Heart · November 8, 2026 · 30-second read

The bitter-bean extract 21,442 older adults took twice a day

The one thing

Cocoa flavanols, about 500 mg a day.

Flavanols are plant compounds in cocoa beans that help blood vessels relax. Most of them are lost when cocoa is processed into chocolate.

Do it today

  1. Look for a cocoa extract that lists its flavanol amount on the label. The study used 500 mg a day.
  2. Skip the chocolate bar as a source. You’d need a lot of sugar and calories to get this dose.
  3. Unsweetened, non-alkalized (not “Dutch-processed”) cocoa powder keeps more flavanols than regular cocoa.

What the study found

Over about 3.6 years, the cocoa group had 27% fewer deaths from cardiovascular disease. Total heart events were 10% lower, but that difference could have been chance.

Who
21,442 adults with an average age of 72, with no heart disease or cancer at the start.
Type of study
Large randomized, placebo-controlled trial (COSMOS) led by Brigham and Women’s Hospital.
Keep in mind
The main goal of the trial (fewer total heart events) was not clearly met. The death result was a secondary finding that needs confirming.

Source: Sesso et al., American Journal of Clinical Nutrition, 2022

Educational information, not medical advice. Read our medical disclaimer.

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