Free shipping on orders over €95 · Ceremonial Grade · Single Origin Vietnam · Contact Sales →
Ceremonial Grade
Single Origin Vietnam
100% Pure Cacao
Stone Ground
No Sugar · No Additives
Direct Trade Farmers
Ethical Sourcing
Vegan · Keto
Ceremonial Grade
Single Origin Vietnam
100% Pure Cacao
Stone Ground
No Sugar · No Additives
Direct Trade Farmers
Health Science · Cognitive Performance · Bioactives

Cacao & Focus

The neuroscience of how ceremonial cacao enhances sustained attention — through PDE inhibition, flavanol-mediated cerebral blood flow, dopaminergic modulation, and a multi-compound neuroactive matrix found in no other whole food.

📅 March 2026 ⏱ 14 min read Science-backed 21 References Cognitive Performance
Cacao & Focus — Clinical Reference Fact Sheet
Primary mechanism
PDE inhibition → cAMP/cGMP ↑ → dopaminergic modulation
Cerebral blood flow
↑ via flavanol-induced NO synthesis
Theobromine / 25g
~400–500mg · PDE inhibitor · 6–10h half-life
Flavanols / 25g
~150–200mg epicatechin + catechin
Focus onset
30–60 min · peak 1–2h · sustained 4–6h
Adenosine receptor
NOT blocked · no crash · no rebound
Cortisol impact
Neutral · no HPA axis activation
Cognitive RCT evidence
Working memory ↑ · processing speed ↑
Mood-cognitive synergy
PEA · Anandamide · MAO-B inhibitors
Tolerance development
Low · distinct from caffeine mechanism

What Is Cognitive Focus — And Why Does It Fail?

Sustained attention — the capacity to maintain effortful cognitive engagement over a period of time — is mediated primarily by prefrontal cortical circuits and their dopaminergic innervation. Attentional control degrades predictably under conditions of low dopamine tone, high cognitive load, disrupted cerebral oxygenation, and elevated cortisol — all of which are measurably modifiable by nutritional bioactives.

The standard pharmacological approach to focus enhancement targets either adenosine receptors (caffeine) or catecholamine reuptake transporters (amphetamine-class stimulants). Ceremonial cacao operates through a fundamentally different set of mechanisms: phosphodiesterase (PDE) inhibition, nitric oxide–mediated cerebral vasodilation, and a multi-compound neuromodulatory matrix that simultaneously supports dopamine tone, reduces cognitive interference, and optimises cerebrovascular delivery of oxygen and glucose to active neurons.

Mechanistic distinction: Caffeine blocks adenosine A1 and A2A receptors — blocking the signal of fatigue but also triggering cortisol release and creating receptor upregulation (tolerance). Theobromine inhibits phosphodiesterase enzymes, elevating intracellular cAMP and cGMP — a distinct upstream mechanism that modulates neuronal excitability without adenosine antagonism and without triggering the cortisol cascade.

Bioactive Focus Matrix: Chemical Identity & Dose Profile

A 25g serving of ceremonial-grade stone-ground cacao paste delivers the following focus-relevant bioactives in a single food matrix — a convergence found in no other whole food or plant beverage:

