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A Heart-to-Heart with Chocolate:

Dark Chocolate vs. Milk Chocolate and its Influence on Cardiovascular Health

Karen McGee

October 5, 2009


“Chocolate is a divine, celestial drink, the sweat of the stars, the vital seed, divine nectar, the drink of the gods, panacea and universal medicine.” – Geronimo Piperni, quoted by Antonio Lavedán, a surgeon in the Spanish Army, 1796




        What if eating one of the world’s most cherished sweets improved your health?  In recent years, studies have proven that chocolate may in fact be good for you.  In particular, there has been much discussion about dark chocolate and its cardiovascular health benefits.  The media and marketing venues have latched on to the idea that the antioxidants in chocolate can improve heart health.  Much of the focus has been on dark chocolate in particular, but there has not been much public discussion about how it compares to its more popular sibling, milk chocolate.  This review will look at the benefits of dark chocolate in comparison to milk chocolate on cardiovascular health. 


History of Chocolate

        The history of chocolate dates back to over 2,000 years ago in Central America.  Mayans and Aztecs both valued cocoa beans, from which chocolate is derived, very highly, as was demonstrated in cave paintings and accounts from explorers of the area.  The first evidence of chocolate use in Central America is among the Maya who made cocoa into a spicy drink called chocolatl.  Later in the 1300s, the Aztec would use cocoa beans as currency as well as in religious and ritual ceremonies ( 


Cocoa beans


        Cocoa beans were first introduced to Europe when Christopher Columbus brought them back from his travels to Central America.  However, Europe was not immediately impressed by these cocoa beans as the beans did not match the sweet tooth that many Europeans had.  It wasn’t until Hernando Cortes began to experiment with chocolate that Europe began appreciating this sweet new discovery.  While in Mexico in the 1500s, Cortes experimented with chocolatl, a sweet chocolate drink consumed by royalty, and added sugar cane to it to make it sweeter and more pleasurable to his Spanish tastes.  When he brought cocoa beans back to Spain, he added imported spices to it and the first European hot chocolate drink was created.  From there, chocolate spread across all of Europe and was acclaimed for its delectableness ( 

        Although chocolate reached popularity in the 1500s, it wasn’t until a few centuries later that chocolate – in both drink and solid form – was made accessible to the masses.  With the advent of the Industrial Revolution, chocolate was easier to manufacture and its prices were lowered.  The inventions of the steam engine, conching machine, and cocoa press all contributed to more efficient ways of processing cocoa.  With these improvements in machinery, the price of cocoa declined.  For the first time, chocolate was not solely available to the elite; all classes of people had access to chocolate products.

        Up until the mid-1800s, all chocolate was either drinking chocolate or dark chocolate, also known as bittersweet or semisweet chocolate.  However, in 1876, Daniel Peter added milk to chocolate in Switzerland, thus creating the world’s first milk chocolate.  Such famous chocolatiers as Henri Nestlé and Milton S. Hershey also got their start in the last 1800s as they jumped on the innovative nature of chocolate creations at that time and began their own chocolate companies.  Since then, chocolate has played a key role in many things, from being an essential in soldiers’ lunchboxes while at war to being the first things kids grab for a snack when they come home from school.


The Making of Chocolate

Chocolate Manufacturing

Chocolate processing chart


        The making of chocolate is an involved process with many steps, but has been refined over the past few centuries into an efficient method today.  The first step in making chocolate is to process the cocoa beans.  According to the National Confectioners Association, this begins with drying and fermenting the beans in the location where they’re grown before shipping them off to factories.  Once the cocoa beans reach the factories, they are cleaned and roasted.  It is in the roasting process that the beans develop their characteristic rich brown color and sweet aroma.  After they are roasted, their thin shells are easily removed and the nibs, or “meat” of the cocoa beans, are all that remains.  Next, the nibs are crushed between heavy discs.  The pressure liquefies the cocoa butter in the nibs into chocolate liquor.  If the liquor is poured into molds and solidifies, it results in unsweetened chocolate.


Conching in a chocolate factory


        For all other chocolate, many more processing steps remain.  First of all, cocoa powder needs to be made.  The chocolate liquor from above is pressed in giant machines to remove the cocoa butter, which is then collected.  Cocoa butter has many essential qualities: first of all, it is used in most all edible chocolate; it also has a melting point just below body temperature which creates the classic melt-in-your-mouth characteristic of chocolate; also, it can be stored for many years without going bad.  Once the cocoa butter is removed, the remaining product is cooled and made into cocoa powder, which is then sent to stores or manufacturers. 

