The Anxiety-Gut Connection: How Gut Health Affects Mood

Anxiety disorders are among the most common mental health issues worldwide, affecting millions of people every year. While traditional treatments such as medication and therapy can be effective, more and more research is pointing to a link between gut health and anxiety. 

Recent studies have revealed that the state of our gut microbiome can have a significant impact on our mood, stress levels, and overall mental health. This connection between the gut and the brain, known as the gut-brain axis, is shedding new light on the underlying causes of anxiety and providing new avenues for treatment. 

In this article, we explore the science behind the gut-anxiety connection and offer practical tips for improving gut health and managing anxiety symptoms.



The gut-brain connection refers to the bidirectional communication between the central nervous system (CNS) and the enteric nervous system (ENS) ( the intrinsic nervous system of the gastrointestinal tract). The ENS is often referred to as the “second brain” because it can operate independently of the CNS, but it also communicates with the CNS through the vagus nerve and other neural pathways.

The gut and the brain are connected via this intricate network of neurons, neurotransmitters, and other signaling molecules, which allows them to influence each other in various ways. For example, the gut can send signals to the brain that affect our mood, behavior, and cognitive function, while the brain can also modulate gut function and affect the microbiome.

Recent research has shown that the gut-brain connection plays a critical role in a wide range of physiological processes, including digestion, metabolism, immunity, and even mental health.(2)



It all comes down to the gut microbiome, which is the collection of microorganisms that live in our gut. These bacteria play an important role in regulating our immune system, producing neurotransmitters, producing short chain fatty acids and absorbing nutrients – all of which can impact our mood. Thus, when the microbiome is in a state of imbalance, this can potentially lead to changes with our mood.

INFLAMMATION- Inflammation is a natural response to injury or infection, but chronic inflammation has been linked to depression and anxiety too. When the gut microbiome is imbalanced, it may lead to chronic inflammation, which can then lead to changes in brain chemistry and neurotransmitter levels. This can affect mood, behaviour, and cognitive function.

NEUROTRANSMITTERS- The gut microbiome produces a number of neurotransmitters that play a role in regulating mood, including serotonin, dopamine, and GABA. In fact, up to 90% of serotonin, which is often referred to as the “happy hormone,” is produced in the gut (3). When the gut microbiome is imbalanced, it can lead to disruptions in the production and function of these neurotransmitters, which can negatively impact mood and mental health.

HORMONES- The gut is also responsible for producing and regulating hormones, including cortisol, which is often referred to as the “stress hormone.” When the gut microbiome is imbalanced, it can lead to disruptions in hormone production and regulation, which can contribute to symptoms of anxiety and depression.

SCFA – Short-chain fatty acids (SCFAs) are produced by the fermentation of dietary fibre by gut bacteria. They are an essential source of energy for gut cells and have several physiological effects in the body, including regulating inflammation, immune function, and gut motility.

Recent studies suggest that SCFAs may also play a role in regulating mood and behaviour. SCFAs can cross the blood-brain barrier and activate receptors in the brain that are involved in regulating mood, including serotonin and GABA receptors. (4)



Scientists have now identified specific gut microbes that may be connected with these mood conditions. (5) One research paper (6) discovered that those with depression had a reduced amount of bacteria called Dialister and Coprococcus residing in their guts. Individuals with more of these bacteria reported higher scores when researchers asked them about their quality of life. 

Having a variety of different strains of bacteria in the gut is key. For example, certain strains of bacteria are involved in the production of neurotransmitters, other strains are involved in the production of short-chain fatty acids and different strains of bacteria can affect the permeability of the gut lining.

Therefore, maintaining a diverse and balanced gut microbiome, including different strains of bacteria is fundamental. 




Research has shown that certain probiotics, or beneficial bacteria, can improve symptoms of anxiety and depression by reducing inflammation and restoring the balance of gut bacteria. (7) Supplements containing Lactobacillus acidophilus and Bifidobacterium bifidum may improve symptoms of anxiety and depression in those with IBS. (8) Try taking a probiotic supplement daily or eating foods that are naturally rich in probiotics, such as yoghurt, kefir, and fermented vegetables, which may help to improve your overall gut microbiome health and support the gut-brain axis. (9)

Check out my article on everything you need to know on probiotics here, with my top picks when it comes to supplementation:


Prebiotics are a type of dietary fibre that are indigestible by the human body, but serve as a food source for the beneficial bacteria in the gut. Prebiotics provide nourishment for our good gut bugs and help to promote a healthy gut microbiome, which is key for overall digestive health and the gut brain connection. 

Short-chain fatty acids (SCFAs) are organic acids that are produced by the fermentation of dietary fibres, such as prebiotics, by the gut bacteria. These prebiotics serve as a food source for the beneficial bacteria in the gut, which produce SCFAs as a byproduct. Due to an increased production of short-chain fatty acids (SCFAs) in the gut, this may improve digestion and the absorption of nutrients.

Prebiotics can also support  an individual’s bowel regularity and movements as SCFAs can help to soften stools and make them easier to pass. 

Prebiotics can be found in certain foods or taken as a supplement. 

