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Cacao polyphenols
1. Publication # 2
Pennington Biomedical Research Center
Division of Education
Phillip Brantley, PhD, Director
Pennington Biomedical Research Center
Steven Heymsfield, MD, Executive Director
PBRC 2012
2. Overview…
An increasing body of epidemiologic evidence supports the
concept that diets rich in fruits and vegetables promote health
and attenuate, or delay, the onset of various diseases, including
cardiovascular disease, cancer, and certain neurodegenerative
disorders.
Epidemiologic data has linked these health benefits, at least in
part, to the presence of certain flavonoids in fruits and
vegetables.
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3. Flavonoids…
Flavonoids are a group of polyphenolic compounds that occur
widely in fruits, vegetables, tea, red wine, and chocolate.
Cocoa and chocolate products have the highest concentration of
flavonoids among commonly consumed foods.
Over 10 percent of the weight of cocoa powder is flavonoids.
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4.
Cocoa and chocolate products have been delicacies for
hundreds of years.
Cocoa and chocolate have only recently have they been
recognized as significant sources of phytochemicals, with
healthful effects.
Cocoa and chocolate are among the most concentrated sources
of the procyanidin flavonoids, catechin, and epicatechin.
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5. The fruit of the Theobroma cacao tree
Corti R et al. Circulation 2009;119:1433-1441
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6. Chocolate Consumption
Americans eat a lot of chocolate in the form of candy
(about 5.5 kg/year per person or 12 pounds), but not as
much as people in some northern European countries.
In Germany, the country with the highest chocolate
consumption, it is estimated at 11.4 kg/year (25
pounds) for each person.
Each candy bar contains about 210 calories, 13 g fat (7
of which is saturated), 23 g of carbohydrate, and 3 g of
protein.
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7. Flavonoids in Chocolate
principally
The flavonoids in cocoa/chocolate,
catechin and epicatechin, exist in long molecules.
In most foods, catechins are fairly short
molecules, maybe two, three linked together, but
in chocolate and cocoa they are much longer.
These structural characteristics of catechin and
epicatechin represent the molecular basis for both
their hydrogen-donating (radical-scavenging)
properties and their metal-chelating antioxidant
properties.
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8. Flavonoids in Chocolate
in 60% loss of total flavonoids.
Processing of cocoa results
Among flavanols, epicatechin has the largest decline (67%).
In terms of flavonols, quercetin declines the most (86%).
Most cocoas undergo fermentation steps which subject
flavonoids in the cocoa to heat and acidic conditions.
High processing temperatures, alkali treatment and longer
processing time all reduce the amount of cocoa polyphenols.
C.L. Hii et al. As. J. Food Ag-Ind. 2009, 2(04), 702-722
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9. Flavonoid Content: Variable
food or beverage product
The actual recipe for the finished
determines the amount of a given cocoa (and flavonoid) added.
Other ingredients can influence the final product such as the
type of fat used, type of milk and milk products used and the
addition of sugar and salt.
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10. Flavonoid Content
varying antioxidant content.
Different types of chocolate contain
In finished products, the amount of cocoa ranges from
7% to 35% in milk chocolate and 30% to 80% in dark
chocolate.
Consequently, there is a lot of variability and is generally
twice as high in dark than in milk chocolate.
Also interesting is the fact that white chocolate does not contain
polyphenols.
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11. Recent Studies
at the total polyphenols in
Several studies have looked
foods and beverages in the American diet, and chocolate
and cocoa have one of the highest levels of antioxidants
consistently.
Cocoa and chocolate have higher levels of polyphenols
than in many fruits. It is 20 times higher than in tomatoes,
2 times higher than in garlic, and over 3 times higher than
in grapes.
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12. Catechin/Epicathecin
concentrations in foods
Flavanol Content, mg/kg or
Source mg/L
Chocolate 460–610
Beans 350–550
Green tea 100–800
Apricots 100–250
Red wine 80–300
Black tea 60–500
Cherries 50–220
Peaches 50–140
Blackberries 130
Apples 20–120
Cider 40
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Circulation March 17, 2009 vol. 119 no. 101433-1441
13.
