Cocoa-Rich Dark Chocolate
- Higher proportion of cocoa
- Naturally contains cocoa flavanols
- Typically less sugar than milk chocolate
- Can provide meaningful amounts of cocoa polyphenols
Quality Matters
Chocolate has a reputation for being an indulgence. But cocoa beans are also one of the richest dietary sources of a group of plant compounds called flavanols.
The difference is that not all chocolate is created equal. The amount of cocoa, the amount of added sugar and fat, and especially how the cocoa is processed can dramatically change what ends up in the finished chocolate.
This guide looks at what makes high-cacao chocolate different, what cocoa flavanols actually are, what the research says about cardiovascular health, and why processing matters.
THE BIG IDEA
COCOA
The healthiest part of chocolate starts with the cocoa bean.
Cocoa beans naturally contain a wide variety of plant compounds, including polyphenols and flavanols.
These compounds are responsible for much of cocoa's characteristic bitterness and astringency. They are also the compounds that have attracted significant scientific interest for their potential effects on blood vessels, blood pressure and cardiovascular health.
When cocoa is turned into conventional chocolate, however, the bean is combined with ingredients such as sugar and cocoa butter, and it may undergo extensive processing.
That means the health properties of a chocolate product depend on much more than simply the word "chocolate" on the package.
Research: Cocoa Polyphenols: Chemistry, Bioavailability and Effects on Cardiovascular Performance
FIRST, WHAT ARE FLAVANOLS?
Flavanols are naturally occurring plant compounds.
Flavanols, also called flavan-3-ols, are a class of polyphenols found in many plants and foods.
Cocoa is particularly rich in flavanols, including compounds such as epicatechin, catechin and procyanidins.
These compounds have been studied for their antioxidant activity and their effects on the cardiovascular system.
Importantly, the science around cocoa is not simply about "antioxidants." Flavanols appear to interact with biological pathways involved in blood-vessel function, including pathways associated with nitric oxide.
That distinction matters because the potential cardiovascular effects of cocoa are more complicated than simply "free radicals are bad and antioxidants are good."
Source: Endothelial function, nitric oxide, and cocoa flavanols
A COMMON SOURCE OF CONFUSION
Flavanols and flavonols are not the same thing.
You may see the words flavanols and flavonols used when reading about cocoa. They sound almost identical, but they refer to different subclasses of flavonoids.
Cocoa is particularly well known for its flavan-3-ols, including epicatechin and catechin.
More broadly, flavonoids are a large family of plant compounds found throughout fruits, vegetables, tea, cocoa and other foods.
For the purposes of chocolate research, the word you will most often want to pay attention to is flavanols.
CHOCOLATE FACT #1
1.17%
Cocoa flavanols have been shown to improve a measure of endothelial function.
A meta-analysis of randomized trials examined the effect of cocoa flavanols on flow-mediated dilation (FMD), a commonly used measure of how well blood vessels respond to increased blood flow.
Across 18 intervention arms, cocoa flavanol intake was associated with an average improvement in FMD of approximately 1.17 percentage points.
This is significant because the endothelium is the thin layer of cells lining our blood vessels and plays an important role in regulating vascular tone and blood flow.
Research: Dose-response relationship between cocoa flavanols and human endothelial function
YOUR BLOOD VESSELS MATTER
One of the most interesting things about cocoa is what it may do to your blood vessels.
Your arteries are not simply pipes carrying blood. Their inner lining, called the endothelium, actively participates in regulating blood flow.
One important signaling molecule involved in this process is nitric oxide.
Nitric oxide helps blood vessels relax and widen when increased blood flow is needed.
Research suggests cocoa flavanols can influence pathways involved in nitric oxide availability and endothelial function.
This is one reason researchers have become interested in cocoa flavanols as a potential contributor to cardiovascular health.
Research: Endothelial function, nitric oxide, and cocoa flavanols
CHOCOLATE FACT #2
~2 mmHg
Flavanol-rich cocoa has been associated with modest reductions in blood pressure.
A Cochrane review examined 35 studies involving more than 1,800 participants and found that flavanol-rich cocoa products produced a small reduction in blood pressure.
The average reduction was approximately 1.8 mmHg.
That is not a replacement for medical treatment, but even small changes in blood pressure can be relevant when considered as part of an overall healthy lifestyle.
CHOCOLATE FACT #3
21,442
One of the largest cocoa studies ever conducted followed more than 21,000 adults.
