A Gut Feeling? Trauma & Gut Health

The Brain-Gut Connection

Trauma and gut health

An estimated 100 trillion bacteria, viruses, fungi, archaea, and eukaryotic make up the gut’s microbiome.

The diversity & balance of the microbiome influence overall physical & mental health.  

Mental Health & Gut Microbiome

Several neurotransmitters (the body’s rapid chemical messengers), hormones (the body’s slower, but more widespread chemical messenger), and vitamins essential for mood & health are synthesized in the gut, and when balanced, contribute towards mental and physical wellbeing.  For example:

• Serotonin, (mood regulating neurotransmitter).

• GABA, (inhibitory & calming neurotransmitter)

• Dopamine, (neurotransmitter involved in reward and mood)

Gut microbiome significantly influences digestion, elimination & absorption of nutrients, hormones, metabolic health, nervous system functioning, immune system & systemic inflammation.

The brain, body, and gut microbiome are in constant communication through the vagus nerve, transmitting information from the body to the brain, known as 'bottom-up' communication (from body to brain, not 'top-down' from brain to body). This accounts for 80% of the body's internal communication. 20% is from the brain to the body.

The relationship between mental and gut health conditions are well documented.1 Trauma/chronic stress can adversely impact gut health, leading to changes in the gut microbiome, which in turn, can influence PTSD symptoms.2

PTSD/digestive/gut conditions

A 2017 study identified that Vietnam veterans with PTSD were three to eight time more likely to suffer from stomach ulcers, irritable bowel syndrome, and constipation. They also had double the chance of suffering from acid reflux.  3 

In 2018, a review of studies identified that people living with PTSD are 2.8 times more likely to have irritable bowel syndrome (compared to people without PTSD).  It remains unclear if PTSD leads to IBS or if PTSD and IBS share the same risk factors for susceptibility. 4 

The RACGP states that Australian veterans with PTSD were 77-81% more likely to undergo upper gastrointestinal procedures – such as endoscopies and ultrasounds – than those without PTSD.  Further commenting “Our studies continue to show how physical and mental health are interrelated. There needs to be more clinician awareness of the association between PTSD and gut symptoms". 5

Physical Exercised & Gut Health

Regular exercise helps managing stress and improving sleep quality & also supports the gut microbiome.  Additionally, exercise aids the production of hormones and neurotransmitters (which may alleviate PTSD symptoms) and regulates the body’s immune and inflammatory response. 6

Alcohol & Gut Health

Childhood adversity studies have identified a strong association between early childhood trauma and increased risk of alcohol dependence in later life.  Research indicates that chronic alcohol use can increase inflammation in the intestine (and throughout the body), which in turn can compound alcohol induced organ damage (in effect, creating a vicious cycle).7

Dietary Considerations

A study of 191 participants, found that those who adhered to a Mediterranean diet experienced fewer PTSD symptoms. Additionally, they identified that that the consumption of red and processed meats was positively associated with PTSD symptoms, and the consumption of plant-based foods was negatively associated with PTSD symptoms. 8

There is inconclusive research for the use of Omega 3 in moderating the mood disorder component of PTSD, with some studies identifying benefits and others identifying that the results were a placebo effect.

• Studies indicate that the Mediterranean diet (rich in vegetables, fruit, and fish) may assist in moderating PTSD symptoms.

• Try to eat unprocessed, whole foods.

• Limit refined sugar and saturated fat intake.

• Try to maintain a high fibre diet (e.g. whole flour bread, nuts, beans, cauliflower).

• Limit or eliminate alcohol intake (using alcohol to ‘block out’ or avoid distress / memories, indicates that you may benefit from trauma focused therapy).

The use of pre and probiotic supplements, whilst widely available in supermarkets, have not yet been medically proven in humans to be beneficial for PTSD related symptoms. 

Before commencing any diet or lifestyle change, including the commencement of pro/prebiotics, vitamins, and minerals, it is strongly recommended you consult with a suitable GP/Health Practitioner.

Probiotics & PTSD

Although research into this area remains limited and in its early stages, there are some tentative indications that the use of probiotics (foods or supplements that contains live ‘good’ micro-organisms) and prebiotics (typically high-fibre foods  that act as food for the probiotics) may play a role in the future treatment for PTSD/cPTSD.  For example, a small-scale study on mice provides evidence that probiotic treatment could improve the outcome of PTSD-induced depression and anxiety-like behaviour —the probiotic treatment improved depression, anxiety, and anhedonia, typical symptoms of PTSD (in mice). 9

Sleep and Gut Health

Sleep hygiene is another essential aspect of managing PTSD and gut health. Adequate and quality sleep is important for maintaining the balance of the gut microbiome. Poor sleep can disrupt the gut microbiome balance, potentially leading to increased gut permeability or leaky gut and affecting PTSD symptoms. 5

Exercise, healthy diet, stress reduction strategies, sleep, should all be considered as an important adjunct treatment for people living with PTSD/cPTSD, forming an important component in the holistic treatment of trauma.

