Is dark chocolate high in antioxidants?
Cocoa is measurably high in polyphenols in the laboratory. What that means inside a person is a separate question, and a less settled one.
Emerging research
Real human studies exist and point somewhere, but the body of evidence is small, mixed, short-term or heavily industry-funded.
What the evidence shows
Cocoa and cocoa-derived products contain substantial quantities of polyphenols, principally flavanols such as epicatechin and catechin, and these compounds have measurable antioxidant activity in laboratory assays. Cocoa's polyphenol content per gram compares favourably with many other plant foods on those assays.
What it does not show
Antioxidant activity measured in a test tube does not establish an antioxidant effect in the body. Absorption, metabolism and distribution all intervene, and the ORAC assay in particular was withdrawn by the US Department of Agriculture from its published tables on the grounds that the values had been widely misapplied to imply health effects the data did not support. No health outcome follows from a polyphenol content figure alone.
The amount the finding rests on
Trials reporting effects use standardised cocoa flavanol preparations, commonly in the hundreds of milligrams per day.
Ordinary chocolate is not a comparable delivery vehicle. Flavanol content is not stated on packaging and is heavily reduced by fermentation, roasting and alkalisation.
In practice: No quantity of chocolate is given here because none follows from the evidence. A bar's flavanol content is unknown to its buyer, so a gram figure would be a guess dressed as guidance.
How good is the evidence
The compositional chemistry is well characterised and not in dispute. The step from composition to physiological effect is where the evidence thins, and much of the popular literature elides it. Processing losses compound the problem: fermentation, roasting and especially alkalisation each degrade a substantial share of the flavanols present, and no bar states its flavanol content.
Who this may not apply to
- Anyone reading this to decide on an intake should note that the compounds studied are usually delivered as standardised extracts rather than as chocolate.
Related claims
“Dark chocolate is a health food — the darker the better.”
Research on cocoa flavanols and short-term measures of vascular function is real, and a narrowly scoped EU health claim exists on that basis. It concerns a specified daily intake of flavanol compounds, not chocolate. Flavanol content is not indicated by cocoa percentage, is substantially reduced by ordinary processing, and is not declared on mainstream products. Meanwhile the non-cacao mass of a dark bar is overwhelmingly sugar.
The kernel of truth: The underlying research exists and is not junk. A regulatory body assessed a claim in this area and authorised one, which very few food claims achieve. The overreach is in the distance between 'a specified flavanol intake affects a measure of vessel dilation' and 'chocolate is good for you'.
Where it comes from: Traceable in large part to industry-funded research programmes and the press coverage built on them. The Cochrane review of cocoa and blood pressure notes industry funding across a substantial share of the trials it includes.
Why the ORAC withdrawal matters
The ORAC scale was for years the number quoted on cocoa packaging and in wellness writing. Its withdrawal from the USDA's published tables is the clearest signal available that a laboratory antioxidant measure is not a health claim, and it came from the body that maintained it.
Any product still quoting an ORAC value is quoting a measure its own publisher stopped standing behind.
Related
Health topics
- Cocoa flavanols and blood vessel functionRead alongside Cocoa and antioxidants. There is real evidence that cocoa flavanols affect a specific measure of blood vessel function, and a large gap between that finding and 'chocolate is good for your heart'.
- Sugar in chocolateRead alongside Cocoa and antioxidants. The most reliably calculable fact on this page, and the one that most often goes unmentioned when chocolate is discussed as a health food.
Covered in
- Reading chocolate health claimsWhere the study-to-bar gap is widest, and the ORAC withdrawal that illustrates it.
- Natural cocoaWhat flavanol content does and does not establish.
Sources
- Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 — withdrawal notice — United States Department of Agriculture, Agricultural Research Service, 2012(citation identity confirmed; passage not re-read)
- Scientific Opinion on the substantiation of a health claim related to cocoa flavanols and maintenance of normal endothelium-dependent vasodilation — EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), 2012(citation identity confirmed; passage not re-read)
- Chocolate Science and Technology — Wiley-Blackwell(citation identity confirmed; passage not re-read)
- ChocolateHQ editorial synthesis — ChocolateHQ(citation identity confirmed; passage not re-read)
Nothing on this page is health advice or dietary advice. See the editorial policy.