Cocoa, chocolate and human health across 14 papers
What it found
Cocoa and chocolate have been linked to some health effects in people, but results are mixed and often unclear.
The papers cover hearing, exercise, metabolic syndrome and how cocoa compounds are processed by the body.
What they found
Studies in people
How the body handles flavanols
Stereoisomers of epicatechin made during roasting and alkalization are less bioavailable than the natural form. Gut bacteria break down non-absorbed flavanols into metabolites found in human plasma at roughly five times higher concentrations than epicatechin conjugates.
Hearing and chocolate
Hearing loss was found to be inversely associated with chocolate consumption in a middle-aged subgroup, but tinnitus did not depend on chocolate consumption.
Exercise and cocoa
In a review of thirteen clinical trials with athletes, a reduction of exercise-induced oxidative stress was found. However, results for exercise performance and recovery were inconsistent and no clear conclusion could be drawn.
Metabolic syndrome
There is evidence that cocoa flavanols may affect some risk factors related to metabolic syndrome, such as high blood pressure and problems with glucose and lipid metabolism. In type 2 diabetics, several cardiometabolic parameters were not affected by a flavanol-rich cocoa powder, possibly because simultaneous treatment with potent pharmaceuticals exhausted the effect of cocoa.
Other findings
Flavanols in cocoa
Cocoa and chocolate are particularly rich in flavan-3-ols, mainly epicatechin and its close relatives, the proanthocyanidins.
Storage and processing
Chocolate shows remarkable losses in polyphenols and vitamin E during 18 months of storage, along with changes in sensory profiles, while the flavor still remains acceptable. The cocoa bean shell, a by-product of cocoa production, contains valuable phytochemicals and can be used as an ingredient for functional food.
What the authors conclude
“The hoped-for effects are up to now only partly covered by scientific evidence.”
Also in their conclusions
- They say the hoped-for effects of cocoa products are up to now only partly covered by scientific evidence.
- They remind readers that manufacturers of such products do not only want to make the world a better place, but they also have financial interests.
How it was done
Health-related aspects of cocoa have come into the focus of research in recent decades, and this Special Issue presents the most recent findings on cocoa and health.
The Special Issue presents 14 peer-reviewed articles, including nine original contributions and five reviews from cocoa experts around the world.
What it can’t tell you
- Many of the studies looked at cocoa as a whole, so an observed effect can hardly be ascribed to a single constituent.
- The impact of cocoa metabolites on health has not yet been completely elucidated.
- Results for exercise performance and recovery were inconsistent, so no clear conclusion can be drawn.
Who paid
- Conflicts
- The authors declare no conflict of interest.
- Authors work at
- University of Bonn, Germany; University of Applied Sciences, Germany
The paper
- Title
- Cocoa, Chocolate, and Human Health
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Zimmermann BF, Ellinger S (2020). Cocoa, Chocolate, and Human Health. Nutrients. doi:10.3390/nu12030698Free full textPubMed 32151002DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error