Plain language summary
Flavanols and polyphenolic compounds have been found to produce neuroprotective effects that counteract many aspects of cognitive decline. Recent evidence has shown that cocoa flavanol (CF) consumption improves cognitive function in elderly adults with mild cognitive impairment. The aim of this study was to evaluate the effect of flavanol consumption on cognitive performance in 90 cognitively healthy elderly adults. Participants were randomly assigned to consume a drink containing either a high or low cocoa flavanol concentration for eight weeks. Various cognitive function tests were performed at the baseline and end of the study. The findings of this study indicate that regular CF consumption reduced measures of age-related cognitive dysfunction as well as improved blood pressure and glucose tolerance. These results suggest that habitual intake of flavanols can support healthy cognitive function with age, and indicate a role of glucose metabolism in modulating cognitive function.
Abstract
BACKGROUND Recent evidence has indicated that flavanol consumption may have many health benefits in humans, including improved cognitive activities. OBJECTIVE The aim was to evaluate the effect of flavanol consumption on cognitive performance in cognitively intact elderly subjects. DESIGN This was a double-blind, controlled, parallel-arm study conducted in 90 elderly individuals without clinical evidence of cognitive dysfunction who were randomly assigned to consume daily for 8 wk a drink containing 993 mg [high flavanol (HF)], 520 mg [intermediate flavanol (IF)], or 48 mg [low flavanol (LF)] cocoa flavanols (CFs). Cognitive function was assessed at baseline and after 8 wk by using the Mini-Mental State Examination (MMSE), the Trail Making Test (TMT) A and B, and the Verbal Fluency Test (VFT). RESULTS The changes in MMSE score in response to the 3 different treatments were not different. In contrast, there was a positive impact of the intervention on specific aspects of cognitive function. Mean changes (±SEs) in the time required to complete the TMT A and B after consumption of the HF (-8.6 ± 0.4 and -16.5 ± 0.8 s, respectively) and IF (-6.7 ± 0.5 and -14.2 ± 0.5 s, respectively) drinks significantly (P < 0.0001) differed from that after consumption of the LF drinks (-0.8 ± 1.6 and -1.1 ± 0.7 s, respectively). Similarly, VFT scores significantly improved among all treatment groups, but the magnitude of improvement in the VFT score was significantly (P < 0.0001) greater in the HF group (7.7 ± 1.1 words/60 s) than in the IF (3.6 ± 1.2 words/60 s) and LF (1.3 ± 0.5 words/60 s) groups. Significantly different improvements in insulin resistance (P < 0.0001), blood pressure (P < 0.0001), and lipid peroxidation (P = 0.001) were also observed for the HF and IF groups in comparison with the LF group. Changes in insulin resistance explained ∼17% of changes in composite z score (partial r² = 0.1703, P < 0.0001). CONCLUSIONS This dietary intervention study provides evidence that regular CF consumption can reduce some measures of age-related cognitive dysfunction, possibly through an improvement in insulin sensitivity. These data suggest that the habitual intake of flavanols can support healthy cognitive function with age.
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