Focus Bioactives — 25g Ceremonial Cacao Serving
Theobromine
~400–500mg · Methylxanthine
Primary stimulant. PDE inhibitor → elevates cAMP/cGMP → dopaminergic tone ↑. Half-life 6–10h. Peripheral vasodilator. No adenosine receptor blockade.
Epicatechin + Catechin (Flavanols)
~150–200mg · Flavanols
Upregulate eNOS → NO synthesis → cerebral vasodilation → ↑ O₂ and glucose delivery to prefrontal cortex. Also upregulate BDNF, supporting synaptic plasticity.
Phenylethylamine (PEA)
Trace-moderate · Trace amine
Endogenous trace amine. Releases dopamine and norepinephrine at synaptic level. Enhances attentional arousal and motivational salience. Normally rapidly metabolised — extended by cacao's MAO-B inhibitors.
Anandamide (+ FAAH Inhibitors)
Trace · Endocannabinoid
CB1 receptor agonist. Reduces cognitive interference and anxiety-driven attentional disruption, widening effective attentional bandwidth. Cacao inhibits FAAH — the enzyme that degrades anandamide — prolonging its effect.
MAO-B Inhibitors
Polyphenolic matrix · Monoamine oxidase inhibitors
Slow the degradation of dopamine, serotonin, and PEA at the synapse. Extend and amplify the effect of all catecholaminergic bioactives in the cacao matrix — a natural entourage amplifier.
Magnesium
~64mg · 16% RDI
NMDA receptor co-factor. Magnesium deficiency directly impairs working memory and executive function. Regulates HPA axis — lowering baseline cortisol and reducing cognitive load from chronic stress.
Caffeine
~5–15mg (trace only)
Present only in trace amounts (~5–15mg per 25g, vs ~80–150mg in coffee). Contributes modestly to adenosine antagonism without the cortisol and anxiety liabilities of high-dose caffeine.
Procyanidins + Polyphenols
Variable · Oligomeric flavanols
Activate Nrf2 pathway → upregulate endogenous antioxidant enzymes → reduce neuroinflammation. Chronic neuroinflammation is a direct suppressor of prefrontal cognitive function.

Mechanism of Action: Four Converging Pathways

Ceremonial cacao's focus effect is not attributable to a single compound but emerges from the convergence of four independent, mechanistically distinct pathways acting simultaneously on cognitive function:

1
PDE Inhibition · Dopaminergic Pathway
Theobromine — Phosphodiesterase Inhibition & Dopaminergic Tone
Theobromine is a non-selective phosphodiesterase (PDE) inhibitor. PDEs are the enzymes responsible for breaking down cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) — the intracellular second messengers that mediate dopaminergic and noradrenergic signalling in prefrontal cortical neurons. By inhibiting PDE, theobromine elevates intracellular cAMP and cGMP levels, prolonging and amplifying catecholaminergic signal transduction. In prefrontal circuits, this corresponds to enhanced D1 receptor signalling — the primary dopaminergic mechanism for working memory, attentional control, and goal-directed behaviour.12 Critically, this mechanism does not involve adenosine receptor blockade and therefore does not trigger the cortisol release, tolerance development, or adenosine rebound crash characteristic of caffeine.
2
NO-Mediated Vasodilation · Cerebrovascular Pathway
Flavanols — Cerebral Blood Flow Enhancement via Nitric Oxide
Epicatechin and catechin — cacao's primary flavanols — upregulate endothelial nitric oxide synthase (eNOS) in cerebral blood vessel walls. The resulting increase in nitric oxide (NO) production causes smooth muscle relaxation and vasodilation in cerebral arteries and arterioles, increasing blood flow to metabolically active regions of the brain.3 fMRI studies have directly visualised this: following flavanol-rich cocoa consumption, cerebrovascular reactivity increases significantly in frontal and parietal regions — precisely the cortical areas supporting attention, working memory and executive function.4 For cognitive tasks requiring sustained effort, the limiting factor is often not neuronal capacity but metabolic substrate delivery — and flavanol-mediated vasodilation directly addresses this constraint.
3
Monoaminergic Pathway · Attentional Arousal
PEA + MAO-B Inhibition — Dopamine and Norepinephrine Amplification
Phenylethylamine (PEA) is an endogenous trace amine that releases dopamine and norepinephrine at the synaptic level, producing a state of heightened attentional arousal and motivational engagement. Under normal dietary conditions, PEA is rapidly metabolised by monoamine oxidase B (MAO-B) — its half-life is extremely short. Cacao's polyphenolic matrix contains compounds with mild MAO-B inhibitory activity, extending PEA's synaptic residence time and amplifying its dopaminergic and noradrenergic effects.5 The result is a modest but sustained elevation in monoaminergic tone — contributing to the subjective quality of engaged, motivated focus characteristic of ceremonial cacao consumption.
4
Endocannabinoid Pathway · Cognitive Interference Reduction
Anandamide — Widening Attentional Bandwidth via CB1 Activation
Anandamide — cacao's endocannabinoid component — activates CB1 receptors expressed throughout the prefrontal cortex and limbic system. At physiological levels, CB1 activation modulates GABAergic and glutamatergic signalling in ways that reduce anxious ruminative thought patterns — the primary source of cognitive interference in healthy adults attempting focused work.6 By attenuating the intrusion of anxious self-referential processing into working memory, anandamide effectively widens usable attentional bandwidth — allowing more cognitive resources to be allocated to the target task. Cacao additionally contains N-acylethanolamines that inhibit FAAH (fatty acid amide hydrolase), the enzyme responsible for anandamide degradation, prolonging its effect beyond what endogenous anandamide alone would produce.7

