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ADHD

Overview

ADHD shares overlapping biological dysfunctions with other neurocognitive conditions, notably chronic inflammation, neurochemical imbalance, mitochondrial impairment, oxidative stress, impaired methylation, gut–brain axis disruption, and glucose dysregulation (see Tardy et al. 2020; Mohamed and Kobeissy 2024). Targeted dietary trials—from restricted elimination diets to Mediterranean-leaning protocols—show modest yet reproducible symptom relief alongside cardiometabolic benefits (see Stevenson et al. 2014; Darabi et al. 2022; Aksoy and Doguer 2025).

Biological Target Matrix

Gut–Brain Axis & Enteric Nervous System (ENS)

Gut–Brain Axis & Enteric Nervous System (ENS)

SubstanceFoodsMechanism of Action
BerberineSuppresses SIBO, Candida, and pathobionts; reduces LPS translocation; increases nutrient absorption (B12, iron, tryptophan); increases SCFA resilience
Beta-GlucansAct as prebiotics supporting beneficial gut bacteria; enhance microbial diversity; support SCFA production; modulate gut barrier integrity
CholineCholine is metabolised by gut bacteria; some strains (e.g. Lactobacillus) can produce acetylcholine. Microbial choline metabolism (e.g. trimethylamine) shows inter-individual variability and may influence host metabolism and gut–brain signalling.
EGCG (Green Tea Catechin)Green tea catechins increase Faecalibacterium and Roseburia; inhibit Enterobacteriaceae; reduce NF-κB activation
PolysaccharidesAct as prebiotics supporting beneficial gut bacteria; enhance microbial diversity; support SCFA production; modulate gut barrier integrity
AcetateByproduct of fibre fermentation; supports intestinal barrier integrity; regulates immune responses; promotes synthesis of key neurotransmitters such as dopamine and serotonin
ButyrateByproduct of fibre fermentation; supports intestinal barrier integrity; regulates immune responses; promotes synthesis of key neurotransmitters such as dopamine and serotonin
PropionateByproduct of fibre fermentation; supports intestinal barrier integrity; regulates immune responses
Short-Chain Fatty Acids (SCFAs)Byproducts of fibre fermentation; support intestinal barrier integrity; regulate immune responses; promote synthesis of key neurotransmitters such as dopamine and serotonin
Urolithin AProduced from ellagitannins by gut bacteria; production varies by individual gut microbiome composition, particularly Firmicutes-to-Bacteroidetes ratio; higher polyphenol intake and microbial diversity increase urolithin A production
GlycineSupports gut barrier integrity through collagen and gelatin synthesis; helps seal gut lining and reduce permeability; affects inflammation and gut-brain communication
Vitamin DSupports gut barrier integrity; nutrient deficiencies including vitamin D disrupt tight junctions, increasing permeability
Inflammation & Oxidative Stress

