Dietary Influences on Cognitive Functions: Insights from Experimental Crossover Studies

We have to process a lot of incoming information around us using different cognitive functions such as working memory, spatial attention, temporal attention, cognitive control, and inhibitory control. It is an ongoing quest to boost our ability to gather and process this information as quickly and accurately as possible. In addition to these, nutritional and pharmacological approaches have been gaining popularity. Dietary supplements are commonly used not only for cognitive improvements but also to protect existing cognitive capabilities. Among these, alongside coffee, cocoa stands out as one of the most widely consumed products worldwide.
Based on the mixed, and, at times, still preliminary results from previous studies, the current thesis investigated the impact of commonly consumed dietary elements on cognitive functions. Throughout this thesis, we primarily focused on testing the acute effects of cocoa flavanols on specific cognitive functions, which were not previously targeted individually as such. These included working memory updating and maintenance, spatial and temporal attention, as well as cognitive control and response inhibition with comprehensive tasks involving sufficient trials in each task condition. In all of them, we clearly observed the expected task effects (e.g., an attentional blink, a memory load effect, a congruency effect, etc.). We took the same approach to also examine the interaction of caffeine with cocoa flavanols, and the effects of GABA on working memory, spatial and temporal attention through randomized, placebo-controlled, double-blind, gender-balanced, counterbalanced crossover studies in healthy young adults.