The COSMOS cocoa trial enrolled 21,442 U.S. adults aged 60 and older.
Participants received either a cocoa extract supplement providing 500 mg of cocoa flavanols per day or a placebo.
The study is important because it moved beyond short-term measurements such as blood pressure and endothelial function and examined actual cardiovascular events.
Research: COSMOS Cocoa Trial
WHAT THE BIG STUDY ACTUALLY FOUND
The results were promising — but not a reason to overstate the science.
In the COSMOS trial, cocoa extract supplementation did not statistically significantly reduce total cardiovascular events during the study period.
However, researchers observed a statistically significant 27% reduction in cardiovascular death as a secondary outcome.
The researchers concluded that additional research is needed to clarify whether cocoa flavanols can reduce cardiovascular events.
In other words: the evidence is interesting and encouraging, but chocolate should not be presented as a cardiovascular treatment.
Research: COSMOS Randomized Clinical Trial
CHOCOLATE FACT #4
42
A meta-analysis of 42 randomized trials found improvements in several cardiovascular risk factors.
Researchers reviewed 42 randomized controlled trials involving approximately 1,297 participants.
They found that cocoa, chocolate and flavan-3-ol interventions improved flow-mediated dilation and were associated with modest reductions in diastolic blood pressure.
The researchers described the evidence as promising but noted limitations including short study durations, differences among interventions and other methodological concerns.
ANTIOXIDANTS
Cocoa is naturally rich in antioxidant polyphenols.
Cocoa contains a variety of polyphenolic compounds, including flavanols and proanthocyanidins.
These compounds can participate in antioxidant processes and have been investigated for their effects on oxidative stress, inflammation and vascular biology.
But there is an important distinction between antioxidant activity measured in a laboratory and a proven health outcome in humans.
A chocolate having a high antioxidant measurement does not automatically mean that eating it will prevent disease.
The most compelling human evidence for cocoa currently involves areas such as endothelial function and blood pressure rather than a simple "antioxidant = healthier" equation.
THIS PART REALLY MATTERS
Processing can change the chemistry of cocoa.
Cocoa beans do not go straight from the tree into a chocolate bar. They undergo fermentation, drying, roasting and other processing steps before becoming chocolate.
Each step can change the concentration and composition of cocoa's naturally occurring polyphenols and flavanols.
01
Fermentation
Necessary for developing chocolate's characteristic flavor, but it can substantially reduce certain flavanols.
02
Drying
Removes moisture and helps prepare the beans for further processing. Conditions can influence polyphenol retention.
03
Roasting
Develops chocolate flavor but can reduce some heat-sensitive flavanols depending on temperature and time.
04
Alkalization
Also called Dutch processing. It can dramatically reduce the flavanol content of cocoa.
Research: From Cocoa to Chocolate: Effect of Processing on Flavanols and Methylxanthines
CHOCOLATE FACT #5
89%
Heavy alkalization can remove the vast majority of cocoa's measurable flavanols.
In one analysis of commercial cocoa powders, natural, non-alkalized cocoa contained substantially more flavanols than alkalized cocoa.
Average total flavanol content in the study was approximately:
Cocoa Type
Total Flavanols
Natural Cocoa
34.6 mg/g
Lightly Alkalized
13.8 mg/g
Medium Alkalized
7.8 mg/g
Heavily Alkalized
3.9 mg/g
That represents a dramatic decline as alkalization increases.
This is one reason the phrase "dark chocolate" by itself does not tell you everything you need to know about a product's potential flavanol content.
Research: Impact of alkalization on the antioxidant and flavanol content of commercial cocoa powders
HIGH CACAO
Why does cacao percentage matter?
The percentage printed on a chocolate package generally indicates the proportion of the chocolate made from cacao-derived ingredients.
As cacao percentage increases, there is generally less room for added sugar and other ingredients.
A higher cacao percentage can therefore be a useful starting point when looking for chocolate with more cocoa and less added sugar.
But remember: cacao percentage does not guarantee a specific flavanol concentration.
Two 85% dark chocolates can have different flavanol profiles depending on the cocoa variety and how the beans and chocolate were processed.
Source: American Heart Association: Are there health benefits from chocolate?
CHOCOLATE FACT #6
70–85%
Dark chocolate in this range generally contains considerably more cocoa than milk chocolate.
The American Heart Association notes that dark chocolate commonly contains a substantially higher proportion of cocoa than milk chocolate.