Inflammation & Oxidative Stress

SubstanceFoodsMechanism of Action
BerberineReduces LPS translocation and dampens LPS-driven inflammation through antimicrobial effects on pathobionts
Beta-GlucansImmune-modulating properties; may help reduce inflammatory responses; support immune cell function; specific beta-glucans like lentinan (Shiitake) and D-fraction (Maitake) have been extensively studied for immune support
CholineCholine-derived betaine supports homocysteine remethylation; elevated homocysteine is linked to oxidative stress and inflammatory signalling. Phosphatidylcholine supports membrane integrity and cell signalling in immune and redox contexts.
EGCG (Green Tea Catechin)Polyphenol antioxidant and anti-inflammatory effects; reduces inflammatory signaling
PolysaccharidesImmune-modulating properties; may help reduce inflammatory responses; support immune cell function
AcetateSupports immune regulation and anti-inflammatory processes
ButyrateHas anti-inflammatory effects, potentially reducing neuroinflammation; deficiencies linked to many neurological disorders including ADHD
PropionateHelps reduce neuroinflammation and protects the blood-brain barrier; enhances cognitive function
Short-Chain Fatty Acids (SCFAs)Butyrate has anti-inflammatory effects, potentially reducing neuroinflammation; propionate helps reduce neuroinflammation and protects the blood-brain barrier
Urolithin APowerful antioxidant; supports anti-inflammatory effects
Quercetin (and Isoquercetin)Anti-inflammatory, anti-neuroinflammatory, and neuroprotective properties; supports gut barrier integrity and TLR4 suppression
Omega-3 Fatty AcidsSpecialized Pro-Resolving Mediators (SPMs) - resolvins, protectins, maresins terminate inflammation without immunosuppression, downregulate COX-2, inhibit neutrophil infiltration, enhance macrophage clearance, limit glutamate-induced excitotoxicity. Production of DHEA and EPEA (N-acyl ethanolamines) feeds into CB2-related anti-inflammatory signalling; ECS lipid mediators regulate immune tone and microglial activation (primary anchor for ECS mechanism: Inflammation & Oxidative Stress).
Vitamin C (Ascorbate)Antioxidant properties; supports anti-inflammatory effects
β-CaroteneAnti-inflammatory properties; supports immune regulation
LuteinAnti-inflammatory properties; supports immune regulation
LycopeneAnti-inflammatory properties; supports immune regulation
ZeaxanthinAnti-inflammatory properties; supports immune regulation
Curcumin (Turmeric)Anti-inflammatory and neuroprotective effects; supports BDNF expression through polyphenol synergy
GenisteinAnti-inflammatory and anti-neuroinflammatory properties; reduces neuroinflammation
Hydroxytyrosol (Olive Polyphenol)Strong anti-inflammatory profile; contributes to neuroprotective effects of extra-virgin olive oil
OleocanthalNF-κB inhibition; strong anti-inflammatory effects similar to ibuprofen; contributes to neuroprotective effects of extra-virgin olive oil
OleuropeinAnti-inflammatory properties; contributes to neuroprotective effects of extra-virgin olive oil
Saffron (Crocin, Safranal)Anti-inflammatory effects
ALA (Alpha-Linolenic Acid)Essential omega-3 precursor; limited conversion to DHA/EPA; contributes to omega-3 pool for anti-inflammatory effects
DHA (Docosahexaenoic Acid)Precursor to specialized pro-resolving mediators (SPMs) including protectins and maresins; terminates inflammation without immunosuppression. Production of docosahexaenoyl ethanolamide (DHEA), an N-acyl ethanolamine for endocannabinoid-like signalling, feeds into CB2-related anti-inflammatory signalling; ECS lipid mediators regulate immune tone and microglial activation (primary anchor: Inflammation & Oxidative Stress).
DPA (Docosapentaenoic Acid)Important in vascular health, repair, and immune modulation; emerging brain-health roles (less studied than EPA and DHA)
EPA (Eicosapentaenoic Acid)Potent anti-inflammatory; precursor to E-series resolvins; specialized pro-resolving mediators (SPMs) terminate inflammation without immunosuppression, downregulate COX-2, inhibit neutrophil infiltration, enhance macrophage clearance. Production of eicosapentaenoyl ethanolamide (EPEA), an N-acyl ethanolamine for endocannabinoid-like signalling, feeds into CB2-related anti-inflammatory signalling; ECS lipid mediators regulate immune tone and microglial activation (primary anchor: Inflammation & Oxidative Stress).
Arachidonic Acid (AA, n-6)Omega-6 PUFA that gives rise to eicosanoids with predominantly pro-inflammatory actions; overall dietary n-6:n-3 balance affects inflammatory tone
Linoleic Acid (LA, n-6)Essential omega-6 fatty acid; precursor to arachidonic acid and eicosanoids; excessive n-6:n-3 ratios may skew toward pro-inflammatory eicosanoids
CopperParticipates in redox enzymes and antioxidant networks
ZincSupports immune signaling; gut barrier integrity disrupted by nutrient deficiencies including zinc
Metabolic & Neuroendocrine Stress (HPA Axis & ANS)

Metabolic & Neuroendocrine Stress (HPA Axis & ANS)

SubstanceFoodsMechanism of Action
CholineCholine supports hepatic VLDL assembly and lipid export; methyl donors (choline, betaine) may influence adenosine metabolism and HPA axis activity. Adequate choline status supports metabolic stability and stress physiology.
EGCG (Green Tea Catechin)Contributes to stress buffering through polyphenol effects
GlycineImproves sleep latency and quality; supports stress resilience through improved sleep regulation
Vitamin DModulates immune responses to reduce inflammation in the brain; supports stress response through neurotrophic and immune effects
L-TheanineIncreases alpha waves and promotes calm without sedation; supports relaxation
Quercetin (and Isoquercetin)Contributes to LPS and immune defense; supports stress response modulation
TaurineBuffers HPA axis dysregulation; reduces cortisol; supports stress resilience
Phosphatidylserine (PS)Supports membrane dynamics and signaling; used for cognition and stress modulation
Omega-3 Fatty AcidsImprove vagal tone and HRV control, improve cortisol rhythms
MagnesiumHelps manage stress responses; combined with vitamin D reduced behavioral problems; synergy with zinc and omega-3s reported
Vitamin B5 (Pantothenic Acid)Supports stress response through energy metabolism and ATP production
Vitamin C (Ascorbate)Supports stress response through antioxidant and neurochemical effects
Methylation & One-Carbon Metabolism

