Vibrant Functional Academy

The Gut-Performance Connection: Enhancing Executive Function Through Digestive Health

Written by Dr. Susan Lovelle, MD | Apr 7, 2025 7:07:48 PM

As a healthcare provider, understanding the link between gut health and cognitive function is crucial for supporting clients in optimizing their mental performance, emotional resilience, and overall well-being.  

The gut-brain axis plays a critical role in cognitive health by influencing neurotransmitter production, inflammation levels, and hormonal balance. Integrating functional testing and lifestyle interventions can provide a more holistic and sustainable approach to mental clarity and stress adaptation.   

In this article, we explore how gut health affects cognitive function and how incorporating functional testing and integrating diet and lifestyle interventions can improve both. 

Table of Contents

The Gut-Brain Axis: A Two-Way Communication Superhighway 

Case Study 2: Managing Stress-Induced Gut Dysbiosis 

The Impact of Stress on the Gut Microbiome and Mental Clarity 

Case Study 3: ADD in a Young Adult 

Executive Function and Gut Health 

How You Can Support Your Clients 

Case Study 1: Reversing Brain Fog and Cognitive Fatigue 

How Gut Health Matters for Cognitive Function

 

The Gut-Brain Axis: A Two-Way Communication Superhighway 

The gut and brain communicate through a complex network involving the nervous system, immune system, and gut microbiota. The gut microbiome influences the production of key neurotransmitters such as serotonin—responsible for mood regulation—and dopamine, which influences motivation and focus¹.  

Approximately 90% of serotonin is produced in the gut, underscoring its importance to mental health². 

Dysbiosis and Cognitive Function 

An imbalanced microbiome—a condition known as dysbiosis—can disrupt this harmony. Factors like poor diet, chronic stress, and exposure to environmental toxinsoften cause dysbiosis. This can lead to systemic inflammation, increased gut permeability, and reduced production of beneficial neurotransmitters.  

The unfortunate result? Brain fog, mood swings, difficulty concentrating, and even heightened risk of burnout³. 

Emerging research also links dysbiosis to neurodevelopmental disorders such as ADD/ADHD and autism spectrum disorder (ASD). Children and adults with these conditions often exhibit altered gut microbiota composition, increased gut permeability, and chronic low-grade inflammation, which can exacerbate cognitive and behavioral symptoms⁴.  

Addressing thegut and mental health connection through dietary and probiotic interventions has shown promise in improving symptoms associated with these conditions. 

The Impact of Stress on the Gut Microbiome and Mental Clarity 

Chronic stress significantly impacts gut microbiome diversity, composition, and function. Stress triggers the hypothalamic-pituitary-adrenal (HPA) axis, leading to prolonged elevations in cortisol and other stress hormones. High cortisol levels reduce microbial diversity and increase pathogenic bacteria while depleting beneficial species like Lactobacillus and Bifidobacterium⁵. 

Gut Permeability and Gut Motility 

Additionally, stress-induced changes in gut permeability, often referred to as “leaky gut,” result in the passage of endotoxins (such as lipopolysaccharides) into the bloodstream. This hampers the protective negative feedback loop of cortisol release and triggers systemic inflammation.  

This inflammation has been linked to neuroinflammatory conditions, brain fog, and increased susceptibility to mood disorders such as depression and anxiety. 

Furthermore, stress alters gut motility, often leading to constipation or diarrhea and further exacerbating gut-brain communication imbalances. Chronic stress also impairs the production of short-chain fatty acids (SCFAs), which are essential for sustaining key bacteria, maintaining gut barrier integrity, and supporting anti-inflammatory pathways. 

Executive Function and Gut Health 

Executive function is a suite of cognitive processes, including working memory, flexible thinking, and self-control. These skills allow individuals to manage time, pay attention, plan, and organize tasks effectively. Deficiencies in these areas can have profound implications on daily life and work environments.  

Research suggests that foods that promote gut health, such as those rich in probiotics and prebiotics, positively influence cognitive functions. 

Case Study 1: Reversing Brain Fog and Cognitive Fatigue 

A 48-year-old male executive presented with persistent brain fog, difficulty concentrating, and mid-afternoon energy crashes despite optimizing sleep and exercise. 

Assessment Findings

  • Gut Zoomer Test revealed significant dysbiosis with a low diversity of beneficial bacteria and an overgrowth of opportunistic species. 
  • Micronutrient Panel revealed deficiencies in B vitamins and magnesium, both critical for neurotransmitter synthesis and cognitive function. 

Interventions 

  • Dietary modifications: Increased intake of prebiotic and probiotic-rich foods to support microbial diversity. 
  • Supplementation: Added probiotics, magnesium, and B-complex vitamins to address deficiencies. 
  • Stress management: Implemented guided breathing exercises and a structured work-rest cycle. 

Outcomes 

After eight weeks, the client reported improved mental clarity, sustained energy levels, and enhanced concentration. 


Case Study 2: Managing Stress-Induced Gut Dysbiosis 

Mia, a 42-year-old female entrepreneur, struggled with mood swings, poor sleep, anxiety, and gut discomfort, especially under work-related stress. 

Assessment Findings

  • A Gut Zoomer Test revealed low levels of Lactobacillus and Bifidobacterium species, key regulators of stress resilience. 