More cocoa generally means more of the compounds naturally associated with cocoa, while darker chocolate typically contains less added sugar than milk chocolate.
This is one reason high-cacao chocolate can be a more sensible choice when you want chocolate primarily for its cocoa content rather than simply for sweetness.
Source: American Heart Association
NOT ALL CHOCOLATE IS THE SAME
Chocolate can mean very different things.
Milk Chocolate
- Lower proportion of cocoa
- Typically more added sugar
- Milk ingredients dilute the cocoa proportion
- Generally less cocoa-derived flavanol content
White Chocolate
- Contains cocoa butter but no cocoa solids
- Does not provide the cocoa solids responsible for most cocoa flavanols
- Primarily a sweet confection
CHOCOLATE MYTHS
What people often get wrong about dark chocolate.
✕ MYTH
"All dark chocolate is healthy."
✓ FACT
Dark chocolate varies enormously in cocoa content, sugar, processing and flavanol content. The label "dark chocolate" alone does not guarantee a particular nutritional profile.
✕ MYTH
"The darker the chocolate, the more flavanols it always has."
✓ FACT
Higher cacao percentage can mean more cocoa, but processing can substantially change flavanol levels. Cacao percentage and flavanol content are not interchangeable measurements.
✕ MYTH
"Chocolate is an antioxidant supplement."
✓ FACT
Cocoa contains antioxidant polyphenols, but chocolate is still a calorie-containing food. It should be viewed as part of an overall diet rather than a replacement for fruits, vegetables or other nutrient-rich foods.
✕ MYTH
"More chocolate means more health benefits."
✓ FACT
More is not necessarily better. Chocolate can be energy-dense, and the amount of cocoa flavanols actually consumed depends heavily on the product.
✕ MYTH
"Chocolate lowers blood pressure."
✓ FACT
Research suggests flavanol-rich cocoa can produce modest reductions in blood pressure, but chocolate is not a treatment for hypertension and should not replace prescribed care.
✕ MYTH
"All cocoa processing is bad."
✓ FACT
Processing is necessary to make chocolate safe, flavorful and enjoyable. The issue is that certain processing steps can reduce flavanols. The goal is not "no processing" but thoughtful processing that preserves desirable cocoa characteristics.
WHY MINIMAL PROCESSING MATTERS
We don't want to process the good stuff out of the bean.
Cocoa processing exists for very good reasons. Fermentation, drying and roasting transform raw cacao into something that actually tastes like chocolate.
The challenge is that some of the same processes that make chocolate more appealing can also reduce naturally occurring flavanols.
This is particularly important with alkalization, which is used to reduce acidity and bitterness and produce darker colors.
Research has repeatedly demonstrated that alkalization can substantially reduce cocoa flavanol concentrations.
For a chocolate designed around the natural qualities of cocoa, preserving as much of the bean's beneficial compounds as practical becomes part of the manufacturing philosophy.
Research: Impact of alkalization on the antioxidant and flavanol content of commercial cocoa powders
CHOCOLATE FACT #7
>80%
Certain processing steps can cause dramatic losses of individual cocoa flavanols.
Research examining cocoa processing found substantial decreases in catechin and epicatechin under certain fermentation conditions, while roasting and alkalization can also affect flavanol levels.
The exact amount lost depends on the cocoa variety and the specific processing conditions.
This is why "cocoa" is not a single standardized ingredient from a nutritional perspective.
Research: Impact of fermentation, drying, roasting, and Dutch processing on epicatechin and catechin
THE HEART CONNECTION
Why are researchers so interested in cocoa and cardiovascular health?
Cardiovascular disease involves many interconnected processes, including blood pressure, endothelial function, inflammation, blood-vessel health and metabolic health.
Cocoa flavanols have been studied in relation to several of these pathways.
Blood Vessel Function
Cocoa flavanols have been associated with improved flow-mediated dilation.
Nitric Oxide
Flavanol-rich cocoa may influence nitric-oxide signaling, which plays a role in vascular relaxation.
Blood Pressure
Clinical trials and meta-analyses have found modest reductions in blood pressure.
Oxidative Stress
Cocoa polyphenols have antioxidant properties and have been studied in relation to oxidative processes.
Platelet Activity
Cocoa polyphenols have been investigated for potential effects on platelet adhesion and function.
Metabolic Health
Cocoa and flavanol interventions have also been studied for effects on insulin sensitivity and other metabolic markers.
A BETTER WAY TO THINK ABOUT CHOCOLATE
Chocolate doesn't have to be either "healthy" or "junk food."
