How functional testing revealed the root causes behind focus, mood, and digestive issues in one adult with ADHD
As a Nutritional Therapist with a functional medicine approach, I often see how interconnected the body systems are—particularly the gut and the brain. One of my recent clients, whom I’ll call “Alex,” is a great example of how personalising nutrition and lifestyle strategies through gut and genetic insights can lead to significant improvements in both physical and cognitive wellbeing.
Background
Alex, a professional in his 30s, came to see me seeking support for ongoing digestive issues—bloating, irregular bowel movements, and a sense of “gut discomfort” that he couldn’t quite pinpoint. He also lived with ADHD, which had been diagnosed in adulthood. While he was managing reasonably well with routines and occasional medication, he often felt “wired but tired,” struggled with focus and emotional regulation, and had noticed his symptoms worsened when his gut was unsettled.
This overlap between gut symptoms and neurocognitive challenges is something I see often in practice. We decided to take a deeper look into both his gut microbiome and his genetic makeup.
Testing and Key Findings
- Comprehensive Stool (Microbiome) Analysis
Alex’s stool test revealed signs of dysbiosis—an imbalance in gut bacteria. Key findings included:
- Low levels of beneficial Bifidobacterium and Lactobacillus strains
- Overgrowth of opportunistic bacteria and elevated beta-glucuronidase (an enzyme linked to poor detoxification and hormone re-circulation)
- Mild intestinal inflammation markers
These imbalances can disrupt the gut-brain axis, affecting neurotransmitter production and mood, and are often linked to digestive symptoms like Alex’s.
- Nutrigenomic Testing
We also explored Alex’s nutrigenomic profile, looking at how specific genetic variations (SNPs) might be influencing his brain chemistry, stress response, and nutrient needs. Relevant findings included:
- COMT (Val/Val variant) – Suggesting faster breakdown of dopamine, which can contribute to low dopamine availability and drive ADHD-related traits like impulsivity or difficulty focusing.
- MAO-A – Indicating potentially faster breakdown of serotonin and norepinephrine, which may impact mood regulation.
- DAT1 – A dopamine transporter variant linked to altered dopamine signalling, frequently found in ADHD.
- GAD1/GABA-related SNPs – Suggesting a reduced ability to convert glutamate to GABA, a calming neurotransmitter, potentially contributing to anxiety and sleep difficulties.
- VDR (Vitamin D Receptor) – Variants here may reduce the efficiency of vitamin D uptake and signalling, with downstream effects on immune regulation and mood.
Personalised Nutrition and Lifestyle Plan
Using this combined data, we tailored a plan to support Alex’s neurobiology, reduce gut inflammation, and restore microbial balance. Key areas we focused on:
- Gut Restoration
- Introduced targeted probiotic and prebiotic to increase levels of beneficial bacteria
- Used antimicrobial herbs (under supervision) to rebalance opportunistic overgrowth
- Supported gut lining and inflammation with specific nutraceuticals
- Encouraged dietary diversity to support microbial richness
- Dopamine and Neurotransmitter Support
- Based on his COMT and DAT1 variants, we focused on gentle dopamine support through:
- Tyrosine-rich foods (e.g., eggs, turkey, lentils)
- B-vitamin support (especially B6, B12, folate) to aid neurotransmitter synthesis
- Supported GABA production with magnesium, taurine, and calming practices like breathwork and meditation
- Vitamin D Optimisation
- Given the VDR SNPs and suboptimal blood levels, we included a high-quality vitamin D3 supplement and monitored levels.
- Nervous System Regulation
- Added adaptogens (after assessing tolerance) to help with stress resilience
- Recommended morning light exposure and regular movement to support circadian rhythm and dopamine regulation
Outcomes After 3 Months
After just a few weeks, Alex noticed improvements in his digestion—less bloating, more regular bowel movements, and much less discomfort after eating. By the 3-month mark, he reported:
- More sustained focus and fewer ADHD “crashes” during the day
- Better sleep quality and fewer anxious “wired” evenings
- Increased emotional stability and reduced overwhelm
- A sense of empowerment from understanding much more about how his body works
Final Thoughts
This case highlights the power of a personalised, integrative approach. Rather than viewing gut health and ADHD as separate issues, we explored their shared roots—inflammation, neurotransmitter balance, nutrient processing, and genetic individuality. With the right data and a tailored plan, we supported Alex’s body in a way that supported his individual biochemistry—and helped him feel more like himself again.
If you’re curious about how your gut and genes might be impacting your focus, mood, or digestion, feel free to get in touch. I offer free initial discovery calls to explore whether this approach might be a good fit for you.
Disclaimer:
This article shares the experience of one individual and is intended for general information only—it’s not medical advice. Everyone’s health journey is unique, especially when it comes to gut health and genetics. If you’re thinking about making changes to your diet, supplements, or lifestyle, it’s a good idea to speak with a qualified health professional first.