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Cof5.0
Cocoa Flavanols Research
Mostly mechanism / observational
84 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Cocoa Flavanols studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from high-quality meta-analyses and randomised trials published 2003–2026 with a typical study size of 666 participants.
Based on 84 studies · 5 meta-analyses · 71 RCTs · 43,478 total participants
Confidence
High confidence
By outcome
Heart & blood pressureSmall blood-pressure reduction (~2 mmHg) and improved endothelial function; COSMOS missed its primary CV endpoint but cut CV death 27% as a secondary outcome · 2-8 weeks for BP/vascular markers; years for hard outcomes
Mostly mechanism / observational11 studies
Neuroprotection & brain agingMechanistic increases in cerebral blood flow; one positive memory RCT, but the large COSMOS-Mind trial found no cognitive benefit · 8-12 weeks (inconsistent)
Too few graded studies1 study
Active research area
31 studies in the last 5 years · Latest meta-analysis: 2024
200320142026
1Meta-Analysisn=573 · large study2024
Vyas CM, Manson JE, Sesso HD, Cook NR, Rist PM, Weinberg A, Moorthy MV, Baker LD, Espeland MA, Yeung LK, Brickman AM, Okereke OI. · The American journal of clinical nutrition (2024)
Conclusions In COSMOS-Clinic, daily MVM supplementation leads to a significantly more favorable 2-y change in episodic memory.
The meta-analysis within COSMOS cognitive substudies indicates that daily MVM significantly benefits both global cognition and episodic memory.
These findings within the COSMOS trial support the benefits of a daily MVM in preventing cognitive decline among older adults.
In plain English: Conclusions The consumption of cocoa showed protective effects on major cardiometabolic risk markers that have a clinical impact in terms of cardiovascular risk reduction.
Arisi TOP, da Silva DS, Stein E, Weschenfelder C, de Oliveira PC, Marcadenti A, Lehnen AM, Waclawovsky G. · Nutrients (2024)
Yet, there was a reduction in total cholesterol (-8.35 mg/dL, 95% CI -14.01; -2.69 mg/dL), LDL-c (-9.47 mg/dL, 95% CI -13.75; -5.20 mg/dL), fasting blood glucose (-4.91 mg/dL, 95% CI -8.29; -1.52 mg/dL), SBP (-2.52 mmHg, 95% CI -4.17; -0.88 mmHg), and DBP (-1.58 mmHg, 95% CI -2.54; -0.62 mmHg).
Results Thirty-one studies were included, totaling 1986 participants.
Cocoa consumption showed no effects on body weight, BMI, waist circumference, triglycerides, HDL-c and HbA1c.
Vyas CM, Manson JE, Sesso HD, Rist PM, Weinberg A, Kim E, Moorthy MV, Cook NR, Okereke OI. · The American journal of clinical nutrition (2024)
Results Participants' mean age (standard deviation) was 69.6 (5.3); 49.2% were females.
Daily supplementation with CE, compared with placebo, had no significant effect on 2-y change in global cognition {mean difference [95% confidence interval (CI)]: -0.01 (-0.08, 0.05) standard deviation units (SU)}.
CE, compared with placebo, had no significant effects on 2-y change in episodic memory [mean difference (95% CI): -0.01 (-0.13, 0.10) SU] or executive function/attention [mean difference (95% CI): 0.003 (-0.07, 0.08) SU].
Christen WG, Rist PM, Moorthy MV, Smith DC, Holman B, Clar A, Glynn RJ, Mares JA, Sobrin L, Shadyab AH, Allison MA, Millen AE, Manson JE, Sesso HD, COSMOS Research Group. · JAMA ophthalmology (2025)
Results Mean (SD) participant age was 72.1 (6.6) years, and 12 666 participants (59.1%) were female.
During a median (IQR) period of 3.6 (3.2-4.2) years of treatment and follow-up, 344 participants (1.6%) experienced a confirmed AMD event (316 incident AMD, 28 progression to advanced AMD).
For the primary composite end point, there were 159 cases (1.5%) in the cocoa extract group and 185 cases (1.7%) in the placebo group (hazard ratio [HR], 0.87; 95% CI, 0.71-1.08; P = .21).
In plain English: Cocoa extract supplementation did not significantly reduce total cardiovascular events among older adults but reduced CVD death by 27%.
Sesso HD, Manson JE, Aragaki AK, Rist PM, Johnson LG, et al.; COSMOS Research Group · Am J Clin Nutr (2022)
21,442 older US adults, 500mg flavanols/day, median 3.6 years, double-blind placebo-controlled
PRIMARY endpoint (total CV events) NOT significant: HR 0.90 (95% CI 0.78-1.02, P=0.11)
Secondary CVD death reduced 27%: HR 0.73 (95% CI 0.54-0.98)
In plain English: The Cocoa Supplement and Multivitamin Outcomes
Li J, Manson JE, Rist PM, Clar A, Moorthy MV, Kim E, Sarkissian A, Sesso HD. · The American journal of clinical nutrition (2026)
In intention-to-treat analysis, the hazard ratio for MVM compared with placebo was 0.93 for COVID-19 incidence [95% confidence interval (CI): 0.81, 1.07].
Among the 338 cases with detailed symptom data, the odds ratio for symptomatic COVID-19 comparing MVM with placebo was 0.70 (95% CI: 0.44, 1.11).
In per-protocol analyses, among participants compliant with study pills during 2020, the odds ratio for symptomatic COVID-19 was 0.60 (95% CI: 0.37, 0.99).