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

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.