Methylation & One-Carbon Metabolism

SubstanceFoodsMechanism of Action
CholinePrecursor to trimethylglycine (TMG/betaine), a dietary methyl donor that helps recycle homocysteine to methionine via an alternative pathway; supports one-carbon metabolism alongside folate, riboflavin, and B12; influences methylation dynamics relevant to MTHFR and COMT activity
Omega-3 Fatty AcidsSupport homocysteine reduction in combination with B12, phospholipid methylation (PLM) dependent on SAMe
ZincDeficiencies in vitamins and minerals essential for methylation, such as folate, vitamin B12, and zinc, are correlated to ADHD symptoms; supplementing these micronutrients has shown potential in supporting methylation and reducing symptom severity
MethionineEssential amino acid that forms S-adenosylmethionine (SAMe), the universal methyl donor for neurotransmitter synthesis and membrane phospholipid methylation
Vitamin B12 (Cobalamin)Essential cofactor in remethylation of homocysteine to methionine, which is converted to S-adenosylmethionine (SAMe); works with B6, B2, and folate; contributes meaningfully to homocysteine reduction, especially in combination with omega-3 fatty acids
Vitamin B2 (Riboflavin)FAD acts as a critical cofactor for MTHFR, linking riboflavin to homocysteine recycling and methylation capacity
Vitamin B6 (Pyridoxine → PLP)Essential cofactor in remethylation of homocysteine to methionine, which is converted to S-adenosylmethionine (SAMe); works with B2, folate, and B12
Vitamin B9 (Folate; 5-MTHF)Essential cofactor in remethylation of homocysteine to methionine, which is converted to S-adenosylmethionine (SAMe); SAMe fuels synthesis of dopamine, norepinephrine, and serotonin and drives phospholipid methylation in neuronal membranes
Mitochondrial Function & Bioenergetics