My favourite prebiotic supplement is Invivo PHGG

And some delicious and nutritious prebiotic rich food sources include:

  • Garlic: This flavorful bulb contains fructooligosaccharides (FOS), a type of prebiotic fibre.
  • Onions: Like garlic, onions are a good source of FOS, with about 1-3 grams per 100 grams of raw onion.
  • Leeks: These mild-flavoured vegetables are also a good source of inulin, with about 3-4 grams per 100 grams of raw leek.
  • Asparagus: This vegetable is a good source of inulin and FOS, with about 2-3 grams of prebiotic fibre per 100 grams of raw asparagus.
  • Bananas: While not as high in prebiotics as some other foods, bananas do contain resistant starch, which can act as a prebiotic.
  • Whole grains: Whole grains, such as oats, barley, and wheat, contain prebiotic fibres such as beta-glucan and arabinoxylan.
  • Legumes: Lentils, chickpeas, and beans are all good sources of prebiotic fibre, including inulin and resistant starch.



Working on intestinal permeability, also known as “leaky gut,” can help improve your gut health and mood. Leaky gut occurs when the lining of the intestinal wall becomes damaged, allowing undigested food particles, toxins, and bacteria to leak into the bloodstream, leading to inflammation and other negative effects on the body, including mood disturbances.

There are numerous ways to support intestinal permeability, with some of the main ones including:

  • Diet (see below)
  • Probiotic use (see above)
  • Digestive enzymes- Digestive enzymes can help to break down food molecules more effectively, reducing the likelihood of larger molecules passing through the gut lining
  • Stress reduction (see below) 

Consider working with a Nutritional Therapist if you think your intestinal permeability may need support. I offer a GUT HEALTH package in my clinic where we work on getting to the root cause, email for more details. 



A diet rich in fibre, fruits, vegetables, and whole grains can help support a healthy gut microbiome. These foods provide the essential nutrients that your gut bacteria need to thrive, while also promoting digestive health and reducing inflammation. 

Aim to avoid ultra- processed foods, high sugar snacks and artificial sweeteners as they can disrupt the gut microbiome. A high sugar intake has been linked to increased inflammation and gut dysbiosis, while it has been suggested that artificial sweeteners may negatively impact the gut microbiome. 

Consume a variety of whole foods in their natural states, aiming to eat as many different plants as possible for that all important gut diversity. The mediterranean diet is naturally high in fibre, plant foods, lean sources of protein and healthy fats, and is the best diet you can adopt for your gut health. 



Chronic stress may negatively impact gut health and contribute to imbalances in the gut microbiome. Managing stress through activities such as exercise, meditation, deep breathing, and yoga can help to support optimal gut health and promote your overall wellness. Check out my article on 7 ways to combat stress, which includes some of my favourite stress busting supplements here.



Sleep is essential for our overall health and wellness, and it is particularly important for supporting the gut-brain axis. Sleep deprivation has been shown to alter the gut microbiome, reducing the diversity and abundance of beneficial gut bacteria (10). Sleep also impacts the rhythmic contractions of the muscles in the digestive system, which are necessary for moving food and waste through the gut. Disruptions to this process can lead to a change in bowel movements resulting in constipation or diarrhoea

Read more about how sleep may be impacting your gut health and my top ways to improve your sleep here:



In conclusion, there is mounting evidence that suggests a strong connection between gut health and anxiety. The gut-brain axis, which connects the central nervous system to the enteric nervous system, plays a significant role in regulating mood and emotions. A healthy gut microbiome can help to produce and regulate neurotransmitters, such as serotonin and GABA, which are essential for maintaining a positive mood and reducing anxiety. Additionally, a balanced and diverse gut microbiome can help to reduce inflammation and oxidative stress, which are associated with anxiety and other mental health disorders. Therefore, taking care of your gut health by maintaining a healthy diet, staying hydrated, and managing stress can be a promising strategy for managing anxiety and improving overall mental wellbeing.

If you are experiencing ongoing symptoms of gut problems, seek professional help. I can help you get to the root cause of your gut complications, working with you to support the gut-brain axis for optimal physical and mental health.

Get in touch 

*If you are dealing with chronic anxiety, it is important to seek help from a healthcare professional. Anxiety disorders can be debilitating and have a significant impact on your quality of life. A doctor can help to diagnose the type of anxiety disorder you may have and recommend appropriate treatments such as therapy, medication, or a combination of both



References: (1) (2) (3)

Bourassa MW, Alim I, Bultman SJ, Ratan RR. Butyrate, neuroepigenetics and the gut microbiome: Can a high fiber diet improve brain health? Neuroscience Letters. 2016;625:56-63. doi:10.1016/j.neulet.2016.02.009 (4) (5)   (6)  (7) (8) (9) (10)

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Hi there

London Nutritionist Clarissa Lenherr

I’m Clarissa, a registered nutritionist (mBANT) and workplace wellness expert. In my practice, I have helped hundreds of clients reach optimal health through creating sustainable, effective habits and dietary adjustments. My aim is to empower people with the skills, tools and knowledge to take their health into their own hands and feel the happiest, healthiest versions of themselves. Featured in The Daily Mail, Women’s Health, The Telegraph, and more.




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