Is stress wreaking havoc in your gut?

Is stress wreaking havoc in your gut?

As a naturopath I see a lot of people who present with digestive issues, whether it’s bloating or nausea after eating, food sensitivities, and even IBS. When I dig a little deeper, I find that the majority of these cases have one underlying factor in common. Yes, you guessed it…Stress!


Before we go any further we need to understand what ‘stress’ is, because it’s a term that’s used rather loosely in our society.

Stress can be defined as any disturbance to the body which requires adjustment or adaption to a new situation.

Thus, a wide range of events or conditions could be considered physiologically ‘stressful’ because they inspire a cascade of chemical and hormonal changes to occur in the body. These events include, but are not limited to, calorie restriction, poor nutritional status, surgery, sleep deprivation or poor quality sleep, excessive exercise, or strong emotional reactions such as anxiety, fear and worry.

Thanks to our modern high-stress culture, our stress response is activated so often that the body does not always have a chance to return to normal. This can lead to health problems resulting from too much circulating cortisol (our long-term stress management hormone).

Stress responses have evolved from the original “fight or flight” mechanism, designed to protect us from immediate physical danger, to chronic engagement of the fight or flight response as result of minor day-today stressors.



The gut barrier is the lining of our gastrointestinal tract (GIT). The GIT is basically one long tube from the mouth all the way to the rectum. So if you view it this way, the intestinal tract is exposed to the external environment, from harmful bacteria to food particles that need to be digested before being allowed into the body.

So we want to prevent our gut lining from becoming permeable. When working normally, the gut barrier functions like a sieve – only allowing particles into the blood stream that are beneficial, and keeping the things we don’t want, out. However, when the junctions between the gastrointestinal cells become loose, the intestinal lining becomes “leaky”. This is what’s known as intestinal hyperpermeability or “leaky gut”.

Researchers have known for a long time that severe physical stress such as trauma or surgery causes the intestinal lining to become “leaky”, but more recent research has started to look at the effect of chronic psychological stress on the gut barrier (1).

In one particular study, rats were repeatedly subjected to water aversion stress where they were placed on a platform surrounded by water. The researchers found that this is a mild stressor for the rats, similar to the type of chronic mild stress that we face on a daily basis. So what happened to these rats? They developed intestinal permeability that took several days of no stress to heal (2). So the question is when’s the last time you went several days without any stress whatsoever?

This research also showed that mast cells play a large role in the increased intestinal permeability that occurs as a result of stress. Mast cells are the cells involved in allergic reactions. They are responsible for releasing histamine when they become unstable or “degranulate”. This chemical causes the typical allergic response – runny nose, watery eyes, congestion, etc.

What’s interesting is that mast cells are also found along the gut’s mucosal wall and they contain CRH receptors. CRH is Corticotrophin Releasing Hormone and is released by the hypothalamus at the beginning of the “fight or flight” reaction. Since mast cells have CRH receptors it means that when the stress response is activated we’re going to have a high amount of CRH flowing through the body and attaching to mast cells. When this happens the mast cells lining our GIT will degranulate and release histamine and other chemicals into our gut.

Researchers also found that when the rats were bred to have no mast cells in their intestines, they didn’t show increased intestinal permeability under stress (1). This tells us that mast cells play a very important role in the integrity of the gut lining when we are dealing with stress, and that unstable and degranulated mast cells as a result of CRH leads to intestinal permeability.


Let’s now look at the immune system because the majority of our immune system is actually housed in the gut. Our gut-associated lymph tissue (GALT for short) makes up almost 70% of our immune system. And this is for good reason. Our gut is in constant contact with the external environment in the form of food particles and bacteria and therefore needs to have strong immune defences.

As part of the gut’s immune system, it secretes an antibody called immunoglobulin A (IgA), which is its’ first line of defence when it comes to all the substances the gut is in contact with. This important antibody is also produced in other parts of the body that are exposed to the outside world – it’s found in saliva, tears, and the lungs. Chronic stress reduces the production of secretory IgA, and because of this, it leaves us open to colonisation by pathogenic bacteria in the gut.

Studies show that students under academic stress have lower levels of salivary IgA than those under less stress (3). Up to two weeks after exam stress has dissipated, students still showed lower levels of salivary IgA with no indication of recovery. Relaxation exercises, on the other hand, actively increase IgA production (4).

Low IgA levels leaves us susceptible not only to infections in the gut, but also to infections in the rest of the body. Low IgA also gives bad bacteria the chance to take hold, changing our gut microflora.


This brings me to my next point. We all know that our gut bacteria is absolutely vital to our digestive health, but stress changes its composition in our gut, shifting it in a less favourable manner. Under chronic psychosocial stress, mice develop a condition called dysbiosis, the relative overabundance of bad bacteria coupled with low amounts of good bacteria in the gut (5).

This imbalance is associated with digestive problems like IBS and Crohn’s disease. Not only does stress alter the balance of our bacteria, it also reduces our gut’s microbial diversity. Interestingly, the less diverse our gut bacteria, the more likely we are to be overweight and have allergic diseases.


Stress is part of everyday life and only becomes pathological when it is severe or prolonged. As a naturopath, I develop effective treatment plans which improve an individual’s immediate and long-term response to stress. The naturopathic approach of combining herbal and nutritional medicine with lifestyle modification offers an effective solution for giving our bodies the necessary tools for mastering stress, preventing chronic disease and giving us optimal energy to meet life’s demands and to flourish.

~ Michelle


  1. Faries, P., Simon, R., Martella, A., Lee, M., & Machiedo, G. (1998). Intestinal Permeability Correlates with Severity of Injury in Trauma Patients. The Journal Of Trauma: Injury, Infection, And Critical Care44(6), 1031-1036. doi: 10.1097/00005373-199806000-00016
  1. Santos, J., Benjamin, M., Yang, P., Prior, T., & Perdue, M. (2000). Chronic stress impairs rat growth and jejunal epithelial barrier function: role of mast cells. American Journal Of Physiology-Gastrointestinal And Liver Physiology278(6), G847-G854. doi: 10.1152/ajpgi.2000.278.6.g847
  1. Deinzer, R., Kleineidam, C., Stiller-Winkler, R., Idel, H., & Bachg, D. (2000). Prolonged reduction of salivary immunoglobulin A (sIgA) after a major academic exam. International Journal of Psychophysiology, 37(3), 219-232. doi: 10.1016/s0167-8760(99)00112-9
  1. Pawlow, L., & Jones, G. (2005). The Impact of Abbreviated Progressive Muscle Relaxation on Salivary Cortisol and Salivary Immunoglobulin A (sIgA). Applied Psychophysiology and Biofeedback, 30(4), 375-387. doi: 10.1007/s10484-005-8423-2
  1. Bailey, M., Dowd, S., Galley, J., Hufnagle, A., Allen, R., & Lyte, M. (2011). Exposure to a social stressor alters the structure of the intestinal microbiota: Implications for stressor-induced immunomodulation. Brain, Behavior, And Immunity, 25(3), 397-407. doi: 10.1016/j.bbi.2010.10.023