Mitochondrial Function & Bioenergetics

SubstanceFoodsMechanism of Action
CholinePhosphatidylcholine and other choline-containing phospholipids support mitochondrial membrane integrity and energy metabolism; choline-derived betaine contributes to one-carbon status that can influence mitochondrial resilience
ButyrateSupports mitochondrial function, enhancing brain energy metabolism; aids in reducing cholesterol and neuroinflammation
Short-Chain Fatty Acids (SCFAs)Butyrate supports mitochondrial function, enhancing brain energy metabolism; aids in reducing cholesterol and neuroinflammation
Urolithin ASupports mitochondrial resilience and mitophagy; improves cognitive endurance; may extend to executive function
Quercetin (and Isoquercetin)Enhances mitochondrial baseline activity and energy production; supports mitochondrial function
TaurineProtects mitochondrial function under oxidative stress; stabilizes mitochondrial membranes; supports ATP production
Omega-3 Fatty AcidsECS-related lipid signalling may influence mitochondrial coupling/efficiency (context-dependent; largely preclinical). Omega-3 incorporation changes membrane fluidity (secondary anchor for ECS mechanism: Mitochondrial Function & Bioenergetics).
MagnesiumSupports enzymes involved in glycolysis and the Krebs cycle (processes that generate ATP from glucose); binds to ATP and all triphosphates in cells to activate them
Vitamin B5 (Pantothenic Acid)Forms CoA (coenzyme A), required for β-oxidation and TCA cycle acetyl-CoA flux; deficiency impairs ATP production impacting brain energy
OleuropeinOleuropein aglycone (the active form) supports mitophagy, SIRT1 activation, and AMPK activation; enhances mitochondrial function, autophagy, and neuroprotective effects through modulation of mitochondrial dynamics and antioxidant pathways
DHA (Docosahexaenoic Acid)ECS-related lipid signalling may influence mitochondrial coupling/efficiency (context-dependent; largely preclinical). Omega-3 incorporation changes membrane fluidity (secondary anchor for ECS mechanism: Mitochondrial Function & Bioenergetics).
EPA (Eicosapentaenoic Acid)ECS-related lipid signalling may influence mitochondrial coupling/efficiency (context-dependent; largely preclinical). Omega-3 incorporation changes membrane fluidity (secondary anchor for ECS mechanism: Mitochondrial Function & Bioenergetics).
Vitamin B1 (Thiamine)Essential for mitochondrial glucose metabolism in the brain leading to ATP production; supports PDH (pyruvate dehydrogenase) and α-KGDH (alpha-ketoglutarate dehydrogenase) function
Vitamin B12 (Cobalamin)Crucial role in conversion of methylmalonyl-CoA to succinyl-CoA, a key step in mitochondrial energy production; deficiency leads to buildup of methylmalonic acid and odd-chain fatty acids, which are neurotoxic
Vitamin B2 (Riboflavin)Forms FMN/FAD coenzymes, supporting oxidative metabolism and redox balance; facilitates metabolism of B12, B6, and niacin; supports antioxidant enzymes
AstaxanthinSupports mitochondrial and cellular resilience through antioxidant protection
Coenzyme Q10 (CoQ10)Electron transport chain cofactor; supports ATP production; antioxidant protection for neurons
CreatineSupports ATP recycling via phosphocreatine system; buffers high-energy demand in neurons; enhances mitochondrial energy buffering
NitrateDietary nitrates convert to nitric oxide (NO), which supports vascular function and cerebral blood flow, enhancing oxygen and nutrient delivery to brain tissue; nitric oxide improves mitochondrial efficiency by optimizing blood flow and supporting vascular tone
ArgininePrecursor for creatine synthesis (along with glycine and methionine); creatine supports ATP recycling via the phosphocreatine system in neurons; important for vegetarians who rely on endogenous creatine synthesis
Capric Triglyceride (Tridecanoin)Capric triglyceride (C10) is converted to ketones (beta-hydroxybutyrate) in the liver, which serve as an alternative energy substrate for mitochondria; ketones can be used by brain mitochondria when glucose metabolism is impaired, supporting ATP production and mitochondrial function
Caproic Triglyceride (Tricaproin)Caproic triglyceride (C6) is converted to ketones (beta-hydroxybutyrate) in the liver, which serve as an alternative energy substrate for mitochondria; ketones can be used by brain mitochondria when glucose metabolism is impaired, supporting ATP production and mitochondrial function
Caprylic Triglyceride (Trioctanoin)Caprylic triglyceride (C8) is converted to ketones (beta-hydroxybutyrate) in the liver, which serve as an alternative energy substrate for mitochondria; ketones can be used by brain mitochondria when glucose metabolism is impaired, supporting ATP production and mitochondrial function
MCT (Medium-Chain Triglycerides)MCTs are converted to ketones (beta-hydroxybutyrate) in the liver, which serve as an alternative energy substrate for mitochondria; ketones can be used by brain mitochondria when glucose metabolism is impaired, supporting ATP production and mitochondrial function
IronCritical for oxygen delivery to the brain via hemoglobin; supports mitochondrial function and energy production
ManganeseSupports mitochondrial antioxidant defense through MnSOD activity
SeleniumProtects mitochondria from oxidative damage through antioxidant enzyme activity
Vitamin B3 (Niacin; Niacinamide)Replenishes NAD+, supporting oxidative phosphorylation, sirtuin signaling, and mitochondrial biogenesis; key for neuronal energy metabolism
Neurotransmitter Regulation

