What do studies not funded by the chocolate industry show about the effect of cocoa on arterial health?
Dark Chocolate and Artery Function
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Chocolate: beauty, or the beast, or both? Although cocoa itself is frequently found in foods like “chocolate which can contain high levels of fat and sugar,” the cocoa powder itself “may have beneficial effects in a number of chronic disease conditions, including [heart] disease.”
Flow-mediated dilation, measured in the main artery of the arm, which is about the same caliber as our coronary arteries, is considered one of the best measures of arterial function—a predictor of cardiovascular mortality. A little bit of cocoa doesn’t do anything. But a little more, or a lot more, gives one a significant boost in arterial function within hours of consumption. How much does it take? Not much—just a teaspoon of natural cocoa powder, which would be like a tablespoon or more of Dutch cocoa.
Now, makes you a little suspicious that the author works in Hershey, Pennsylvania, at the Hershey Medical Center, and, indeed, has accepted money from our largest chocolate manufacturer’s Center for Health and Nutrition, conveniently located near the intersection of Chocolate and Cocoa Avenues.
Putting together all of the best available science, though—dozens of randomized controlled trials—arterial function was significantly improved within hours, and after weeks and months of chronic cocoa consumption. It’s always difficult to tease out fact from fiction when such powerful financial interests are involved. “Many [of these] studies were funded by industry” as well, “and [as] in all areas of research evidence suggests that industry funding is associated with pro-industry conclusions.” But, even after removing “those studies funded by industry,” they found the same protective effect.
The reason they measure arterial function in the arm, rather than where you really need it—the coronary arteries of the heart—is that that would require an angiogram, which is a little more invasive. But if you were able to find people already scheduled for an angiogram anyway… Here we go.
Double-blind randomized trial finds that dark chocolate actually opens up coronary arteries themselves. And, when they did what’s called a cold-pressor test, where they plunge your hand into a bucket of ice water—which normally causes your arteries to constrict—but, after dark chocolate, they dilated. Dark chocolate may also improve blood flow to the heart of our kidneys.
“Because chocolate also contains fat and sugar,” though, we have to be careful. “Furthermore, most chocolate products are manufactured with milk, a compound known to influence antioxidant…capacity in [our blood].” Even if milk chocolate had the same flavonoid phytonutrient content as dark chocolate, “the antioxidant effect of cocoa is potentially [weakened] in the [blood]” when milk is consumed.
So, not only are there triple the antioxidants in dark, compared to milk, chocolate, but the milk actively works against the effects in the human body. So, eat dark chocolate, and get a nice spike in the antioxidant power of our bloodstream within an hour. Milk chocolate—nothing. And, if you eat that same dark chocolate with a cup of milk, the benefit is suppressed. The “[a]ddition of milk”—either in our stomach, or in the chocolate itself—”inhibits the [within-body] antioxidant activity of chocolate and the absorption into the bloodstream of [one of the target phytonutrients].”
Sugar isn’t good for us, either. Sugar impairs arterial function. One bottle of soda’s worth of sugar can temporarily cripple arterial function. That’s why sugar-free cocoa improves arterial function better than the same amount of cocoa with sugar added. So, “[e]liminating sugar…appears to amplify the beneficial effects of cocoa.”
Bottom line: “Although the positive effects of chocolate and cocoa products seem apparent, precautions exist” when we’re talking about the calories, fat, and sugar in chocolate. Cocoa powder, then, offers the best of both worlds. “Although [not as tasty], cocoa-based products with little or no sugar or…fat are certainly preferred.” And, you can make them tasty, as I note in my healthy chocolate milkshake recipe, and my healthy chocolate ice cream video.
Please consider volunteering to help out on the site.
- S Vertuani, E Scalambra, T Vittorio, A Bino, G Malisardi, A Baldisserotto, S Manfredini. Evaluation of antiradical activity of different cocoa and chocolate products: Relation with lipid and protein composition. J Med Food 2014 17(4):512 – 516.
- J D Lambert. Cocoa and human health. Mol Nutr Food Res 2013 57(6):933 – 933.
- L Hooper, C Kay, A Abdelhamid, P A Kroon, J S Cohn, E B Rimm, A Cassidy. Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: A systematic review and meta-analysis of randomized trials. Am J Clin Nutr 2012 95(3):740 – 751.
- A J Flammer, F Hermann, I Sudano, L Spieker, M Hermann, K A Cooper, M Serafini, T F Lüscher, F Ruschitzka, G Noll, R Corti. Dark chocolate improves coronary vasomotion and reduces platelet reactivity. Circulation 2007 116(21):2376 – 2382.
