Biological Regulatory Systems
The BRAIN Framework was developed from research into ADHD, depression, anxiety, cognitive decline, and other brain-related disorders. Across these conditions, studies have repeatedly identified associations within six broad biological domains: neurotransmitter regulation, methylation, inflammation and oxidative stress, bioenergetics, gut–brain signalling, and metabolic regulation.
These recurring themes are organised into six Biological Regulatory Systems (BRS), which form the foundation of the BRAIN Diet. The framework proposes that these systems do not operate in isolation but interact as part of a wider regulatory architecture. Their combined state may therefore be more informative than viewing individual nutrients, pathways, or mechanisms alone.
The Six Biological Regulatory Systems
BRS1 - Neurotransmitter Regulation
Signal layer: synaptic communication and behavioural expression.
BRS2 - Methylation & One-Carbon Metabolism
Biochemical regulation: synthesis, repair, and epigenetic control.
BRS3 - Inflammation & Oxidative Stress
Immune/redox regulation: inflammatory tone, antioxidant defence, and repair balance.
BRS4 - Mitochondrial Function & Bioenergetics
Capacity layer: ATP production, mitochondrial resilience, and bioenergetic efficiency.
BRS5 - Gut-Brain Axis & Enteric Nervous System
Peripheral neural-immune interface: gut signalling, microbial metabolites, and vagal integration.
BRS6 - Metabolic & Neuroendocrine Stress
Whole-body regulation: stress allocation, autonomic tone, hormonal coordination, and energy prioritisation.
BRS-X - Cross-System Regulation
Cross-system networks spanning multiple BRS domains — including the endocannabinoid system and hormone signalling.
Diet and lifestyle are interpreted as inputs that influence the biological conditions within which these systems operate. By supporting the nutritional and environmental requirements of multiple BRS simultaneously, the framework aims to promote greater biological balance, resilience, and brain health across the lifespan.
Future versions of the BRAIN Diet Framework will include detailed mechanisms for cross-system modulators such as sleep, circadian alignment, physical activity, and stress regulation. For now, these are highlighted under section 7 Lifestyle Levers on each primary mechanism page.
At a practical level, meals are designed as a complementary rotation across the day, aligned with natural rhythms from breakfast through to dinner. Rather than trying to optimise everything in a single meal, each meal plays a role, and each day builds on the next, creating a balanced pattern over time. This reflects how the body actually uses nutrients-absorbing, storing, and reusing them dynamically-so meals are structured to work together, supporting different systems in a coordinated and sustainable way.
Within each system:
- Key Constraints (KCs) describe shared substrate, precursor, and structural biological pools whose availability constrains the effective operation of multiple primary mechanisms.
- Primary Mechanisms (PMs) describe the core biological mechanisms, processing systems, and regulatory interactions operating within those shared constraints.
- Functional Mechanisms (FMs) represent integrated biological states that emerge from the coordinated activity of related Primary Mechanisms (PMs). They describe the functional capacities, desired states or regulatory conditions that arise from underlying biological processes and serve as the principal biological targets of the framework.
- Specific Mechanisms (SMs) are interpretation layers that provide additional biological context for applying the BRAIN Framework. Current SM categories include SM-SNP (genetic variation), SM-Male and SM-Female (sex-specific biology), SM-Lifestage (e.g. childhood, pregnancy, older adulthood), SM-Pattern (e.g. vegan, vegetarian, ketogenic), and SM-Phenotype (e.g. hyperarousal, emotional dysregulation, sensory regulation). Individual SMs may be combined to create richer biological profiles and support future precision-nutrition applications.
How the framework organises biology
The BRAIN Framework draws conceptually on Metabolic Control Analysis [1], constraint-based biology [2], and allostatic physiology [3][4]. MCA supports the idea that biological control is distributed across networks rather than governed by single rate-limiting steps [1]. Constraint-based models show that biological systems operate within feasible state spaces shaped by substrate, energetic, enzymatic, and resource-allocation limits [2]. Allostasis and allostatic load describe regulatory capacity dynamically allocated under adaptive, behavioural, and environmental pressures, with cumulative cost when stress-mediator systems are chronically overactive or poorly regulated [3][4]. Together, these ideas support the framework’s hierarchy of KCs as shared feasibility conditions, PMs as operational biological mechanisms, FMs as integrated biological states, and SMs as context-dependent expressions of those states [1][2][3][4].
Biological effects rarely arise from a single nutrient, pathway, or control point in isolation; they emerge through the integration of multiple systems operating under shared physiological demands [1][2][3][4].
Within each system, Key Constraints (KCs) describe shared substrate, precursor, and structural biological pools whose availability constrains the effective operation of multiple primary mechanisms. These are not themselves mechanisms; they are distributed biological infrastructure within which multiple downstream processes must operate. Examples include amino acid substrate availability, methyl donor sufficiency, essential fatty acid balance, and fermentable substrate availability [1][2].
Primary Mechanisms (PMs) describe the core biological mechanisms, processing systems, and regulatory interactions operating within those shared constraints. Functional Mechanisms (FMs) represent integrated biological states that emerge from the coordinated activity of related Primary Mechanisms (PMs). They describe the functional capacities, desired states or regulatory conditions that arise from underlying biological processes and serve as the principal biological targets of the framework. Specific Mechanisms (SMs) are interpretation layers for context-specific interpretations of established biological regulation — phenotype-sensitive, variant-sensitive, or cross-system — without redefining PM or FM biology.
Viewed this way, the framework is not intended to divide biology into separate boxes. It is a structured way of understanding how shared constraints, distributed regulation, integrated biological states, and context-specific expression interact across the six systems that contribute to our brain and overall health.