Table 2.
Main characteristics of selected interventional studies.
| Reference | Type of Study | n | Participants | Age | Duration | Intervention | Outcomes | Main Findings |
|---|---|---|---|---|---|---|---|---|
| Sorond et al., 2008 [57] | Single-arm intervention | 13 | Healthy | 59–83 | 2 weeks | 900 mg cocoa flavanols drink per day | Transcranial Doppler ultrasound | Mean blood flow velocity increased after 1 or 2 weeks of flavanols intake |
| Sorond et al., 2008 [57] | Parallel RCT | 21 | Healthy | 59–83 | 1 week | 900 mg cocoa flavanols drink per day or placebo | Transcranial Doppler ultrasound | No cerebrovascular resistance or vasoreactivity improvements after the intervention. Mean blood flow velocity response increased in the intervention group but without statistical significance among groups |
| Sorond et al., 2013 [54] | Parallel RCT | 60 | With vascular risk factors, cognitively intact | >65 | 30 days | 609 mg cocoa flavanols drink or 13 mg, two times per day | MMSE, cerebral blood flow velocity and MRI | Cocoa consumption was associated with neurovascular coupling and MMSE improvements in neurovascular coupling impaired patients |
| Desideri et al., 2012 [53] | Parallel RCT | 90 | MCI | 71 ± 5 | 8 weeks | 690, 520 or 45 mg cocoa flavanols drink per day | MMSE and TMT | Improvement in cognitive performance associated with cocoa use, also at an intermediate dosage |
| Mastroiacovo et al., 2015 [55] | Parallel RCT | 90 | Cognitively intact | 61–85 | 8 weeks | 690, 520 or 45 mg cocoa flavanols drink per day | MMSE, TMT and VFT | Improvement in cognitive performance associated with cocoa use, also at an intermediate dosage |
| Crews et al., 2008 [58] | Parallel RCT | 101 | Cognitively intact | >60 | 6 weeks | 37 g dark chocolate with 397.30 mg proanthocyanins/g and 237 mL of cocoa beverage with 357.41 mg proanthocyanins/g per day or placebo (0.2 and 40.87 mg/g, respectively) | Neuropsychological test battery | No improvement after cocoa and chocolate intake |
| Suominen et al., 2020 [65] | Parallel RCT | 100 | Cognitively intact | 65–75 | 8 weeks | 50 g dark chocolate with 410 mg or 86 mg of flavanols per day | TMT and VFT | No improvement after cocoa and chocolate intake |
| Neshatdoust et al., 2016 [56] | Cross-over RCT | 40 | Healthy | 62–75 | 12 weeks | 494 mg or 23 mg flavanols cocoa drink per day | Serum BDNF levels, neuropsychological test battery | Significant increase in BDNF levels after high flavanols intake with improved cognitive function |
| García-Cordero et al., 2021 [59] | Parallel RTC | 60 | Healthy | 50–75 | 12 weeks | Cocoa powder with 200 mg of flavanols per day, red berries mixture or both | Serum BDNF levels, neuropsychological test battery | No changes in BDNF levels. Neurocognitive enhancement in all groups |
| Brickman et al., 2014 [60] | Parallel RCT | 41 | Healthy | 50–69 | 3 months | Cocoa with 900 mg or 45 mg of flavanol per day | CBV-fMRI, ModBent Task and mod Rey auditory learning task | Correlation between increased cerebral blood volume and better performance in the dentate gyrus after the high flavanol intake |
| Sloan et al., 2021 [66] | Parallel RCT | 211 | Healthy | 50–75 | 12 weeks | 260, 510 or 770 mg of cocoa flavanol capsules per day or placebo | CBV-fMRI, ModBent Task and mod Rey auditory learning task, List-Sorting Working Memory Test |
Object-recognition list-sorting tasks were not improved after the intervention. An improvement in list-learning performance was associated with the cocoa intervention |