Functional Systems
Your Gut Is the
Foundation of
Longevity
The gut is far more than a digestive organ. It regulates immunity, influences brain function, and plays a central role in how well — and how long — you live.
The Gut at a Glance
Five key roles your gut plays in your overall health
Microbiome
Trillions of microorganisms living in your gut shape immunity, metabolism, and mood.
Immunity
70% of immune cells reside in the gut lining — your first line of systemic defence.
Gut-Brain Axis
Bidirectional communication between gut and brain governs mood, cognition, and stress.
Understanding the Gut
What Is Gut Health?
Gut health refers to the balance and function of microorganisms that live throughout your gastrointestinal tract. A healthy gut microbiome is diverse, resilient, and in dynamic equilibrium — supporting digestion, nutrient absorption, and immune defence.
When this balance is disrupted — a state known as dysbiosis — it can trigger a cascade of effects across the body: increased intestinal permeability (often called "leaky gut"), heightened systemic inflammation, and compromised immune signalling.
Research now links gut dysbiosis to conditions as diverse as metabolic syndrome, depression, autoimmune disease, and accelerated biological ageing. Understanding your gut is foundational to understanding your long-term health trajectory.
Why Gut Matters for Longevity
Studies of centenarians consistently show a more diverse microbiome and lower inflammatory markers. Your gut health today is one of the strongest predictors of your healthspan tomorrow.
- Reduces chronic inflammation
- Supports cognitive function
- Regulates immune response
- Improves metabolic health
Anatomy
Key Organs Involved
Small Intestine
Where 90% of nutrient absorption occurs
By the Numbers
Key Facts About the Gut
Primary Function
Digestion, nutrient absorption, and waste elimination — the gut processes everything you consume and determines what enters your bloodstream.
Scale
The gut microbiome contains over 38 trillion microorganisms — outnumbering human cells and encoding 150× more genes than the human genome.
Immune Hub
Approximately 70–80% of the body's immune cells are located in gut-associated lymphoid tissue (GALT), making the gut the primary interface of immunity.
Serotonin Production
Around 90% of the body's serotonin is produced in the gut — directly linking gut health to mood, sleep, and mental wellbeing.
Understand Your Gut. Extend Your Health.
FOXO is building the tools to track, understand, and optimise your functional systems. Join the waitlist for early access.
Deep Dive
How the Gut Shapes Your Health
Three lenses for understanding the gut's role in your body and longevity.
Biology
Core Biological Processes
The gut orchestrates a complex network of biological activity — from enzymatic digestion and nutrient absorption to the production of short-chain fatty acids that fuel colonocytes and regulate systemic metabolism. Understanding these processes is the foundation of functional health.
Systems
Interaction with Other Systems
The gut does not operate in isolation. Through the gut-brain axis, the enteric nervous system, immune signalling, and hormonal crosstalk, it communicates bidirectionally with every major organ system — from the liver and lungs to the cardiovascular and endocrine systems.
Health
Impact on Overall Health
A well-functioning gut underpins systemic resilience. Disruptions to gut integrity are now linked to metabolic disease, neurodegeneration, autoimmunity, and accelerated biological ageing. Optimising gut health is one of the highest-leverage interventions for long-term wellbeing.
FAQs
Common Questions,
Clear Answers
Everything you need to know about gut health, the science behind it, and how FOXO can help you take action.
The gut microbiome is the ecosystem of trillions of microorganisms — bacteria, fungi, viruses, and archaea — that live in your gastrointestinal tract. These organisms play critical roles in digestion, immune regulation, hormone production, and even brain function. No two microbiomes are alike; yours is as unique as a fingerprint.
Dysbiosis — an imbalance in the microbiome — can be triggered by antibiotics, a diet high in processed foods and sugar, chronic stress, poor sleep, environmental toxins, and infections. Even a single course of antibiotics can alter microbial diversity for months. The good news: the microbiome is highly responsive to positive lifestyle changes.
Through the gut-brain axis, your gut and brain communicate bidirectionally via the vagus nerve, immune signalling, and neurotransmitter production. Around 90% of the body's serotonin is synthesised in the gut. Disruptions to the microbiome are increasingly linked to anxiety, depression, cognitive fog, and poor stress resilience.
Yes. Centenarian studies consistently show greater microbial diversity and lower systemic inflammation compared to age-matched controls. Chronic gut dysbiosis drives inflammaging — low-grade, persistent inflammation that accelerates biological ageing across virtually every organ system. Optimising your gut is one of the highest-leverage longevity interventions available.
A diverse, fibre-rich diet is the single strongest predictor of microbiome diversity. Fermented foods (yoghurt, kefir, kimchi, sauerkraut), prebiotic fibres (onions, garlic, leeks, oats), polyphenol-rich foods (berries, olive oil, dark chocolate), and omega-3 fatty acids all show consistent benefit. Ultra-processed foods, artificial sweeteners, and excess alcohol are the primary dietary disruptors.
FOXO is a longevity health platform that translates cutting-edge biological science into personalised, actionable intelligence. We track functional systems — starting with the gut — to help you understand your biology at a deeper level and make decisions grounded in your own data, not generic population averages.
Waitlist members get priority early access when FOXO launches, along with exclusive educational content, behind-the-scenes product updates, and the opportunity to shape the product through early feedback sessions. We'll reach out with a personal invite when your spot is ready.
Neither — and both, eventually. FOXO is building a functional health intelligence platform. Our initial focus is on helping you understand and track your gut health through biomarker data and personalised insights. Specific recommendations — whether dietary, lifestyle, or supplemental — will be evidence-graded and tailored to your individual biology.
Still have questions? We're happy to help.
Contact UsHow FOXO Helps
Tools Built for the
Biology That Matters
FOXO translates the latest gut health science into actionable intelligence — so you can make decisions grounded in your own biology, not generic advice.
Personalised Biomarker Tracking
Monitor the specific markers that reflect your gut's functional state in real time.
Longitudinal Health Trends
See how your gut changes over weeks and months — not just a snapshot.
Science-Backed Interventions
Receive evidence-graded recommendations tailored to your unique microbiome profile.
Microorganisms in the gut microbiome
Of immune cells reside in gut tissue
Of serotonin is produced in the gut
More genes than the human genome