vagus nerve Archives • Alison Mitchell Naturopath https://www.naturopathnsw.com.au/tag/vagus-nerve Find information about naturopathy, my clinic and myself as a practitioner Mon, 04 May 2026 05:00:07 +0000 en-US hourly 1 https://wordpress.org/?v=7.0 What you need to know about ADHD and gut health https://www.naturopathnsw.com.au/adhd-guthealth https://www.naturopathnsw.com.au/adhd-guthealth#respond Mon, 04 May 2026 04:58:35 +0000 https://www.naturopathnsw.com.au/?p=33404

If you or your child has ADHD, the gut might be a bigger piece of the puzzle than you'd expect. Here's what the research says about the gut-brain connection, the microbiome, neuroinflammation, and how naturopathic support — including microbiome testing — can help.

The post What you need to know about ADHD and gut health appeared first on Alison Mitchell Naturopath.

]]>

TL;DR
  • The gut and brain communicate constantly via the gut-brain axis and vagus nerve — and for many people with ADHD, the gut is a significant piece of the puzzle.
  • The gut microbiome produces around 90% of the body’s serotonin, as well as dopamine precursors and calming neurotransmitters like GABA.
  • Compromised gut lining (leaky gut) can trigger neuroinflammation that directly impacts focus, mood, and behaviour.
  • Microba gut microbiome testing can show us exactly what’s happening rather than guessing — and help build targeted, effective support.

Why the gut keeps coming up in ADHD

If you or your child has ADHD, chances are most of the focus so far has been on the brain. Medications, strategies, routines, sensory tools. And all of that absolutely has its place. But there’s another system worth paying serious attention to, and it lives a lot further south.

The gut.

Over the last decade, research into ADHD gut health has grown enormously. What’s emerging is genuinely fascinating: the gut communicates constantly with the brain, produces a significant portion of the body’s neurotransmitters, and houses an immune system that can either support or undermine how we think, focus and feel. When the gut is struggling, the brain often is too.

In clinic, I see this pattern regularly. Kids and adults with ADHD who also deal with constipation, bloating, food sensitivities, or a history of frequent antibiotic use. It’s rarely a coincidence.

Gut health isn’t separate from brain health in ADHD — they’re part of the same conversation.

The gut-brain axis: a two-way conversation

The gut-brain axis is a sophisticated communication network linking the digestive system and the central nervous system. It works through the vagus nerve, the enteric nervous system (the gut’s own independent nerve network), immune signalling, and hormonal pathways.

The vagus nerve is the superhighway of this system. Here’s what surprises most people: roughly 80 to 90 percent of the signals travelling along it go from the gut up to the brain, not the other way around. The gut is quite literally briefing the brain all day long.

For people with ADHD, vagal tone — how efficiently the vagus nerve functions — is an area of growing research interest. Poor vagal tone has been associated with difficulty regulating the nervous system, increased impulsivity, emotional dysregulation, and reduced attentional control.

The enteric nervous system adds another layer. This network of over 500 million neurons lining the gut wall operates largely independently of the brain. When its environment is disrupted, the signals it sends upstream change accordingly.

The microbiome and ADHD: what your gut bacteria are doing

The gut microbiome — the trillions of bacteria and other microorganisms living in the digestive tract — has an outsized influence on brain function. Here’s how:

Serotonin production

Around 90–95% of the body’s serotonin is made in the gut. Serotonin influences mood, sleep, impulse regulation, and is a precursor to melatonin. When the microbiome isn’t producing adequate serotonin, all of those areas are affected.

Dopamine precursors

Dopamine is the neurotransmitter most directly implicated in ADHD. While dopamine itself doesn’t cross the blood-brain barrier, gut bacteria influence the availability of the precursors that do — including L-DOPA.

GABA

GABA is the brain’s primary calming neurotransmitter, playing a key role in reducing anxiety and supporting focus. Certain gut bacteria are involved in its production — and these species are consistently lower in people with ADHD.