Pharmacokinetics: Onset, Peak, Duration

Understanding the time-course of cacao's focus effect enables optimal timing for cognitive work. The different bioactive components have distinct pharmacokinetic profiles that together produce a broader and more sustained cognitive support window than any single-compound stimulant.

Theobromine Pharmacokinetic Profile · 25g Ceremonial Cacao
Focus Window Parameters
30–60m
Onset of effect
1–2h
Peak cognitive support
6–10h
Theobromine half-life
None
Adenosine rebound crash
SIMULATED ALERTNESS CURVE — THEOBROMINE VS CAFFEINE (EQUIVALENT DOSE, SINGLE ADMINISTRATION)
0h 2h 4h 6h 8h 10h
Theobromine — gradual onset, extended plateau, gentle decline (~6–10h)
Caffeine — rapid spike, shorter plateau, faster decline (~3–5h)
Simulated pharmacokinetic profile based on published half-life and Tmax data. Not to clinical scale. For illustrative purposes.
Cacao Focus Timeline — Post-Consumption
0–30 minutes
Absorption & Early Onset
Theobromine and flavanols absorbed through gastrointestinal tract. Cacao butter matrix slows absorption compared to isolated compounds, producing a smoother onset. Anandamide and PEA begin entering circulation.
30–60 minutes
PDE Inhibition & Vasodilation Onset
Theobromine reaches effective plasma concentrations. PDE inhibition begins elevating cAMP/cGMP. Flavanol-mediated eNOS upregulation increases cerebral NO production. Subjective increase in mental clarity and alertness begins.
1–2 hours
Peak Cognitive Support Window
Theobromine at peak plasma concentration. Cerebral blood flow enhancement maximal — documented by fMRI at ~2h post-consumption. Dopaminergic tone elevated via cAMP pathway. Optimal window for sustained cognitive work.
2–5 hours
Sustained Background Support
Theobromine's long half-life (6–10h) maintains background PDE inhibition. Focus effect becomes subtler but remains as cognitive infrastructure rather than active stimulation — supporting work without overstimulation.
5–10 hours
Gradual Clearance — No Crash
Theobromine clears via CYP1A2 hepatic metabolism. Effect tails off gradually without adenosine rebound. Evening consumption at lower doses (15–20g) is compatible with sleep for most individuals — unlike caffeine at equivalent stimulant effect.

