The heart isn't the only organ that depends on healthy blood vessels. The brain uses about 20% of the body's oxygen and energy despite making up only 2% of its weight, and its function depends heavily on how well blood reaches it.
This is where the same mechanism behind the EU-authorised cardiovascular claim becomes relevant to the brain. Cacao flavanols, particularly epicatechin, stimulate nitric oxide production, which relaxes blood vessels. When this happens in the vessels supplying the brain, researchers call it an increase in cerebral blood flow.
What the studies found
Sorond et al. (2008) used Doppler ultrasound to measure blood flow velocity in older adults after they consumed flavanol-rich cocoa, and found a measurable increase. Francis et al. (2006) used fMRI and observed a similar effect on blood flow to the brain following cocoa flavanol intake. Field et al. (2011) linked flavanol intake to short-term improvements in visual and cognitive test performance in young adults.
These are acute, single-dose effects. The more interesting question is what happens with regular intake over time.
Longer-term evidence
Mastroiacovo et al. (2015), known as the CoCoA study, followed 90 healthy older adults over 8 weeks, comparing a high dose (993mg flavanols/day), a medium dose (520mg), and a low dose (45mg). Those in the high- and medium-dose groups showed improvements on tests of attention, processing speed, task-switching, working memory, and verbal fluency, relative to the low-dose group.
COSMOS-Mind, one of the largest studies of its kind, followed thousands of older adults over three years and tested whether daily cocoa extract (500mg flavanols) improved cognition compared to placebo (Baker et al., 2023). A related analysis by Brickman et al. (2023), published in PNAS, found that the cognitive benefit wasn't evenly spread. It was concentrated in participants who started the study with lower habitual flavanol intake or lower overall diet quality. Participants who already ate a good diet saw little additional benefit.
That last point matters. It suggests the effect isn't a general brain boost so much as a correction for people whose baseline nutrition has more room for improvement.
Theobromine
Cacao naturally contains theobromine, a mild stimulant related to caffeine but with a longer, gentler onset. This is one of the reasons cacao's effects are often described as steadier than coffee's, though direct comparative research on this specific point is limited.
Where this fits
Most of the cognitive research on cacao flavanols has focused on older adults or people with existing vascular risk factors, where the effect on blood flow and cognition tends to be more pronounced. In healthy younger adults, the acute effects are smaller and less consistent across studies.
Flavanol content also depends on how the cacao is processed. Our Raw Cacao Powder, Raw Cacao Beans, Raw Cacao Nibs, and Raw Cacao Bar 100% are minimally processed and independently lab-tested for flavanol content, batch by batch.
Summary
The research on cacao flavanols and brain blood flow is genuine and growing, spanning acute lab measurements to multi-year trials in thousands of people. It points to a modest, mechanism-specific effect, most relevant for people with lower baseline diet quality, rather than a general cognitive enhancer for everyone. Better circulation to the brain is a reasonable, evidence-backed reason to include flavanol-rich cacao in your diet. Claims beyond that outrun what the studies currently show.
References
Sorond F.A., Lipsitz L.A., Hollenberg N.K. & Fisher N.D.L. Cerebral blood flow response to flavanol-rich cocoa in healthy elderly humans. Neuropsychiatric Disease and Treatment, 2008;4(2):433–440. https://doi.org/10.2147/ndt.s2434
Francis S.T., Head K., Morris P.G. & Macdonald I.A. The effect of flavanol-rich cocoa on the fMRI response to a cognitive task in healthy young people. Journal of Cardiovascular Pharmacology, 2006;47(Suppl 2):S215–S220. https://doi.org/10.1097/00005344-200606001-00018
Field D.T., Williams C.M. & Butler L.T. Consumption of cocoa flavanols results in an acute improvement in visual and cognitive functions. Physiology & Behavior, 2011;103(3-4):255–260. https://doi.org/10.1016/j.physbeh.2011.02.013
Mastroiacovo D., Kwik-Uribe C., Grassi D., Necozione S., Raffaele A., Pistacchio L., Righetti R., Bocale R., Lechiara M.C., Marini C., Ferri C. & Desideri G. Cocoa flavanol consumption improves cognitive function, blood pressure control, and metabolic profile in elderly subjects: the Cocoa, Cognition, and Aging (CoCoA) Study. The American Journal of Clinical Nutrition, 2015;101(3):538–548. https://doi.org/10.3945/ajcn.114.092189
Baker L.D., Manson J.E., Rapp S.R., Sesso H.D., Gaussoin S.A., Shumaker S.A., Espeland M.A., Resnick S.M., Whitmer R.A., Kivipelto M., Luchsinger J.A., Coker L.H., Yasar S., Shadyab A.H., Wallace R.B., Johnson K.C., Hayden K.M. & Small B.J. Effects of cocoa extract and a multivitamin on cognitive function: a randomized clinical trial (COSMOS-Mind). Alzheimer’s & Dementia, 2023;19(4):1308–1319. https://doi.org/10.1002/alz.12767
Brickman A.M., Yeung L.K., Alschuler D.M., Ottaviani J.I., Kuhnle G.G.C., Sloan R.P., et al. Dietary flavanols restore hippocampal-dependent memory in older adults with lower diet quality and lower habitual flavanol consumption. Proceedings of the National Academy of Sciences, 2023;120(23):e2216932120. https://doi.org/10.1073/pnas.2216932120