Food exists on a spectrum.
A chocolate bar made primarily from cocoa, with a high cacao percentage, limited added sugar and careful processing is fundamentally different from a highly sweetened candy bar containing relatively little cocoa.
That does not make dark chocolate a superfood or a medicine.
It means that chocolate can be enjoyed as part of a healthy diet while also providing naturally occurring compounds that have been extensively studied for their potential health effects.
The goal isn't to make chocolate "healthy." The goal is to make chocolate better.
WHAT TO LOOK FOR
How to choose a better dark chocolate.
01
Look for a high cacao percentage.
Higher cacao generally means more cocoa-derived ingredients and less room for added sugar.
02
Check the ingredient list.
A shorter, simpler ingredient list can make it easier to understand what you're actually eating.
03
Don't confuse dark color with flavanol content.
Very dark color can result from alkalization. Color alone is not a reliable measure of flavanol content.
04
Pay attention to added sugar.
A product can contain a high percentage of cacao while still being formulated as a very sweet confection.
05
Look for information about processing.
If preserving cocoa flavanols is part of the goal, look for products that avoid unnecessary alkalization and excessive processing.
WHY HAC LOVES CHOCOLATE
Chocolate should taste indulgent without being treated like junk food.
At HAC, we start with chocolate because we believe you shouldn't have to give up the foods you love to pursue a healthier lifestyle.
Our chocolate products are built around high-quality cocoa and dark chocolate, rather than treating cocoa as an afterthought.
We also believe in keeping the ingredient philosophy simple: start with good ingredients, preserve what makes them valuable, and make something you actually want to eat.
HIGH CACAO
Cocoa-forward chocolate
DARK CHOCOLATE
Rich, naturally complex cocoa flavor
SIMPLE
Chocolate made to be enjoyed
THE RESEARCH
Cocoa & Dark Chocolate Research Library
The information on this page is based on randomized trials, systematic reviews, meta-analyses and scientific reviews. Research into cocoa flavanols is ongoing, and not every proposed benefit has been established.
Cocoa Flavanols & Endothelial Function
A systematic review and meta-analysis examining the relationship between cocoa flavanol intake and vascular endothelial function.
Read the research →Cocoa & Blood Pressure
Cochrane review examining randomized trials of cocoa and chocolate products and their effects on blood pressure.
Read the Cochrane review →COSMOS Cocoa Trial
One of the largest randomized clinical trials examining cocoa flavanol supplementation and cardiovascular outcomes.
Read the study →Cocoa, Chocolate & Cardiovascular Health
Systematic review and meta-analysis of randomized trials examining cardiovascular risk factors.
Read the research →Cocoa Processing & Flavanols
Review examining how fermentation, drying, roasting and other processing steps influence cocoa flavanols.
Read the review →Alkalization & Cocoa Flavanols
Research examining how Dutch processing changes flavanol and antioxidant content in cocoa powders.
Read the research →THE BOTTOM LINE
Good chocolate starts with good cocoa.
Cocoa isn't simply the ingredient that makes chocolate taste like chocolate. It is a complex plant food containing flavanols, polyphenols and other naturally occurring compounds that have been studied extensively for their potential cardiovascular and metabolic effects.
The strongest evidence points toward improvements in measures such as endothelial function and modest reductions in blood pressure, while the evidence for preventing actual cardiovascular events remains less definitive.
And processing matters. High cacao percentage can be useful, but it isn't the whole story. How the cocoa is fermented, roasted and alkalized can dramatically affect the compounds that make cocoa interesting in the first place.
So when you're choosing chocolate, think beyond "dark."
Think cocoa content, ingredients, processing and quality.
Chocolate can be an indulgence. It can also be made with ingredients worth understanding.
This page is intended for general educational and informational purposes only. It is not medical advice and is not intended to diagnose, treat, cure or prevent any disease or medical condition.
Research involving cocoa flavanols is ongoing. Findings from studies of cocoa extracts, cocoa powders or isolated flavanols should not automatically be interpreted as evidence that every chocolate product will produce the same effects. Chocolate can be calorie-dense and may contain significant amounts of saturated fat and added sugar. Dark chocolate should be considered as one component of an overall dietary pattern, not as a replacement for fruits, vegetables, whole grains, physical activity or medical treatment.
If you have cardiovascular disease, high blood pressure, diabetes, or another medical condition, speak with your healthcare professional about dietary choices appropriate for you.