Clinical Evidence: Randomised Controlled Trial Data

Cacao's cognitive benefits are among the most extensively documented of any food bioactive in randomised controlled trial literature. The evidence spans both acute (single-dose) and chronic (multi-week) administration protocols:

🧠
Working Memory
A 2021 RCT in Scientific Reports (n=90) found significant improvements in working memory capacity following cocoa flavanol supplementation over 30 days in healthy adults. Effect size was meaningful across age groups and was correlated with baseline cerebral blood flow markers.8
Strong RCT evidence
Processing Speed
The same 2021 Scientific Reports RCT found significant improvements in information processing speed — a direct cognitive correlate of prefrontal blood flow and dopaminergic efficiency. Improvements were observed from week 2 of supplementation.8
Strong RCT evidence
🎯
Sustained Attention
A 2006 fMRI study directly documented increased activation in prefrontal and parietal cortex during sustained attention tasks following flavanol-rich cocoa consumption — providing mechanistic neuroimaging evidence of attention enhancement.4
Neuroimaging evidence
🧓
Executive Function (Elderly)
The CoCoA Study (2012, n=90 elderly participants with mild cognitive impairment) found significant improvements in attention, executive function and processing speed after 8 weeks of high-flavanol cocoa consumption — at doses achievable through dietary cacao.9
Strong RCT evidence
🔬
Cerebral Blood Flow (fMRI)
Flavanol-rich cocoa consumption produced measurable increases in cerebrovascular reactivity in frontal cortex on fMRI — directly correlating with improved task performance on attention and working memory tests in the same subjects.3
Neuroimaging evidence
💤
Focus Without Sleep Disruption
Unlike caffeine, theobromine's focus effect does not disrupt sleep architecture. A 2013 study found no significant sleep disruption from theobromine doses equivalent to ceremonial cacao servings, preserving the slow-wave and REM sleep that is essential for next-day cognitive performance.10
Moderate evidence

Cacao vs Other Focus Strategies: Mechanistic Comparison

Mechanism / Outcome Ceremonial Cacao Coffee (Caffeine) Matcha Nootropic Supplements
Primary mechanism PDE inhibition · cAMP/cGMP ↑ ✓ Unique Adenosine A1/A2A antagonism Adenosine antagonism + L-theanine Varies by compound
Cerebral blood flow ↑ flavanol-mediated NO synthesis Neutral / mild vasoconstriction Modest via EGCG Varies (Ginkgo: modest)
Cortisol impact Neutral — no HPA axis activation ↑ cortisol (acute) — anxiety liability Blunted by L-theanine Varies
Focus duration 6–10h (theobromine t½) ✓ Longest 3–5h (caffeine t½) 3–5h Varies
Crash / rebound None — no adenosine rebound Yes — adenosine rebound crash Mild — blunted by theanine Rarely
Tolerance development Low — distinct receptor target High — receptor upregulation Moderate Varies
Sleep disruption risk Low — sleep-compatible at standard doses High — 6h half-life disrupts sleep Moderate Low-moderate
Mood-cognitive synergy PEA + Anandamide + MAO-B inhibitors ✓ Unique None beyond stimulation L-theanine (calming) Limited
Mineral support (cognitive) Magnesium 64mg — NMDA co-factor Depletes Mg (urinary excretion ↑) Minimal Depends on formulation
Peer-reviewed RCT data Multiple cognitive RCTs Multiple (mostly acute) Some Variable — often limited

The Entourage Effect: Why Whole Cacao Outperforms Isolated Compounds

The focus effects documented in cacao research cannot be replicated by consuming any single compound in isolation. The cognitive benefit of ceremonial cacao is an emergent property of the whole-food bioactive matrix — what might be called a neurochemical entourage effect, directly analogous to the polypharmacopoeia effects observed in herbal medicine and whole-plant research.

Theobromine's PDE inhibition creates the cAMP/cGMP environment in which dopaminergic signalling operates more efficiently. Flavanols ensure that cerebral vasodilation delivers adequate oxygen and glucose to the neurons whose firing is being optimised by theobromine. PEA provides the motivational arousal component that converts increased processing capacity into engaged attention. Anandamide clears the anxious cognitive interference that would otherwise consume the working memory bandwidth unlocked by the first three. And magnesium ensures that NMDA receptor function — essential for synaptic plasticity and working memory encoding — is not limited by nutritional deficiency. Each compound's effect is amplified by the presence of the others.11

Processing integrity matters: This entourage effect requires an intact bioactive matrix. Alkalization (Dutch processing) destroys 60–90% of flavanols. High-temperature roasting degrades PEA and volatile bioactives. Commercial chocolate's sugar and dairy matrix dilutes theobromine dose below therapeutic range. Only minimally processed, unalkalized stone-ground ceremonial cacao paste delivers the full matrix at meaningful concentrations.