        After separating the cocoa beans into all of the aforementioned basic parts, the ingredients are then combined again in the desired proportions to make eating chocolate.  Eating chocolate can include cocoa butter, cocoa powder, sugar, milk, and any other desired spices.  Once all of these ingredients are mixed, they must be “conched” in a conching machine which rolls the chocolate mass so that it is completely mixed and smooth.  The chocolate mixture is then cooled and reheated until it is molded into the desired shape ( 


Types of Chocolate

        In the mid-1900s, there were over 40,000 different varieties of chocolate in the United States (  It is safe to assume that that number has only increased in the twenty-first century.  Although there are countless varieties of chocolate, there are a few overarching chocolate categories that should be considered as we take a look at the effects of different varieties of chocolate on heart health.  Below are the definitions for some key chocolate categories as given by the Hershey Company:

Unsweetened or baking chocolate: chocolate liquor

Baking chocolate -

Semisweet or bittersweet chocolate (dark chocolate): combination of chocolate liquor (at least 35%), cocoa butter, and sugar

Dark chocolate -

Milk chocolate: combination of chocolate liquor (at least 10%), cocoa butter, sugar, and milk or cream (at least 12%)

Milk chocolate -

White chocolate: same ingredients as milk chocolate but without nonfat cocoa solids; at least 20% cocoa butter and 14% milk (

White chocolate -


What are Antioxidants?

        Antioxidants have been the main focus of chocolate research in the past few decades.  But what are antioxidants?  Many people know that antioxidants are said to be beneficial, but most people do not know anything about the role antioxidants play in health.

        Oxidation is a process that occurs in humans every day.  It is “the process of adding oxygen to a compound” (  When oxidation occurs, “free radicals,” which can cause cellular damage, result.  This damage can cause cardiovascular disease and diabetes, as well as other diseases and issues.  Antioxidants can prevent or repair this damage ( 

        Flavonoids, a type of antioxidant found in chocolate, have been shown to have some cardiovascular benefits.  It appears that eating chocolate delays LDL-oxidation, decreases platelet activity, and has an “aspirin’-like” effect on blood-clotting.  The flavonoids in chocolate also seem to lower blood pressure when consumed over time (

        Many website, such as Hershey’s or the American Dietetic Association website, both listed above, tout the benefits of antioxidants because they are promoting an idea that will assist their organizations.  However, they both do so without fault.  They use scientific research to back their findings and do not make extraordinary claims about the health benefits of chocolate.  Especially for the Hershey’s company, clearly explaining the benefits of antioxidants in a way the most common person can understand will assist their sales and boost their product.  In reviewing many of these websites, I have found that they are modest in promoting chocolate consumption and most, including WebMD and Hershey’s recognize and make clear that chocolate should not replace consumption of healthier, antioxidant-rich foods.  


How Chocolate Compares to Itself and Other Antioxidant-Rich Foods

        Chocolate certainly isn’t the only antioxidant-rich food.  In fact, several other foods reigned in the spotlight years before the benefits of chocolate came on the scene.  Some foods that also contain antioxidants are blueberries, raspberries, cranberries, red grapes, red wine, almonds, raisins, pecans, cherries, walnuts, and prunes.  These antioxidant-rich foods are rated on their Oxygen Radical Absorbance Capacity, or ORAC, which measures how powerful the antioxidants are.  Chocolate, specifically the dark variety, ranks higher than most antioxidant foods on the ORAC scale (Steinberg, Bearden, & Keen, 2003).  As can be seen by the chart below, dark chocolate ranks highest, but even milk chocolate ranks above red grapes, almonds, and raisins.

        In comparison to itself, different types of chocolate vary greatly in their antioxidant content.  From the highest polyphenol content to lowest, cocoa contains the most polyphenols, followed by dark chocolate, milk chocolate, and hot cocoa (Vinson, Proch, & Zubik,1999).


Cardiovascular Health

        Heart health is one of the most important issues in the medical community right now.  Cardiovascular disease can include everything from coronary artery disease, heart failure, arrhythmias, congenital heart disease, cardiomyopathy, and vascular disease, to name a few (  According to WebMD, a few ways you can lower your risk for cardiovascular disease is to lower high blood pressure, eat a heart-healthy diet, exercise, and watch your cholesterol.  For cholesterol, you want to have low LDL (low-density lipoprotein – “bad” cholesterol) and higher HDL (high-density lipoprotein – “good” cholesterol) because LDL is the main cause of plaque and HDL clears cholesterol from the blood (  A heart-healthy diet includes eating more fish, vegetables, fruits, and whole grains; being picky about fat calories and limiting fat intake; eating a variety of proteins; and limiting cholesterol intake ( 


Benefits of Dark Chocolate

        At this point, it is well-accepted that dark chocolate has health benefits.  Since dark chocolate has a high amount of antioxidants, and antioxidants help prevent cardiovascular disease, eating a moderate amount of dark chocolate can have cardiovascular benefits.  WebMD makes an important point that it is a moderate amount of dark chocolate that has health benefits; calorie-intake should still be monitored when consuming chocolate.  It suggests exchanging your usual milk chocolate snack for dark chocolate, not trading in a plate of broccoli for a chocolate bar ( 