- K D Monahan. Effect of cocoa/chocolate ingestion on brachial artery flow-mediated dilation and its relevance to cardiovascular health and disease in humans. Arch Biochem Biophys 2012 527(2):90 – 94.
- V Y Njike, Z Faridi, K Shuval, S Dutta, C D Kay, S G West, P M Kris-Etherton, D L Katz. Effects of sugar-sweetened and sugar-free cocoa on endothelial function in overweight adults. Int. J. Cardiol. 2011 149(1):83 – 88.
- C M Akbari, R Saouaf, D F Barnhill, P A Newman, F W LoGerfo, A Veves. Endothelium-dependent vasodilatation is impaired in both microcirculation and macrocirculation during acute hyperglycemia. J Vas Surg 1998 28(4):687 – 694.
- M Serafini, R Bugianesi, G Maiani, S Valtuena, S De Santis, A Crozier. Plasma antioxidants from chocolate. Nature 2003 424(6952):1013 – 1013.
- J Stebbing, V Gajapathy, Lowdell C. Chocolate: delicious beauty or harmful beast? Lancet Oncol 2013 14(6):457 – 458.
- L S Latham, Z K Hensen, D S Minor. Chocolate—Guilty Pleasure or Healthy Supplement? J Clin Hypertens 2014 16(2):101 – 106.
- M Pruijm, L Hofmann, J Charollais-Thoenig, V Forni, M Maillard, A Coristine, M Stuber, M Burnier, B Vogt. Effect of dark chocolate on renal tissue oxygenation as measured by BOLD-MRI in healthy volunteers. Clin Nephrol. 2013 Sep;80(3):211-7.
Images thanks to Bob.Fornal via flickr and Bronayur via Wikimedia
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Chocolate: beauty, or the beast, or both? Although cocoa itself is frequently found in foods like “chocolate which can contain high levels of fat and sugar,” the cocoa powder itself “may have beneficial effects in a number of chronic disease conditions, including [heart] disease.”
Flow-mediated dilation, measured in the main artery of the arm, which is about the same caliber as our coronary arteries, is considered one of the best measures of arterial function—a predictor of cardiovascular mortality. A little bit of cocoa doesn’t do anything. But a little more, or a lot more, gives one a significant boost in arterial function within hours of consumption. How much does it take? Not much—just a teaspoon of natural cocoa powder, which would be like a tablespoon or more of Dutch cocoa.
Now, makes you a little suspicious that the author works in Hershey, Pennsylvania, at the Hershey Medical Center, and, indeed, has accepted money from our largest chocolate manufacturer’s Center for Health and Nutrition, conveniently located near the intersection of Chocolate and Cocoa Avenues.
Putting together all of the best available science, though—dozens of randomized controlled trials—arterial function was significantly improved within hours, and after weeks and months of chronic cocoa consumption. It’s always difficult to tease out fact from fiction when such powerful financial interests are involved. “Many [of these] studies were funded by industry” as well, “and [as] in all areas of research evidence suggests that industry funding is associated with pro-industry conclusions.” But, even after removing “those studies funded by industry,” they found the same protective effect.
The reason they measure arterial function in the arm, rather than where you really need it—the coronary arteries of the heart—is that that would require an angiogram, which is a little more invasive. But if you were able to find people already scheduled for an angiogram anyway… Here we go.
Double-blind randomized trial finds that dark chocolate actually opens up coronary arteries themselves. And, when they did what’s called a cold-pressor test, where they plunge your hand into a bucket of ice water—which normally causes your arteries to constrict—but, after dark chocolate, they dilated. Dark chocolate may also improve blood flow to the heart of our kidneys.
“Because chocolate also contains fat and sugar,” though, we have to be careful. “Furthermore, most chocolate products are manufactured with milk, a compound known to influence antioxidant…capacity in [our blood].” Even if milk chocolate had the same flavonoid phytonutrient content as dark chocolate, “the antioxidant effect of cocoa is potentially [weakened] in the [blood]” when milk is consumed.
So, not only are there triple the antioxidants in dark, compared to milk, chocolate, but the milk actively works against the effects in the human body. So, eat dark chocolate, and get a nice spike in the antioxidant power of our bloodstream within an hour. Milk chocolate—nothing. And, if you eat that same dark chocolate with a cup of milk, the benefit is suppressed. The “[a]ddition of milk”—either in our stomach, or in the chocolate itself—”inhibits the [within-body] antioxidant activity of chocolate and the absorption into the bloodstream of [one of the target phytonutrients].”
