plays a significant role in diseases of the brain.


Sleep Disturbances and Fatigue

There is no substitute for a good night’s sleep, and it now seems that the lifestyle disorders that plague modern society, such as type 2 diabetes, hypertension, and heart disease, are linked to low-grade inflammation going back many years before symptoms appear.

Whilst sleep remains a relative mystery. Current research shows, your brain clears out toxins during the night. So, if you cut your sleep short, your brain can fall behind in this vital detoxification. The body and brain have been designed to sleep at night, so shift workers who sleep in the day develop unbalanced biorhythms.

The majority of the body's serotonin, a hormone that affects mood and sleep, is produced in the gut. So gut damage can impair your ability to sleep well and may lead to chronic fatigue. Serotonin is the neurotransmitter responsible for stimulating the parts of the brain that control sleep and waking. Whether you sleep or wake depends on what area is stimulated and which serotonin receptor is used.

Getting enough Tryptophan is important as it is the precursor to Serotonin production. Eating foods rich in tryptophan such as oats, nuts, seeds, fish/turkey, soy or cheese, are important for serotonin.



If you are feeling fatigued and or have disordered sleep there maybe a variety of factors influencing this including stress, anxiety, sleep hygiene or other lifestyle related factors. However, your GBA and microbiome may have a key role to play, as research reports more and more information on food malabsorption, intolerance and autoimmune disease influencing levels of fatigue and sleep disorder.

If you are regularly suffering from the 3.30 slump, the best place to start is of course a discussion with your GP.

If you would like to learn more about lifestyle causes of fatigue and strategies to improve energy come along to MLT’s Anti- Snooze webinar led by naturopath and corporate wellbeing coach , Tim Altman. Register here:


Disclaimer: Nothing in this article purports to be medical advice. For specific and personalised medical advice please see your doctor.