Dosage, Sourcing & Bioactive Retention

Cognitive benefit is dose-dependent and highly sensitive to processing method. The following comparison illustrates how radically bioactive content varies across cacao product types:

Product Type Theobromine / 25g Flavanols / 25g Magnesium / 25g Focus utility
Ceremonial cacao paste (stone-ground) ~400–500mg ✓ Full dose ~150–200mg ✓ Full dose ~64mg · 16% RDI Optimal
Raw cacao powder (unalkalized) ~450–550mg ~180–220mg ~55mg High — lacks fat carrier
Dark chocolate 85%+ ~280–350mg ~80–130mg ~45mg Moderate
Dutch-process cocoa powder ~200–280mg ~20–60mg 60–90% loss ~40mg Low
Commercial hot chocolate mix ~50–120mg ~5–20mg ~15mg Negligible
Milk chocolate ~40–80mg ~10–30mg ~10mg Negligible

Practical note: The daily ritual dose of 25g ceremonial cacao paste (~150–200mg flavanols, ~400–500mg theobromine) is within the range showing cognitive benefits in multiple published RCTs. Consistent daily consumption over 4–8 weeks appears to produce compounding benefit through the accumulation of flavanol-induced vascular remodelling and BDNF upregulation — beyond the acute per-dose effect.

Safety Profile & Considerations

Ceremonial cacao at standard dietary doses has an excellent safety profile for healthy adults. The following parameters define the boundaries of safe and effective use:

Standard dose range: 20–40g of ceremonial cacao paste per serving (1–2 servings/day) is consistent with doses used in clinical research. Theobromine doses above ~1,000mg/day may produce mild vasodilatory effects (mild headache, flushing) in sensitive individuals. This threshold is approximately 50g+ of ceremonial cacao paste in a single serving — significantly above a typical ritual preparation. Theobromine is not acutely toxic to humans at culinary doses; the lethal dose is approximately 1,000mg/kg bodyweight, making dietary toxicity essentially impossible.

Pregnancy: The methylxanthine content of cacao (primarily theobromine, with trace caffeine) warrants moderation during pregnancy. Doses equivalent to 1–2 standard cups of coffee's caffeine equivalent are generally cited as the threshold for caution — 25g of ceremonial cacao paste is substantially below this threshold, but pregnant individuals should consult a healthcare professional regarding their total methylxanthine intake.

Pet toxicity: Theobromine is highly toxic to dogs and cats due to their significantly slower CYP1A2-mediated metabolism. Ceremonial cacao must be kept away from companion animals regardless of dose.

MAO inhibitor interactions: Cacao's mild MAO-B inhibitory activity is orders of magnitude weaker than pharmaceutical MAO inhibitors and does not produce the dietary tyramine interactions associated with MAOI medications. Individuals taking prescribed MAOI antidepressants should however consult their physician before regular ceremonial cacao consumption.

CYP1A2 variability: Theobromine is metabolised via the CYP1A2 hepatic enzyme. Individuals with slow CYP1A2 activity (genetic polymorphism affecting approximately 10% of the population, and common in cigarette smokers or those on CYP1A2-inhibiting medications) may experience extended duration of theobromine effect.

kakao.guru is an information platform specializing in ethically produced and fermented cacao sourced from Vietnam. All health science content on this platform reflects the peer-reviewed literature as of the publication date listed and is provided for informational purposes only. Nothing on this platform constitutes medical advice, diagnosis, or treatment recommendations.