Sugar isn’t good for us, either. Sugar impairs arterial function. One bottle of soda’s worth of sugar can temporarily cripple arterial function. That’s why sugar-free cocoa improves arterial function better than the same amount of cocoa with sugar added. So, “[e]liminating sugar…appears to amplify the beneficial effects of cocoa.”
Bottom line: “Although the positive effects of chocolate and cocoa products seem apparent, precautions exist” when we’re talking about the calories, fat, and sugar in chocolate. Cocoa powder, then, offers the best of both worlds. “Although [not as tasty], cocoa-based products with little or no sugar or…fat are certainly preferred.” And, you can make them tasty, as I note in my healthy chocolate milkshake recipe, and my healthy chocolate ice cream video.
Please consider volunteering to help out on the site.
- S Vertuani, E Scalambra, T Vittorio, A Bino, G Malisardi, A Baldisserotto, S Manfredini. Evaluation of antiradical activity of different cocoa and chocolate products: Relation with lipid and protein composition. J Med Food 2014 17(4):512 – 516.
- J D Lambert. Cocoa and human health. Mol Nutr Food Res 2013 57(6):933 – 933.
- L Hooper, C Kay, A Abdelhamid, P A Kroon, J S Cohn, E B Rimm, A Cassidy. Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: A systematic review and meta-analysis of randomized trials. Am J Clin Nutr 2012 95(3):740 – 751.
- A J Flammer, F Hermann, I Sudano, L Spieker, M Hermann, K A Cooper, M Serafini, T F Lüscher, F Ruschitzka, G Noll, R Corti. Dark chocolate improves coronary vasomotion and reduces platelet reactivity. Circulation 2007 116(21):2376 – 2382.
- K D Monahan. Effect of cocoa/chocolate ingestion on brachial artery flow-mediated dilation and its relevance to cardiovascular health and disease in humans. Arch Biochem Biophys 2012 527(2):90 – 94.
- V Y Njike, Z Faridi, K Shuval, S Dutta, C D Kay, S G West, P M Kris-Etherton, D L Katz. Effects of sugar-sweetened and sugar-free cocoa on endothelial function in overweight adults. Int. J. Cardiol. 2011 149(1):83 – 88.
- C M Akbari, R Saouaf, D F Barnhill, P A Newman, F W LoGerfo, A Veves. Endothelium-dependent vasodilatation is impaired in both microcirculation and macrocirculation during acute hyperglycemia. J Vas Surg 1998 28(4):687 – 694.
- M Serafini, R Bugianesi, G Maiani, S Valtuena, S De Santis, A Crozier. Plasma antioxidants from chocolate. Nature 2003 424(6952):1013 – 1013.
- J Stebbing, V Gajapathy, Lowdell C. Chocolate: delicious beauty or harmful beast? Lancet Oncol 2013 14(6):457 – 458.
- L S Latham, Z K Hensen, D S Minor. Chocolate—Guilty Pleasure or Healthy Supplement? J Clin Hypertens 2014 16(2):101 – 106.
- M Pruijm, L Hofmann, J Charollais-Thoenig, V Forni, M Maillard, A Coristine, M Stuber, M Burnier, B Vogt. Effect of dark chocolate on renal tissue oxygenation as measured by BOLD-MRI in healthy volunteers. Clin Nephrol. 2013 Sep;80(3):211-7.
Images thanks to Bob.Fornal via flickr and Bronayur via Wikimedia
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Dark Chocolate and Artery Function
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Content URLDoctor's Note
Here are links to the videos I mentioned: A Treatment for Chronic Fatigue Syndrome.
For more on the corrupting effect of money in nutrition research, see Academy of Nutrition & Dietetics Conflicts of Interest.
Since this video came out, I added more videos on chocolate:
What effects do other foods have on arterial function? See:
- Tea & Artery Function
- Olive Oil & Artery Function
- Sodium & Arterial Function: A-Salting our Endothelium
- Vinegar & Artery Function
- Plant-Based Diets & Artery Function
- Fatty Meals May Impair Artery Function
- Coffee and Artery Function
- Walnuts and Artery Function
- Eggs and Arterial Function
- Benefits of Blueberries for Artery Function
- Low Carb Diets & Coronary Blood Flow
For a delicious and healthy chocolate recipe, try my Cran-Chocolate Pomegranate BROL Bowl.
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