What’s your gut got to do with your brain (part 2)

In Part 1 of this blog I discussed how the gut and the brain communicate with one another; how the gut impacts our moods; and the research identifying specific strains of bacteria that influence anxiety, stress and depression.


In this post, I’m going to talk about the different ways that the gut microbiome can be disrupted (known as gut dysbiosis). I’ll then discuss the different ways to address gut dysbiosis to support healthier moods.


“Gut dysbiosis is characterised by a lack of beneficial bacteria and an increase in less beneficial (potentially harmful) bacteria or other organisms such as yeast and parasites. This can contribute to anxiety and depression”



What causes gut dysbiosis?


The balance of bacteria living in the gut is key to optimal gut health, brain function and balanced moods. We need the right type of bacteria to have a healthy gut. There are many ways in which the gut microbiome can be thrown out of balance.

Firstly, our gut flora is colonised at birth and in the early years of life.  If we are born naturally (i.e. through the vaginal canal) we receive bacteria from our mother during childbirth.  Our gut flora is shaped by our mother’s bacteria.  If we are breastfed, we receive immune factors in the breast-milk that help to shape our gut flora and immune system. Being born naturally and being breastfed encourages a good diversity of gut bacteria to support a healthy gut and immune system (1). The stress we are exposed to in the womb and in our early life also impacts on our gut flora (2). On the flipside, being born by Caesarean and not being breastfed can adversely affect a babies gut microbiome and result in a lack of beneficial gut bacteria and lower immune function. 

Clearly, we can’t change our birth or whether we were breastfed or anything else that happened in our past. But there are factors that we are exposed to that influence our gut that we can change or improve, such as:

  • Long-term diet: a high fat and high sugar diet (3) can alter the microbes in our gut for the worse by increasing the level of inflammation produced by gut bacteria. In contrast, a high fibre diet can support the diversity of microbes in our gut and support healthy gut function (4)


  • Antibiotic use: broad-spectrum antibiotics such as Amoxicillin can significantly reduce the number and diversity of bacteria in the gut. Furthermore, they don’t always replenish to their original state after antibiotics have been discontinued (5)


  • Stress: chronic stress can elevate cortisol causing low-grade inflammation in the gut (2). This can cause gut dysbiosis via lowering levels of Bifidobacterium (a beneficial bacterial species)


  • Pesticides and herbicides: Roundup (glyphosate) is one of the world’s most commonly used herbicides across the world and is found in 80% of GMO corn, sugar, cotton, soy and rapeseed. Its exposure can cause gut dysbiosis. It is also a probable carcinogen (6)


  • Poor sleep quality (7) (8): fragmented sleep alters gut bacteria via raising cortisol and increasing inflammation


  • Gut infections such as C. Difficile, E-coli and H. Pylori (9) (10) can all alter the balance of bacteria in the gut


  • Food intolerances such as gluten intolerance (11) can cause gut dysbiosis by increasing inflammation


  • Poor digestion: undigested proteins and carbohydrates are fermented by gut bacteria. Over-fermentation can cause an imbalance in the type of organisms growing in the gut, especially less beneficial organisms (12)


  • Early life trauma known as Adverse Childhood Events (ACE) may instil long-term anxiety, leading to an impaired stress response. A heightened stress response can cause disrupted gut microbiota via the gut-brain axis (2) (13)


“All of the above influence the gut microbiome and can result in a loss of beneficial bacteria and an increase in the more pathogenic (harmful) bacteria”


“This can increase inflammation in the gut which can alter neurotransmitters, immune messengers and inflammatory signals in the brain contributing to anxiety and depression”


How can we address anxiety and depression via the gut-brain axis?


To reduce inflammation and stress, and to support healthy neurotransmitter production, a multi-pronged approach is essential. We need to take into account all of the different factors mentioned above such as:

  • The quality of the diet: introduce prebiotic, (if tolerated) fermented and high fibre foods to support the growth of beneficial bacteria. Eliminate or reduce pro-inflammatory foods such as inflammatory fats, high sugar and refined carbohydrates. Prebiotic foods include garlic, onions, leeks, bananas, asparagus, Jerusalem artichokes, oats and apples. Inflammatory fats include high amounts of saturated fat and hydrogenated/trans fats.


  • Stress management and stress reduction: find techniques that work for you to lower your stress levels or simply find time to relax and unwind on a regular basis to lower your exposure to stress


  • Sleep quality: take a look at your sleep hygiene to improve your sleep quality. Find ways to relax and support melatonin production (the sleep hormone) before bed to support good sleep quality


  • Gut infections and food intolerances: without addressing these the gut microbiome will continue to be disrupted. Specific protocols may be needed to address gut infections such as small intestinal bacterial overgrowth (SIBO), candida overgrowth and other bacterial or parasitic infections. The most common food intolerances are gluten, dairy, egg, corn, soy and nuts. Sugar can also aggravate food intolerances


  • Rebalance the gut microbiome: use appropriate probiotics to replenish beneficial bacteria that may have been depleted


  • Neurotransmitters: support the production of calming neurotransmitters via diet and supplementation if appropriate


  • Adrenal glands: support the adrenal glands which may have become “fatigued” due to chronic stress and can, therefore, result in a lowered resilience to stress


  • Digestion: support digestion with betaine hydrochloride (i.e. stomach acid) and digestive enzymes to reduce food intolerances and improve nutrient absorption, to support optimal health


  • Emotional trauma: deal with repressed trauma or unaddressed emotional pain. Living in a state of chronic stress due to repressed trauma may hinder any progress you make with your diet and lifestyle





“Gut health plays a central role in regulating our moods. Gut dysbiosis can impair our moods by altering neurotransmitters, producing pro-inflammatory chemicals and by triggering our stress response”


Long-lasting change isn’t about taking some probiotics or a supplement. It’s about taking a holistic approach to nutrition and lifestyle, and getting to the root of the problem whether that be a food intolerance, a gut infection, an imbalanced diet, poor stress management, emotional pain or any other cause.

It can be difficult to know where to start, as there may be more than one factor at play. Starting with a wholefood, mainly organic diet, improving our sleep and managing our stress will create a good foundation to build on for addressing anxiety or digestive issues.

A healthy mind really does start with a healthy gut!


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