The short-term effect of dark chocolate flavanols on cognition in older adults: A randomized controlled trial (FlaSeCo)

Cocoa flavanols in the diet have had positive effects on cognition, blood lipid levels, and glucose metabolism. Cognitively healthy older adults aged 65–75 years were recruited for an eight-week randomized, double-blind controlled trial to investigate the effectiveness of cocoa flavanols on cognitive functions. At baseline, nutrient and polyphenol intakes from diet were assessed with three-day food diaries. The intervention group received 50 g dark chocolate containing 410 mg of flavanols per day, and the control group 50 g dark chocolate containing 86 mg of flavanols per day, for eight weeks. Cognition was assessed with Verbal Fluency (VF) and the Trail Making Test (TMT) A and B as the main outcome measures. Changes in blood lipids and glucose were also measured. The older adults participating numbered 100 (63% women), mean 69 y (range 65 to 74). They were highly educated with a mean 14.9 years of education (SD 3.6). No differences in changes in cognition were seen between groups. The mean change (± SEs) in the time to complete the TMT A and B in the intervention group was −4.6 s (−7.1 to −2.1) and −16.1 s (−29.1 to −3.1), and in the controls −4.4 s (−7.0 to −1.9) and −12.5 s (−22.8 to −2.1)(TMT A p = 0.93; TMT B p = 0.66). No difference was apparent in the changes in blood lipids, glucose levels, or body weight between the groups. The healthy older adults showed no effect from the eight-week intake of dark chocolate flavanols on cognition. •Only few trials have studied how dark chocolate affects cognition in older adults.•Short-term dark chocolate consumption did not show beneficial effects on cognition.•Dark chocolate is a safe source of cocoa flavanols for healthy older adults.