Understanding Stress and Gut Health: The Vicious Cycle

Stress- something we all expericence in day to day life. Stress is often linked to many different physical and mental health conditions. The way that most people percieve this is that if they could do things better, be better at coping, mentally stronger then they would be healthier. We do tend to blame ourselves and beat ourselves up about not being good enough. This perception is not only incorrect but is also very damaging to us. The major issue is that our nervous system developed to cope with the conditions in which we lived as tribespeople, not for the stresses of modern life.

Humans are not meant to live in a constant stress state.  Think of a tribesperson back 15,000 years ago.  There would be a sudden threat – imagine a tiger.  You would experience a sudden surge of cortisol (hormone to activate stress response) and adrenaline.  The part of the brain that analyses and reacts to stress would signal to the glands to produce these hormones  – This is known as the HPA axis and stands for the hypothalamic-pituitary-adrenal axis.  The hormones cause many changes in the body, and these changes are designed to enable us to meet the threat we are under.  Blood supply is diverted to prioritise the skeletal muscles, heart and lungs.  This enables us to flee away from or fight the threat.  In this state the digestive system is not a priority and it has a significant drop in blood supply.  In very severe stress, it is common for the gut to want to empty – diarrhoea  and vomiting can happen.  The diarrhoea aspect of IBS can come from this mechanism.  The other common response is to experience a stop in their digestion, experienced as reduced gastric emptying and/or constipation.   The drop in the blood supply to the gut has a large impact on the gut microbiome.  The beneficial bacteria in our gut are vital for our gut health, immune health and brain health.  Common beneficial bacteria such as the lactobacillus and bifidobacterium are aerobic – oxygen dependent.  When we are in a stress response, the drop in oxygen to the gut lining changes the balance of gut bacteria very quickly – within minutes.  We lose beneficial bacteria and have an increase in the more harmful, anaerobic bacteria.  These harmful bacteria cause inflammation and damage to the gut lining and release bacterial toxins such as lipopolysaccharides (LPS).  The gut can become leaky, allowing bacteria, bacterial toxins and food particles into the blood stream.  The other impact of this low oxygen state in the gut is that the gut lining then also receives less oxygen, and this leads to a loss of the integrity of the gut barrier.  It becomes leaky, allowing substances across the gut membrane into the blood that would not normally cross.   In normal short bursts of acute stress, this is reversible.  The problem is when you are under sustained chronic stress, there is no repair time to deal with the damage, and it builds into a far bigger problem.

The impact of LPS, bacteria and incompletely digested food getting into the blood stream is large.  The immune system becomes activated to deal with the threat from the gut, leading to low level inflammation throughout the body, and this also affects the brain.  Anxiety, depression,  many autoimmune conditions and  degenerative disease are very much linked to imbalanced gut bacteria (dysbiosis)  and leaky gut.

People with healthy guts who are injected with LPS experience social withdrawl, fatigue, low mood and anxiety within hours.  For those with leaky gut and dysbiosis the constant LPS exposure leads to many brain effects – anxiety, depression, problems coping with stress, fatigue, brain fog and loss of sense of self are all really common. 

It becomes a vicious cycle – with the constant stress keeping the gut bacteria imbalanced, and the gut leaky, leading to LPS driven immune activation, inflammation, brain inflammation, leading to increased problems coping with stress, more stress, more oxygen deprivation to the gut, more dysbiosis and so on. 

 There are 4 major areas that need working on to fix this issue:

  • Gut bacteria balance
  • Gut lining repair
  • Nutritional and herbal support of the stress response
  • Cognitive/ brain based support of a healthy stress response