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Cocoa flavanols (CF) positively influence physiological processes in ways that suggest their consumption may improve aspects of cognitive function. This study investigated the acute cognitive and subjective effects of CF consumption during sustained mental demand. In this randomized, controlled, double-blinded, balanced, three period crossover trial 30 healthy adults consumed drinks containing 520 mg, 994 mg CF and a matched control, with a three-day washout between drinks. Assessments included the state anxiety inventory and repeated 10-min cycles of a Cognitive Demand Battery comprising of two serial subtraction tasks (Serial Threes and Serial Sevens), a Rapid Visual Information Processing (RVIP) task and a 'mental fatigue' scale, over the course of 1 h. Consumption of both 520 mg and 994 mg CF significantly improved Serial Threes performance. The 994 mg CF beverage significantly speeded RVIP responses but also resulted in more errors during Serial Sevens. Increases in self-reported 'mental fatigue' were significantly attenuated by the consumption of the 520 mg CF beverage only. This is the first report of acute cognitive improvements following CF consumption in healthy adults. While the mechanisms underlying the effects are unknown they may be related to known effects of CF on endothelial function and blood flow.

BACKGROUND AND PURPOSE: Cerebral ischemia is a common, morbid condition accompanied by cognitive decline. Recent reports on the vascular health benefits of flavanol-containing foods signify a promising approach to the treatment of cerebral ischemia. Our study was designed to investigate the effects of flavanol-rich cocoa (FRC) consumption on cerebral blood flow in older healthy volunteers. METHODS: We used transcranial Doppler (TCD) ultrasound to measure mean blood flow velocity (MFV) in the middle cerebral artery (MCA) in thirty-four healthy elderly volunteers (72 +/- 6 years) in response to the regular intake of FRC or flavanol-poor cocoa (FPC). RESULTS: In response to two weeks of FRC intake, MFV increased by 8% +/- 4% at one week (p = 0.01) and 10% +/- 4% (p = 0.04) at two weeks. In response to one week of cocoa, significantly more subjects in the FRC as compared with the FPC group had an increase in their MFV (p < 0.05). CONCLUSIONS: In summary, we show that dietary intake of FRC is associated with a significant increase in cerebral blood flow velocity in the MCA as measured by TCD. Our data suggest a promising role for regular cocoa flavanol's consumption in the treatment of cerebrovascular ischemic syndromes, including dementias and stroke.

Diet and exercise have a profound impact on brain function. In particular, natural nutrients found in plants may influence neuronal survival and plasticity. Here, we tested whether consumption of a plant-derived flavanol, (-)epicatechin, enhances cognition in sedentary or wheel-running female C57BL/6 mice. Retention of spatial memory in the water maze was enhanced by ingestion of (-)epicatechin, especially in combination with exercise. Improved spatial memory was associated with increased angiogenesis and neuronal spine density, but not newborn cell survival, in the dentate gyrus of the hippocampus. Moreover, microarray analysis showed upregulation of genes associated with learning and downregulation of markers of neurodegeneration in the hippocampus. Together, our data show that ingestion of a single flavanol improves spatial memory retention in adult mammals.

Foods and beverages rich in flavonoids are being heralded as potential preventive agents for a range of pathologic conditions, ranging from hypertension to coronary heart disease to stroke and dementia. We and others have demonstrated that short-term ingestion of cocoa, particularly rich in the subclass of flavonoids known as flavanols, induced a consistent and striking peripheral vasodilation in healthy people, improving endothelial function in a nitric oxide-dependent manner. The vasodilator response was reversed by N-nitro-L-arginine methyl ester, an arginine analog that blocks nitric oxide synthesis. Flavanol-poor cocoa induced much smaller responses. Because impairment of endothelial function is a nearly universal accompaniment of the aging process, we examined the peripheral vasodilator response to flavanol-rich cocoa in healthy older subjects. Observations point to a favorable response among the older. Together with peripheral vascular disease, cerebrovascular disease is responsible for significant mortality with advancing age. An association of decreased cerebral perfusion with dementia has been recently highlighted. The prospect of increasing cerebral perfusion with cocoa flavanols is extremely promising. Our still preliminary data hold out the promise that the cerebral blood supply in the elderly participates in the vasodilator response. With the modalities of transcranial Doppler and MRI, we have the capabilities of analyzing the potential benefits of flavanols on brain perfusion and, subsequently, on cognition.

Flavanols are the main flavonoids found in cocoa and chocolate, and can be especially abundant in certain cocoas. Research over the past decade has identified flavanols as showing diverse beneficial physiologic and antioxidant effects, particularly in context of vascular function. The present study employed functional magnetic resonance imaging based on blood oxygenation level-dependent (BOLD) contrast to explore the effect of flavanols on the human brain. Magnetic resonance imaging was used to measure BOLD responses to a cognitive task in 16 healthy young subjects. The data presented show an increase in the BOLD signal intensity in response to a cognitive task following ingestion of flavanol-rich cocoa (5 days of 150 mg of cocoa flavanols). This may arise either as a result of altered neuronal activity, or a change in vascular responsiveness, or both--the net effect then being dependent on which of the two effects is dominant. No significant effects were evident in behavioral reaction times, switch cost, and heart rate after consumption of this moderate dose of cocoa flavanols. A pilot study evaluated the relationship between cerebral blood flow and a single acute dose (450 mg flavanols) of flavanol-rich cocoa and showed that flavanol-rich cocoa can increase the cerebral blood flow to gray matter, suggesting the potential of cocoa flavanols for treatment of vascular impairment, including dementia and strokes, and thus for maintaining cardiovascular health.