Please note that this is an introductory blog on the relationship between trauma and gut health.  It is not intended as a comprehensive review of adjunct or dietary research and recommendations for optimal health or PTSD/complex PTSD treatment/symptom reduction.

For more information or to read our other blogs on trauma, PTSD and complex PTSD, visit www.vistatherapy.com.au or register for a 2-day trauma masterclass workshops in 2025.

To book an appointment for therapy with our trauma specialist, visit our 'Book appointment' page on our website.

References & Bibliography

1.     Person H, Keefer L. Psychological comorbidity in gastrointestinal diseases: Update on the brain-gut-microbiome axis. Prog Neuropsychopharmacology Biol Psychiatry. 2021 Apr 20;107:110209. doi:

2.     Yadav SK, Ahmad R, Moshfegh CM, Sankarasubramanian J, Joshi V, Elkhatib SK, Chhonker YS, Murry DJ, Talmon GA, Guda C, Case AJ, Singh AB. Repeated Social Defeat Stress Induces an Inflammatory Gut Milieu by Altering the Mucosal Barrier Integrity and Gut Microbiota Homeostasis. Biol Psychiatry Glob Open Sci. 2023 Mar 30;3(4):824-836. doi: 10.1016/j.bpsgos.2023.03.005. PMID: 37881577; PMCID: PMC10593959. Gallipoli Medical Research.  The Gut Reaction To PTSD.  Sourced from https://www.gallipoliresearch.com.au/2017/03/20/the-gut-reaction-to-ptsd/.  Sourced on 25.11.24.

3.     Healthline.  Can Post-Traumatic Stress Disorder (PTSD) cause irritable bowel syndrome?  Sourced from https://www.healthline.com/health/ibs/can-ptsd-cause-ibs.  Sourced on 25.11.24.

4.     RACGP.  New research uncovers major link between PTSD and gut problems. Sourced from https://www.racp.edu.au/news-and-events/media-releases/new-research-uncovers-major-link-between-ptsd-and-gut-problems.  Sourced on 25.11.2024.

5.     Yoshimura, H.  (2024).  Addressing Gut-Brain Connection in PTSD and Trauma Survivors through Functional Medicine.   Rupa Health.  Sourced from https://www.rupahealth.com/post/addressing-gut-brain-connection-in-ptsd-and-trauma-survivors-through-functional-medicine. Sourced on 25.11.2024.

10.1016/j.pnpbp.2020.110209. Epub 2020 Dec 14. PMID: 33326819; PMCID: PMC8382262.

6.     Bishehsari, F., Magno, E., Swanson, G., Desai, V., Voigt, RM.,Forsyth, CB., and Keshavarzian, A .  (2017). Alcohol and Gut-Derived Inflammation.  Alcohol Research Current Reviews.  Sourced from Alcohol and Gut-Derived Inflammation | Alcohol Research: Current Reviews (nih.gov).  Sourced on 27.11.24

7.     Ke, S., Wang, X., Ratanatharathorn, A., Huang, T., Roberts, A.L.,  Grodstein, F., Kubzansky, L.D.,  Koenen, K.,  Liu, Y.  (2019).  Association of probable post-traumatic stress disorder with dietary pattern and gut microbiome in a cohort of women.  Nature Mental Health, October 19, 2023, doi: 10.1038/s44220-023-00145-6

8.     Mohd Faiz Khan, Gopal Khodve, Sanjay Yadav, Keya Mallick, Sugato Banerjee.  (2024).  Probiotic treatment improves post-traumatic stress disorder outcomes in mice.  Behavioural Brain Research. Volume 476, 2025, 115246, ISSN 0166-4328, https://doi.org/10.1016/j.bbr.2024.115246. (https://www.sciencedirect.com/science/article/pii/S0166432824004029)

9.     Cloyd, J., (2024).  A Functional Medicine Protocol for Leaky Gut Syndrome.  Rupa Health.  Updated on 17.09.2024.  Sourced from https://www.rupahealth.com/post/a-functional-medicine-protocol-for-leaky-gut-syndrome.  Sourced on 10.12.24.