Review of the Literature


Chocolate Flavonoids and Cardiovascular Health

Much research has been done on chocolate and cardiovascular health.  In 2003, Francene M. Steinberg, Monica M. Bearden, and Carl L. Keen published an article in the Journal of the American Dietetic Association about chocolate flavonoids and cardiovascular health.  They looked at an exhaustive list of the components of chocolate and how each may contribute to health.  They admit that while it is clear that a high intake of fruits and vegetables (full of antioxidants) leads to a lower risk of cardiovascular disease, it is simply hypothetical that things such as chocolate, tea, or wine, which all contain antioxidants, also lead to lower cardiovascular disease risk.  They say that this is because the scientific community does not have a clear grasp on how flavonoids work.  In this article, the dietary contributions of dark chocolate, milk chocolate, and other antioxidant-rich foods are charted.  These charts show that dark chocolate exceeds milk chocolate in its quantitative values.  Dark chocolate has more flavonoids because it has a higher concentration of cocoa liquor than milk chocolate; thus it can be inferred that the authors would agree that dark chocolate, with more flavonoids, has more cardiovascular benefits than milk chocolate.  They conclude their article by saying that conclusions about a daily intake of flavonoids, whether in chocolate or other foods, to lower the risk of cardiovascular disease cannot be made at this time (Steinberg et al., 2003).


Chocolate and the Prevention of Cardiovascular Disease – a Review

        In 2006, Eric L. Ding, Susan M. Hutfless, Xin Ding, and Sake Girotra did a comprehensive review of the literature on chocolate and cardiovascular disease.  Through their review, they concluded that chocolate studies show clear benefits for cardiovascular health as chocolate seems to lower bloods pressure, inflammation, platelet function, and LDL oxidation.  However, they also said that ethical restrictions in studies make it difficult to make solid epidemiologic conclusions.  In looking at other researchers’ data, they note that dark chocolate contains significantly more phenols, catechins, and flavonoids than milk chocolate.  They also mentioned that the milk in milk chocolate may prevent the absorption of flavonoids in the intestines, thus significantly reducing the amount of flavonoids in milk chocolate that could potentially have cardiovascular benefits.  As for cardiovascular disease mortality, they said that through prospective observational studies, it can be reasonably concluded that flavonoids do lower cardiovascular disease.  Once again, since they note that dark chocolate has more flavonoids than milk chocolate, it can be concluded that dark chocolate has more cardiovascular benefits than milk chocolate.  They conclude that it would be much wiser to consume dark chocolate with high flavonoid content than milk chocolate (Ding, Hutfless, Ding, & Girotra, 2006).


Dark Chocolate vs. Milk Chocolate

        One of the most often-referenced chocolate articles is one by Mauro Serafini, Rossana Bugianesi, Giusseppe Maiani, Silvia Valtuena, Simone De Santis, and Alan Crozier that appeared in Nature in 2003.  This is one of the few scholarly research articles that compares dark chocolate directly to milk chocolate.  Their research showed that milk might interfere with the absorption of the antioxidants from chocolate.  They looked at three products: dark chocolate, dark chocolate consumed with milk, and milk chocolate.  Through in vitro observations and observations of a small sample of humans, they observed that dark chocolate raised plasma antioxidant levels much more than the other two.  They also noticed that antioxidant activity was inhibited in vitro with the addition of milk.  At the end of their article, they supposed that foods other than milk may also inhibit the absorption of antioxidants.  However, their overarching conclusion was that the addition of milk to the consumption of chocolate – whether directly mixed into the chocolate or consumed with dark chocolate – lowers or inhibits antioxidant activity.  Thus, it can be concluded from their article that dark chocolate has more cardiovascular benefits than milk chocolate (Serafini et al., 2003).




        So, can it be concluded that dark chocolate holds more benefits towards cardiovascular health than milk chocolate?  Through looking at the above literature and chocolate resources, it has been shown that dark chocolate contains more antioxidants than milk chocolate because it has a higher content of chocolate liquor (often 35+% chocolate liquor in dark chocolate and 10% in milk chocolate), which is rich in antioxidants.  Recent studies have shown the possibility that milk might inhibit the absorption of antioxidants into the bloodstream, so consuming milk chocolate may all but negate the health benefits of the antioxidants it contains.

        As many of the authors of these articles admit, there is much research left to be done on the cardiovascular health benefits of chocolate, and especially the differences between dark chocolate and other varieties of chocolate.  Since there is no regulation of the proportions of different ingredients in chocolate from the Food and Drug Administration, it is difficult to say that all dark chocolate contains more antioxidants and has more heart health qualities than milk chocolate.  However, with all the current research compiled, it is clear that dark chocolate is generally more beneficial towards cardiovascular health than milk chocolate because it contains antioxidants that are not inhibited by the addition of milk. 

        Regardless of the health benefits of chocolate, it is important to keep in mind that any kind of chocolate, even if it has great health benefits, should not replace a diet high in fruit and vegetable intake.  In order to effectively introduce antioxidant-rich dark chocolate into your life, dark chocolate should replace a less healthy part of your diet and be consumed in conjunction with fruits, vegetables, and other healthy foods.

        Dark chocolate or milk chocolate – invest in the dark until further research on antioxidants and the effects of milk is completed!


Your heart and chocolate – a sweet combination!



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