Numerous dietary intervention studies in humans and animals
indicate that flavanol-rich foods and beverages might exert
cardioprotective effects with respect to vascular function and
platelet reactivity. There is an improvement in blood vessel wall
function, reduction in platelets, and improvement in blood
pressure, insulin resistance and blood lipids.
Circulation . 2009; 119: 1433-1441
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15. Atherogenesis…
Phenolic antioxidants have been
shown to inhibit the oxidation of low-
density lipoprotein (LDL) cholesterol,
and mounting evidence suggests
that it is the oxidized form of LDL
that leads to the buildup of fatty
plaques in arteries.
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16. Atherogenesis…
have also shown to
Extracts of cocoa powder
significantly inhibit LDL oxidation.
Studies have found that cocoa preserves the lipids in
the lipid droplets in the circulatory system and it is
concentration-dependent. Higher amount of cocoa
polyphenols preserves greater amount of lipid droplets.
Cocoa phenols has shown to inhibit LDL oxidation by
75%, whereas red wines only inhibit LDL oxidation by
37-65%.
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19.
Interestingly, cocoa powder and cocoa extracts have been shown
to exhibit greater antioxidant capacity than many other flavanol-
rich foods and food extracts, such as green and black tea, red
wine, blueberry, garlic, and strawberries.
However, no long-term studies have evaluated the effects of
cocoa polyphenol compounds on the oxidative modification of
LDL in humans.
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20. Short-term human studies…
and catechin were measured
The levels of epicatechin
in humans at zero, one, two, and six hours following
consumption of a single meal of chocolate.
The concentration in plasma levels peaked at about
one hour; however, by six hours the concentrations had
almost disappeared from the plasma.
Indicated that cocoa flavonoids are absorbed and
cleared from circulation relatively quickly.
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21. Short-term human studies…
Support the recommendations to
consume several servings of fruit and
vegetables per day as seen in a
number of clinical trials with chocolate
and other flavonoid-rich foods. at mor
e fruit
E
Spacing intake of flavonoid-rich foods
throughout the day could help to
provide a continuous supply. AM: PM:
Berries Grapes
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22. More studies…
seven times more
Because there is six to
epicatechin than catechin in cocoa/chocolate, most
attention has focused on epicatechin in scientific
studies.
Consistent with early studies, human studies indicate
that small doses of epicatechin are effective.
There is a statistically significant increase in plasma
antioxidant capacity and reduction in lipid peroxides
following cocoa/chocolate consumption.
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23. Benefits…
Epicatechin and other flavonoids not only have a
direct antioxidant effect, but they may also have a
sparing effect on other antioxidants such as
Vitamins C and E.
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24. Other Mechanisms…
Although flavanol-rich cocoa and chocolate have the potential to
improve an individual’s antioxidant defense system, there are
other cellular mechanisms through which these flavanol-rich
foods can affect cardiovascular health:
Inflammation
Platelet aggregation
Nitric oxide (NO)-mediated endothelial changes
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26.
Atherosclerosis and heart failure, as well as risk factors such
as hypertension and hypercholesterolemia, can activate
several proinflammatory enzyme systems.
Once activated, these enzymes produce reactive oxygen species
and other radicals that can modify nitric oxide availability and
LDL and contribute to blood vessel dysfunction.
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27.
Flavanol-rich cocoa liquor has been shown to stimulate nitric
oxide production and to significantly reduce the activities of
enzymes involved in oxidative stress.
In addition, cocoa flavanols and procyanidins may modulate
other mediators of inflammation.
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29.
In addition to its influence on oxidative defense mechanisms,
polyphenols seem to benefit cardiovascular health in other ways-
through regulation of platelet reactivity.
Given the prominent role of platelets in the development and
manifestation of acute myocardial infarction, stroke, and venous
thromboembolism, antiplatelet strategies are an important
consideration.
A modest decrease in platelet reactivity can be of value because it
reduces the probability of clotting.
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30.
In one study to determine whether cocoa inhibits platelet
activation and function, subjects were given either water or 300
ml of cocoa that provided a very high amount of polyphenols.
During the six hour time period following intake of cocoa, there
was a reduction in adhesion molecules on the surface of the
platelets, making the platelets less likely to adhere to other
molecules in the bloodstream.
This is the same response that would be seen following intake
of antiplatelet agents such as aspirin.
