PBRC 2012

Pennington Biomedical Research CenterPennington Biomedical Research CenterDivision of EducationDivision of Education

Phillip Brantley, PhD, DirectorPhillip Brantley, PhD, DirectorPennington Biomedical Research Pennington Biomedical Research

CenterCenterSteven Heymsfield, MD, Executive Director Steven Heymsfield, MD, Executive Director

Publication # 2

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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Overview…

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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Flavonoids…

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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Corti R et al. Circulation 2009;119:1433-1441PBRC 2012

The fruit of the Theobroma cacao tree

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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Chocolate Consumption

The flavonoids in cocoa/chocolate, principally

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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Flavonoids in Chocolate

Processing of cocoa results in 60% loss of total flavonoids.

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.

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Flavonoids in Chocolate

C.L. Hii et al. As. J. Food Ag-Ind. 2009, 2(04), 702-722

The actual recipe for the finished food or beverage product

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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Flavonoid Content: Variable

Different types of chocolate contain varying antioxidant content. 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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Flavonoid Content

Several studies have looked at the total polyphenols in

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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Recent Studies

Source

Flavanol Content, mg/kg or mg/L

Chocolate 460–610Beans 350–550Green tea 100–800Apricots 100–250Red wine 80–300Black tea 60–500Cherries 50–220Peaches 50–140Blackberries 130Apples 20–120Cider 40

Catechin/Epicathecin concentrations in foods

PBRC 2012Circulation March 17, 2009 vol. 119 no. 101433-1441

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.

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Circulation.2009; 119: 1433-1441

Antioxidant Capacity

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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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Atherogenesis…

Extracts of cocoa powder have also shown to

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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Atherogenesis…

Corti R et al. Circulation 2009;119:1433-1441

Health-relevant effect of epicatechins

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Corti R et al. Circulation 2009;119:1433-1441

Endothelium-dependent effect of cocoa polyphenols

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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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The levels of epicatechin and catechin were measured

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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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.

Spacing intake of flavonoid-rich foods throughout the day could help to provide a continuous supply.

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Short-term human studies…

Eat more

fruit

AM:Berries

PM:Grapes

Because there is six to seven times more

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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More studies…

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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Benefits…

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:

InflammationPlatelet aggregation

Nitric oxide (NO)-mediated endothelial changes

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Other Mechanisms…

Inflammation

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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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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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Platelets

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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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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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Endothelium

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There are many things that can disrupt blood vessel function such

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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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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Conclusions…

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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

References

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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‘

References

VISIONOur vision is to lead the world in eliminating chronic diseases. 

MISSIONOur mission is to discover the triggers of chronic diseases through innovative research that improves human health across the lifespan.  We are helping people live Well Beyond the Expected.

The Pennington Center has several research areas, including: Clinical Obesity Research Experimental Obesity Functional Foods Health and Performance Enhancement Nutrition and Chronic Diseases Nutrition and the Brain Dementia, Alzheimer’s and healthy aging Diet, exercise, weight loss and weight loss maintenanceThe research fostered in these areas can have a profound impact on healthy living and on the prevention of common chronic diseases, such as heart disease, cancer, diabetes, hypertension and osteoporosis.  The Division of Education provides education and information to the scientific community and the public about research findings, training programs and research areas, and coordinates educational events for the public on various health issues. We invite people of all ages and backgrounds to participate in the exciting research studies being conducted at the Pennington Center in Baton Rouge, Louisiana. If you would like to take part, visit the clinical trials web page at www.pbrc.edu or call (225) 763-3000.

PBRC 2012

Pennington Biomedical Research Center