Frequently Asked Questions

Does cacao improve focus?

Yes — through multiple independent mechanisms. Theobromine inhibits phosphodiesterase enzymes, elevating cAMP and cGMP levels that modulate dopaminergic signalling and neuronal excitability. Flavanols increase cerebral blood flow via NO-mediated vasodilation, improving oxygen and glucose delivery to prefrontal cortex. Multiple RCTs have documented improvements in working memory, attention and processing speed with regular cocoa flavanol consumption.89

Is cacao better than coffee for focus?

Cacao and coffee operate through fundamentally different mechanisms — making them complementary rather than directly comparable. Caffeine blocks adenosine receptors, producing rapid stimulation but also triggering cortisol release and tolerance development. Theobromine inhibits PDE enzymes and modulates dopamine without blocking adenosine receptors, producing softer, more sustained focus without cortisol, anxiety, or rebound fatigue. For sustained, multi-hour cognitive work, the cacao mechanism is particularly well-suited — and unlike coffee, cacao simultaneously improves cerebral blood flow, replenishes magnesium, and supports mood through multiple independent pathways.

How long does cacao focus last?

Theobromine has a half-life of approximately 6–10 hours — significantly longer than caffeine's 3–5 hours. Onset is typically 30–60 minutes after consumption, peak effect at 1–2 hours, with sustained background cognitive support for 4–6 hours. The flavanol-mediated cerebral blood flow enhancement is most pronounced at approximately 2 hours post-consumption, contributing to the peak cognitive window. Because theobromine does not produce an adenosine rebound, there is no sharp decline in cognitive performance at the end of the effect window.

How much ceremonial cacao is needed for focus benefits?

A standard ceremonial serving of 25g provides ~400–500mg theobromine and ~150–200mg flavanols — within the dose range showing cognitive benefit in multiple published RCTs. Daily consistency over 4–8 weeks is likely more important than any single high dose, given the cumulative vascular and neuroplastic adaptations documented in multi-week RCTs.

Does cacao cause a focus crash?

No. This is one of theobromine's key distinctions from caffeine. Because theobromine does not block adenosine receptors, it does not create the adenosine rebound that produces the crash following caffeine metabolism. Theobromine's effect tails off gradually over 6–10 hours without a sharp withdrawal. Additionally, cacao does not trigger cortisol release, avoiding the anxiety-to-crash cycle common with high-dose caffeine use.

Can I use cacao and coffee together for focus?

Yes — the mechanisms are complementary and additive. Theobromine's PDE inhibition and flavanol-mediated cerebral blood flow enhancement are entirely independent of caffeine's adenosine receptor antagonism. Many practitioners report consuming a lower coffee dose alongside ceremonial cacao, noting a smoother stimulation profile and reduced anxiety compared to coffee alone. The magnesium in cacao may also partially buffer caffeine's urinary magnesium excretion effect. At high total methylxanthine doses, sleep disruption risk should be factored into timing decisions.

Does dark chocolate provide the same focus benefit?

Partially. 85%+ dark chocolate retains meaningful theobromine content (~280–350mg per 25g) but typically contains alkalized cocoa base, added sugar, and dairy — all of which reduce the effective flavanol dose and introduce confounding variables. For the full four-pathway mechanism — PDE inhibition, cerebral blood flow enhancement, PEA/MAO synergy, and anandamide signalling — ceremonial-grade stone-ground cacao paste delivers a substantially more complete and concentrated bioactive matrix.

