15/02/2026
Love dark chocolate!!!
One of the core components of my microcirculation phytonutrient diet is cocoa, usually as very dark chocolate (85 to 90%), chosen for its higher flavanol density and lower sugar load. A 2025 systematic review rigorously evaluated the clinical evidence to determine whether cocoa flavanols meaningfully enhance microvascular function. The review included 19 randomised, placebo-controlled human trials, comprising 13 acute studies and 7 chronic studies (with one study containing both phases), spanning effects on skin, skeletal muscle, cerebral and retinal microvascular beds.
Participants were not simply eating ordinary chocolate. Most of the trials used standardised, high-flavanol cocoa beverages, concentrated cocoa extracts in capsules, or specially prepared high-percentage dark chocolate, delivering pharmacological doses of flavanols. Acute doses commonly ranged from 500 to 1350 mg total flavanols (with 45 to 255 mg of (-)-epicatechin), and some chronic studies delivered up to 900 to 1800 mg/day.
A conventional meta-analysis was not possible because the studies varied widely in assessed vascular beds, measurement techniques (Laser Doppler, plethysmography etc), and stimulus conditions (reactive hyperaemia, hypoxia, mental stress, exercise). The authors therefore used vote counting, a Cochrane-recognised fallback method. In this approach, each study subgroup was assigned a “vote” based solely on whether cocoa performed better than placebo (1) or not (0), regardless of statistical significance or effect size. They then tested whether the proportion of positive directions exceeded chance (50%).
Using vote counting (direction-of-effect analysis), 12 of 14 acute subgroups (85.7%) showed improved vasodilator responses with cocoa flavanols, a proportion significantly greater than chance (p = 0.013), with 100% of the low-risk-of-bias (higher quality) acute studies favouring cocoa. For chronic supplementation, the direction was also generally favourable but less robust: 8 of 11 subgroups (72.7%) showed improved vasodilator responses and 7 of 9 (77.7%) favoured cocoa at rest, but these proportions did not reach statistical significance. (Note that some trials generated more than one subgroup for analysis.)
Hence the strongest signal was for acute enhancement of microvascular reactivity within 1 to 3 hours after ingestion, coinciding with peak circulating flavanol metabolites and nitric oxide-related activity. Chronic effects were less consistent, and there was little evidence of structural microvascular remodelling or reversal of established disease. The current clinical data therefore position high-dose cocoa flavanol extracts as performance enhancing short-term endothelial modulators that may enhance vascular responsiveness under stress (cognitive demand, hypoxia, reactive hyperaemia).
The fact that the clinical evidence favours acute effects from cocoa does not rule out benefits from long-term chronic intake. However, it does highlight that the use of a multicomponent sustained input, as per my microcirculation diet, is more likely to have the greatest impact on chronic microvascular compromise.
For more information see: https://pubmed.ncbi.nlm.nih.gov/40217225/
