There is something I have been reflecting on more deeply in recent years, both through the lens of my clinical work and my own personal experience. It is the way certain patterns begin long before we ever think of them as “symptoms,” and how easily they can be dismissed as personality traits rather than early signals from the body.
When I look back at my own childhood, I can recognise that I had clear obsessive–compulsive tendencies. I was a particularly picky eater, very selective with food, and I developed small rituals that, at the time, felt essential. I remember avoiding stepping on cracks in the pavement, feeling the need to touch a wall or an object “just right,” or repeating certain actions a set number of times — often five — until it felt complete. If I didn’t do them, there was an underlying sense of discomfort, as though something might go wrong. These behaviours weren’t dramatic or disruptive, but they were consistent, and they gave me a sense of control and reassurance that everything would be okay.
At no point did it occur to me that these behaviours might be connected to my physiology. They were simply part of who I was.
Now, with the benefit of hindsight and years of working with complex autoimmune and neurological cases, I see a far more intricate and interconnected picture.
The Gut–Brain Axis: How Gut Health Influences OCD
One of the most important shifts in our understanding of mental health is the recognition that the brain does not operate in isolation. There is constant communication between the gut, the immune system, and the nervous system — a relationship often referred to as the gut–brain axis.
The gut microbiome plays a central role in this communication. It influences the production and regulation of key neurotransmitters such as serotonin, dopamine, and GABA, all of which are involved in mood, behaviour, and thought patterns. At the same time, the gut is one of the largest immune organs in the body, meaning that any disruption within it can trigger inflammatory responses that extend far beyond digestion.
When the microbiome is balanced, this system functions with a degree of harmony. However, when it becomes disrupted — through stress, infections, environmental exposures, or dietary factors — we begin to see changes not only in digestive health, but also in cognitive and emotional patterns.
This is where the link with obsessive–compulsive tendencies becomes increasingly compelling.
When the Body Feels Unsafe
In clinic, one of the most consistent patterns I observe in individuals with OCD traits is a nervous system that does not feel fully settled. There is often a heightened sensitivity to uncertainty, a tendency towards repetitive thoughts, and behaviours that provide temporary relief or reassurance.
When we look beneath this, we frequently find physiological drivers that are contributing to that internal state. These may include gut dysbiosis, reduced microbial diversity, increased intestinal permeability, chronic low-grade inflammation, and deficiencies in nutrients such as B vitamins, zinc, and iron.
These imbalances do not just affect the body; they influence how the brain processes information and responds to stress. When the system is under strain, the brain becomes more vigilant, more reactive, and more driven to seek certainty. For some, this manifests as obsessive thoughts or compulsive behaviours.
The Overlap with Fatigue and Burnout
Another pattern that is difficult to ignore is the overlap between obsessive–compulsive traits and fatigue. Many of those experiencing intrusive thoughts or compulsive tendencies also report significant exhaustion, brain fog, and reduced stamina.
This is often underpinned by mitochondrial dysfunction, blood sugar instability, and chronic inflammation. The body is effectively operating in a high-demand state, while lacking the resources required to sustain it. Over time, this creates a cycle of both mental and physical depletion, where the nervous system remains activated but energy reserves continue to decline.
PANDAS and OCD: How Strep Infections Affect the Brain
A particularly striking example of the gut–immune–brain connection is seen in a condition known as Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections, or PANDAS.
In this condition, a streptococcal infection — such as strep throat — triggers a sudden and often severe onset of obsessive–compulsive symptoms or tic disorders in children. These symptoms can appear rapidly, sometimes almost overnight, and are often accompanied by heightened anxiety, emotional lability, and significant behavioural changes.
What PANDAS highlights is the powerful role that infection and immune activation can play in influencing neurological function. While it is a specific diagnosis, it offers a broader insight into how microbial imbalances may contribute to obsessive–compulsive patterns more generally.
In my own clinical work, I have frequently observed elevated levels of streptococcal species in clients presenting with OCD traits. This is not something that would typically be identified without deeper investigation, which is why comprehensive stool testing can be such a valuable tool.