Short-chain fatty acids

SCFAs like butyrate are produced when gut bacteria ferment dietary fibre. Butyrate feeds the gut lining, supports blood-brain barrier integrity, and has anti-inflammatory effects in the central nervous system. Altered SCFA profiles are consistently found in children with ADHD.

What the research says

Studies consistently find distinct microbiome profiles in people with ADHD — lower Bifidobacterium, lower Lactobacillus, and lower Faecalibacterium. A 2025 meta-analysis also found a 63% increased risk of IBS in people with ADHD, covering data from over 175,000 individuals.

Leaky gut, neuroinflammation, and ADHD

The gut lining is designed to be selectively permeable — allowing nutrients through while keeping bacteria, toxins, and larger molecules out. When that lining becomes compromised (leaky gut), things get through that shouldn’t.

This triggers an immune response. Inflammatory signalling compounds called cytokines increase in circulation, and inflammation begins to affect the brain as well as the gut. This state of neuroinflammation is increasingly understood as a meaningful contributing factor in ADHD symptoms.

The current model gaining traction in research: gut dysbiosis leads to increased intestinal permeability → systemic inflammation → impaired blood-brain barrier function → neurological environment associated with worsening of symptoms associated with ADHD. It’s not the whole picture, but it’s a significant part of it.

Signs that gut health may be contributing to ADHD symptoms: frequent digestive complaints, history of repeated antibiotic use, significant food sensitivities, strong sugar or processed food cravings, sleep difficulties, mood instability or anxiety alongside ADHD, and history of formula feeding or caesarean birth.

Microbiome testing: actually seeing what’s going on

One of the most valuable things we can do when ADHD and gut symptoms overlap is to look at what’s actually happening in the microbiome — rather than applying a generic protocol and hoping for the best.

This is where I find gut microbiome testing genuinely useful. I currently use Microba, a gut testing service that uses deep shotgun metagenomic sequencing — a significantly more detailed method than standard testing. Rather than just identifying which bacterial families are present, it can identify bacteria at the species and strain level, measure functional capacity, and assess markers like SCFA-producing potential and inflammation-related species and metabolites.

What Microba testing can show

  • Microbiome diversity and composition
  • SCFA-producing bacteria and estimated butyrate production capacity
  • Presence of inflammatory or dysbiotic species
  • Markers of intestinal permeability risk
  • Markers associated with poor motility, inflammation, altered immune response, and there are some markers associated with an increased likelihood of mood issues

Testing is done at home with a stool sample and returned to the lab via post — straightforward for both adults and kids. The results are detailed but translated into accessible language, which I find really useful for explaining findings to patients.

This information takes the guesswork out of gut support. Rather than applying a one-size-fits-all approach, we can see exactly where the gaps are and tailor support accordingly — specific probiotic strains, prebiotic foods, dietary shifts, and targeted herbal or nutritional support where indicated.

It currently costs ~$400-$500 depending on which level of test you choose which is not feasible for some people, but certainly gut health work can still be done without this, just not with the same level of fine tuning.

 

Related Reading
The root causes of ADHD — a naturopathic perspective

 