Interventions 

  • Dietary adjustments: Eliminated gluten and dairy while incorporating gut-healing nutrients like L-glutamine and polyphenols. 
  • Probiotic and supplement therapy: Introduced a multi-strain probiotic supplement to restore microbial balance and short-term, low-dose melatonin for sleep assistance. 
  • Lifestyle adjustments: Implemented structured sleep hygiene and adapted mindfulness techniques. 

Outcomes 

Within three months, the client experienced stabilized mood, improved sleep, reduced anxiety, and improved gut function. 

Case Study 3: ADD in a Young Adult 

Jordan, a 22-year-old college student, had been diagnosed with ADD as a child and continued to struggle with attention, impulsivity, and organization in adulthood. Conventional medication helped somewhat but led to unwanted side effects, including sleep disturbances and anxiety. His diet consisted of typical fast food, and he spent late hours studying for exams. 

Assessment Findings

  • A Gut Zoomer Test revealed low levels of beneficial Akkermansia species and elevated inflammatory markers. 
  • A Micronutrient Panel revealed deficiencies in iron, choline, and vitamin B6, all crucial for neurotransmitter function. 
  • Food Sensitivity Testing identified soy and artificial food dye sensitivities, contributing to inflammation and gut distress. 

Interventions 

  • Dietary adjustments: Removed soy and processed foods containing artificial dyes while increasing intake of choline-rich foods such as eggs, nuts, and spinach, as well as fiber. 
  • Probiotic and supplement therapy: Added targeted probiotics, iron, and B6 supplementation. 
  • Lifestyle modifications: Improved productivity planning, strength training, and mindfulness techniques. 

Outcome  

Within three months, Jordan experienced improved focus, reduced impulsivity, better sleep, and an overall enhanced ability to manage academic and personal responsibilities. 

How You Can Support Your Clients 

The connection between gut health and brain health is strong. You can support clients with ADD or those experiencing brain fog, mood swings, high stress, or cognitive fatigue through functional testing and dietary and lifestyle interventions.  

1. Incorporate functional testing, including: 

2. Educate clients on dietary interventions 

  • Promote prebiotic and probiotic foods. 
  • Guide clients through elimination diets when necessary. 

3. Integrate lifestyle interventions for gut health 

  • Encourage mindfulness practices such as HRV (heart rate variability) training, meditation, and breathwork. 
  • Recommend movement practices that support the gut-brain axis. 
  • Address sleep hygiene to enhance circadian rhythm and microbiome health. 

How Gut Health Matters for Cognitive Function 

Optimizing gut health is essential for executive function, stress resilience, and long-term cognitive performance. By incorporating gut health testing and micronutrient testing, along with targeted dietary strategies and stress management, you can support your clients’ cognitive and overall well-being. 

About the Author

Dr. Susan Lovelle, a former award-winning plastic surgeon, is the Founder of Balanced Performance, offering all-in-one lifestyle health solutions for busy executives and the innovative companies they lead. She specializes in boosting their energy, optimizing weight, and balancing hormones to unlock peak performance in every aspect of life.  Dr. Susan has been featured on The Doctors, the docu-series Exhausted, Lifetime TV, Forbes, DWEN, and Good Morning Washington. Her book, Thrive! The Five-Week Guide to Mastering Your Energy At Any Age is available on Amazon.

References:

  1. Carabotti M, Scirocco A, Maselli MA, Severi C. The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Ann Gastroenterol. 2015;28(2):203-209. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/
  2. Clarke, G., Grenham, S., Scully, P. et al. The microbiome-gut-brain axis during early life regulates the hippocampal serotonergic system in a sex-dependent manner. Mol Psychiatry 18, 666–673 (2013). Available from: https://doi.org/10.1038/mp.2012.77 
  3. Cryan JF, O'Riordan KJ, Sandhu K, Peterson V, Dinan TG. The gut microbiome in neurological disorders. Lancet Neurol. 2020;19(2):179-194. doi:10.1016/S1474-4422(19)30356-4. Available from: https://pubmed.ncbi.nlm.nih.gov/31753762/ 
  4. Belkaid Y, Hand TW. Role of the microbiota in immunity and inflammation. Cell. 2014;157(1):121-141. doi:10.1016/j.cell.2014.03.011. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC4056765/ 
  5. Foster JA, Rinaman L, Cryan JF. Stress & the gut-brain axis: Regulation by the microbiome. Neurobiol Stress. 2017;7:124-136. Published 2017 Mar 19. doi:10.1016/j.ynstr.2017.03.001. Available from: https://pubmed.ncbi.nlm.nih.gov/29276734/ 

Regulatory Statement:

The information presented in case studies have been de-identified in accordance with the HIPAA Privacy protection.

The general wellness test intended uses relate to sustaining or offering general improvement to functions associated with a general state of health while making reference to diseases or conditions. This test has been laboratory developed and its performance characteristics determined by Vibrant America LLC and Vibrant Genomics, a CLIA-certified and CAP-accredited laboratory performing the test. The lab tests referenced have not been cleared or approved by the U.S. Food and Drug Administration (FDA). Although FDA does not currently clear or approve laboratory-developed tests in the U.S., certification of the laboratory is required under CLIA to ensure the quality and validity of the test