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32.
disrupt blood vessel function such
There are many things that can
as stress, ischemia, inflammation, and disease states such as
atherosclerosis, diabetes mellitus, and hypertension.
Any of the above can influence the vascular tone and cause an
overall shift toward the prothrombotic state.
According to research, it is possible that flavanols, by functioning
as antioxidants, can improve endothelial function through the
prevention and possible reduction of oxidative damage.
About 150 mg of flavonoids is needed to modulate anti-
inflammatory prostacylin and pro-inflammatory leukotriene
concentrations.
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33. Conclusions…
Several large scale studies have shown that regular dietary
intake of plant-derived foods and beverages reduces the risk of
coronary heart disease and stroke and is inversely associated
with the risk of cardiovascular disease.
Plants have many phytochemicals including flavonoids.
Consumption of flavanol-rich foods such as white, green, and
black tea, grapes, wine, apple juice, cocoa, lentils, and black-
eyed peas is associated with the reduced risk for cardio vascular
disease.
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34. References
Roberto Corti, Andreas J. Flammer, Norman K. Hollenberg and
Thomas F. Lüscher. Cocoa and Cardiovascular Health. Circulation
2009;119:1433-1441.
C.L. Hii, C.L. Law, S. Suzannah, Misnawi, and M. Cloke.
Polyphenols in cocoa (Theobroma cacao L.) As. J. Food Ag-Ind.
2009, 2(04), 702-722 .
Keen C, et al. Dietary polyphenols and health: Proceedings of the
1st international conference on polyphenols and health. Amer J Clin
Nutr. 2005. 81:1 298S-303S. Available at:
http://www.ajcn.org/cgi/content/full/81/1/298S
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35. References
Keen C. Chocolate: Food as medicine/medicine as food. J
Amer Coll of Nutr. 2001. 20:90005 436S-439S. Available at:
http://www.jacn.org/cgi/content/full/20/suppl_5/436S
Wan Y, et al. Effects of cocoa powder and dark chocolate on
LDL oxidative susceptibility and prostaglandin concentrations in
humans. Amer J Clin Nutr. 2001. 74:5 596-602.
http://pubs.acs.org/hotartcl/tcaw/99/jul/chocolate.html
http://sciweb.nybg.org/science2/pdfs/mb/chocolate.pdf#search=
'alternative%20therapies%20sept/oct%20chocolate‘
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36. Pennington Biomedical Research Center
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Hinweis der Redaktion
Figure 2. The fruit of the theobroma cocoa tree.
Figure 1. Health-relevant effect of epicatechins.
Figure 3. Endothelium-dependent effect of cocoa polyphenols. NO is released from endothelial cells mainly in response to shear stress elicited by the circulating blood or receptor-operated substances such as acetylcholine, bradykinin, or serotonin. NO is synthesized by eNOS from l-arginine in the presence of the cofactor thetrahydrobiopterin. The activation may be due to an increase in Ca2+ or a phosphorylation of eNOS by the PI3-kinase/Akt pathway. Cocoa also lowers vascular arginase activity in human endothelial cell in vitro, thus augmenting the local levels of l-arginine. Once released, NO increases intracellular cGMP concentrations and, in turn, induces a relaxation of vascular smooth muscle cells. NO not only leads to vasodilation but also prevents leukocyte adhesion and migration, smooth muscle cell proliferation, and platelet adhesion and aggregation. Other NO-mediated mechanisms are discussed. Antioxidant effects may reduce the production of reactive oxidant species, thus contributing to an enhanced endothelial function. Cocoa polyphenols may activate endothelium-derived hyperpolarizing factor (EDHF), increase endothelial prostacyclin release, or inhibit the synthesis of endothelin-1 (ET). Moreover, polyphenols may directly inhibit angiotensin-converting enzyme (ACE). AII indicates angiotensin II; AI, angiotensin I; PKC, protein kinase C; SOD, superoxide dismutase; PGI2, prostacyclin; ACE, angiotensin-converting enzyme; ECE, endothelin-converting enzyme; AT1, angiotensin receptor; ET-1, endothelin 1; bET-1, big endothelin 1; ETa/b, endothelin receptor a and b; cGMP, cyclic guanosine monophosphate; and ROS, reactive oxygen species.