Common questions about ADHD and gut health

Does gut health affect ADHD?
Yes. Research consistently shows that people with ADHD have distinct gut microbiome profiles compared to those without the condition. The gut produces key neurotransmitters including serotonin and dopamine precursors, communicates directly with the brain via the vagus nerve, and influences neuroinflammation. Gut health is not the sole cause of ADHD, but it is a meaningful contributing factor for many people.
What gut issues are common in people with ADHD?
Constipation, bloating, irritable bowel syndrome (IBS), reflux, and food sensitivities are all more common in people with ADHD than in the general population. A 2025 meta-analysis found a 63% increased risk of IBS in individuals with ADHD, covering data from more than 175,000 people. These symptoms often indicate underlying gut dysbiosis rather than coincidental digestive complaints.
Can improving gut health help ADHD symptoms?
Supporting gut health can be a helpful part of a broader ADHD management approach. Improving microbiome diversity, reducing gut inflammation, and supporting short-chain fatty acid production may positively influence neurotransmitter balance, sleep, mood stability, and attention — all areas affected in ADHD. It works best alongside, not instead of, other management strategies.
What is the best gut test for ADHD?
Comprehensive microbiome testing using shotgun metagenomic sequencing — such as Microba — provides the most detailed picture of gut health relevant to ADHD. This goes beyond basic bacterial identification to assess functional capacity, SCFA-producing potential, and inflammation markers, allowing for much more targeted support.
How does leaky gut relate to ADHD?
When the gut lining becomes permeable, bacteria, toxins, and inflammatory compounds can enter the bloodstream and trigger immune responses. This chronic low-grade inflammation can affect the brain and contribute to the neuroinflammatory environment associated with ADHD symptoms including inattention, mood dysregulation, and impulsivity.

Naturopathic support for ADHD gut health isn’t about replacing other management strategies — it works alongside them. The focus is on identifying the specific factors influencing your (or your child’s) presentation, and building support from there.

✦   ✦   ✦

References

    1. Ng, R. W., Chen, Z., Yang, L., et al. (2025). Association between attention-deficit/hyperactivity disorders and intestinal disorders: A systematic review and meta-analysis. Scientific Reports, 15, 19278. https://doi.org/10.1038/s41598-025-04303-x
    2. Steckler, R., Magzal, F., Kokot, M., Walkowiak, J., & Tamir, S. (2024). Disrupted gut harmony in attention-deficit/hyperactivity disorder: Dysbiosis and decreased short-chain fatty acids. Brain, Behavior, and Immunity – Health, 40, 100829. https://doi.org/10.1016/j.bbih.2024.100829
    3. Stiernborg, M., Debelius, J. W., Yang, L. L., Skott, E., Millischer, V., Giacobini, M., et al. (2023). Bacterial gut microbiome differences in adults with ADHD and in children with ADHD on psychostimulant medication. Brain, Behavior, and Immunity, 110, 310–321. https://doi.org/10.1016/j.bbi.2023.03.012
    4. Phasouk, K., Saengnipanthkul, S., Lao-araya, M., & Chattipakorn, N. (2025). Impact of psychostimulants on microbiota and short-chain fatty acids alterations in children with attention-deficit/hyperactivity disorder. Scientific Reports, 15. https://doi.org/10.1038/s41598-025-87546-y
    5. Jiang, H., Zhang, X., Yu, Z., Zhang, Z., Deng, M., Zhao, J., & Ge, X. (2021). Gut microbiota signature in treatment-naïve attention-deficit/hyperactivity disorder. Frontiers in Cell and Developmental Biology, 9, 329. https://pmc.ncbi.nlm.nih.gov/articles/PMC12309550/
    6. Liu, Y., Li, W., Zhong, X., et al. (2025). Symptom-specific gut microbial and metabolic profiles in ADHD reveal SCFA deficiency as a key pathogenic mechanism. ISME Journal. https://pmc.ncbi.nlm.nih.gov/articles/PMC12309550/

Ready to look at the bigger picture?

If you or your child is navigating ADHD and you’ve noticed gut symptoms, food sensitivities, sleep struggles or mood instability alongside the attention challenges, it’s worth exploring the gut connection. I offer gut-focused naturopathic consultations for both adults and children, including Microba testing where indicated.

Book a consultation

The post What you need to know about ADHD and gut health appeared first on Alison Mitchell Naturopath.

]]> https://www.naturopathnsw.com.au/adhd-guthealth/feed 0 A Gut Feeling https://www.naturopathnsw.com.au/gutbrainaxis https://www.naturopathnsw.com.au/gutbrainaxis#comments Fri, 04 Jul 2014 12:24:49 +0000 http://www.naturopathnsw.com.au/?p=2330

When your gut controls your mood: the gut-brain axis From as early as the 1930’s, scientists were beginning to understand that the health of our digestive system could influence our mood.  The state of our intestinal lining and the balance...

