Why stress is so bad for your gut

It used to be generally held wisdom that stress gives you ulcers. Then a smart Australian found that a bacterium called Helicobacter pylori was able to directly cause ulcers. This was a pivotal discovery – but does it mean we should throw out the baby with the bathwater? It is important to acknowledge the extent to which stress really does harm your gastrointestinal tract. While other (often more direct) causes are continually discovered, don’t forget about stress!

So what are some of the negative effects of stress on your gut?

The concept of the ‘’brain-gut axis’’ is important here. The brain and the gut are very closely linked and the brain affects the gut in a variety of ways. However, the gut has a huge number of nerves – more than in the spinal cord. This is sometimes known as the ‘’gut mini-brain’’ or the ‘’second brain’’. This ‘’second brain’’ can initiate and perpetuate many of these effects itself – which is what makes gut function so complex

Some of the effects of stress on your gut are:

1) changes in gastrointestinal motility

Stress affects the movement of food through your digestive tract. It can speed it up, slow it down or cause uncoordinated movement, resulting in spasms or cramps.

2) increase in visceral perception

This means that stress makes you more sensitive. It makes you feel every little movement and every little sensation more strongly than normal.

3) changes in gastrointestinal secretion

Stress alters the production of hydrochloric acid, digestive enzymes and bile. Normal amounts and normal timing of production of these is critical for healthy, comfortable bowel function.

4) increase in intestinal permeability

Increased permeability of the intestinal wall is colloquially known as ‘’leaky gut’’, but is a well-established medical fact in various gut conditions and systemic conditions. It can increase your potential for allergic reaction and other forms of immune activation.

5) negative effects on regenerative capacity of gastrointestinal mucosa and mucosal blood flow

The mucosa is the protective inner lining of your gut. Stress affects its ability to heal quickly, and affects the circulation that keeps it healthy.

6) negative effects on intestinal microbiota.

Intestinal flora, or the ‘’good bugs’’ that keep your gut healthy, get (deservedly) quite a lot of press. Stress depletes these ‘’good bugs’’ within hours.

7) Immune effects

Mast cells are chemicals that translate the stress signals into the release of a wide range of neurotransmitters and proinflammatory chemicals called cytokines, which can significantly affect gut function.

Does all this sound like irritable bowel syndrome (IBS)? Not surprisingly, interventions that target stress have been shown to help IBS. For example, there is strong evidence for the benefits of mindfulness meditation, cognitive behavioural therapy and gut-directed hypnotherapy in IBS.

I don’t want to imply that IBS, or other gut issues, are ‘’all in the mind’’. Future posts will focus on some of the specific pathophysiology behind IBS. However, the effects of stress on the gut should not be underestimated. It appears that the irritable bowel is…well, literally irritable!



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