Neurotransmitter Regulation

SubstanceFoodsMechanism of Action
CholineEssential precursor for acetylcholine synthesis, supporting memory, learning, and neuroplasticity; supports membrane phospholipid biosynthesis (PC) which is critical for membrane fluidity and neurotransmitter receptor function; phospholipid methylation (PLM) alters membrane structure, facilitating faster neuronal recovery and influencing ion channel behavior in gamma oscillations linked to attention and cognition
PropionateStimulates secretion of norepinephrine and may influence dopamine regulation; promotes synthesis of key neurotransmitters
Short-Chain Fatty Acids (SCFAs)Propionate stimulates secretion of norepinephrine and may influence dopamine regulation; SCFAs promote synthesis of dopamine and serotonin
GlycineActs as an inhibitory neurotransmitter; improves sleep latency and quality; supports GABA pathways and neurotransmitter balance
L-TheanineSupports GABAergic tone and neurotransmitter balance
TaurineModulates calcium handling; influences GABAergic tone; supports neurotransmitter balance
Phosphatidylserine (PS)Supports neuronal membrane dynamics and signaling
Omega-3 Fatty AcidsMembrane fluidity and neurotransmitter receptor function, ion channel behavior and gamma oscillations, support neurotransmission and phospholipid methylation
CalciumEssential for nerve impulse transmission and neurotransmission
MagnesiumBroad cofactor for neurotransmitter synthesis and receptor modulation (e.g., NMDA, GABA); functions as an NMDA receptor antagonist and GABA receptor modulator; assists enzymes involved in synthesis of dopamine and serotonin
IodineThyroid hormones regulate synthesis and regulation of key neurotransmitters (dopamine and serotonin), supporting cognitive function and development
Vitamin C (Ascorbate)Supports norepinephrine synthesis; transported in brain via SVCT2
GenisteinEnhances endocannabinoid activity; modulates dopamine, glutamate, and GABA signaling pathways
Saffron (Crocin, Safranal)Thought to boost serotonin; supports mood regulation and cognitive function
DHA (Docosahexaenoic Acid)Accounts for ~10–15% of total brain fatty acids, but represents 20–30% of fatty acids in neuronal phospholipids such as PE and PS, and more than 90% of the brain's omega-3 PUFA; critical for membrane fluidity, synaptic vesicle fusion, and neurodevelopment; transported across BBB as LPC-DHA via MFSD2A
EPA (Eicosapentaenoic Acid)Modulates dopamine and serotonin signalling; synergises with DHA but has independent mechanisms; membrane fluidity and neurotransmitter receptor function
CopperCofactor in dopamine β-hydroxylase, supporting catecholamine synthesis; supports norepinephrine synthesis
ZincImportant for DNA synthesis, cell division, and neurotransmitter regulation, particularly in modulating dopamine—a key neurotransmitter implicated in ADHD; acts as an allosteric modulator of the GABA receptor; supports glutamate regulation
Vitamin B12 (Cobalamin)Supports neurotransmitter production through methylation; essential for myelin synthesis
Vitamin B6 (Pyridoxine → PLP)Cofactor for synthesis of dopamine, serotonin, GABA, and glutamate; supports rate-limiting steps in catecholamine synthesis; requires PDXK activation with magnesium and ATP support
Vitamin B9 (Folate; 5-MTHF)Supports neurotransmitter synthesis through methylation; cofactor for dopamine synthesis alongside iron, B6, and omega-3s
ArgininePrecursor for nitric oxide (NO) synthesis; nitric oxide supports cerebral blood flow and vascular function
Capric Triglyceride (Tridecanoin)Ketones produced from capric triglyceride provide ATP through mitochondrial metabolism; ATP is essential for neurotransmitter synthesis, release, and reuptake, indirectly supporting neurochemical balance by ensuring adequate energy for neuronal function
Caproic Triglyceride (Tricaproin)Ketones produced from caproic triglyceride provide ATP through mitochondrial metabolism; ATP is essential for neurotransmitter synthesis, release, and reuptake, indirectly supporting neurochemical balance by ensuring adequate energy for neuronal function
Caprylic Triglyceride (Trioctanoin)Ketones produced from caprylic triglyceride provide ATP through mitochondrial metabolism; ATP is essential for neurotransmitter synthesis, release, and reuptake, indirectly supporting neurochemical balance by ensuring adequate energy for neuronal function
MCT (Medium-Chain Triglycerides)Ketones produced from MCTs provide ATP through mitochondrial metabolism; ATP is essential for neurotransmitter synthesis, release, and reuptake, indirectly supporting neurochemical balance by ensuring adequate energy for neuronal function
IronEssential cofactor for tyrosine hydroxylase, the rate-limiting enzyme in the conversion of tyrosine to dopamine; critical for catecholamine synthesis
L-DOPADirect precursor to dopamine synthesis; bypasses rate-limiting tyrosine hydroxylase step; supports dopamine availability for attention, motivation, and executive function
TyrosolNeuroprotective effects; contributes to brain health benefits of extra-virgin olive oil
TyrosineCatecholamine precursor (dopamine, norepinephrine); brain transport via LAT1 competes with other LNAAs; iron is an essential cofactor for tyrosine hydroxylase, the rate-limiting enzyme in conversion of tyrosine to dopamine; cofactors include iron, B6, folate, omega-3s, and BH₄ (tetrahydrobiopterin) to support rate-limiting steps in catecholamine synthesis
PhenylalanineEssential amino acid that converts to tyrosine and supports catecholamine synthesis (dopamine, norepinephrine); participates in LAT1 competition at the blood-brain barrier
TryptophanPrecursor for serotonin and melatonin; brain entry competes at LAT1 with other large neutral amino acids (LNAAs); carbohydrate-rich, low-protein meals raise the plasma tryptophan:LNAA ratio because insulin pushes competing LNAAs out to muscles; can feed NAD+ synthesis via the kynurenine pathway
Phosphatidylcholine (PC)Major neuronal membrane phospholipid central to membrane fluidity, receptor function, and acetylcholine synthesis; DHA/EPA incorporated into PC are converted to lysophosphatidylcholine (LPC), a key transport form across the BBB
PotassiumCritical for membrane potential, nerve signaling, and neuronal excitability; adequate intake balances sodium effects
SodiumSupports fluid balance, nerve impulse transmission, and muscle function; balance with potassium is relevant for blood pressure and neuronal excitability

References