The post A Gut Feeling appeared first on Alison Mitchell Naturopath.

]]>

When your gut controls your mood: the gut-brain axis

From as early as the 1930’s, scientists were beginning to understand that the health of our digestive system could influence our mood.  The state of our intestinal lining and the balance of bacteria within our digestive system have a major role to play in the production of our neurotransmitters: chemical transmitters that tell our brain whether we should be feeling such ways as happy, sad, agitated, or calm.  But even though the research in this area sky-rocketed in the last decade and continues to grow every day, the concept of our gut-brain connection isn’t very well known.

The gut is linked to the brain

Did you know – When you were just starting to grow in your Mumma’s womb, your brain and your digestive system developed from the same lump of tissue.  During this process of dividing up cells (embryogenesis) this lump of tissue divides and forms our central nervous system and our enteric nervous system (this is the nervous system of our gut – sometimes called the second brain).  These two are connected by an important ‘wire’ – our vagus nerve.  This development can help us understand why there are so many similar chemicals and receptors in both our brain and our digestive system, for instance serotonin.

Gut bugs and your mood

digestionAs soon as you’re born, bacterial colonies start to develop in your digestive system.  Within the first few days, the bacteria starts sending messages to the nervous system and can actually determine our nervous system ‘set point’ long term (1).

When the balance of our gut bacteria (collectively referred to as the microbiome) is affected, this can affect your mood.  Studies have found that the microbiome can have a major impact on stress levels and anxiety (2).  In fact, by treating imbalances in our microbiota, it is possible to support a wide range of mental health disorders (3), (4), (5), (6), (7).

The second brain

The nerves in your digestive system are constantly speaking to your central nervous system.  If your gut is irritated for some reason – say you’ve eaten something that you’re intolerant to (like gluten, for example), you’ve generally got a bad diet, there’s an imbalance in your microbiome (that’s your collective gut bacteria, remember) or you’ve got an infection – this can create an inflammatory reaction and will certainly make you irritated as well.  We know that depression is both associated with, and worsened by inflammation.  This inflammation in the brain can be driven by inflammation in the gut, which can be caused by intestinal permeability (leaky gut) and bacterial imbalances (dysbiosis).  Treating leaky gut can help reduce the severity of depression (4), (8), (9), (10), (11).

Neurotransmitters in our gut

Serotonin is produced in large amounts in our digestive system.  In people with Irritable Bowel Syndrome (IBS) there is too much serotonin in their digestive system.  This is why antidepressants known as SSRI (selective serotonin reuptake inhibitors) can improve the symptoms of IBS: these act by reducing the amount of serotonin taken into cells in the rest of our body which allows more to get into the brain.  However anti-depressants can affect the gut negatively as well, because if you weren’t making enough serotonin in the gut in the first place, you’d end up with even lower levels in the digestive tract and so it can become irritated, affectively you’ll get a depressed gut (12), (13).

PoorDigestionA vicious cycle

When your gut is upset, you feel upset.  But stress can affect your digestive system just as much as it affects your mood.  It can impair the secretion of digestive acids, slow down the motility of the gut, allows the unfriendly bacteria to grow, reduces your friendly bacteria and exacerbates intestinal permeability (leaky gut) (14), (8).  This is a recipe for an unhappy digestive system, and as you know this can then go on to send more messages to your brain: so you can see how the cycle continues.

People with gut problems are more likely to experience anxiety and depression.  Some studies have found a high proportion of anxiety in those with gut conditions such as Irritable Bowel Syndrome(IBS), Crohn’s disease and coeliac disease (15), (16), (17).

Helping the gut-brain axis.

