The Acute Effects of Cocoa Flavanols Intake on Overt and Covert Attention

The Acute Effects of Cocoa Flavanols Intake on Overt and Covert Attention: a Randomized, Double-blind Crossover Trial

The present study aimed to examine whether a cocoa beverage containing 710 mg of flavanols enhances both overt and covert attention in healthy young adults, using a randomized, double-blind, baseline- and placebo-controlled crossover design.

Cocoa flavanols (CF) have various physiological effects that may directly or indirectly enhance cognitive functions. Following CF intake, a series of biochemical processes within vascular smooth muscle cells lead to the relaxation of smooth muscles, the dilation of blood vessels, and an increase in cerebral blood flow. For the brain to function optimally, cerebral blood flow must be maintained at a level that ensures a constant supply of oxygen and glucose to neurons. During periods of intense neuronal activity, neurons require more oxygen and nutrients, which is met by an increase in blood flow. Given that CF has been shown to enhance blood flow and perfusion in brain regions associated with attention (e.g., the parietal cortex, anterior cingulate cortex, and dorsolateral prefrontal cortex), it was hypothesized that CF intake could acutely improve both overt and covert attention.

Inclusion Criteria:

• Normal or corrected-to-normal visual acuity

Exclusion Criteria:

• History of neurological, psychiatric, cardiovascular or metabolic disorders
• Following a medically restricted diet
• Taking antidepressant, anxiolytic, and antipsychotic drugs in the past three months
• Currently taking anticoagulant
• Taking herbal supplements in the past week
• Allergic or intolerant to cocoa, caffeine, sucrose, or fructose
• Color blindness