Through my work at The Autoimmune Nutrition Clinic, I use advanced stool testing to assess the microbiome in detail, identify overgrowths such as streptococcus, and uncover inflammatory patterns that may be contributing to both physical and neurological symptoms.
Food Patterns, Microbiome, and Early Clues
Looking back at my own experience as a picky eater, it is something I now interpret very differently. What may appear behavioural on the surface can often reflect deeper physiological imbalances.
Selective eating can be influenced by gut inflammation, microbial shifts that alter taste perception, or even subconscious avoidance of foods that trigger symptoms. In this context, food becomes a form of regulation rather than simply nourishment.
When the gut is supported and the microbiome begins to rebalance, these patterns often shift naturally, without force or restriction.
How to Calm the Nervous System in OCD
While addressing the gut and immune system is essential, we cannot overlook the role of the nervous system. Many people with obsessive–compulsive tendencies exist in a chronic state of heightened alertness, where the body is primed for threat and constantly seeking safety.
Supporting the nervous system to move into a more regulated, parasympathetic state can be transformative. One tool I often recommend in clinic is the Sensate device, which uses infrasonic vibrations to gently stimulate the vagus nerve. This can help shift the body into a calmer state, supporting emotional regulation, reducing stress signalling, and creating a greater sense of internal safety. If you are considering this, you can use my code AUTOIMMUNENUTRITION or use this link for a 10% discount.
A More Integrated Approach to Recovery
What becomes clear when we take this broader view is that obsessive–compulsive patterns are rarely isolated. They are often part of a wider network of imbalances involving the gut, the immune system, and the nervous system.
When we begin to support these systems together — through targeted nutrition, microbiome support, nutrient repletion, and calming the nervous system — we often see changes that extend far beyond digestion. People describe feeling clearer in their thinking, less caught in repetitive loops, and more able to move through their day without the same underlying tension. The urge to check, repeat, or mentally “fix” things may begin to soften. Energy becomes more consistent, and there is a greater sense of steadiness rather than feeling constantly on edge.
It is not that everything disappears overnight, but there is often a noticeable shift in how the body and mind respond — and that, in itself, can be incredibly powerful.
A Different Way of Understanding the Body
If you recognise some of these patterns in yourself, it is worth considering that they may not simply be traits to manage, but signals to understand.
Because sometimes, the behaviours we have lived with for years are not fixed parts of who we are. They are adaptive responses from a body that has been trying to cope, regulate, and protect.
And when we begin to support the body at its roots, we create the conditions for those patterns to soften, shift, and, in many cases, resolve in ways we may not have thought possible.
One of the most valuable tools I use in clinic is comprehensive stool testing, such as the GI Effects Stool Test. This allows us to assess the microbiome in detail, identify imbalances such as streptococcal overgrowth, detect inflammation, evaluate digestive function, and understand how well the gut is truly working.
Rather than guessing, it gives us clear data — so we can move forward with a targeted, personalised approach.If you would like to explore this further, you can find more information and book your test here
Frequently Asked Questions
Can gut health affect OCD?
Yes, research increasingly shows that the gut microbiome can influence brain function through the gut–brain axis. Imbalances in gut bacteria may affect neurotransmitters, inflammation, and stress signalling, all of which can contribute to obsessive–compulsive patterns.
What is PANDAS and how is it linked to OCD?
PANDAS is a condition where a streptococcal infection triggers a sudden onset of OCD symptoms or tics in children. It highlights how immune activation and infection can directly influence brain function and behaviour.
Can stool testing help identify causes of OCD symptoms?
In some cases, comprehensive stool testing can identify microbial imbalances, inflammation, and digestive issues that may be contributing to symptoms. This allows for a more targeted and personalised approach.
VJ Hamilton, BSc, RNT
VJ Hamilton is a Registered Nutritionist (BANT) and an expert in autoimmune disease. VJ combines her knowledge from her medical science degree in Biochemistry & Immunology with Nutritional Therapy to offer a thorough and personalised approach to support her clients based on the most current scientific research. VJ runs a virtual and in-person nutritional therapy and functional medicine practice, The Autoimmunity Nutritionist, specialising in gut skin and immune health.