Date of Award


Degree Type

Selective Evidence-Based Medicine Review

Degree Name

Master of Science in Health Sciences - Physician Assistant

Department Chair

John Cavenagh, PhD, PA-C


OBJECTIVE: The objective of this selective EBM review is to determine the effect of cocoa flavanol consumption on cognitive behavior.

STUDY DESIGN: Systematic review of three English language randomized, double blind, controlled clinical trials published in 2010, 2011, and 2012.

DATA SOURCES: Three double blind randomized controlled trials comparing cognitive function after consumption of drinks with high cocoa flavanol level were found using PedMed and Ovid.

OUTCOME MEASURED: Cognitive function was measured by various tests: a Cognitive Demand Battery composed of two serial subtraction tasks, a Rapid Visual Information processing task, a mental fatigue scale over 1 hour, the Mini Mental Status Examination, Trail Making Test, a verbal fluency test, and a visual spatial working memory for location task.

RESULTS: The RCT conducted by Desideri et al found the groups who consumed cocoa flavanol had a significantly reduced time to complete the Trail Making test and significantly improved verbal fluency test scores compared with the control. The study did not find significant change in the Mini Mental State examination after cocoa flavanol ingestion. The Scholey et al study found there there were variable changes in the Cognitive Battery Demand testing. With Serial Three subtractions there were statistically significant effects of cocoa flavanol with a greater number correct and fewer errors compared with the control. With the Serial Sevens task and Rapid Visual Information processing tasks there were not any significant differences between the control and the group who consumed cocoa flavanol. The Field et al study showed participants who consumed cocoa flavanol had a statistically significant improvement on visual spatial tasks and a faster reaction time than the control.

CONCLUSIONS: The evidence is inconclusive whether there is an effect of cocoa flavanols on cognitive function. Future studies collecting data on the effect of habitual consumption of cocoa flavanol on cognitive performance could prove most relevant for preventing age related cognitive changes. Two of the studies sampled young adults; compiling more trials with adult participants would be beneficial to assessing whether cocoa flavanols can prevent or improve age related cognitive function decline.