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Cocoa Extract Supplementation and Risk of Type 2 Diabetes: The Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) Randomized Clinical Trial.

  • 2023-10-10
  • Diabetes care 46(12)
    • Jie Li
    • Howard D Sesso
    • Eunjung Kim
    • JoAnn E Manson
    • Georgina Friedenberg
    • Allison Clar
    • Trisha Copeland
    • Aladdin H Shadyab
    • Jean Wactawski-Wende
    • Lesley Tinker
    • Simin Liu

Study Design

Type
Randomized Controlled Trial (RCT)
Sample size
n = 776
Population
18,381 participants without diabetes at enrollment; originally 21,442 U.S. adults free of CVD and recent cancer, including 12,666 women aged ≥65 years and 8,776 men aged ≥60 years
Methods
2 × 2 factorial RCT, cocoa extract (500 mg/day cocoa flavanols, including 80 mg (-)-epicatechin) or placebo, median follow-up of 3.5 years
Blinding
Double-blind
Duration
median follow-up of 3.5 years
Funding
Unclear
  • Large Human Trial

Objective

Observational studies have indicated that cocoa flavanol supplementation may be a promising strategy for type 2 diabetes (T2D) prevention. We aimed to directly evaluate its clinical efficacy in a large randomized clinical trial (RCT).

Research design and method

The Cocoa Supplement and Multivitamin Outcomes Study (COMSOS) was a 2 × 2 factorial RCT performed from June 2015 to December 2020 that tested cocoa extract and a multivitamin for the prevention of cardiovascular disease (CVD) and cancer. A total of 21,442 U.S. adults free of CVD and recent cancer, including 12,666 women aged ≥65 years and 8,776 men aged ≥60 years, were randomly assigned to receive cocoa extract [500 mg/day cocoa flavanols, including 80 mg (-)-epicatechin] or placebo. In this study, we included 18,381 participants without diabetes at enrollment and examined the effect of cocoa extract supplementation on incident self-reported T2D in intention-to-treat analyses.

Results

During a median follow-up of 3.5 years, 801 incident T2D cases were reported. Compared with placebo, taking a cocoa extract supplement did not reduce T2D (adjusted hazard ratio 1.04, 95% CI 0.91-1.20, P = 0.58). Stratification analyses showed that the effect of cocoa extract supplementation was not significantly modified by sex, race, BMI, smoking, physical activity, dietary quality, flavanol status at baseline, or randomized multivitamin assignment.

Conclusions

Middle-aged and older adults taking a cocoa extract supplement for a median of 3.5 years did not reduce their risk of incident T2D. Further studies of cocoa extract supplementation beginning earlier in adulthood and in populations with different background diets are warranted.

Research Insights

  • Cocoa→Reduced Incidence of Type 2 Diabetes

    Compared with placebo, taking a cocoa extract supplement did not reduce T2D (adjusted hazard ratio 1.04, 95% CI 0.91-1.20, P = 0.58).

    Effect
    Neutral
    Effect size
    Small
    Dose
    500 mg/day cocoa flavanols, including 80 mg (-)-epicatechin
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