Is Anxiety Causing Your Poor Gut Health?

The relationship between anxiety and gut health appears to be bidirectional. For decades, researchers have believed irritable bowel syndrome (IBS) and anxiety are closely linked. The symptoms of IBS can trigger anxiety, while anxiety can provoke abdominal pain, changes in bowel motility, bloating and nausea. Moreover, anxiety can influence several processes such as the gut-brain connection, serotonin signalling and gut bacteria.

The Gut-Brain Axis

The brain and digestive system communicate via the parasympathetic, sympathetic and enteric nervous systems. This is referred to as the gut-brain axis. The parasympathetic nervous system is comprised of a network of nerves responsible for controlling digestion and relaxation. It relaxes sphincter muscles in the digestive tract to increase digestion while slowing down the heart rate and conserving energy.

The sympathetic nervous system is responsible for the ‘flight or fight’ response. In response to a perceived threat, blood flow in major muscle groups are stimulated, pupils are dilated, sweating and heart rate increases and digestion is slowed down. In other words, bodily functions deemed non-essential are down-regulated to direct energy towards escaping the threat.

Both the parasympathetic and sympathetic nervous systems alter gut function through their influence on the enteric nervous system. The enteric nervous system is located in the gut and is often called ‘the second brain’. This is why many researchers have hypothesised that anxiety leads to poor digestion and vice versa.

Anxiety causes arousal of the sympathetic nervous system which then decreases gut motility, leading to abnormal bowel movements like constipation or diarrhoea, abdominal pain, reflux and nausea.

Altered Serotonin Signalling

Serotonin is a neurotransmitter responsible for feelings of calm, happiness and emotional stability. On estimate, 95% of serotonin is located in the digestive tract. It stimulates the enteric nervous system to promote healthy digestion. When food enters the mouth, taste buds send signals to nerve cells that trigger serotonin release. Serotonin then mediates a process called peristalsis, which moves food through the digestive tract. Low levels of serotonin are found to cause constipation. Individuals with anxiety tend to have low levels of serotonin, altering gut motility.

Variances in Gut Flora

The bacteria in the gut directly influence the gut-brain axis. The relationship between gut flora and anxiety is bidirectional. Physiological stress and anxiety, as well as poor diet and lifestyle habits, damage good gut bacteria, while poor gut bacteria can also increase anxiety. A lack of fibre, consuming processed foods, foods high in sugar and additives, as well as continuing to consume allergens and food intolerances promotes harmful gut bacteria and increases inflammation, further damaging the delicate balance of microbes as well as the gut wall.

If you’re struggling with anxiety or digestive issues, get in touch. I’d love to help you!

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References

Carabotti, M., Scirocco, A., Maselli, M. A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of gastroenterology, 28(2), 203–209.

Clapp, M., Aurora, N., Herrera, L., Bhatia, M., Wilen, E., & Wakefield, S. (2017). Gut microbiota's effect on mental health: The gut-brain axis. Clinics and practice, 7(4), 987. https://doi.org/10.4081/cp.2017.987 

Hechtman, L. (2019) Clinical naturopathic medicine. Chatswood, NSW: Elsevier.