Scientific References — 21 Peer-Reviewed Sources
1Smit, H.J. (2011). Theobromine and the pharmacology of cocoa. Handbook of Experimental Pharmacology, 200, 201–234. doi:10.1007/978-3-642-13443-2_7
2Arnaud, M.J. (1987). The pharmacology of caffeine. Progress in Drug Research, 31, 273–313. (Comparative context for methylxanthine PDE inhibition class.)
3Heiss, C. et al. (2010). Improvement of endothelial function with dietary flavanols. Journal of the American College of Cardiology, 56(3), 218–224. doi:10.1016/j.jacc.2010.03.039
4Francis, S.T. et al. (2006). The effect of flavanol-rich cocoa on the fMRI response to a cognitive task in healthy young people. Journal of Cardiovascular Pharmacology, 47(S2), S215–S220.
5Sabelli, H. et al. (1996). Phenylethylamine and brain function. Neuropsychobiology, 34(4), 187–193.
6Bhattacharyya, S. et al. (2010). Modulation of mediotemporal and ventrostriatal function in humans by Delta9-tetrahydrocannabinol: a neural basis for the effects of Cannabis sativa on learning and psychosis. Archives of General Psychiatry, 66(4), 442–451. (Mechanistic framework for CB1 and attentional interference.)
7di Tomaso, E., Beltramo, M. and Piomelli, D. (1996). Brain cannabinoids in chocolate. Nature, 382, 677–678.
8Martínez-López, S. et al. (2021). Cocoa flavanols and cognitive function. Scientific Reports, 11, 14423. doi:10.1038/s41598-021-93906-9
9Desideri, G. et al. (2012). Benefits in cognitive function, blood pressure, and insulin resistance through cocoa flavanol consumption in elderly subjects with mild cognitive impairment: the Cocoa, Cognition, and Aging (CoCoA) study. Hypertension, 60(3), 794–801. doi:10.1161/HYPERTENSIONAHA.112.193060
10Shilo, L. et al. (2002). The effects of coffee consumption on sleep and melatonin secretion. Sleep Medicine, 3(3), 271–273. (Comparative reference for caffeine vs theobromine sleep impact.)
11Crozier, S.J. et al. (2011). Cacao seeds are a "Super Fruit." Chemistry Central Journal, 5, 5. doi:10.1186/1752-153X-5-5
12Brickman, A.M. et al. (2014). Enhancing dentate gyrus function with dietary flavanols improves cognition in older adults. Nature Neuroscience, 17(12), 1798–1803.
13Sokolov, A.N. et al. (2013). Chocolate and the brain: neurobiological impact of cocoa flavanols on cognition and behavior. Neuroscience & Biobehavioral Reviews, 37(10), 2445–2453.
14Lamport, D.J. et al. (2012). Positive effects of flavonoid and caffeine combinations on sustained attention with low habitual caffeine consumption. Psychopharmacology, 221(2), 323–334.
15Field, D.T., Williams, C.M. and Butler, L.T. (2011). Consumption of cocoa flavanols results in an acute improvement in visual and cognitive functions. Physiology & Behavior, 103(3–4), 255–260.
16Boyle, N.B. et al. (2017). The effects of magnesium supplementation on subjective anxiety and stress — A systematic review. Nutrients, 9(5), 429. doi:10.3390/nu9050429
17Nehlig, A. (2013). The neuroprotective effects of cocoa flavanol and its influence on cognitive performance. British Journal of Clinical Pharmacology, 75(3), 716–727.
18Scholey, A.B. et al. (2010). Consumption of cocoa flavanols results in acute improvements in mood and cognitive performance during sustained mental effort. Journal of Psychopharmacology, 24(10), 1505–1514.
19Schiborr, C. et al. (2011). Oral bioavailability of curcumin from plant-based preparation in healthy volunteers: characterisation and first evaluation. Food & Function. (Context for polyphenol bioavailability with fat carriers.)
20Grassi, D. et al. (2008). Cocoa reduces blood pressure and insulin resistance and does not induce weight gain in hypertensive patients: a randomized clinical trial. European Journal of Clinical Nutrition, 62(12), 1365–1371.
21Maia, L. and de Mendonça, A. (2002). Does caffeine intake protect from Alzheimer's disease? European Journal of Neurology, 9(4), 377–382. (Comparative reference: adenosine system and cognitive aging.)