By treating digestive problems, sealing leaky gut and balancing your microbiome it is possible to help with conditions such as anxiety and depression, and there’s even research showing the benefits of treating the gut in conditions like chronic fatigue syndrome, schizophrenia and autism (10), (18), (11).  Probiotics are one of your major tools when it comes to treating the gut, but it’s a good idea to consult with a health practitioner to make sure you’re getting the right type, and also to get a good gut healing treatment program to go along with it (19), (4), (9).

Related articles:

Works Cited

1.
Foster JA, McVey Neufield KA. Gut-brain axis: how the microbiome influences anxiety and depression. 2013; 36(5).
2.
Cryan JF, O’Mahony SM. The microbiome-gut-brain axis: from bowel to behavior. 2011; 23(3).
3.
Cryan JF, Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. 2012; 13(10).
4.
Maes M, Kubera M, Leunis JC. The gut-brain barrier in major depression: intestinal mucosal dysfunction with an increased translocation of LPS from gram negative enterobacteria (leaky gut) plays a role in the inflammatory pathophysiology of depression. 2008; 29(1).
5.
Maes M, Mihaylova I, Leunis JC. Increased serum IgA and IgM against LPS of enterobacteria in chronic fatigue syndrome (CFS): indication for the involvement of gram-negative enterobacteria in the etiology of CFS and for the presence of an increased gut-intestinal permeability. 2007; 99(1-3).
6.
Maes M, Coucke F, Leunis JC. Normalization of the increased translocation of endotoxin from gram negative enterobacteria (leaky gut) is accompanied by a remission of chronic fatigue syndrome. 2007; 28(6).
7.
Maes M, Leunis JC. Normalization of leaky gut in chronic fatigue syndrome (CFS) is accompanied by a clinical improvement: effects of age, duration of illness and the translocation of LPS from gram-negative bacteria. 2008; 29(6).
8.
Maes M, Kubera M, Leunis JC, Berk M. Increased IgA and IgM responses against gut commensals in chronic depression: further evidence for increased bacterial translocation or leaky gut. 2012; 141(1).
9.
Logan AC, Katzman M. Major depressive disorder: probiotics may be an adjuvant therapy. 2005; 64(3).
10.
Rook GA, Lowry CA, Raison CL. Hygiene and other early childhood influences on the subsequent function of the immune system. 2014.
11.
Drexhage RC, Weigelt K, van Beveren N, Cohen D, Versnel MA, Nolen WA, et al. Immune and neuroimmune alterations in mood disorders and schizophrenia. 2011;(101).
12.
Ruepert L, Quartero AO, de Wit NJ, van der Heijden GJ, Rubin G, Muris JW. Bulking agents, antispasmodics and antidepressants for the treatment of irritable bowel syndrome. 2011; 10(8).
13.
Olden KW. The use of antidepressants in functional gastrointestinal disorders: new uses for old drugs. 2005; 10(11).
14.
Gorard DA, Gomborone JE, Libby GW, Farthing MJ. Intestinal transit in anxiety and depression. 1996; 39(4).
15.
Addolorato G, Mirijello A, D’Angelo C, Leggio L, Ferrulli A, Abenavoli L, et al. State and trait anxiety and depression in patients. 2008; 62(7).
16.
Hillilä MT, Hämäläinen J, Heikkinen ME, Färkkilä MA. Gastrointestinal complaints among subjects with depressive symptoms in the general population. 2008; 28(5).
17.
Filipovic BR, Filipovic BF. Psychiatric comorbidity in the treatment of patients with inflammatory bowel disease. 2014; 20(7).
18.
Hornig M. The role of microbes and autoimmunity in the pathogenesis of neuropsychiatric illness. 2013; 25(4).
19.
Rao AV, Bested AC, Beaulne TM, Katzman MA, Iorio C, Berardi JM, et al. A randomized, double-blind, placebo-controlled pilot study of a probiotic in emotional symptoms of chronic fatigue syndrome. 2099; 19(1).

 

[fb_button]

The post A Gut Feeling appeared first on Alison Mitchell Naturopath.

]]> https://www.naturopathnsw.com.au/gutbrainaxis/feed 4